Update version

While UnsafeRelaxedJsonEscaping sounds scary, there is no risk
here since the JSON data is saved directly into a file.  See #450

.config/dotnet-tools.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "xamlstyler.console": {
+      "version": "3.2003.9",
+      "commands": [
+        "xstyler"
+      ]
+    }
+  }
+}

.gitattributes

@@ -1,63 +0,0 @@
-###############################################################################
-# Set default behavior to automatically normalize line endings.
-###############################################################################
-* text=auto
-
-###############################################################################
-# Set default behavior for command prompt diff.
-#
-# This is need for earlier builds of msysgit that does not have it on by
-# default for csharp files.
-# Note: This is only used by command line
-###############################################################################
-#*.cs     diff=csharp
-
-###############################################################################
-# Set the merge driver for project and solution files
-#
-# Merging from the command prompt will add diff markers to the files if there
-# are conflicts (Merging from VS is not affected by the settings below, in VS
-# the diff markers are never inserted). Diff markers may cause the following 
-# file extensions to fail to load in VS. An alternative would be to treat
-# these files as binary and thus will always conflict and require user
-# intervention with every merge. To do so, just uncomment the entries below
-###############################################################################
-#*.sln       merge=binary
-#*.csproj    merge=binary
-#*.vbproj    merge=binary
-#*.vcxproj   merge=binary
-#*.vcproj    merge=binary
-#*.dbproj    merge=binary
-#*.fsproj    merge=binary
-#*.lsproj    merge=binary
-#*.wixproj   merge=binary
-#*.modelproj merge=binary
-#*.sqlproj   merge=binary
-#*.wwaproj   merge=binary
-
-###############################################################################
-# behavior for image files
-#
-# image files are treated as binary by default.
-###############################################################################
-#*.jpg   binary
-#*.png   binary
-#*.gif   binary
-
-###############################################################################
-# diff behavior for common document formats
-# 
-# Convert binary document formats to text before diffing them. This feature
-# is only available from the command line. Turn it on by uncommenting the 
-# entries below.
-###############################################################################
-#*.doc   diff=astextplain
-#*.DOC   diff=astextplain
-#*.docx  diff=astextplain
-#*.DOCX  diff=astextplain
-#*.dot   diff=astextplain
-#*.DOT   diff=astextplain
-#*.pdf   diff=astextplain
-#*.PDF   diff=astextplain
-#*.rtf   diff=astextplain
-#*.RTF   diff=astextplain

.github/FUNDING.yml

@@ -0,0 +1,3 @@
+github: Tyrrrz
+patreon: Tyrrrz
+custom: ['buymeacoffee.com/Tyrrrz', 'tyrrrz.me/donate']

.github/workflows/CD.yml

@@ -0,0 +1,71 @@
+name: CD
+
+on:
+  push:
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2.3.3
+
+      - name: Install .NET (v3.1)
+        uses: actions/setup-dotnet@v1.7.2
+        with:
+          dotnet-version: 3.1.x
+
+      - name: Install .NET (v5.0)
+        uses: actions/setup-dotnet@v1.7.2
+        with:
+          dotnet-version: 5.0.x
+
+      - name: Build & publish (CLI)
+        run: dotnet publish DiscordChatExporter.Cli/ -o DiscordChatExporter.Cli/bin/Publish/ --configuration Release
+
+      - name: Build & publish (GUI)
+        run: dotnet publish DiscordChatExporter.Gui/ -o DiscordChatExporter.Gui/bin/Publish/ --configuration Release
+
+      - name: Pack (CLI)
+        run: Compress-Archive -Path DiscordChatExporter.Cli/bin/Publish/* -DestinationPath DiscordChatExporter.Cli/bin/Publish/Archive.zip -Force
+        shell: pwsh
+
+      - name: Pack (GUI)
+        run: Compress-Archive -Path DiscordChatExporter.Gui/bin/Publish/* -DestinationPath DiscordChatExporter.Gui/bin/Publish/Archive.zip -Force
+        shell: pwsh
+
+      - name: Create release
+        id: create_release
+        uses: actions/create-release@v1.0.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ github.ref }}
+          body: |
+            [Changelog](https://github.com/Tyrrrz/DiscordChatExporter/blob/master/Changelog.md)
+          draft: false
+          prerelease: false
+
+      - name: Upload release asset (CLI)
+        uses: actions/upload-release-asset@v1.0.2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: DiscordChatExporter.Cli/bin/Publish/Archive.zip
+          asset_name: DiscordChatExporter.CLI.zip
+          asset_content_type: application/zip
+
+      - name: Upload release asset (GUI)
+        uses: actions/upload-release-asset@v1.0.2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: DiscordChatExporter.Gui/bin/Publish/Archive.zip
+          asset_name: DiscordChatExporter.zip
+          asset_content_type: application/zip

.github/workflows/CI.yml

@@ -0,0 +1,39 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2.3.3
+
+      - name: Install .NET (v3.1)
+        uses: actions/setup-dotnet@v1.7.2
+        with:
+          dotnet-version: 3.1.x
+
+      - name: Install .NET (v5.0)
+        uses: actions/setup-dotnet@v1.7.2
+        with:
+          dotnet-version: 5.0.x
+
+      - name: Build & publish (CLI)
+        run: dotnet publish DiscordChatExporter.Cli/ -o DiscordChatExporter.Cli/bin/Publish/ --configuration Release
+
+      - name: Build & publish (GUI)
+        run: dotnet publish DiscordChatExporter.Gui/ -o DiscordChatExporter.Gui/bin/Publish/ --configuration Release
+
+      - name: Upload build artifacts (CLI)
+        uses: actions/upload-artifact@v1
+        with:
+          name: DiscordChatExporter.CLI
+          path: DiscordChatExporter.Cli/bin/Publish/
+
+      - name: Upload build artifact (GUI)
+        uses: actions/upload-artifact@v1
+        with:
+          name: DiscordChatExporter
+          path: DiscordChatExporter.Gui/bin/Publish/

.gitignore

@@ -1,264 +1,21 @@
-## Ignore Visual Studio temporary files, build results, and
-## files generated by popular Visual Studio add-ons.
-
 # User-specific files
 *.suo
 *.user
 *.userosscache
 *.sln.docstates
-
+.idea/
-# User-specific files (MonoDevelop/Xamarin Studio)
-*.userprefs
 
 # Build results
 [Dd]ebug/
 [Dd]ebugPublic/
 [Rr]elease/
 [Rr]eleases/
-x64/
+[Xx]64/
-x86/
+[Xx]86/
+[Bb]uild/
 bld/
 [Bb]in/
 [Oo]bj/
-[Ll]og/
 
-# Visual Studio 2015 cache/options directory
+# Coverage
-.vs/
+*.opencover.xml
-# Uncomment if you have tasks that create the project's static files in wwwroot
-#wwwroot/
-
-# MSTest test Results
-[Tt]est[Rr]esult*/
-[Bb]uild[Ll]og.*
-
-# NUNIT
-*.VisualState.xml
-TestResult.xml
-
-# Build Results of an ATL Project
-[Dd]ebugPS/
-[Rr]eleasePS/
-dlldata.c
-
-# DNX
-project.lock.json
-project.fragment.lock.json
-artifacts/
-
-*_i.c
-*_p.c
-*_i.h
-*.ilk
-*.meta
-*.obj
-*.pch
-*.pdb
-*.pgc
-*.pgd
-*.rsp
-*.sbr
-*.tlb
-*.tli
-*.tlh
-*.tmp
-*.tmp_proj
-*.log
-*.vspscc
-*.vssscc
-.builds
-*.pidb
-*.svclog
-*.scc
-
-# Chutzpah Test files
-_Chutzpah*
-
-# Visual C++ cache files
-ipch/
-*.aps
-*.ncb
-*.opendb
-*.opensdf
-*.sdf
-*.cachefile
-*.VC.db
-*.VC.VC.opendb
-
-# Visual Studio profiler
-*.psess
-*.vsp
-*.vspx
-*.sap
-
-# TFS 2012 Local Workspace
-$tf/
-
-# Guidance Automation Toolkit
-*.gpState
-
-# ReSharper is a .NET coding add-in
-_ReSharper*/
-*.[Rr]e[Ss]harper
-*.DotSettings.user
-
-# JustCode is a .NET coding add-in
-.JustCode
-
-# TeamCity is a build add-in
-_TeamCity*
-
-# DotCover is a Code Coverage Tool
-*.dotCover
-
-# NCrunch
-_NCrunch_*
-.*crunch*.local.xml
-nCrunchTemp_*
-
-# MightyMoose
-*.mm.*
-AutoTest.Net/
-
-# Web workbench (sass)
-.sass-cache/
-
-# Installshield output folder
-[Ee]xpress/
-
-# DocProject is a documentation generator add-in
-DocProject/buildhelp/
-DocProject/Help/*.HxT
-DocProject/Help/*.HxC
-DocProject/Help/*.hhc
-DocProject/Help/*.hhk
-DocProject/Help/*.hhp
-DocProject/Help/Html2
-DocProject/Help/html
-
-# Click-Once directory
-publish/
-
-# Publish Web Output
-*.[Pp]ublish.xml
-*.azurePubxml
-# TODO: Comment the next line if you want to checkin your web deploy settings
-# but database connection strings (with potential passwords) will be unencrypted
-#*.pubxml
-*.publishproj
-
-# Microsoft Azure Web App publish settings. Comment the next line if you want to
-# checkin your Azure Web App publish settings, but sensitive information contained
-# in these scripts will be unencrypted
-PublishScripts/
-
-# NuGet Packages
-*.nupkg
-# The packages folder can be ignored because of Package Restore
-**/packages/*
-# except build/, which is used as an MSBuild target.
-!**/packages/build/
-# Uncomment if necessary however generally it will be regenerated when needed
-#!**/packages/repositories.config
-# NuGet v3's project.json files produces more ignoreable files
-*.nuget.props
-*.nuget.targets
-
-# Microsoft Azure Build Output
-csx/
-*.build.csdef
-
-# Microsoft Azure Emulator
-ecf/
-rcf/
-
-# Windows Store app package directories and files
-AppPackages/
-BundleArtifacts/
-Package.StoreAssociation.xml
-_pkginfo.txt
-
-# Visual Studio cache files
-# files ending in .cache can be ignored
-*.[Cc]ache
-# but keep track of directories ending in .cache
-!*.[Cc]ache/
-
-# Others
-ClientBin/
-~$*
-*~
-*.dbmdl
-*.dbproj.schemaview
-*.jfm
-*.pfx
-*.publishsettings
-node_modules/
-orleans.codegen.cs
-
-# Since there are multiple workflows, uncomment next line to ignore bower_components
-# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
-#bower_components/
-
-# RIA/Silverlight projects
-Generated_Code/
-
-# Backup & report files from converting an old project file
-# to a newer Visual Studio version. Backup files are not needed,
-# because we have git ;-)
-_UpgradeReport_Files/
-Backup*/
-UpgradeLog*.XML
-UpgradeLog*.htm
-
-# SQL Server files
-*.mdf
-*.ldf
-
-# Business Intelligence projects
-*.rdl.data
-*.bim.layout
-*.bim_*.settings
-
-# Microsoft Fakes
-FakesAssemblies/
-
-# GhostDoc plugin setting file
-*.GhostDoc.xml
-
-# Node.js Tools for Visual Studio
-.ntvs_analysis.dat
-
-# Visual Studio 6 build log
-*.plg
-
-# Visual Studio 6 workspace options file
-*.opt
-
-# Visual Studio LightSwitch build output
-**/*.HTMLClient/GeneratedArtifacts
-**/*.DesktopClient/GeneratedArtifacts
-**/*.DesktopClient/ModelManifest.xml
-**/*.Server/GeneratedArtifacts
-**/*.Server/ModelManifest.xml
-_Pvt_Extensions
-
-# Paket dependency manager
-.paket/paket.exe
-paket-files/
-
-# FAKE - F# Make
-.fake/
-
-# JetBrains Rider
-.idea/
-*.sln.iml
-
-# CodeRush
-.cr/
-
-# Python Tools for Visual Studio (PTVS)
-__pycache__/
-*.pyc
-
-# Ammy auto-generated XAML
-*.g.xaml

Changelog.md

@@ -0,0 +1,272 @@
+### v2.26 (29-Dec-2020)
+
+- [HTML] Added support for replies. (Thanks [@Sanqui](https://github.com/Sanqui))
+- [HTML] Improved styling of non-media attachments (regular files, i.e. not video, audio, or image). (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- [HTML] Improved initial export performance.
+- [JSON] Relaxed escaping rules for unicode characters. (Thanks [@Sanqui](https://github.com/Sanqui))
+- [JSON] Added support for replies. (Thanks [@Sanqui](https://github.com/Sanqui))
+- [CLI] Added channel names to errors shown on failures when exporting multiple channels. (Thanks [@Sanqui](https://github.com/Sanqui))
+- [CLI] Added support for passing message IDs (snowflakes) to `--after` and `--before` options. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Files downloaded by the "download referenced media" option now have their dates set according to the `Last-Modified` header provided by Discord CDN. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Fixed an issue where the application sometimes crashed with `NullReferenceException` when retrying a failed HTTP request.
+- Migrated to Discord API v8.
+
+### v2.25 (23-Nov-2020)
+
+- [JSON] Added `mentions` property to the output. This contains users referenced inside the message text, but doesn't include mentions in embeds. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- [HTML] Added better previews for attached video and audio. They are now rendered using a browser native player element. The actual file path can still be retrieved by right clicking and selecting "Copy file path". (Thanks [@sas41](https://github.com/sas41))
+- [CLI] Fixed an issue where using `--media` option without providing a rooted path via `--output` option triggered an error.
+- [CLI] Fixed an issue where using `--reuse-media` option without also providing `--media` option was accepted, but didn't actually do anything. Now this produces an error instead. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+
+### v2.24 (24-Oct-2020)
+
+- [CLI] Updated to [CliFx v1.5](https://github.com/Tyrrrz/CliFx), which brings some UX improvements.
+- [GUI] Added dark mode, which can be enabled in settings. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- [GUI] Improved the UX in a few minor places.
+- [JSON] Added `embed.color` property to the output. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Added additional date formats: `unix` to write dates as a unix timestamp and `unixms` for the milliseconds version. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Added retry policy for downloading media content. This is mostly a workaround for transient failures that sometimes may occur when downloading assets referenced from embeds. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Added an option to reuse already downloaded media to avoid redundant network requests. It can be enabled in settings in GUI, or by passing `--reuse-media` in CLI. To facilitate this feature, the file name strategy has been changed as well -- now instead of relying on the original file name and adding `(n)` to the end in case of duplicates, a URL hash is injected in every file name. This also means that when the "reuse media" option is disabled, existing files inside the media directory may be overwritten. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+
+### v2.23 (14-Sep-2020)
+
+- [CLI] Added a command to export all channels across all servers. Use `exportall` to do it. (Thanks [@wyattscarpenter](https://github.com/wyattscarpenter))
+- [HTML] Fixed an issue where Whitney fonts were not being loaded properly, causing the browser to fall back to Helvetica.
+- Fixed an issue where self-contained export crashed occasionally. This usually happened when the server hosting the file did not serve the stream properly. Such files are now ignored after the first failed attempt.
+
+### v2.22 (12-Aug-2020)
+
+- [GUI] Improved the channel list by adding collapsible category groups. (Thanks [@CarJem Generations](https://github.com/CarJem))
+- [GUI] Improved exporting options by adding a set of controls that can be used to limit the date range of the export down to minutes. Previously it was only possible to configure the date range without the time component. (Thanks [@CarJem Generations](https://github.com/CarJem))
+- [HTML] Fixed an issue where the export didn't reflect changes in nicknames between messages sent by bots. This affected chat logs that contained interactions with the Tupperbox bot. (Thanks [@CarJem Generations](https://github.com/CarJem))
+- [CLI] Fixed an issue where the application crashed if there were two environment variables defined that had the same name but in different case.
+
+### v2.21.2 (30-Jul-2020)
+
+- [GUI] When copy-pasting token, any surrounding spaces are now discarded, in addition to double quotes.
+- [HTML] Changed underlying templating engine to provide higher performance and better error messages. New templating engine adds a small cold start, but any export after the first should be faster.
+- Changed naming schema for downloaded media so that it follows `<original filename> (nn)` format rather than `<original filename>-salt`.
+- [HTML] Fixed an issue where downloaded media was sometimes inaccessible due to reserved characters appearing in the URL.
+- Fixed an issue where the application crashed when trying to download media with a file name that exceeds system's maximum allowed length.
+- Fixed an issue where the application crashed when trying to download media with illegal characters in the file name.
+
+### v2.21.1 (19-Jul-2020)
+
+- Fixed an issue where the export crashed if an embedded image has been deleted. Such media files are now ignored.
+- Changed the naming convention for downloaded media files so that the original file names are used when possible.
+
+### v2.21 (18-Jul-2020)
+
+- Added a new option that enables self-contained exports for all output formats. You can turn it on in the export setup dialog in GUI or using the `--media` option in CLI. When using this, the application will additionally download any media content directly referenced from the exported file instead of linking back to Discord CDN. The files which are downloaded include: guild icons, user avatars, attachments, embedded images, reaction emojis. Note that only files which are actually referenced by the export are downloaded, which means that, for example, user avatars will not be downloaded when using plain text export format. This option is not meant to enable complete offline viewing for HTML exports, but rather to make it easier to archive media content that may eventually get deleted from Discord servers. Also keep in mind that this option may make the export drastically slower and the total file size larger.
+- Changed "discordapp.com" to "discord.com" where applicable as Discord is migrating to a new domain. CDN will remain on "cdn.discordapp.com" for the foreseeable future.
+
+Note that all existing and current HTML exports will likely not render accurately because Discord enabled CORS for their font resources, which prevents them from loading locally. Please refer to [issue #322](https://github.com/Tyrrrz/DiscordChatExporter/issues/322) for discussion on this topic. 
+
+### v2.20 (27-Apr-2020)
+
+- [CLI] Added environment variables as fallback for `--token` and `--bot` options. They are `DISCORD_TOKEN` and `DISCORD_TOKEN_BOT` respectively.
+- [GUI] Fixed a crash that occurred if the application was closed in the middle of an auto-update.
+- [GUI] Added a link to project's wiki in the usage guide.
+- [HTML] Added full spoiler support for text and images. To spoil the hidden content you now need to click on it, similarly to how it works in Discord. (Thanks [@FM-96](https://github.com/FM-96))
+- [HTML] Updated grammar for consecutive single-line quotes. Previously they appeared separately, now they're grouped together as if it was one multi-line quote instead.
+- [HTML] Fixed an issue where messages sent by the same bot but with different usernames were grouped together when they shouldn't be.
+- [HTML] Updated grammar for single-line code blocks to accept double backticks as synonymous with single backticks. This change makes code blocks appear the same, whether they were inserted manually or using Discord's buggy markdown preview mode.
+- [HTML] Fixed styling inconsistencies and other minor issues.
+- [TXT/JSON] Fixed an issue where markdown was not parsed correctly in embed fields.
+- [HTML] Changed markdown formatting in embeds so it follows the same set of rules as in Discord.
+- Added channel category to the default file name used when exporting chat logs.
+- [HTML/TXT/JSON] Added channel category to exported metadata.
+- [CLI] Updated commands to also show channel category as well as channel name wherever relevant.
+- Starting with this release, Docker images will have new tags: `stable` for latest stable release and `2.20` for a specific version.
+
+### v2.19 (26-Mar-2020)
+
+- Added parallel exporting. This option allows you to export multiple channels faster by doing it in parallel. You can configure the parallel limit in settings (GUI) or with the `--parallel` option (CLI). Default value is `1`, which means there is no parallelization. Warning: be careful when using this option, as this will result in higher volume of concurrent HTTP requests sent to Discord, which might get you flagged. Use at your own risk.
+- [HTML] Added support for user colors. User names are now appropriately colored according to the assigned guild roles.
+- [HTML] Added support for nicknames. User names are replaced with nicknames where it's applicable. It's still possible to see the full user name by hovering your mouse over the nickname.
+- [HTML] Improved styling for mentions to bring it more in line with how it looks in Discord.
+
+### v2.18 (04-Feb-2020)
+
+- Added JSON export format. It's a structured data format which is easy to parse. If you're using DiscordChatExporter to export chat logs for further ingestion by another tool, this is most likely the format you will want to use.
+- [GUI] You can now quickly jump to a specific channel in a list. For example, if you want to jump to a channel named "General", you can simply press the 'g' key in the channel list view. You can also press 'g', 'e' and 'n' in quick succession which will jump to the next channel that starts with "gen". This mechanic is consistent with other Windows applications.
+- [CLI] Improved help text screen.
+
+### v2.17 (12-Jan-2020)
+
+- Fixed an issue where an empty file was produced when exporting a channel with no messages (for specified period). With the new behavior, no file will be created and instead a message will be shown to the user informing of the failure.
+- [HTML/TXT] Added message count to the bottom of the file. This number shows how many messages were exported as part of the current file. Prior to 2.16 this number was present along with the rest of the metadata at the top, then removed due to changes in the exporter, and now brought back at the end of the file instead.
+- [HTML] Fixed an issue where some emojis were not properly rendered.
+- [GUI] Added a setting that lets you configure whether to remember the last used token. Previously it was the default behavior, but now you can disable it if you don't want the token persisted on your system.
+
+### v2.16 (08-Dec-2019)
+
+- Migrated from .NET Framework to .NET Core. To run this and future versions of DiscordChatExporter you will need [.NET Core runtime for desktop apps](https://dotnet.microsoft.com/download/dotnet-core/3.1/runtime) (for GUI/CLI version on Windows) or [.NET Core base runtime](https://dotnet.microsoft.com/download/dotnet-core/3.1) (for CLI version on Windows, Linux or macOS).
+- Reworked the exporter engine to render output using streaming data source. This means that only a very small portion of messages are cached in memory when exporting. In other words, you are only limited by storage space and not how much RAM you have, so you can now export terabytes of chat logs without hitting out of memory exceptions. I still recommend using partitions if you're exporting very large chat logs (250k+ messages) to HTML, unless you want your computer to catch fire when you try to open the export in browser.
+- Changed how partitioned files are named, due to the fact that total number of partitions is no longer known ahead of time.
+- Added a warning about automating user accounts to the usage guide in both GUI and CLI versions.
+- Added support for announcement (news) channels. You will now be able to see them in the list and export them.
+- Fixed various issues that resulted in exceptions during export process.
+- [HTML/TXT] Removed message count from the metadata. Due to the fact that the messages are exported as they are streamed, total number of messages is not known ahead of time.
+- [HTML] Changed default color of the embed color pill to match the theme.
+- [HTML] Changed emoji parser to be less greedy. As a result it should match fewer character sequences that look like emojis but really aren't, but on the other hand it might miss some actual emojis. This means that some standard emojis (i.e. not custom server emojis) may not look like in Discord. This is a compromise I'm willing to take because detecting emojis in text is really hard to get right and not worth it at all.
+- [HTML] Some other minor styling adjustments.
+- [CSV] Replaced semicolons (;) with (,) as separators.
+
+Please note that CSV export is most likely not going to receive future updates and will remain only as an option for those who wish to use it for text analysis. In other words, it won't contain any of the rich media features like embeds. If you're currently using CSV as a structured output to feed into your program, JSON output will replace that in the future.
+
+### v2.15 (15-Sep-2019)
+
+- Improved markdown parser and made it even faster for non-HTML formats.
+- [HTML] Added support for block quotes.
+- [HTML] Links pointing to a Discord message will now navigate to the linked message inside exported chat log if it's there.
+- [HTML] Updated light theme to match how it looks in Discord after recent changes.
+- [HTML] Added indication for when a message is pinned. Pinned messages now have a tinted background.
+- [HTML] Fixed an issue where multiline code blocks sometimes had incorrect formatting applied to them.
+- [TXT] Added indication for when a message is pinned. Pinned messages now have `(pinned)` next to timestamp and author.
+- [CSV] Added message author's user ID to output.
+- [GUI] Streamlined auto-update process a bit.
+- [GUI] Added some tooltips.
+
+### v2.14 (15-Jun-2019)
+
+- [TXT] Added support for embeds.
+- [TXT] Added support for reactions.
+- [CSV] Added support for reactions.
+- [TXT] Changed how attachments are rendered.
+
+### v2.13.1 (06-Jun-2019)
+
+- Fixed an issue where the app sometimes crashed when exporting due to `System.InvalidCastException`.
+- [HTML] Added `data-user-id` attribute to `span.chatlog__author-name`. The value of this attribute is author's Discord user ID.
+
+### v2.13 (15-May-2019)
+
+- Updated usage instructions.
+- [HTML] Added BOT tags to messages posted by bots.
+- [GUI] UI will now be disabled when exporting.
+- [GUI] Notification informing that the export has completed will now appear after all exports have completed, instead of each of them separately.
+
+### v2.12.1 (12-Apr-2019)
+
+- [GUI] Fixed an issue where the app crashed when trying to export multiple channels.
+- [HTML] Fixed an issue where some of the emojis were rendered via Twemoji while Discord renders them as plain text.
+- [HTML] Fixed an issue where emojis weren't jumbo if there were more than one of them.
+
+### v2.12 (11-Apr-2019)
+
+- Improved markdown parsing performance which speeds up the final stage of exporting by around 4.5 times.
+- Improved performance when exporting as PlainText or CSV.
+- [GUI] Fixed an issue where the app would freeze up and report as "not responding" during the final stage of exporting.
+- [CLI] Fixed an issue where it would say "Completed" after exporting a chat log, even if the process failed.
+
+### v2.11 (14-Mar-2019)
+
+- [HTML] Added syntax highlighting for multiline code blocks via Highlight.js.
+- Added retry policy for all 5xx status codes to prevent random crashes.
+
+### v2.10.2 (10-Mar-2019)
+
+- [HTML] Updated message grouping algorithm to make it the same as in Discord. Removed "message group limit" setting and parameter.
+- [HTML] Added small margin at the end of the chatlog so it doesn't look like it was truncated.
+- [CLI] Fixed an issue where the app would crash if stdout was redirected. Progress will not be reported in such cases.
+
+### v2.10.1 (06-Mar-2019)
+
+- [HTML] Fixed an issue where multiple emojis on a single line would get rendered as one emoji.
+- [HTML] Fixed an issue where an open square bracket character would incorrectly render as an emoji.
+- [HTML] Added alt text to emoji images so that they will be rendered using default font when Twemoji images are not available.
+
+### v2.10 (03-Mar-2019)
+
+- [HTML] Reworked the entire markdown parsing engine which fixes numerous rendering inconsistencies (over 15 issues fixed).
+- [HTML] Added support for animated emojis.
+- [HTML] Standard emojis are now rendered using Twemoji, the same image set that Discord uses.
+- [HTML] Fixed an issue where video attachments would render incorrectly.
+- [HTML] Minor fixes in styling.
+- [GUI] Aggregated export progress is now shown in the taskbar.
+- [GUI] Checkmarks are now displayed next to channels that are selected.
+- [CLI] Added progress reporting when exporting chat logs.
+
+### v2.9.1 (10-Feb-2019)
+
+- Fixed an issue where some of the last messages in a channel would sometimes not get exported.
+
+### v2.9 (09-Feb-2019)
+
+- Added categories to channel list in GUI. Channels are now also grouped by category.
+- Added ability to export multiple channels at once in GUI by selecting them with shift or ctrl keys.
+- Added CLI command to export all available channels in a guild (`exportguild`).
+- Added CLI command to export all direct message channels (`exportdm`).
+- Added retry policy for 503 status code errors to prevent random crashes.
+- Changed how channels are exported in GUI. Now you need to select them first and then click a button to export. You can also double click a single channel to export it as before.
+- Improved default file name generation by adding date ranges and channel ID to the file name.
+- Improved naming of files exported with partitioning.
+- Improved usage instructions.
+- Improved GUI layout and styling.
+- Fixed an issue where dialogs would sometimes appear over other windows.
+- Fixed an issue where launching DiscordChatExporter from Windows Start Menu would make it crash.
+
+### v2.8 (03-Nov-2018)
+
+- Added support for partitioning which lets you split the output into multiple files by setting the partition message limit (`-p` parameter for CLI).
+- Exported file will no longer open automatically on completion.
+- Reduced amount of memory used during exporting.
+- Disabled message grouping in PlainText export.
+- Improved encoding of newlines in CSV export.
+- Improved error messages in the GUI app during crashes.
+
+### v2.7 (14-Sep-2018)
+
+- Updated instructions on how to obtain the user token.
+- Expanded CLI with new commands: `channels` (get a list of channels in a guild), `dm` (get a list of DM channels), `guilds` (get a list of guilds), on top of `export` (export chatlog).
+- Improved help text and error messages in CLI.
+- In CLI, the file name will be automatically generated if the provided output file path is a directory.
+
+### v2.6 (25-Jul-2018)
+
+- Added support for bot tokens as an alternative to user tokens. For GUI, use the button in the top-left to switch between user and bot token. For CLI, pass the `--bot` switch to indicate that the given token is a bot token.
+- Added support for animated avatars.
+
+### v2.5.1 (01-Jul-2018)
+
+- Fixed a bug that would prevent timestamps from rendering properly in CSV and PlainText exports.
+- Fixed incorrect layout in CSV export.
+- Improved readability of PlainText export.
+
+### v2.5 (28-Jun-2018)
+
+- Added support for embeds and webhooks (HTML only).
+- Implemented progress reporting when downloading messages.
+- Added support for reactions (HTML only).
+- Selected date range is now shown in the export (HTML and PlainText).
+- Added placeholders for guild icons to display while the icons are loading.
+- Added support for jumbo emojis (custom emojis only).
+- Added basic retry policy for 429 error responses.
+- Added validation for from/to dates in the UI which prevents choosing invalid date ranges.
+- Added an error message when trying to export a deleted channel.
+
+### v2.4.1 (15-Apr-2018)
+
+- Added CSV export format.
+- Channels are now ordered by name in the UI.
+- Exported file is now always opened upon completion.
+
+### v2.4 (08-Apr-2018)
+
+- Added channel topic to output.
+- Added a command line interface alternative to the current graphical user interface.
+- Implemented application auto-update (can be disabled in settings).
+- Improved some GUI elements and replaced some dialogs with notifications.
+- Fixed a lot of issues with the markdown processor.
+- Fixed DM group chats that have a custom name being shown as blank in the list.
+
+### v2.3 (27-Oct-2017)
+
+- Improved message date filtering, it's now marginally faster.
+- Fixed underscores not recognized as italics in markdown.
+- Added support for custom emojis.
+- Added support for user and role mentions.
+- Added support for channel mentions.
+- Fixed text in pre blocks not being wrapped correctly.
+- Added workaround for non-default message types.

Directory.Build.props

@@ -0,0 +1,13 @@
+<Project>
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <Version>2.26</Version>
+    <Company>Tyrrrz</Company>
+    <Copyright>Copyright (c) Alexey Golub</Copyright>
+    <LangVersion>preview</LangVersion>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>nullable</WarningsAsErrors>
+  </PropertyGroup>
+
+</Project>

DiscordChatExporter.Cli/Commands/Base/ExportCommandBase.cs

@@ -0,0 +1,87 @@
+using System.IO;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Exceptions;
+using CliFx.Utilities;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting;
+
+namespace DiscordChatExporter.Cli.Commands.Base
+{
+    public abstract class ExportCommandBase : TokenCommandBase
+    {
+        [CommandOption("output", 'o', Description = "Output file or directory path.")]
+        public string OutputPath { get; init; } = Directory.GetCurrentDirectory();
+
+        [CommandOption("format", 'f', Description = "Export format.")]
+        public ExportFormat ExportFormat { get; init; } = ExportFormat.HtmlDark;
+
+        [CommandOption("after", Description = "Only include messages sent after this date or message ID.")]
+        public Snowflake? After { get; init; }
+
+        [CommandOption("before", Description = "Only include messages sent before this date or message ID.")]
+        public Snowflake? Before { get; init; }
+
+        [CommandOption("partition", 'p', Description = "Split output into partitions limited to this number of messages.")]
+        public int? PartitionLimit { get; init; }
+
+        [CommandOption("media", Description = "Download referenced media content.")]
+        public bool ShouldDownloadMedia { get; init; }
+
+        [CommandOption("reuse-media", Description = "Reuse already existing media content to skip redundant downloads.")]
+        public bool ShouldReuseMedia { get; init; }
+
+        [CommandOption("dateformat", Description = "Format used when writing dates.")]
+        public string DateFormat { get; init; } = "dd-MMM-yy hh:mm tt";
+
+        protected ChannelExporter GetChannelExporter() => new(GetDiscordClient());
+
+        protected async ValueTask ExportAsync(IConsole console, Guild guild, Channel channel)
+        {
+            console.Output.Write($"Exporting channel '{channel.Category} / {channel.Name}'... ");
+            var progress = console.CreateProgressTicker();
+
+            var request = new ExportRequest(
+                guild,
+                channel,
+                OutputPath,
+                ExportFormat,
+                After,
+                Before,
+                PartitionLimit,
+                ShouldDownloadMedia,
+                ShouldReuseMedia,
+                DateFormat
+            );
+
+            await GetChannelExporter().ExportChannelAsync(request, progress);
+
+            console.Output.WriteLine();
+            console.Output.WriteLine("Done.");
+        }
+
+        protected async ValueTask ExportAsync(IConsole console, Channel channel)
+        {
+            var guild = await GetDiscordClient().GetGuildAsync(channel.GuildId);
+            await ExportAsync(console, guild, channel);
+        }
+
+        protected async ValueTask ExportAsync(IConsole console, Snowflake channelId)
+        {
+            var channel = await GetDiscordClient().GetChannelAsync(channelId);
+            await ExportAsync(console, channel);
+        }
+
+        public override ValueTask ExecuteAsync(IConsole console)
+        {
+            if (ShouldReuseMedia && !ShouldDownloadMedia)
+            {
+                throw new CommandException("The --reuse-media option cannot be used without the --media option.");
+            }
+
+            return default;
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/Base/ExportMultipleCommandBase.cs

@@ -0,0 +1,79 @@
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Utilities;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exceptions;
+using DiscordChatExporter.Domain.Exporting;
+using DiscordChatExporter.Domain.Utilities;
+using Gress;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Cli.Commands.Base
+{
+    public abstract class ExportMultipleCommandBase : ExportCommandBase
+    {
+        [CommandOption("parallel", Description = "Limits how many channels can be exported in parallel.")]
+        public int ParallelLimit { get; init; } = 1;
+
+        protected async ValueTask ExportMultipleAsync(IConsole console, IReadOnlyList<Channel> channels)
+        {
+            // This uses a different route from ExportCommandBase.ExportAsync() because it runs
+            // in parallel and needs another way to report progress to console.
+
+            console.Output.Write($"Exporting {channels.Count} channels... ");
+            var progress = console.CreateProgressTicker();
+
+            var operations = progress.Wrap().CreateOperations(channels.Count);
+
+            var successfulExportCount = 0;
+            var errors = new ConcurrentBag<(Channel, string)>();
+
+            await channels.Zip(operations).ParallelForEachAsync(async tuple =>
+            {
+                var (channel, operation) = tuple;
+
+                try
+                {
+                    var guild = await GetDiscordClient().GetGuildAsync(channel.GuildId);
+
+                    var request = new ExportRequest(
+                        guild,
+                        channel,
+                        OutputPath,
+                        ExportFormat,
+                        After,
+                        Before,
+                        PartitionLimit,
+                        ShouldDownloadMedia,
+                        ShouldReuseMedia,
+                        DateFormat
+                    );
+
+                    await GetChannelExporter().ExportChannelAsync(request, operation);
+
+                    Interlocked.Increment(ref successfulExportCount);
+                }
+                catch (DiscordChatExporterException ex) when (!ex.IsCritical)
+                {
+                    errors.Add((channel, ex.Message));
+                }
+                finally
+                {
+                    operation.Dispose();
+                }
+            }, ParallelLimit.ClampMin(1));
+
+            console.Output.WriteLine();
+
+            foreach (var (channel, error) in errors)
+                console.Error.WriteLine($"Channel '{channel}': {error}");
+
+            console.Output.WriteLine($"Successfully exported {successfulExportCount} channel(s).");
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/Base/TokenCommandBase.cs

@@ -0,0 +1,27 @@
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Domain.Discord;
+
+namespace DiscordChatExporter.Cli.Commands.Base
+{
+    public abstract class TokenCommandBase : ICommand
+    {
+        [CommandOption("token", 't', IsRequired = true, EnvironmentVariableName = "DISCORD_TOKEN", Description = "Authorization token.")]
+        public string TokenValue { get; init; } = "";
+
+        [CommandOption("bot", 'b', EnvironmentVariableName = "DISCORD_TOKEN_BOT", Description = "Authorize as a bot.")]
+        public bool IsBotToken { get; init; }
+
+        protected AuthToken GetAuthToken() => new(
+            IsBotToken
+                ? AuthTokenType.Bot
+                : AuthTokenType.User,
+            TokenValue
+        );
+
+        protected DiscordClient GetDiscordClient() => new(GetAuthToken());
+
+        public abstract ValueTask ExecuteAsync(IConsole console);
+    }
+}

DiscordChatExporter.Cli/Commands/ExportAllCommand.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord.Models;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("exportall", Description = "Export all accessible channels.")]
+    public class ExportAllCommand : ExportMultipleCommandBase
+    {
+        [CommandOption("include-dm", Description = "Include direct message channels.")]
+        public bool IncludeDirectMessages { get; init; } = true;
+
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var channels = new List<Channel>();
+
+            // Aggregate channels from all guilds
+            await foreach (var guild in GetDiscordClient().GetUserGuildsAsync())
+            {
+                // Skip DMs if instructed to
+                if (!IncludeDirectMessages && guild.Id == Guild.DirectMessages.Id)
+                    continue;
+
+                await foreach (var channel in GetDiscordClient().GetGuildChannelsAsync(guild.Id))
+                {
+                    channels.Add(channel);
+                }
+            }
+
+            await ExportMultipleAsync(console, channels);
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/ExportChannelCommand.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("export", Description = "Export a channel.")]
+    public class ExportChannelCommand : ExportCommandBase
+    {
+        [CommandOption("channel", 'c', IsRequired = true, Description = "Channel ID.")]
+        public Snowflake ChannelId { get; init; }
+
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            await base.ExecuteAsync(console);
+            await ExportAsync(console, ChannelId);
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/ExportDirectMessagesCommand.cs

@@ -0,0 +1,19 @@
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("exportdm", Description = "Export all direct message channels.")]
+    public class ExportDirectMessagesCommand : ExportMultipleCommandBase
+    {
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var channels = await GetDiscordClient().GetGuildChannelsAsync(Guild.DirectMessages.Id);
+            await ExportMultipleAsync(console, channels);
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/ExportGuildCommand.cs

@@ -0,0 +1,22 @@
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("exportguild", Description = "Export all channels within specified guild.")]
+    public class ExportGuildCommand : ExportMultipleCommandBase
+    {
+        [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
+        public Snowflake GuildId { get; init; }
+
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var channels = await GetDiscordClient().GetGuildChannelsAsync(GuildId);
+            await ExportMultipleAsync(console, channels);
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/GetChannelsCommand.cs

@@ -0,0 +1,25 @@
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("channels", Description = "Get the list of channels in a guild.")]
+    public class GetChannelsCommand : TokenCommandBase
+    {
+        [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
+        public Snowflake GuildId { get; init; }
+
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var channels = await GetDiscordClient().GetGuildChannelsAsync(GuildId);
+
+            foreach (var channel in channels.OrderBy(c => c.Category).ThenBy(c => c.Name))
+                console.Output.WriteLine($"{channel.Id} | {channel.Category} / {channel.Name}");
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/GetDirectMessageChannelsCommand.cs

@@ -0,0 +1,22 @@
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("dm", Description = "Get the list of direct message channels.")]
+    public class GetDirectMessageChannelsCommand : TokenCommandBase
+    {
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var channels = await GetDiscordClient().GetGuildChannelsAsync(Guild.DirectMessages.Id);
+
+            foreach (var channel in channels.OrderBy(c => c.Category).ThenBy(c => c.Name))
+                console.Output.WriteLine($"{channel.Id} | {channel.Category} / {channel.Name}");
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/GetGuildsCommand.cs

@@ -0,0 +1,21 @@
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("guilds", Description = "Get the list of accessible guilds.")]
+    public class GetGuildsCommand : TokenCommandBase
+    {
+        public override async ValueTask ExecuteAsync(IConsole console)
+        {
+            var guilds = await GetDiscordClient().GetUserGuildsAsync();
+
+            foreach (var guild in guilds.OrderBy(g => g.Name))
+                console.Output.WriteLine($"{guild.Id} | {guild.Name}");
+        }
+    }
+}

DiscordChatExporter.Cli/Commands/GuideCommand.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+
+namespace DiscordChatExporter.Cli.Commands
+{
+    [Command("guide", Description = "Explains how to obtain token, guild or channel ID.")]
+    public class GuideCommand : ICommand
+    {
+        public ValueTask ExecuteAsync(IConsole console)
+        {
+            console.WithForegroundColor(ConsoleColor.White, () =>
+                console.Output.WriteLine("To get user token:")
+            );
+            console.Output.WriteLine(" 1. Open Discord");
+            console.Output.WriteLine(" 2. Press Ctrl+Shift+I to show developer tools");
+            console.Output.WriteLine(" 3. Navigate to the Application tab");
+            console.Output.WriteLine(" 4. Select \"Local Storage\" > \"https://discord.com\" on the left");
+            console.Output.WriteLine(" 5. Press Ctrl+R to reload");
+            console.Output.WriteLine(" 6. Find \"token\" at the bottom and copy the value");
+            console.Output.WriteLine(" *  Automating user accounts is technically against TOS, use at your own risk.");
+            console.Output.WriteLine();
+
+            console.WithForegroundColor(ConsoleColor.White, () =>
+                console.Output.WriteLine("To get bot token:")
+            );
+            console.Output.WriteLine(" 1. Go to Discord developer portal");
+            console.Output.WriteLine(" 2. Open your application's settings");
+            console.Output.WriteLine(" 3. Navigate to the Bot section on the left");
+            console.Output.WriteLine(" 4. Under Token click Copy");
+            console.Output.WriteLine();
+
+            console.WithForegroundColor(ConsoleColor.White, () =>
+                console.Output.WriteLine("To get guild ID or guild channel ID:")
+            );
+            console.Output.WriteLine(" 1. Open Discord");
+            console.Output.WriteLine(" 2. Open Settings");
+            console.Output.WriteLine(" 3. Go to Appearance section");
+            console.Output.WriteLine(" 4. Enable Developer Mode");
+            console.Output.WriteLine(" 5. Right click on the desired guild or channel and click Copy ID");
+            console.Output.WriteLine();
+
+            console.WithForegroundColor(ConsoleColor.White, () =>
+                console.Output.WriteLine("To get direct message channel ID:")
+            );
+            console.Output.WriteLine(" 1. Open Discord");
+            console.Output.WriteLine(" 2. Open the desired direct message channel");
+            console.Output.WriteLine(" 3. Press Ctrl+Shift+I to show developer tools");
+            console.Output.WriteLine(" 4. Navigate to the Console tab");
+            console.Output.WriteLine(" 5. Type \"window.location.href\" and press Enter");
+            console.Output.WriteLine(" 6. Copy the first long sequence of numbers inside the URL");
+            console.Output.WriteLine();
+
+            console.WithForegroundColor(ConsoleColor.White,
+                () => console.Output.WriteLine("For more information, check out the wiki:")
+            );
+            console.WithForegroundColor(ConsoleColor.Blue,
+                () => console.Output.WriteLine("https://github.com/Tyrrrz/DiscordChatExporter/wiki")
+            );
+
+            return default;
+        }
+    }
+}

DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <ApplicationIcon>..\favicon.ico</ApplicationIcon>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="CliFx" Version="1.6.0" />
+    <PackageReference Include="Gress" Version="1.2.0" />
+    <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DiscordChatExporter.Domain\DiscordChatExporter.Domain.csproj" />
+  </ItemGroup>
+
+</Project>

DiscordChatExporter.Cli/Internal/Pollyfills.cs

@@ -0,0 +1,9 @@
+// ReSharper disable CheckNamespace
+// TODO: remove after moving to .NET 5
+
+namespace System.Runtime.CompilerServices
+{
+    internal static class IsExternalInit
+    {
+    }
+}

DiscordChatExporter.Cli/Program.cs

@@ -0,0 +1,14 @@
+using System.Threading.Tasks;
+using CliFx;
+
+namespace DiscordChatExporter.Cli
+{
+    public static class Program
+    {
+        public static async Task<int> Main(string[] args) =>
+            await new CliApplicationBuilder()
+                .AddCommandsFromThisAssembly()
+                .Build()
+                .RunAsync(args);
+    }
+}

DiscordChatExporter.Domain/Discord/AuthToken.cs

@@ -0,0 +1,27 @@
+using System.Net.Http.Headers;
+
+namespace DiscordChatExporter.Domain.Discord
+{
+    public enum AuthTokenType { User, Bot }
+
+    public class AuthToken
+    {
+        public AuthTokenType Type { get; }
+
+        public string Value { get; }
+
+        public AuthToken(AuthTokenType type, string value)
+        {
+            Type = type;
+            Value = value;
+        }
+
+        public AuthenticationHeaderValue GetAuthorizationHeader() => Type switch
+        {
+            AuthTokenType.Bot => new AuthenticationHeaderValue("Bot", Value),
+            _ => new AuthenticationHeaderValue(Value)
+        };
+
+        public override string ToString() => Value;
+    }
+}

DiscordChatExporter.Domain/Discord/DiscordClient.cs

@@ -0,0 +1,254 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Text.Json;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exceptions;
+using DiscordChatExporter.Domain.Internal;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Http;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord
+{
+    public class DiscordClient
+    {
+        private readonly HttpClient _httpClient;
+        private readonly AuthToken _token;
+
+        private readonly Uri _baseUri = new("https://discord.com/api/v8/", UriKind.Absolute);
+
+        public DiscordClient(HttpClient httpClient, AuthToken token)
+        {
+            _httpClient = httpClient;
+            _token = token;
+        }
+
+        public DiscordClient(AuthToken token)
+            : this(Http.Client, token) {}
+
+        private async ValueTask<HttpResponseMessage> GetResponseAsync(string url) =>
+            await Http.ResponsePolicy.ExecuteAsync(async () =>
+            {
+                using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));
+                request.Headers.Authorization = _token.GetAuthorizationHeader();
+
+                return await _httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
+            });
+
+        private async ValueTask<JsonElement> GetJsonResponseAsync(string url)
+        {
+            using var response = await GetResponseAsync(url);
+
+            if (!response.IsSuccessStatusCode)
+            {
+                throw response.StatusCode switch
+                {
+                    HttpStatusCode.Unauthorized => DiscordChatExporterException.Unauthorized(),
+                    HttpStatusCode.Forbidden => DiscordChatExporterException.Forbidden(),
+                    HttpStatusCode.NotFound => DiscordChatExporterException.NotFound(),
+                    _ => DiscordChatExporterException.FailedHttpRequest(response)
+                };
+            }
+
+            return await response.Content.ReadAsJsonAsync();
+        }
+
+        private async ValueTask<JsonElement?> TryGetJsonResponseAsync(string url)
+        {
+            using var response = await GetResponseAsync(url);
+
+            return response.IsSuccessStatusCode
+                ? await response.Content.ReadAsJsonAsync()
+                : (JsonElement?) null;
+        }
+
+        public async IAsyncEnumerable<Guild> GetUserGuildsAsync()
+        {
+            yield return Guild.DirectMessages;
+
+            var currentAfter = Snowflake.Zero;
+
+            while (true)
+            {
+                var url = new UrlBuilder()
+                    .SetPath("users/@me/guilds")
+                    .SetQueryParameter("limit", "100")
+                    .SetQueryParameter("after", currentAfter.ToString())
+                    .Build();
+
+                var response = await GetJsonResponseAsync(url);
+
+                var isEmpty = true;
+                foreach (var guild in response.EnumerateArray().Select(Guild.Parse))
+                {
+                    yield return guild;
+
+                    currentAfter = guild.Id;
+                    isEmpty = false;
+                }
+
+                if (isEmpty)
+                    yield break;
+            }
+        }
+
+        public async ValueTask<Guild> GetGuildAsync(Snowflake guildId)
+        {
+            if (guildId == Guild.DirectMessages.Id)
+                return Guild.DirectMessages;
+
+            var response = await GetJsonResponseAsync($"guilds/{guildId}");
+            return Guild.Parse(response);
+        }
+
+        public async IAsyncEnumerable<Channel> GetGuildChannelsAsync(Snowflake guildId)
+        {
+            if (guildId == Guild.DirectMessages.Id)
+            {
+                var response = await GetJsonResponseAsync("users/@me/channels");
+                foreach (var channelJson in response.EnumerateArray())
+                    yield return Channel.Parse(channelJson);
+            }
+            else
+            {
+                var response = await GetJsonResponseAsync($"guilds/{guildId}/channels");
+
+                var categories = response
+                    .EnumerateArray()
+                    .ToDictionary(
+                        j => j.GetProperty("id").GetString(),
+                        j => j.GetProperty("name").GetString()
+                    );
+
+                foreach (var channelJson in response.EnumerateArray())
+                {
+                    var parentId = channelJson.GetPropertyOrNull("parent_id")?.GetString();
+                    var category = !string.IsNullOrWhiteSpace(parentId)
+                        ? categories.GetValueOrDefault(parentId)
+                        : null;
+
+                    var channel = Channel.Parse(channelJson, category);
+
+                    // Skip non-text channels
+                    if (!channel.IsTextChannel)
+                        continue;
+
+                    yield return channel;
+                }
+            }
+        }
+
+        public async IAsyncEnumerable<Role> GetGuildRolesAsync(Snowflake guildId)
+        {
+            if (guildId == Guild.DirectMessages.Id)
+                yield break;
+
+            var response = await GetJsonResponseAsync($"guilds/{guildId}/roles");
+
+            foreach (var roleJson in response.EnumerateArray())
+                yield return Role.Parse(roleJson);
+        }
+
+        public async ValueTask<Member?> TryGetGuildMemberAsync(Snowflake guildId, User user)
+        {
+            if (guildId == Guild.DirectMessages.Id)
+                return Member.CreateForUser(user);
+
+            var response = await TryGetJsonResponseAsync($"guilds/{guildId}/members/{user.Id}");
+            return response?.Pipe(Member.Parse);
+        }
+
+        private async ValueTask<string> GetChannelCategoryAsync(Snowflake channelParentId)
+        {
+            var response = await GetJsonResponseAsync($"channels/{channelParentId}");
+            return response.GetProperty("name").GetString();
+        }
+
+        public async ValueTask<Channel> GetChannelAsync(Snowflake channelId)
+        {
+            var response = await GetJsonResponseAsync($"channels/{channelId}");
+
+            var parentId = response.GetPropertyOrNull("parent_id")?.GetString().Pipe(Snowflake.Parse);
+
+            var category = parentId != null
+                ? await GetChannelCategoryAsync(parentId.Value)
+                : null;
+
+            return Channel.Parse(response, category);
+        }
+
+        private async ValueTask<Message?> TryGetLastMessageAsync(Snowflake channelId, Snowflake? before = null)
+        {
+            var url = new UrlBuilder()
+                .SetPath($"channels/{channelId}/messages")
+                .SetQueryParameter("limit", "1")
+                .SetQueryParameter("before", before?.ToString())
+                .Build();
+
+            var response = await GetJsonResponseAsync(url);
+            return response.EnumerateArray().Select(Message.Parse).LastOrDefault();
+        }
+
+        public async IAsyncEnumerable<Message> GetMessagesAsync(
+            Snowflake channelId,
+            Snowflake? after = null,
+            Snowflake? before = null,
+            IProgress<double>? progress = null)
+        {
+            // Get the last message in the specified range.
+            // This snapshots the boundaries, which means that messages posted after the exported started
+            // will not appear in the output.
+            // Additionally, it provides the date of the last message, which is used to calculate progress.
+            var lastMessage = await TryGetLastMessageAsync(channelId, before);
+            if (lastMessage == null || lastMessage.Timestamp < after?.ToDate())
+                yield break;
+
+            // Keep track of first message in range in order to calculate progress
+            var firstMessage = default(Message);
+            var currentAfter = after ?? Snowflake.Zero;
+
+            while (true)
+            {
+                var url = new UrlBuilder()
+                    .SetPath($"channels/{channelId}/messages")
+                    .SetQueryParameter("limit", "100")
+                    .SetQueryParameter("after", currentAfter.ToString())
+                    .Build();
+
+                var response = await GetJsonResponseAsync(url);
+
+                var messages = response
+                    .EnumerateArray()
+                    .Select(Message.Parse)
+                    .Reverse() // reverse because messages appear newest first
+                    .ToArray();
+
+                // Break if there are no messages (can happen if messages are deleted during execution)
+                if (!messages.Any())
+                    yield break;
+
+                foreach (var message in messages)
+                {
+                    firstMessage ??= message;
+
+                    // Ensure messages are in range (take into account that last message could have been deleted)
+                    if (message.Timestamp > lastMessage.Timestamp)
+                        yield break;
+
+                    // Report progress based on the duration of parsed messages divided by total
+                    progress?.Report(
+                        (message.Timestamp - firstMessage.Timestamp) /
+                        (lastMessage.Timestamp - firstMessage.Timestamp)
+                    );
+
+                    yield return message;
+                    currentAfter = message.Id;
+                }
+            }
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Attachment.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#attachment-object
+    public partial class Attachment : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public string Url { get; }
+
+        public string FileName { get; }
+
+        public int? Width { get; }
+
+        public int? Height { get; }
+
+        public bool IsImage => ImageFileExtensions.Contains(Path.GetExtension(FileName));
+
+        public bool IsVideo => VideoFileExtensions.Contains(Path.GetExtension(FileName));
+
+        public bool IsAudio => AudioFileExtensions.Contains(Path.GetExtension(FileName));
+
+        public bool IsSpoiler =>
+            (IsImage || IsVideo || IsAudio) && FileName.StartsWith("SPOILER_", StringComparison.Ordinal);
+
+        public FileSize FileSize { get; }
+
+        public Attachment(Snowflake id, string url, string fileName, int? width, int? height, FileSize fileSize)
+        {
+            Id = id;
+            Url = url;
+            FileName = fileName;
+            Width = width;
+            Height = height;
+            FileSize = fileSize;
+        }
+
+        public override string ToString() => FileName;
+    }
+
+    public partial class Attachment
+    {
+        private static readonly HashSet<string> ImageFileExtensions = new(StringComparer.OrdinalIgnoreCase)
+            {".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp"};
+
+        private static readonly HashSet<string> VideoFileExtensions = new(StringComparer.OrdinalIgnoreCase)
+            {".mp4", ".webm"};
+
+        private static readonly HashSet<string> AudioFileExtensions = new(StringComparer.OrdinalIgnoreCase)
+            {".mp3", ".wav", ".ogg", ".flac", ".m4a"};
+
+        public static Attachment Parse(JsonElement json)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var url = json.GetProperty("url").GetString();
+            var width = json.GetPropertyOrNull("width")?.GetInt32();
+            var height = json.GetPropertyOrNull("height")?.GetInt32();
+            var fileName = json.GetProperty("filename").GetString();
+            var fileSize = json.GetProperty("size").GetInt64().Pipe(FileSize.FromBytes);
+
+            return new Attachment(id, url, fileName, width, height, fileSize);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Channel.cs

@@ -0,0 +1,93 @@
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#channel-object-channel-types
+    // Order of enum fields needs to match the order in the docs.
+    public enum ChannelType
+    {
+        GuildTextChat,
+        DirectTextChat,
+        GuildVoiceChat,
+        DirectGroupTextChat,
+        GuildCategory,
+        GuildNews,
+        GuildStore
+    }
+
+    // https://discord.com/developers/docs/resources/channel#channel-object
+    public partial class Channel : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public ChannelType Type { get; }
+
+        public bool IsTextChannel =>
+            Type == ChannelType.GuildTextChat ||
+            Type == ChannelType.DirectTextChat ||
+            Type == ChannelType.DirectGroupTextChat ||
+            Type == ChannelType.GuildNews ||
+            Type == ChannelType.GuildStore;
+
+        public Snowflake GuildId { get; }
+
+        public string Category { get; }
+
+        public string Name { get; }
+
+        public string? Topic { get; }
+
+        public Channel(Snowflake id, ChannelType type, Snowflake guildId, string category, string name, string? topic)
+        {
+            Id = id;
+            Type = type;
+            GuildId = guildId;
+            Category = category;
+            Name = name;
+            Topic = topic;
+        }
+
+        public override string ToString() => Name;
+    }
+
+    public partial class Channel
+    {
+        private static string GetDefaultCategory(ChannelType channelType) => channelType switch
+        {
+            ChannelType.GuildTextChat => "Text",
+            ChannelType.DirectTextChat => "Private",
+            ChannelType.DirectGroupTextChat => "Group",
+            ChannelType.GuildNews => "News",
+            ChannelType.GuildStore => "Store",
+            _ => "Default"
+        };
+
+        public static Channel Parse(JsonElement json, string? category = null)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var guildId = json.GetPropertyOrNull("guild_id")?.GetString().Pipe(Snowflake.Parse);
+            var topic = json.GetPropertyOrNull("topic")?.GetString();
+
+            var type = (ChannelType) json.GetProperty("type").GetInt32();
+
+            var name =
+                json.GetPropertyOrNull("name")?.GetString() ??
+                json.GetPropertyOrNull("recipients")?.EnumerateArray().Select(User.Parse).Select(u => u.Name).JoinToString(", ") ??
+                id.ToString();
+
+            return new Channel(
+                id,
+                type,
+                guildId ?? Guild.DirectMessages.Id,
+                category ?? GetDefaultCategory(type),
+                name,
+                topic
+            );
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Common/FileSize.cs

@@ -0,0 +1,65 @@
+using System;
+
+namespace DiscordChatExporter.Domain.Discord.Models.Common
+{
+    // Loosely based on https://github.com/omar/ByteSize (MIT license)
+    public readonly partial struct FileSize
+    {
+        public long TotalBytes { get; }
+
+        public double TotalKiloBytes => TotalBytes / 1024.0;
+        public double TotalMegaBytes => TotalKiloBytes / 1024.0;
+        public double TotalGigaBytes => TotalMegaBytes / 1024.0;
+        public double TotalTeraBytes => TotalGigaBytes / 1024.0;
+        public double TotalPetaBytes => TotalTeraBytes / 1024.0;
+
+        public FileSize(long bytes) => TotalBytes = bytes;
+
+        private double GetLargestWholeNumberValue()
+        {
+            if (Math.Abs(TotalPetaBytes) >= 1)
+                return TotalPetaBytes;
+
+            if (Math.Abs(TotalTeraBytes) >= 1)
+                return TotalTeraBytes;
+
+            if (Math.Abs(TotalGigaBytes) >= 1)
+                return TotalGigaBytes;
+
+            if (Math.Abs(TotalMegaBytes) >= 1)
+                return TotalMegaBytes;
+
+            if (Math.Abs(TotalKiloBytes) >= 1)
+                return TotalKiloBytes;
+
+            return TotalBytes;
+        }
+
+        private string GetLargestWholeNumberSymbol()
+        {
+            if (Math.Abs(TotalPetaBytes) >= 1)
+                return "PB";
+
+            if (Math.Abs(TotalTeraBytes) >= 1)
+                return "TB";
+
+            if (Math.Abs(TotalGigaBytes) >= 1)
+                return "GB";
+
+            if (Math.Abs(TotalMegaBytes) >= 1)
+                return "MB";
+
+            if (Math.Abs(TotalKiloBytes) >= 1)
+                return "KB";
+
+            return "bytes";
+        }
+
+        public override string ToString() => $"{GetLargestWholeNumberValue():0.##} {GetLargestWholeNumberSymbol()}";
+    }
+
+    public partial struct FileSize
+    {
+        public static FileSize FromBytes(long bytes) => new(bytes);
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Common/IHasId.cs

@@ -0,0 +1,7 @@
+namespace DiscordChatExporter.Domain.Discord.Models.Common
+{
+    public interface IHasId
+    {
+        Snowflake Id { get; }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Common/IdBasedEqualityComparer.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+
+namespace DiscordChatExporter.Domain.Discord.Models.Common
+{
+    public partial class IdBasedEqualityComparer : IEqualityComparer<IHasId>
+    {
+        public bool Equals(IHasId? x, IHasId? y) => x?.Id == y?.Id;
+
+        public int GetHashCode(IHasId obj) => obj.Id.GetHashCode();
+    }
+
+    public partial class IdBasedEqualityComparer
+    {
+        public static IdBasedEqualityComparer Instance { get; } = new();
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Embed.cs

@@ -0,0 +1,95 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Internal.Extensions;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#embed-object
+    public partial class Embed
+    {
+        public string? Title { get; }
+
+        public string? Url { get; }
+
+        public DateTimeOffset? Timestamp { get; }
+
+        public Color? Color { get; }
+
+        public EmbedAuthor? Author { get; }
+
+        public string? Description { get; }
+
+        public IReadOnlyList<EmbedField> Fields { get; }
+
+        public EmbedImage? Thumbnail { get; }
+
+        public EmbedImage? Image { get; }
+
+        public EmbedFooter? Footer { get; }
+
+        public Embed(
+            string? title,
+            string? url,
+            DateTimeOffset? timestamp,
+            Color? color,
+            EmbedAuthor? author,
+            string? description,
+            IReadOnlyList<EmbedField> fields,
+            EmbedImage? thumbnail,
+            EmbedImage? image,
+            EmbedFooter? footer)
+        {
+            Title = title;
+            Url = url;
+            Timestamp = timestamp;
+            Color = color;
+            Author = author;
+            Description = description;
+            Fields = fields;
+            Thumbnail = thumbnail;
+            Image = image;
+            Footer = footer;
+        }
+
+        public override string ToString() => Title ?? "<untitled embed>";
+    }
+
+    public partial class Embed
+    {
+        public static Embed Parse(JsonElement json)
+        {
+            var title = json.GetPropertyOrNull("title")?.GetString();
+            var description = json.GetPropertyOrNull("description")?.GetString();
+            var url = json.GetPropertyOrNull("url")?.GetString();
+            var timestamp = json.GetPropertyOrNull("timestamp")?.GetDateTimeOffset();
+            var color = json.GetPropertyOrNull("color")?.GetInt32().Pipe(System.Drawing.Color.FromArgb).ResetAlpha();
+
+            var author = json.GetPropertyOrNull("author")?.Pipe(EmbedAuthor.Parse);
+            var thumbnail = json.GetPropertyOrNull("thumbnail")?.Pipe(EmbedImage.Parse);
+            var image = json.GetPropertyOrNull("image")?.Pipe(EmbedImage.Parse);
+            var footer = json.GetPropertyOrNull("footer")?.Pipe(EmbedFooter.Parse);
+
+            var fields =
+                json.GetPropertyOrNull("fields")?.EnumerateArray().Select(EmbedField.Parse).ToArray() ??
+                Array.Empty<EmbedField>();
+
+            return new Embed(
+                title,
+                url,
+                timestamp,
+                color,
+                author,
+                description,
+                fields,
+                thumbnail,
+                image,
+                footer
+            );
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/EmbedAuthor.cs

@@ -0,0 +1,36 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#embed-object-embed-author-structure
+    public partial class EmbedAuthor
+    {
+        public string? Name { get; }
+
+        public string? Url { get; }
+
+        public string? IconUrl { get; }
+
+        public EmbedAuthor(string? name, string? url, string? iconUrl)
+        {
+            Name = name;
+            Url = url;
+            IconUrl = iconUrl;
+        }
+
+        public override string ToString() => Name ?? "<unnamed author>";
+    }
+
+    public partial class EmbedAuthor
+    {
+        public static EmbedAuthor Parse(JsonElement json)
+        {
+            var name = json.GetPropertyOrNull("name")?.GetString();
+            var url = json.GetPropertyOrNull("url")?.GetString();
+            var iconUrl = json.GetPropertyOrNull("icon_url")?.GetString();
+
+            return new EmbedAuthor(name, url, iconUrl);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/EmbedField.cs

@@ -0,0 +1,36 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#embed-object-embed-field-structure
+    public partial class EmbedField
+    {
+        public string Name { get; }
+
+        public string Value { get; }
+
+        public bool IsInline { get; }
+
+        public EmbedField(string name, string value, bool isInline)
+        {
+            Name = name;
+            Value = value;
+            IsInline = isInline;
+        }
+
+        public override string ToString() => $"{Name} | {Value}";
+    }
+
+    public partial class EmbedField
+    {
+        public static EmbedField Parse(JsonElement json)
+        {
+            var name = json.GetProperty("name").GetString();
+            var value = json.GetProperty("value").GetString();
+            var isInline = json.GetPropertyOrNull("inline")?.GetBoolean() ?? false;
+
+            return new EmbedField(name, value, isInline);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/EmbedFooter.cs

@@ -0,0 +1,32 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#embed-object-embed-footer-structure
+    public partial class EmbedFooter
+    {
+        public string Text { get; }
+
+        public string? IconUrl { get; }
+
+        public EmbedFooter(string text, string? iconUrl)
+        {
+            Text = text;
+            IconUrl = iconUrl;
+        }
+
+        public override string ToString() => Text;
+    }
+
+    public partial class EmbedFooter
+    {
+        public static EmbedFooter Parse(JsonElement json)
+        {
+            var text = json.GetProperty("text").GetString();
+            var iconUrl = json.GetPropertyOrNull("icon_url")?.GetString();
+
+            return new EmbedFooter(text, iconUrl);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/EmbedImage.cs

@@ -0,0 +1,34 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#embed-object-embed-image-structure
+    public partial class EmbedImage
+    {
+        public string? Url { get; }
+
+        public int? Width { get; }
+
+        public int? Height { get; }
+
+        public EmbedImage(string? url, int? width, int? height)
+        {
+            Url = url;
+            Height = height;
+            Width = width;
+        }
+    }
+
+    public partial class EmbedImage
+    {
+        public static EmbedImage Parse(JsonElement json)
+        {
+            var url = json.GetPropertyOrNull("url")?.GetString();
+            var width = json.GetPropertyOrNull("width")?.GetInt32();
+            var height = json.GetPropertyOrNull("height")?.GetInt32();
+
+            return new EmbedImage(url, width, height);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Emoji.cs

@@ -0,0 +1,79 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using JsonExtensions.Reading;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/emoji#emoji-object
+    public partial class Emoji
+    {
+        public string? Id { get; }
+
+        public string Name { get; }
+
+        public bool IsAnimated { get; }
+
+        public string ImageUrl { get; }
+
+        public Emoji(string? id, string name, bool isAnimated)
+        {
+            Id = id;
+            Name = name;
+            IsAnimated = isAnimated;
+
+            ImageUrl = GetImageUrl(id, name, isAnimated);
+        }
+
+        public override string ToString() => Name;
+    }
+
+    public partial class Emoji
+    {
+        private static IEnumerable<Rune> GetRunes(string emoji)
+        {
+            var lastIndex = 0;
+            while (lastIndex < emoji.Length && Rune.TryGetRuneAt(emoji, lastIndex, out var rune))
+            {
+                // Skip variant selector rune
+                if (rune.Value != 0xfe0f)
+                    yield return rune;
+
+                lastIndex += rune.Utf16SequenceLength;
+            }
+        }
+
+        private static string GetTwemojiName(IEnumerable<Rune> runes) =>
+            runes.Select(r => r.Value.ToString("x")).JoinToString("-");
+
+        public static string GetImageUrl(string? id, string name, bool isAnimated)
+        {
+            // Custom emoji
+            if (!string.IsNullOrWhiteSpace(id))
+            {
+                // Animated
+                if (isAnimated)
+                    return $"https://cdn.discordapp.com/emojis/{id}.gif";
+
+                // Non-animated
+                return $"https://cdn.discordapp.com/emojis/{id}.png";
+            }
+
+            // Standard emoji
+            var emojiRunes = GetRunes(name).ToArray();
+            var twemojiName = GetTwemojiName(emojiRunes);
+            return $"https://twemoji.maxcdn.com/2/72x72/{twemojiName}.png";
+        }
+
+        public static Emoji Parse(JsonElement json)
+        {
+            var id = json.GetPropertyOrNull("id")?.GetString();
+            var name = json.GetProperty("name").GetString();
+            var isAnimated = json.GetPropertyOrNull("animated")?.GetBoolean() ?? false;
+
+            return new Emoji(id, name, isAnimated);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Guild.cs

@@ -0,0 +1,49 @@
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/guild#guild-object
+    public partial class Guild : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public string Name { get; }
+
+        public string IconUrl { get; }
+
+        public Guild(Snowflake id, string name, string iconUrl)
+        {
+            Id = id;
+            Name = name;
+            IconUrl = iconUrl;
+        }
+
+        public override string ToString() => Name;
+    }
+
+    public partial class Guild
+    {
+        public static Guild DirectMessages { get; } = new(Snowflake.Zero, "Direct Messages", GetDefaultIconUrl());
+
+        private static string GetDefaultIconUrl() =>
+            "https://cdn.discordapp.com/embed/avatars/0.png";
+
+        private static string GetIconUrl(Snowflake id, string iconHash) =>
+            $"https://cdn.discordapp.com/icons/{id}/{iconHash}.png";
+
+        public static Guild Parse(JsonElement json)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var name = json.GetProperty("name").GetString();
+            var iconHash = json.GetProperty("icon").GetString();
+
+            var iconUrl = !string.IsNullOrWhiteSpace(iconHash)
+                ? GetIconUrl(id, iconHash)
+                : GetDefaultIconUrl();
+
+            return new Guild(id, name, iconUrl);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Member.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/guild#guild-member-object
+    public partial class Member : IHasId
+    {
+        public Snowflake Id => User.Id;
+
+        public User User { get; }
+
+        public string Nick { get; }
+
+        public IReadOnlyList<Snowflake> RoleIds { get; }
+
+        public Member(User user, string? nick, IReadOnlyList<Snowflake> roleIds)
+        {
+            User = user;
+            Nick = nick ?? user.Name;
+            RoleIds = roleIds;
+        }
+
+        public override string ToString() => Nick;
+    }
+
+    public partial class Member
+    {
+        public static Member CreateForUser(User user) => new(user, null, Array.Empty<Snowflake>());
+
+        public static Member Parse(JsonElement json)
+        {
+            var user = json.GetProperty("user").Pipe(User.Parse);
+            var nick = json.GetPropertyOrNull("nick")?.GetString();
+
+            var roleIds =
+                json.GetPropertyOrNull("roles")?.EnumerateArray().Select(j => j.GetString().Pipe(Snowflake.Parse)).ToArray() ??
+                Array.Empty<Snowflake>();
+
+            return new Member(
+                user,
+                nick,
+                roleIds
+            );
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Message.cs

@@ -0,0 +1,152 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#message-object-message-types
+    public enum MessageType
+    {
+        Default = 0,
+        RecipientAdd = 1,
+        RecipientRemove = 2,
+        Call = 3,
+        ChannelNameChange = 4,
+        ChannelIconChange = 5,
+        ChannelPinnedMessage = 6,
+        GuildMemberJoin = 7,
+        Reply = 19
+    }
+
+    // https://discord.com/developers/docs/resources/channel#message-object
+    public partial class Message : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public MessageType Type { get; }
+
+        public User Author { get; }
+
+        public DateTimeOffset Timestamp { get; }
+
+        public DateTimeOffset? EditedTimestamp { get; }
+
+        public DateTimeOffset? CallEndedTimestamp { get; }
+
+        public bool IsPinned { get; }
+
+        public string Content { get; }
+
+        public IReadOnlyList<Attachment> Attachments { get; }
+
+        public IReadOnlyList<Embed> Embeds { get; }
+
+        public IReadOnlyList<Reaction> Reactions { get; }
+
+        public IReadOnlyList<User> MentionedUsers { get; }
+
+        public MessageReference? Reference { get; }
+
+        public Message? ReferencedMessage { get; }
+
+        public Message(
+            Snowflake id,
+            MessageType type,
+            User author,
+            DateTimeOffset timestamp,
+            DateTimeOffset? editedTimestamp,
+            DateTimeOffset? callEndedTimestamp,
+            bool isPinned,
+            string content,
+            IReadOnlyList<Attachment> attachments,
+            IReadOnlyList<Embed> embeds,
+            IReadOnlyList<Reaction> reactions,
+            IReadOnlyList<User> mentionedUsers,
+            MessageReference? messageReference,
+            Message? referencedMessage)
+        {
+            Id = id;
+            Type = type;
+            Author = author;
+            Timestamp = timestamp;
+            EditedTimestamp = editedTimestamp;
+            CallEndedTimestamp = callEndedTimestamp;
+            IsPinned = isPinned;
+            Content = content;
+            Attachments = attachments;
+            Embeds = embeds;
+            Reactions = reactions;
+            MentionedUsers = mentionedUsers;
+            Reference = messageReference;
+            ReferencedMessage = referencedMessage;
+        }
+
+        public override string ToString() => Content;
+    }
+
+    public partial class Message
+    {
+        public static Message Parse(JsonElement json)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var author = json.GetProperty("author").Pipe(User.Parse);
+            var timestamp = json.GetProperty("timestamp").GetDateTimeOffset();
+            var editedTimestamp = json.GetPropertyOrNull("edited_timestamp")?.GetDateTimeOffset();
+            var callEndedTimestamp = json.GetPropertyOrNull("call")?.GetPropertyOrNull("ended_timestamp")?.GetDateTimeOffset();
+            var type = (MessageType) json.GetProperty("type").GetInt32();
+            var isPinned = json.GetPropertyOrNull("pinned")?.GetBoolean() ?? false;
+            var messageReference = json.GetPropertyOrNull("message_reference")?.Pipe(MessageReference.Parse);
+            var referencedMessage = json.GetPropertyOrNull("referenced_message")?.Pipe(Message.Parse);
+
+            var content = type switch
+            {
+                MessageType.RecipientAdd => "Added a recipient.",
+                MessageType.RecipientRemove => "Removed a recipient.",
+                MessageType.Call =>
+                    $"Started a call that lasted {callEndedTimestamp?.Pipe(t => t - timestamp).Pipe(t => (int) t.TotalMinutes) ?? 0} minutes.",
+                MessageType.ChannelNameChange => "Changed the channel name.",
+                MessageType.ChannelIconChange => "Changed the channel icon.",
+                MessageType.ChannelPinnedMessage => "Pinned a message.",
+                MessageType.GuildMemberJoin => "Joined the server.",
+                _ => json.GetPropertyOrNull("content")?.GetString() ?? ""
+            };
+
+            var attachments =
+                json.GetPropertyOrNull("attachments")?.EnumerateArray().Select(Attachment.Parse).ToArray() ??
+                Array.Empty<Attachment>();
+
+            var embeds =
+                json.GetPropertyOrNull("embeds")?.EnumerateArray().Select(Embed.Parse).ToArray() ??
+                Array.Empty<Embed>();
+
+            var reactions =
+                json.GetPropertyOrNull("reactions")?.EnumerateArray().Select(Reaction.Parse).ToArray() ??
+                Array.Empty<Reaction>();
+
+            var mentionedUsers =
+                json.GetPropertyOrNull("mentions")?.EnumerateArray().Select(User.Parse).ToArray() ??
+                Array.Empty<User>();
+
+            return new Message(
+                id,
+                type,
+                author,
+                timestamp,
+                editedTimestamp,
+                callEndedTimestamp,
+                isPinned,
+                content,
+                attachments,
+                embeds,
+                reactions,
+                mentionedUsers,
+                messageReference,
+                referencedMessage
+            );
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/MessageReference.cs

@@ -0,0 +1,37 @@
+using System.Text.Json;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#message-object-message-reference-structure
+    public partial class MessageReference
+    {
+        public Snowflake? MessageId { get; }
+
+        public Snowflake? ChannelId { get; }
+
+        public Snowflake? GuildId { get; }
+
+        public MessageReference(Snowflake? messageId, Snowflake? channelId, Snowflake? guildId)
+        {
+            MessageId = messageId;
+            ChannelId = channelId;
+            GuildId = guildId;
+        }
+
+        public override string ToString() => MessageId?.ToString() ?? "<unknown reference>";
+    }
+
+    public partial class MessageReference
+    {
+        public static MessageReference Parse(JsonElement json)
+        {
+            var messageId = json.GetPropertyOrNull("message_id")?.GetString().Pipe(Snowflake.Parse);
+            var channelId = json.GetPropertyOrNull("channel_id")?.GetString().Pipe(Snowflake.Parse);
+            var guildId = json.GetPropertyOrNull("guild_id")?.GetString().Pipe(Snowflake.Parse);
+
+            return new MessageReference(messageId, channelId, guildId);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Reaction.cs

@@ -0,0 +1,32 @@
+using System.Text.Json;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/channel#reaction-object
+    public partial class Reaction
+    {
+        public Emoji Emoji { get; }
+
+        public int Count { get; }
+
+        public Reaction(Emoji emoji, int count)
+        {
+            Emoji = emoji;
+            Count = count;
+        }
+
+        public override string ToString() => $"{Emoji} ({Count})";
+    }
+
+    public partial class Reaction
+    {
+        public static Reaction Parse(JsonElement json)
+        {
+            var count = json.GetProperty("count").GetInt32();
+            var emoji = json.GetProperty("emoji").Pipe(Emoji.Parse);
+
+            return new Reaction(emoji, count);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/Role.cs

@@ -0,0 +1,49 @@
+using System.Drawing;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Internal.Extensions;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/topics/permissions#role-object
+    public partial class Role : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public string Name { get; }
+
+        public int Position { get; }
+
+        public Color? Color { get; }
+
+        public Role(Snowflake id, string name, int position, Color? color)
+        {
+            Id = id;
+            Name = name;
+            Position = position;
+            Color = color;
+        }
+
+        public override string ToString() => Name;
+    }
+
+    public partial class Role
+    {
+        public static Role Parse(JsonElement json)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var name = json.GetProperty("name").GetString();
+            var position = json.GetProperty("position").GetInt32();
+
+            var color = json.GetPropertyOrNull("color")?
+                .GetInt32()
+                .Pipe(System.Drawing.Color.FromArgb)
+                .ResetAlpha()
+                .NullIf(c => c.ToRgb() <= 0);
+
+            return new Role(id, name, position, color);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Models/User.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Text.Json;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Utilities;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Domain.Discord.Models
+{
+    // https://discord.com/developers/docs/resources/user#user-object
+    public partial class User : IHasId
+    {
+        public Snowflake Id { get; }
+
+        public bool IsBot { get; }
+
+        public int Discriminator { get; }
+
+        public string Name { get; }
+
+        public string FullName => $"{Name}#{Discriminator:0000}";
+
+        public string AvatarUrl { get; }
+
+        public User(Snowflake id, bool isBot, int discriminator, string name, string avatarUrl)
+        {
+            Id = id;
+            IsBot = isBot;
+            Discriminator = discriminator;
+            Name = name;
+            AvatarUrl = avatarUrl;
+        }
+
+        public override string ToString() => FullName;
+    }
+
+    public partial class User
+    {
+        private static string GetDefaultAvatarUrl(int discriminator) =>
+            $"https://cdn.discordapp.com/embed/avatars/{discriminator % 5}.png";
+
+        private static string GetAvatarUrl(Snowflake id, string avatarHash)
+        {
+            // Animated
+            if (avatarHash.StartsWith("a_", StringComparison.Ordinal))
+                return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.gif";
+
+            // Non-animated
+            return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.png";
+        }
+
+        public static User Parse(JsonElement json)
+        {
+            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
+            var discriminator = json.GetProperty("discriminator").GetString().Pipe(int.Parse);
+            var name = json.GetProperty("username").GetString();
+            var avatarHash = json.GetProperty("avatar").GetString();
+            var isBot = json.GetPropertyOrNull("bot")?.GetBoolean() ?? false;
+
+            var avatarUrl = !string.IsNullOrWhiteSpace(avatarHash)
+                ? GetAvatarUrl(id, avatarHash)
+                : GetDefaultAvatarUrl(discriminator);
+
+            return new User(id, isBot, discriminator, name, avatarUrl);
+        }
+    }
+}

DiscordChatExporter.Domain/Discord/Snowflake.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Globalization;
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Domain.Discord
+{
+    public readonly partial struct Snowflake
+    {
+        public ulong Value { get; }
+
+        public Snowflake(ulong value) => Value = value;
+
+        public DateTimeOffset ToDate() =>
+            DateTimeOffset.FromUnixTimeMilliseconds((long) ((Value >> 22) + 1420070400000UL)).ToLocalTime();
+
+        public override string ToString() => Value.ToString(CultureInfo.InvariantCulture);
+    }
+
+    public partial struct Snowflake
+    {
+        public static Snowflake Zero { get; } = new(0);
+
+        public static Snowflake FromDate(DateTimeOffset date)
+        {
+            var value = ((ulong) date.ToUnixTimeMilliseconds() - 1420070400000UL) << 22;
+            return new Snowflake(value);
+        }
+
+        public static Snowflake? TryParse(string? str, IFormatProvider? formatProvider = null)
+        {
+            if (string.IsNullOrWhiteSpace(str))
+                return null;
+
+            // As number
+            if (Regex.IsMatch(str, @"^\d{15,}$") &&
+                ulong.TryParse(str, NumberStyles.Number, formatProvider, out var value))
+            {
+                return new Snowflake(value);
+            }
+
+            // As date
+            if (DateTimeOffset.TryParse(str, formatProvider, DateTimeStyles.None, out var date))
+            {
+                return FromDate(date);
+            }
+
+            return null;
+        }
+
+        public static Snowflake Parse(string str, IFormatProvider? formatProvider) =>
+            TryParse(str, formatProvider) ?? throw new FormatException($"Invalid snowflake: {str}.");
+
+        public static Snowflake Parse(string str) => Parse(str, null);
+    }
+
+    public partial struct Snowflake : IEquatable<Snowflake>
+    {
+        public bool Equals(Snowflake other) => Value == other.Value;
+
+        public override bool Equals(object? obj) => obj is Snowflake other && Equals(other);
+
+        public override int GetHashCode() => Value.GetHashCode();
+
+        public static bool operator ==(Snowflake left, Snowflake right) => left.Equals(right);
+
+        public static bool operator !=(Snowflake left, Snowflake right) => !(left == right);
+    }
+}

DiscordChatExporter.Domain/DiscordChatExporter.Domain.csproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="JsonExtensions" Version="1.0.1" />
+    <PackageReference Include="MiniRazor" Version="2.0.3" />
+    <PackageReference Include="Polly" Version="7.2.1" />
+    <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Include="Exporting\Writers\Html\Core.css" />
+    <EmbeddedResource Include="Exporting\Writers\Html\Dark.css" />
+    <EmbeddedResource Include="Exporting\Writers\Html\Light.css" />
+    <AdditionalFiles Include="Exporting\Writers\Html\PreambleTemplate.cshtml" IsRazorTemplate="true" />
+    <AdditionalFiles Include="Exporting\Writers\Html\PostambleTemplate.cshtml" IsRazorTemplate="true" />
+    <AdditionalFiles Include="Exporting\Writers\Html\MessageGroupTemplate.cshtml" IsRazorTemplate="true" />
+  </ItemGroup>
+
+</Project>

DiscordChatExporter.Domain/Exceptions/DiscordChatExporterException.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Net.Http;
+
+namespace DiscordChatExporter.Domain.Exceptions
+{
+    public partial class DiscordChatExporterException : Exception
+    {
+        public bool IsCritical { get; }
+
+        public DiscordChatExporterException(string message, bool isCritical = false)
+            : base(message)
+        {
+            IsCritical = isCritical;
+        }
+    }
+
+    public partial class DiscordChatExporterException
+    {
+        internal static DiscordChatExporterException FailedHttpRequest(HttpResponseMessage response)
+        {
+            var message = $@"
+Failed to perform an HTTP request.
+
+{response.RequestMessage}
+
+{response}";
+
+            return new DiscordChatExporterException(message.Trim(), true);
+        }
+
+        internal static DiscordChatExporterException Unauthorized()
+        {
+            const string message = "Authentication token is invalid.";
+            return new DiscordChatExporterException(message);
+        }
+
+        internal static DiscordChatExporterException Forbidden()
+        {
+            const string message = "Access is forbidden.";
+            return new DiscordChatExporterException(message);
+        }
+
+        internal static DiscordChatExporterException NotFound()
+        {
+            const string message = "Requested resource does not exist.";
+            return new DiscordChatExporterException(message);
+        }
+
+        internal static DiscordChatExporterException ChannelIsEmpty()
+        {
+            var message = $"No messages for the specified period.";
+            return new DiscordChatExporterException(message);
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/ChannelExporter.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Discord.Models.Common;
+using DiscordChatExporter.Domain.Exceptions;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    public class ChannelExporter
+    {
+        private readonly DiscordClient _discord;
+
+        public ChannelExporter(DiscordClient discord) => _discord = discord;
+
+        public ChannelExporter(AuthToken token) : this(new DiscordClient(token)) {}
+
+        public async ValueTask ExportChannelAsync(ExportRequest request, IProgress<double>? progress = null)
+        {
+            // Build context
+            var contextMembers = new HashSet<Member>(IdBasedEqualityComparer.Instance);
+            var contextChannels = await _discord.GetGuildChannelsAsync(request.Guild.Id);
+            var contextRoles = await _discord.GetGuildRolesAsync(request.Guild.Id);
+
+            var context = new ExportContext(
+                request,
+                contextMembers,
+                contextChannels,
+                contextRoles
+            );
+
+            // Export messages
+            await using var messageExporter = new MessageExporter(context);
+
+            var exportedAnything = false;
+            var encounteredUsers = new HashSet<User>(IdBasedEqualityComparer.Instance);
+            await foreach (var message in _discord.GetMessagesAsync(request.Channel.Id, request.After, request.Before, progress))
+            {
+                // Resolve members for referenced users
+                foreach (var referencedUser in message.MentionedUsers.Prepend(message.Author))
+                {
+                    if (!encounteredUsers.Add(referencedUser))
+                        continue;
+
+                    var member =
+                        await _discord.TryGetGuildMemberAsync(request.Guild.Id, referencedUser) ??
+                        Member.CreateForUser(referencedUser);
+
+                    contextMembers.Add(member);
+                }
+
+                // Export message
+                await messageExporter.ExportMessageAsync(message);
+                exportedAnything = true;
+            }
+
+            // Throw if no messages were exported
+            if (!exportedAnything)
+                throw DiscordChatExporterException.ChannelIsEmpty();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/ExportContext.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.IO;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Internal.Extensions;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    internal class ExportContext
+    {
+        private readonly MediaDownloader _mediaDownloader;
+
+        public ExportRequest Request { get; }
+
+        public IReadOnlyCollection<Member> Members { get; }
+
+        public IReadOnlyCollection<Channel> Channels { get; }
+
+        public IReadOnlyCollection<Role> Roles { get; }
+
+        public ExportContext(
+            ExportRequest request,
+            IReadOnlyCollection<Member> members,
+            IReadOnlyCollection<Channel> channels,
+            IReadOnlyCollection<Role> roles)
+        {
+            Request = request;
+            Members = members;
+            Channels = channels;
+            Roles = roles;
+
+            _mediaDownloader = new MediaDownloader(request.OutputMediaDirPath, request.ShouldReuseMedia);
+        }
+
+        public string FormatDate(DateTimeOffset date) => Request.DateFormat switch
+        {
+            "unix" => date.ToUnixTimeSeconds().ToString(),
+            "unixms" => date.ToUnixTimeMilliseconds().ToString(),
+            var dateFormat => date.ToLocalString(dateFormat)
+        };
+
+        public Member? TryGetMember(Snowflake id) => Members.FirstOrDefault(m => m.Id == id);
+
+        public Channel? TryGetChannel(Snowflake id) => Channels.FirstOrDefault(c => c.Id == id);
+
+        public Role? TryGetRole(Snowflake id) => Roles.FirstOrDefault(r => r.Id == id);
+
+        public Color? TryGetUserColor(Snowflake id)
+        {
+            var member = TryGetMember(id);
+            var roles = member?.RoleIds.Join(Roles, i => i, r => r.Id, (_, role) => role);
+
+            return roles?
+                .Where(r => r.Color != null)
+                .OrderByDescending(r => r.Position)
+                .Select(r => r.Color)
+                .FirstOrDefault();
+        }
+
+        public async ValueTask<string> ResolveMediaUrlAsync(string url)
+        {
+            if (!Request.ShouldDownloadMedia)
+                return url;
+
+            try
+            {
+                var filePath = await _mediaDownloader.DownloadAsync(url);
+
+                // We want relative path so that the output files can be copied around without breaking.
+                // Base directory path may be null if the file is stored at the root or relative to working directory.
+                var relativeFilePath = !string.IsNullOrWhiteSpace(Request.OutputBaseDirPath)
+                    ? Path.GetRelativePath(Request.OutputBaseDirPath, filePath)
+                    : filePath;
+
+                // HACK: for HTML, we need to format the URL properly
+                if (Request.Format == ExportFormat.HtmlDark || Request.Format == ExportFormat.HtmlLight)
+                {
+                    // Need to escape each path segment while keeping the directory separators intact
+                    return relativeFilePath
+                        .Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar)
+                        .Select(Uri.EscapeDataString)
+                        .JoinToString(Path.AltDirectorySeparatorChar.ToString());
+                }
+
+                return relativeFilePath;
+            }
+            // Try to catch only exceptions related to failed HTTP requests
+            // https://github.com/Tyrrrz/DiscordChatExporter/issues/332
+            // https://github.com/Tyrrrz/DiscordChatExporter/issues/372
+            catch (Exception ex) when (ex is HttpRequestException || ex is OperationCanceledException)
+            {
+                // TODO: add logging so we can be more liberal with catching exceptions
+                // We don't want this to crash the exporting process in case of failure
+                return url;
+            }
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/ExportFormat.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    public enum ExportFormat
+    {
+        PlainText,
+        HtmlDark,
+        HtmlLight,
+        Csv,
+        Json
+    }
+
+    public static class ExportFormatExtensions
+    {
+        public static string GetFileExtension(this ExportFormat format) => format switch
+        {
+            ExportFormat.PlainText => "txt",
+            ExportFormat.HtmlDark => "html",
+            ExportFormat.HtmlLight => "html",
+            ExportFormat.Csv => "csv",
+            ExportFormat.Json => "json",
+            _ => throw new ArgumentOutOfRangeException(nameof(format))
+        };
+
+        public static string GetDisplayName(this ExportFormat format) => format switch
+        {
+            ExportFormat.PlainText => "TXT",
+            ExportFormat.HtmlDark => "HTML (Dark)",
+            ExportFormat.HtmlLight => "HTML (Light)",
+            ExportFormat.Csv => "CSV",
+            ExportFormat.Json => "JSON",
+            _ => throw new ArgumentOutOfRangeException(nameof(format))
+        };
+    }
+}

DiscordChatExporter.Domain/Exporting/ExportRequest.cs

@@ -0,0 +1,140 @@
+using System.IO;
+using System.Text;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Internal;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    public partial class ExportRequest
+    {
+        public Guild Guild { get; }
+
+        public Channel Channel { get; }
+
+        public string OutputPath { get; }
+
+        public string OutputBaseFilePath { get; }
+
+        public string OutputBaseDirPath { get; }
+
+        public string OutputMediaDirPath { get; }
+
+        public ExportFormat Format { get; }
+
+        public Snowflake? After { get; }
+
+        public Snowflake? Before { get; }
+
+        public int? PartitionLimit { get; }
+
+        public bool ShouldDownloadMedia { get; }
+
+        public bool ShouldReuseMedia { get; }
+
+        public string DateFormat { get; }
+
+        public ExportRequest(
+            Guild guild,
+            Channel channel,
+            string outputPath,
+            ExportFormat format,
+            Snowflake? after,
+            Snowflake? before,
+            int? partitionLimit,
+            bool shouldDownloadMedia,
+            bool shouldReuseMedia,
+            string dateFormat)
+        {
+            Guild = guild;
+            Channel = channel;
+            OutputPath = outputPath;
+            Format = format;
+            After = after;
+            Before = before;
+            PartitionLimit = partitionLimit;
+            ShouldDownloadMedia = shouldDownloadMedia;
+            ShouldReuseMedia = shouldReuseMedia;
+            DateFormat = dateFormat;
+
+            OutputBaseFilePath = GetOutputBaseFilePath(
+                guild,
+                channel,
+                outputPath,
+                format,
+                after,
+                before
+            );
+
+            OutputBaseDirPath = Path.GetDirectoryName(OutputBaseFilePath) ?? OutputPath;
+            OutputMediaDirPath = $"{OutputBaseFilePath}_Files{Path.DirectorySeparatorChar}";
+        }
+    }
+
+    public partial class ExportRequest
+    {
+        private static string GetOutputBaseFilePath(
+            Guild guild,
+            Channel channel,
+            string outputPath,
+            ExportFormat format,
+            Snowflake? after = null,
+            Snowflake? before = null)
+        {
+            // Output is a directory
+            if (Directory.Exists(outputPath) || string.IsNullOrWhiteSpace(Path.GetExtension(outputPath)))
+            {
+                var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);
+                return Path.Combine(outputPath, fileName);
+            }
+
+            // Output is a file
+            return outputPath;
+        }
+
+        public static string GetDefaultOutputFileName(
+            Guild guild,
+            Channel channel,
+            ExportFormat format,
+            Snowflake? after = null,
+            Snowflake? before = null)
+        {
+            var buffer = new StringBuilder();
+
+            // Guild and channel names
+            buffer.Append($"{guild.Name} - {channel.Category} - {channel.Name} [{channel.Id}]");
+
+            // Date range
+            if (after != null || before != null)
+            {
+                buffer.Append(" (");
+
+                // Both 'after' and 'before' are set
+                if (after != null && before != null)
+                {
+                    buffer.Append($"{after?.ToDate():yyyy-MM-dd} to {before?.ToDate():yyyy-MM-dd}");
+                }
+                // Only 'after' is set
+                else if (after != null)
+                {
+                    buffer.Append($"after {after?.ToDate():yyyy-MM-dd}");
+                }
+                // Only 'before' is set
+                else
+                {
+                    buffer.Append($"before {before?.ToDate():yyyy-MM-dd}");
+                }
+
+                buffer.Append(")");
+            }
+
+            // File extension
+            buffer.Append($".{format.GetFileExtension()}");
+
+            // Replace invalid chars
+            PathEx.EscapePath(buffer);
+
+            return buffer.ToString();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/MediaDownloader.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Net.Http;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Internal;
+using DiscordChatExporter.Domain.Internal.Extensions;
+using DiscordChatExporter.Domain.Utilities;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    internal partial class MediaDownloader
+    {
+        private readonly HttpClient _httpClient;
+        private readonly string _workingDirPath;
+        private readonly bool _reuseMedia;
+
+        // URL -> Local file path
+        private readonly Dictionary<string, string> _pathCache = new(StringComparer.Ordinal);
+
+        public MediaDownloader(HttpClient httpClient, string workingDirPath, bool reuseMedia)
+        {
+            _httpClient = httpClient;
+            _workingDirPath = workingDirPath;
+            _reuseMedia = reuseMedia;
+        }
+
+        public MediaDownloader(string workingDirPath, bool reuseMedia)
+            : this(Http.Client, workingDirPath, reuseMedia) {}
+
+        public async ValueTask<string> DownloadAsync(string url)
+        {
+            if (_pathCache.TryGetValue(url, out var cachedFilePath))
+                return cachedFilePath;
+
+            var fileName = GetFileNameFromUrl(url);
+            var filePath = Path.Combine(_workingDirPath, fileName);
+
+            // Reuse existing files if we're allowed to
+            if (_reuseMedia && File.Exists(filePath))
+                return _pathCache[url] = filePath;
+
+            Directory.CreateDirectory(_workingDirPath);
+
+            // This catches IOExceptions which is dangerous as we're working also with files
+            await Http.ExceptionPolicy.ExecuteAsync(async () =>
+            {
+                // Download the file
+                using var response = await _httpClient.GetAsync(url);
+                await using (var output = File.Create(filePath))
+                {
+                    await response.Content.CopyToAsync(output);
+                }
+
+                // Try to set the file date according to the last-modified header
+                var lastModified = response.Content.Headers.TryGetValue("Last-Modified")?.Pipe(s =>
+                    DateTimeOffset.TryParse(s, CultureInfo.InvariantCulture, DateTimeStyles.None, out var date)
+                        ? date
+                        : (DateTimeOffset?) null
+                );
+
+                if (lastModified != null)
+                {
+                    File.SetCreationTimeUtc(filePath, lastModified.Value.UtcDateTime);
+                    File.SetLastWriteTimeUtc(filePath, lastModified.Value.UtcDateTime);
+                    File.SetLastAccessTimeUtc(filePath, lastModified.Value.UtcDateTime);
+                }
+            });
+
+            return _pathCache[url] = filePath;
+        }
+    }
+
+    internal partial class MediaDownloader
+    {
+        private static string GetUrlHash(string url)
+        {
+            using var hash = SHA256.Create();
+
+            var data = hash.ComputeHash(Encoding.UTF8.GetBytes(url));
+            return data.ToHex().Truncate(5); // 5 chars ought to be enough for anybody
+        }
+
+        private static string GetFileNameFromUrl(string url)
+        {
+            var urlHash = GetUrlHash(url);
+
+            // Try to extract file name from URL
+            var fileName = Regex.Match(url, @".+/([^?]*)").Groups[1].Value;
+
+            // If it's not there, just use the URL hash as the file name
+            if (string.IsNullOrWhiteSpace(fileName))
+                return urlHash;
+
+            // Otherwise, use the original file name but inject the hash in the middle
+            var fileNameWithoutExtension = Path.GetFileNameWithoutExtension(fileName);
+            var fileExtension = Path.GetExtension(fileName);
+
+            return PathEx.EscapePath(fileNameWithoutExtension.Truncate(42) + '-' + urlHash + fileExtension);
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/MessageExporter.cs

@@ -0,0 +1,113 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting.Writers;
+
+namespace DiscordChatExporter.Domain.Exporting
+{
+    internal partial class MessageExporter : IAsyncDisposable
+    {
+        private readonly ExportContext _context;
+
+        private long _messageCount;
+        private int _partitionIndex;
+        private MessageWriter? _writer;
+
+        public MessageExporter(ExportContext context)
+        {
+            _context = context;
+        }
+
+        private bool IsPartitionLimitReached() =>
+            _messageCount > 0 &&
+            _context.Request.PartitionLimit != null &&
+            _context.Request.PartitionLimit != 0 &&
+            _messageCount % _context.Request.PartitionLimit == 0;
+
+        private async ValueTask ResetWriterAsync()
+        {
+            if (_writer != null)
+            {
+                await _writer.WritePostambleAsync();
+                await _writer.DisposeAsync();
+                _writer = null;
+            }
+        }
+
+        private async ValueTask<MessageWriter> GetWriterAsync()
+        {
+            // Ensure partition limit has not been exceeded
+            if (IsPartitionLimitReached())
+            {
+                await ResetWriterAsync();
+                _partitionIndex++;
+            }
+
+            // Writer is still valid - return
+            if (_writer != null)
+                return _writer;
+
+            var filePath = GetPartitionFilePath(_context.Request.OutputBaseFilePath, _partitionIndex);
+
+            var dirPath = Path.GetDirectoryName(_context.Request.OutputBaseFilePath);
+            if (!string.IsNullOrWhiteSpace(dirPath))
+                Directory.CreateDirectory(dirPath);
+
+            var writer = CreateMessageWriter(filePath, _context.Request.Format, _context);
+            await writer.WritePreambleAsync();
+
+            return _writer = writer;
+        }
+
+        public async ValueTask ExportMessageAsync(Message message)
+        {
+            var writer = await GetWriterAsync();
+            await writer.WriteMessageAsync(message);
+            _messageCount++;
+        }
+
+        public async ValueTask DisposeAsync() => await ResetWriterAsync();
+    }
+
+    internal partial class MessageExporter
+    {
+        private static string GetPartitionFilePath(
+            string baseFilePath,
+            int partitionIndex)
+        {
+            // First partition - don't change file name
+            if (partitionIndex <= 0)
+                return baseFilePath;
+
+            // Inject partition index into file name
+            var fileNameWithoutExt = Path.GetFileNameWithoutExtension(baseFilePath);
+            var fileExt = Path.GetExtension(baseFilePath);
+            var fileName = $"{fileNameWithoutExt} [part {partitionIndex + 1}]{fileExt}";
+            var dirPath = Path.GetDirectoryName(baseFilePath);
+
+            return !string.IsNullOrWhiteSpace(dirPath)
+                ? Path.Combine(dirPath, fileName)
+                : fileName;
+        }
+
+        private static MessageWriter CreateMessageWriter(
+            string filePath,
+            ExportFormat format,
+            ExportContext context)
+        {
+            // Stream will be disposed by the underlying writer
+            var stream = File.Create(filePath);
+
+            return format switch
+            {
+                ExportFormat.PlainText => new PlainTextMessageWriter(stream, context),
+                ExportFormat.Csv => new CsvMessageWriter(stream, context),
+                ExportFormat.HtmlDark => new HtmlMessageWriter(stream, context, "Dark"),
+                ExportFormat.HtmlLight => new HtmlMessageWriter(stream, context, "Light"),
+                ExportFormat.Json => new JsonMessageWriter(stream, context),
+                _ => throw new ArgumentOutOfRangeException(nameof(format), $"Unknown export format '{format}'.")
+            };
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/CsvMessageWriter.cs

@@ -0,0 +1,103 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors;
+using DiscordChatExporter.Domain.Internal.Extensions;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers
+{
+    internal partial class CsvMessageWriter : MessageWriter
+    {
+        private readonly TextWriter _writer;
+
+        public CsvMessageWriter(Stream stream, ExportContext context)
+            : base(stream, context)
+        {
+            _writer = new StreamWriter(stream);
+        }
+
+        private string FormatMarkdown(string? markdown) =>
+            PlainTextMarkdownVisitor.Format(Context, markdown ?? "");
+
+        public override async ValueTask WritePreambleAsync() =>
+            await _writer.WriteLineAsync("AuthorID,Author,Date,Content,Attachments,Reactions");
+
+        private async ValueTask WriteAttachmentsAsync(IReadOnlyList<Attachment> attachments)
+        {
+            var buffer = new StringBuilder();
+
+            foreach (var attachment in attachments)
+            {
+                buffer
+                    .AppendIfNotEmpty(',')
+                    .Append(await Context.ResolveMediaUrlAsync(attachment.Url));
+            }
+
+            await _writer.WriteAsync(CsvEncode(buffer.ToString()));
+        }
+
+        private async ValueTask WriteReactionsAsync(IReadOnlyList<Reaction> reactions)
+        {
+            var buffer = new StringBuilder();
+
+            foreach (var reaction in reactions)
+            {
+                buffer
+                    .AppendIfNotEmpty(',')
+                    .Append(reaction.Emoji.Name)
+                    .Append(' ')
+                    .Append('(')
+                    .Append(reaction.Count)
+                    .Append(')');
+            }
+
+            await _writer.WriteAsync(CsvEncode(buffer.ToString()));
+        }
+
+        public override async ValueTask WriteMessageAsync(Message message)
+        {
+            // Author ID
+            await _writer.WriteAsync(CsvEncode(message.Author.Id.ToString()));
+            await _writer.WriteAsync(',');
+
+            // Author name
+            await _writer.WriteAsync(CsvEncode(message.Author.FullName));
+            await _writer.WriteAsync(',');
+
+            // Message timestamp
+            await _writer.WriteAsync(CsvEncode(Context.FormatDate(message.Timestamp)));
+            await _writer.WriteAsync(',');
+
+            // Message content
+            await _writer.WriteAsync(CsvEncode(FormatMarkdown(message.Content)));
+            await _writer.WriteAsync(',');
+
+            // Attachments
+            await WriteAttachmentsAsync(message.Attachments);
+            await _writer.WriteAsync(',');
+
+            // Reactions
+            await WriteReactionsAsync(message.Reactions);
+
+            // Finish row
+            await _writer.WriteLineAsync();
+        }
+
+        public override async ValueTask DisposeAsync()
+        {
+            await _writer.DisposeAsync();
+            await base.DisposeAsync();
+        }
+    }
+
+    internal partial class CsvMessageWriter
+    {
+        private static string CsvEncode(string value)
+        {
+            value = value.Replace("\"", "\"\"");
+            return $"\"{value}\"";
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/Core.css

@@ -0,0 +1,525 @@
+/* General */
+
+@font-face {
+    font-family: Whitney;
+    src: url(https://cdn.jsdelivr.net/gh/Tyrrrz/DiscordFonts@master/whitney-300.woff);
+    font-weight: 300;
+}
+
+@font-face {
+    font-family: Whitney;
+    src: url(https://cdn.jsdelivr.net/gh/Tyrrrz/DiscordFonts@master/whitney-400.woff);
+    font-weight: 400;
+}
+
+@font-face {
+    font-family: Whitney;
+    src: url(https://cdn.jsdelivr.net/gh/Tyrrrz/DiscordFonts@master/whitney-500.woff);
+    font-weight: 500;
+}
+
+@font-face {
+    font-family: Whitney;
+    src: url(https://cdn.jsdelivr.net/gh/Tyrrrz/DiscordFonts@master/whitney-600.woff);
+    font-weight: 600;
+}
+
+@font-face {
+    font-family: Whitney;
+    src: url(https://cdn.jsdelivr.net/gh/Tyrrrz/DiscordFonts@master/whitney-700.woff);
+    font-weight: 700;
+}
+
+body {
+    font-family: "Whitney", "Helvetica Neue", Helvetica, Arial, sans-serif;
+    font-size: 17px;
+}
+
+a {
+    text-decoration: none;
+}
+
+a:hover {
+    text-decoration: underline;
+}
+
+img {
+    object-fit: contain;
+}
+
+.markdown {
+    max-width: 100%;
+    line-height: 1.3;
+    overflow-wrap: break-word;
+}
+
+.preserve-whitespace {
+    white-space: pre-wrap;
+}
+
+.spoiler {
+    /* width: fit-content; */
+    display: inline-block;
+    /* This is more consistent across browsers, the old attribute worked well under Chrome but not FireFox. */
+}
+
+.spoiler--hidden {
+    cursor: pointer;
+}
+
+.spoiler-text {
+    border-radius: 3px;
+}
+
+.spoiler--hidden .spoiler-text {
+    color: rgba(0, 0, 0, 0);
+}
+
+.spoiler--hidden .spoiler-text::selection {
+    color: rgba(0, 0, 0, 0);
+}
+
+.spoiler-image {
+    position: relative;
+    overflow: hidden;
+    border-radius: 3px;
+}
+
+.spoiler--hidden .spoiler-image {
+    box-shadow: 0 0 1px 1px rgba(0, 0, 0, 0.1);
+}
+
+.spoiler--hidden .spoiler-image * {
+    filter: blur(44px);
+}
+
+.spoiler--hidden .spoiler-image:after {
+    content: "SPOILER";
+    color: #dcddde;
+    background-color: rgba(0, 0, 0, 0.6);
+    position: absolute;
+    left: 50%;
+    top: 50%;
+    transform: translate(-50%, -50%);
+    font-weight: 600;
+    padding: 100%;
+    border-radius: 20px;
+    letter-spacing: 0.05em;
+    font-size: 0.9em;
+}
+
+.spoiler--hidden:hover .spoiler-image:after {
+    color: #fff;
+    background-color: rgba(0, 0, 0, 0.9);
+}
+
+.quote {
+    margin: 0.1em 0;
+    padding-left: 0.6em;
+    border-left: 4px solid;
+    border-radius: 3px;
+}
+
+.pre {
+    font-family: "Consolas", "Courier New", Courier, monospace;
+}
+
+.pre--multiline {
+    margin-top: 0.25em;
+    padding: 0.5em;
+    border: 2px solid;
+    border-radius: 5px;
+}
+
+.pre--inline {
+    padding: 2px;
+    border-radius: 3px;
+    font-size: 0.85em;
+}
+
+.mention {
+    border-radius: 3px;
+    padding: 0 2px;
+    color: #7289da;
+    background: rgba(114, 137, 218, .1);
+    font-weight: 500;
+}
+
+.emoji {
+    width: 1.25em;
+    height: 1.25em;
+    margin: 0 0.06em;
+    vertical-align: -0.4em;
+}
+
+.emoji--small {
+    width: 1em;
+    height: 1em;
+}
+
+.emoji--large {
+    width: 2.8em;
+    height: 2.8em;
+}
+
+/* Preamble */
+
+.preamble {
+    display: grid;
+    margin: 0 0.3em 0.6em 0.3em;
+    max-width: 100%;
+    grid-template-columns: auto 1fr;
+}
+
+.preamble__guild-icon-container {
+    grid-column: 1;
+}
+
+.preamble__guild-icon {
+    max-width: 88px;
+    max-height: 88px;
+}
+
+.preamble__entries-container {
+    grid-column: 2;
+    margin-left: 0.6em;
+}
+
+.preamble__entry {
+    font-size: 1.4em;
+}
+
+.preamble__entry--small {
+    font-size: 1em;
+}
+
+/* Chatlog */
+
+.chatlog {
+    max-width: 100%;
+}
+
+.chatlog__message-group {
+    display: grid;
+    margin: 0 0.6em;
+    padding: 0.9em 0;
+    border-top: 1px solid;
+    grid-template-columns: auto 1fr;
+}
+
+.chatlog__reference-symbol {
+    grid-column: 1;
+    border-style: solid;
+    border-width: 2px 0 0 2px;
+    border-radius: 8px 0 0 0;
+    margin-left: 16px;
+    margin-top: 8px;
+}
+
+.chatlog__reference {
+    display: flex;
+    grid-column: 2;
+    margin-left: 1.2em;
+    margin-bottom: 0.25em;
+    font-size: 0.875em;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    align-items: center;
+}
+
+.chatlog__reference-avatar {
+    border-radius: 50%;
+    height: 16px;
+    width: 16px;
+    margin-right: 0.25em;
+}
+
+.chatlog__reference-name {
+    margin-right: 0.25em;
+    font-weight: 600;
+}
+
+.chatlog__reference-link {
+    flex-grow: 1;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.chatlog__reference-link:hover {
+    text-decoration: none;
+}
+
+.chatlog__reference-content > * {
+    display: inline;
+}
+
+.chatlog__reference-edited-timestamp {
+    margin-left: 0.25em;
+    font-size: 0.8em;
+}
+
+.chatlog__author-avatar-container {
+    grid-column: 1;
+    width: 40px;
+    height: 40px;
+}
+
+.chatlog__author-avatar {
+    border-radius: 50%;
+    height: 40px;
+    width: 40px;
+}
+
+.chatlog__messages {
+    grid-column: 2;
+    margin-left: 1.2em;
+    min-width: 50%;
+}
+
+.chatlog__author-name {
+    font-weight: 500;
+}
+
+.chatlog__timestamp {
+    margin-left: 0.3em;
+    font-size: 0.75em;
+}
+
+.chatlog__message {
+    padding: 0.1em 0.3em;
+    margin: 0 -0.3em;
+    background-color: transparent;
+    transition: background-color 1s ease;
+}
+
+.chatlog__content {
+    font-size: 0.95em;
+    word-wrap: break-word;
+}
+
+.chatlog__edited-timestamp {
+    margin-left: 0.15em;
+    font-size: 0.8em;
+}
+
+.chatlog__attachment {
+    margin-top: 0.3em;
+}
+
+.chatlog__attachment-thumbnail {
+    vertical-align: top;
+    max-width: 45vw;
+    max-height: 500px;
+    border-radius: 3px;
+}
+
+.chatlog__attachment-container {
+    height: 40px;
+    width: 100%;
+    max-width: 520px;
+    padding: 10px;
+    border: 1px solid;
+    border-radius: 3px;
+    overflow: hidden;
+}
+
+.chatlog__attachment-icon {
+    float: left;
+    height: 100%;
+    margin-right: 10px;
+}
+
+.chatlog__attachment-icon > .a {
+    fill: #f4f5fb;
+    d: path("M50,935a25,25,0,0,1-25-25V50A25,25,0,0,1,50,25H519.6L695,201.32V910a25,25,0,0,1-25,25Z");
+}
+
+.chatlog__attachment-icon > .b {
+    fill: #7789c4;
+    d: path("M509.21,50,670,211.63V910H50V50H509.21M530,0H50A50,50,0,0,0,0,50V910a50,50,0,0,0,50,50H670a50,50,0,0,0,50-50h0V191Z");
+}
+
+.chatlog__attachment-icon > .c {
+    fill: #f4f5fb;
+    d: path("M530,215a25,25,0,0,1-25-25V50a25,25,0,0,1,16.23-23.41L693.41,198.77A25,25,0,0,1,670,215Z");
+}
+
+.chatlog__attachment-icon > .d {
+    fill: #7789c4;
+    d: path("M530,70.71,649.29,190H530V70.71M530,0a50,50,0,0,0-50,50V190a50,50,0,0,0,50,50H670a50,50,0,0,0,50-50Z");
+}
+
+.chatlog__attachment-filesize {
+    color: #72767d;
+    font-size: 12px;
+}
+
+.chatlog__attachment-filename {
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+}
+
+.chatlog__embed {
+    display: flex;
+    margin-top: 0.3em;
+    max-width: 520px;
+}
+
+.chatlog__embed-color-pill {
+    flex-shrink: 0;
+    width: 0.25em;
+    border-top-left-radius: 3px;
+    border-bottom-left-radius: 3px;
+}
+
+.chatlog__embed-content-container {
+    display: flex;
+    flex-direction: column;
+    padding: 0.5em 0.6em;
+    border: 1px solid;
+    border-top-right-radius: 3px;
+    border-bottom-right-radius: 3px;
+}
+
+.chatlog__embed-content {
+    display: flex;
+    width: 100%;
+}
+
+.chatlog__embed-text {
+    flex: 1;
+}
+
+.chatlog__embed-author {
+    display: flex;
+    margin-bottom: 0.3em;
+    align-items: center;
+}
+
+.chatlog__embed-author-icon {
+    margin-right: 0.5em;
+    width: 20px;
+    height: 20px;
+    border-radius: 50%;
+}
+
+.chatlog__embed-author-name {
+    font-size: 0.875em;
+    font-weight: 600;
+}
+
+.chatlog__embed-title {
+    margin-bottom: 0.2em;
+    font-size: 0.875em;
+    font-weight: 600;
+}
+
+.chatlog__embed-description {
+    font-weight: 500;
+    font-size: 0.85em;
+}
+
+.chatlog__embed-fields {
+    display: flex;
+    flex-wrap: wrap;
+}
+
+.chatlog__embed-field {
+    flex: 0;
+    min-width: 100%;
+    max-width: 506px;
+    padding-top: 0.6em;
+    font-size: 0.875em;
+}
+
+.chatlog__embed-field--inline {
+    flex: 1;
+    flex-basis: auto;
+    min-width: 150px;
+}
+
+.chatlog__embed-field-name {
+    margin-bottom: 0.2em;
+    font-weight: 600;
+}
+
+.chatlog__embed-field-value {
+    font-weight: 500;
+}
+
+.chatlog__embed-thumbnail {
+    flex: 0;
+    margin-left: 1.2em;
+    max-width: 80px;
+    max-height: 80px;
+    border-radius: 3px;
+}
+
+.chatlog__embed-image-container {
+    margin-top: 0.6em;
+}
+
+.chatlog__embed-image {
+    max-width: 500px;
+    max-height: 400px;
+    border-radius: 3px;
+}
+
+.chatlog__embed-footer {
+    margin-top: 0.6em;
+}
+
+.chatlog__embed-footer-icon {
+    margin-right: 0.2em;
+    width: 20px;
+    height: 20px;
+    border-radius: 50%;
+    vertical-align: middle;
+}
+
+.chatlog__embed-footer-text {
+    font-size: 0.75em;
+    font-weight: 500;
+}
+
+.chatlog__reactions {
+    display: flex;
+}
+
+.chatlog__reaction {
+    display: flex;
+    align-items: center;
+    margin: 0.35em 0.1em 0.1em 0.1em;
+    padding: 0.2em 0.35em;
+    border-radius: 3px;
+}
+
+.chatlog__reaction-count {
+    min-width: 9px;
+    margin-left: 0.35em;
+    font-size: 0.875em;
+}
+
+.chatlog__bot-tag {
+    position: relative;
+    top: -.2em;
+    margin-left: 0.3em;
+    padding: 0.05em 0.3em;
+    border-radius: 3px;
+    vertical-align: middle;
+    line-height: 1.3;
+    background: #7289da;
+    color: #ffffff;
+    font-size: 0.625em;
+    font-weight: 500;
+}
+
+/* Postamble */
+
+.postamble {
+    margin: 1.4em 0.3em 0.6em 0.3em;
+    padding: 1em;
+    border-top: 1px solid;
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/Dark.css

@@ -0,0 +1,147 @@
+/* General */
+
+body {
+    background-color: #36393e;
+    color: #dcddde;
+}
+
+a {
+    color: #0096cf;
+}
+
+.spoiler-text {
+    background-color: rgba(255, 255, 255, 0.1);
+}
+
+.spoiler--hidden .spoiler-text {
+    background-color: #202225;
+}
+
+.spoiler--hidden:hover .spoiler-text {
+    background-color: rgba(32, 34, 37, 0.8);
+}
+
+.quote {
+    border-color: #4f545c;
+}
+
+.pre {
+    background-color: #2f3136 !important;
+}
+
+.pre--multiline {
+    border-color: #282b30 !important;
+    color: #b9bbbe !important;
+}
+
+/* === Preamble === */
+
+.preamble__entry {
+    color: #ffffff;
+}
+
+/* Chatlog */
+
+.chatlog__message-group {
+    border-color: rgba(255, 255, 255, 0.1);
+}
+
+.chatlog__reference-symbol {
+    border-color: #4f545c;
+}
+
+.chatlog__reference {
+    color: #b5b6b8;
+}
+
+.chatlog__reference-link {
+    color: #b5b6b8;
+}
+
+.chatlog__reference-link:hover {
+    color: #ffffff;
+}
+
+.chatlog__reference-edited-timestamp {
+    color: rgba(255, 255, 255, 0.2);
+}
+
+.chatlog__author-name {
+    color: #ffffff;
+}
+
+.chatlog__timestamp {
+    color: rgba(255, 255, 255, 0.2);
+}
+
+.chatlog__message--highlighted {
+    background-color: rgba(114, 137, 218, 0.2) !important;
+}
+
+.chatlog__message--pinned {
+    background-color: rgba(249, 168, 37, 0.05);
+}
+
+.chatlog__attachment-container {
+    background-color: #2f3136;
+    border-color: #292b2f;
+}
+
+.chatlog__edited-timestamp {
+    color: rgba(255, 255, 255, 0.2);
+}
+
+.chatlog__embed-color-pill--default {
+    background-color: rgba(79, 84, 92, 1);
+}
+
+.chatlog__embed-content-container {
+    background-color: rgba(46, 48, 54, 0.3);
+    border-color: rgba(46, 48, 54, 0.6);
+}
+
+.chatlog__embed-author-name {
+    color: #ffffff;
+}
+
+.chatlog__embed-author-name-link {
+    color: #ffffff;
+}
+
+.chatlog__embed-title {
+    color: #ffffff;
+}
+
+.chatlog__embed-description {
+    color: rgba(255, 255, 255, 0.6);
+}
+
+.chatlog__embed-field-name {
+    color: #ffffff;
+}
+
+.chatlog__embed-field-value {
+    color: rgba(255, 255, 255, 0.6);
+}
+
+.chatlog__embed-footer {
+    color: rgba(255, 255, 255, 0.6);
+}
+
+.chatlog__reaction {
+    background-color: rgba(255, 255, 255, 0.05);
+}
+
+.chatlog__reaction-count {
+    color: rgba(255, 255, 255, 0.3);
+}
+
+/* Postamble */
+
+.postamble {
+    border-color: rgba(255, 255, 255, 0.1);
+}
+
+.postamble__entry {
+    color: #ffffff;
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/LayoutTemplateContext.cs

@@ -0,0 +1,18 @@
+namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+{
+    internal class LayoutTemplateContext
+    {
+        public ExportContext ExportContext { get; }
+
+        public string ThemeName { get; }
+
+        public long MessageCount { get; }
+
+        public LayoutTemplateContext(ExportContext exportContext, string themeName, long messageCount)
+        {
+            ExportContext = exportContext;
+            ThemeName = themeName;
+            MessageCount = messageCount;
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/Light.css

@@ -0,0 +1,149 @@
+/* General */
+
+body {
+    background-color: #ffffff;
+    color: #23262a;
+    font-weight: 500;
+}
+
+a {
+    color: #00b0f4;
+}
+
+.spoiler-text {
+    background-color: rgba(0, 0, 0, 0.1);
+}
+
+.spoiler--hidden .spoiler-text {
+    background-color: #b9bbbe;
+}
+
+.spoiler--hidden:hover .spoiler-text {
+    background-color: rgba(185, 187, 190, 0.8);
+}
+
+.quote {
+    border-color: #c7ccd1;
+}
+
+.pre {
+    background-color: #f9f9f9 !important;
+}
+
+.pre--multiline {
+    border-color: #f3f3f3 !important;
+    color: #657b83 !important;
+}
+
+/* Preamble */
+
+.preamble__entry {
+    color: #2f3136;
+}
+
+/* Chatlog */
+
+.chatlog__message-group {
+    border-color: #eceeef;
+}
+
+.chatlog__reference-symbol {
+    border-color: #c7ccd1;
+}
+
+.chatlog__reference {
+    color: #5f5f60;
+}
+
+.chatlog__reference-link {
+    color: #5f5f60;
+}
+
+.chatlog__reference-link:hover {
+    color: #2f3136;
+}
+
+.chatlog__reference-edited-timestamp {
+    color: #747f8d;
+}
+
+.chatlog__author-name {
+    font-weight: 600;
+    color: #2f3136;
+}
+
+.chatlog__timestamp {
+    color: #747f8d;
+}
+
+.chatlog__message--highlighted {
+    background-color: rgba(114, 137, 218, 0.2) !important;
+}
+
+.chatlog__message--pinned {
+    background-color: rgba(249, 168, 37, 0.05);
+}
+
+.chatlog__attachment-container {
+    background-color: #f2f3f5;
+    border-color: #ebedef;
+}
+
+.chatlog__edited-timestamp {
+    color: #747f8d;
+}
+
+.chatlog__embed-color-pill--default {
+    background-color: rgba(227, 229, 232, 1);
+}
+
+.chatlog__embed-content-container {
+    background-color: rgba(249, 249, 249, 0.3);
+    border-color: rgba(204, 204, 204, 0.3);
+}
+
+.chatlog__embed-author-name {
+    color: #4f545c;
+}
+
+.chatlog__embed-author-name-link {
+    color: #4f545c;
+}
+
+.chatlog__embed-title {
+    color: #4f545c;
+}
+
+.chatlog__embed-description {
+    color: #737f8d;
+}
+
+.chatlog__embed-field-name {
+    color: #36393e;
+}
+
+.chatlog__embed-field-value {
+    color: #737f8d;
+}
+
+.chatlog__embed-footer {
+    color: rgba(79, 83, 91, 0.6);
+}
+
+.chatlog__reaction {
+    background-color: rgba(79, 84, 92, 0.06);
+}
+
+.chatlog__reaction-count {
+    color: #747f8d;
+}
+
+/* Postamble */
+
+.postamble {
+    border-color: #eceeef;
+}
+
+.postamble__entry {
+    color: #2f3136;
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/MessageGroup.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using DiscordChatExporter.Domain.Discord.Models;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+{
+    // Used for grouping contiguous messages in HTML export
+    internal partial class MessageGroup
+    {
+        public User Author { get; }
+
+        public DateTimeOffset Timestamp { get; }
+
+        public IReadOnlyList<Message> Messages { get; }
+
+        public MessageReference? Reference { get; }
+
+        public Message? ReferencedMessage {get; }
+
+        public MessageGroup(
+            User author,
+            DateTimeOffset timestamp,
+            MessageReference? reference,
+            Message? referencedMessage,
+            IReadOnlyList<Message> messages)
+        {
+            Author = author;
+            Timestamp = timestamp;
+            Reference = reference;
+            ReferencedMessage = referencedMessage;
+            Messages = messages;
+        }
+    }
+
+    internal partial class MessageGroup
+    {
+        public static bool CanJoin(Message message1, Message message2) =>
+            message1.Author.Id == message2.Author.Id &&
+            string.Equals(message1.Author.FullName, message2.Author.FullName, StringComparison.Ordinal) &&
+            (message2.Timestamp - message1.Timestamp).Duration().TotalMinutes <= 7 &&
+            message2.Reference is null;
+
+        public static MessageGroup Join(IReadOnlyList<Message> messages)
+        {
+            var first = messages.First();
+
+            return new MessageGroup(
+                first.Author,
+                first.Timestamp,
+                first.Reference,
+                first.ReferencedMessage,
+                messages
+            );
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/MessageGroupTemplate.cshtml

@@ -0,0 +1,316 @@
+@using System
+@using System.Linq
+@using System.Threading.Tasks
+@namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+@inherits MiniRazor.TemplateBase<DiscordChatExporter.Domain.Exporting.Writers.Html.MessageGroupTemplateContext>
+
+@{
+    string FormatDate(DateTimeOffset date) => Model.ExportContext.FormatDate(date);
+
+    string FormatMarkdown(string markdown) => Model.FormatMarkdown(markdown);
+
+    string FormatEmbedMarkdown(string markdown) => Model.FormatMarkdown(markdown, false);
+
+    ValueTask<string> ResolveUrlAsync(string url) => Model.ExportContext.ResolveMediaUrlAsync(url);
+
+    var userMember = Model.ExportContext.TryGetMember(Model.MessageGroup.Author.Id);
+
+    var userColor = Model.ExportContext.TryGetUserColor(Model.MessageGroup.Author.Id);
+
+    var userColorStyle = userColor != null
+        ? $"color: rgb({userColor?.R},{userColor?.G},{userColor?.B})"
+        : null;
+
+    var userNick = Model.MessageGroup.Author.IsBot
+        ? Model.MessageGroup.Author.Name
+        : userMember?.Nick ?? Model.MessageGroup.Author.Name;
+
+    var referencedUserMember = Model.MessageGroup.ReferencedMessage != null
+        ? Model.ExportContext.TryGetMember(Model.MessageGroup.ReferencedMessage.Author.Id)
+        : null;
+
+    var referencedUserColor = Model.MessageGroup.ReferencedMessage != null
+        ? Model.ExportContext.TryGetUserColor(Model.MessageGroup.ReferencedMessage.Author.Id)
+        : null;
+
+    var referencedUserColorStyle = referencedUserColor != null
+        ? $"color: rgb({referencedUserColor?.R},{referencedUserColor?.G},{referencedUserColor?.B})"
+        : null;
+
+    var referencedUserNick = Model.MessageGroup.ReferencedMessage != null
+        ? Model.MessageGroup.ReferencedMessage.Author.IsBot
+            ? Model.MessageGroup.ReferencedMessage.Author.Name
+            : referencedUserMember?.Nick ?? Model.MessageGroup.ReferencedMessage.Author.Name
+        : null;
+}
+
+<div class="chatlog__message-group">
+    @if (Model.MessageGroup.Reference != null)
+    {
+        <div class="chatlog__reference-symbol">
+        </div>
+        <div class="chatlog__reference">
+            @if (Model.MessageGroup.ReferencedMessage != null)
+            {
+                <img class="chatlog__reference-avatar" src="@await ResolveUrlAsync(Model.MessageGroup.ReferencedMessage.Author.AvatarUrl)" alt="Avatar">
+                <span class="chatlog__reference-name" title="@Model.MessageGroup.ReferencedMessage.Author.FullName" style="@referencedUserColorStyle">@referencedUserNick</span>
+                <a class="chatlog__reference-link" href="#" onclick="scrollToMessage(event, '@Model.MessageGroup.ReferencedMessage.Id')">
+                    <span class="chatlog__reference-content">
+                        @if (!string.IsNullOrWhiteSpace(Model.MessageGroup.ReferencedMessage.Content))
+                        {
+                            @Raw(FormatMarkdown(Model.MessageGroup.ReferencedMessage.Content))
+                        }
+                        else
+                        {
+                            <em>Click to see original message</em>
+                        }
+                    </span>
+
+                    @if (Model.MessageGroup.ReferencedMessage.EditedTimestamp != null)
+                    {
+                        <span class="chatlog__reference-edited-timestamp" title="@FormatDate(Model.MessageGroup.ReferencedMessage.EditedTimestamp.Value)">(edited)</span>
+                    }
+                </a>
+            }
+            else
+            {
+                <span class="chatlog__reference-unknown">
+                    Original message was deleted.
+                </span>
+            }
+        </div>
+    }
+    <div class="chatlog__author-avatar-container">
+        <img class="chatlog__author-avatar" src="@await ResolveUrlAsync(Model.MessageGroup.Author.AvatarUrl)" alt="Avatar">
+    </div>
+    <div class="chatlog__messages">
+        <span class="chatlog__author-name" title="@Model.MessageGroup.Author.FullName" data-user-id="@Model.MessageGroup.Author.Id" style="@userColorStyle">@userNick</span>
+
+        @if (Model.MessageGroup.Author.IsBot)
+        {
+            <span class="chatlog__bot-tag">BOT</span>
+        }
+
+        <span class="chatlog__timestamp">@FormatDate(Model.MessageGroup.Timestamp)</span>
+
+        @foreach (var message in Model.MessageGroup.Messages)
+        {
+            var isPinnedStyle = message.IsPinned ? "chatlog__message--pinned" : null;
+
+            <div class="chatlog__message @isPinnedStyle" data-message-id="@message.Id" id="message-@message.Id">
+                @if (!string.IsNullOrWhiteSpace(message.Content) || message.EditedTimestamp != null)
+                {
+                    <div class="chatlog__content">
+                        <div class="markdown">
+                            <span class="preserve-whitespace">@Raw(FormatMarkdown(message.Content))</span>
+
+                            @if (message.EditedTimestamp != null)
+                            {
+                                <span class="chatlog__edited-timestamp" title="@FormatDate(message.EditedTimestamp.Value)">(edited)</span>
+                            }
+                        </div>
+                    </div>
+                }
+
+                @foreach (var attachment in message.Attachments)
+                {
+                    <div class="chatlog__attachment">
+                        <div class="@(attachment.IsSpoiler ? "spoiler spoiler--hidden" : "")" onclick="@(attachment.IsSpoiler ? "showSpoiler(event, this)" : "")">
+                            <div class="@(attachment.IsSpoiler ? "spoiler-image" : "")">
+                                @if (attachment.IsImage)
+                                {
+                                    <a href="@await ResolveUrlAsync(attachment.Url)">
+                                        <img class="chatlog__attachment-thumbnail" src="@await ResolveUrlAsync(attachment.Url)" alt="Image attachment" title="@($"Image: {attachment.FileName} ({attachment.FileSize})")">
+                                    </a>
+                                }
+                                else if (attachment.IsVideo)
+                                {
+                                    <video controls class="chatlog__attachment-thumbnail">
+                                        <source src="@await ResolveUrlAsync(attachment.Url)" alt="Video attachment" title="@($"Video: {attachment.FileName} ({attachment.FileSize})")">
+                                    </video>
+                                }
+                                else if (attachment.IsAudio)
+                                {
+                                    <audio controls class="chatlog__attachment-thumbnail">
+                                        <source src="@await ResolveUrlAsync(attachment.Url)" alt="Audio attachment" title="@($"Audio: {attachment.FileName} ({attachment.FileSize})")">
+                                    </audio>
+                                }
+                                else
+                                {
+                                    <div class="chatlog__attachment-container">
+                                        <svg class="chatlog__attachment-icon" viewBox="0 0 720 960">
+                                            <path class="a"/>
+                                            <path class="b"/>
+                                            <path class="c"/>
+                                            <path class="d"/>
+                                        </svg>
+                                        <div class="chatlog__attachment-filename">
+                                            <a href="@await ResolveUrlAsync(attachment.Url)">
+                                                @attachment.FileName
+                                            </a>
+                                        </div>
+                                        <div class="chatlog__attachment-filesize">
+                                            @attachment.FileSize
+                                        </div>
+                                    </div>
+                                }
+                            </div>
+                        </div>
+                    </div>
+                }
+
+                @foreach (var embed in message.Embeds)
+                {
+                    <div class="chatlog__embed">
+                        @if (embed.Color != null)
+                        {
+                            var embedColorStyle = $"background-color: rgba({embed.Color?.R},{embed.Color?.G},{embed.Color?.B},{embed.Color?.A})";
+                            <div class="chatlog__embed-color-pill" style="@embedColorStyle"></div>
+                        }
+                        else
+                        {
+                            <div class="chatlog__embed-color-pill chatlog__embed-color-pill--default"></div>
+                        }
+
+                        <div class="chatlog__embed-content-container">
+                            <div class="chatlog__embed-content">
+                                <div class="chatlog__embed-text">
+                                    @if (embed.Author != null)
+                                    {
+                                        <div class="chatlog__embed-author">
+                                            @if (!string.IsNullOrWhiteSpace(embed.Author.IconUrl))
+                                            {
+                                                <img class="chatlog__embed-author-icon" src="@await ResolveUrlAsync(embed.Author.IconUrl)" alt="Author icon">
+                                            }
+
+                                            @if (!string.IsNullOrWhiteSpace(embed.Author.Name))
+                                            {
+                                                <span class="chatlog__embed-author-name">
+                                                    @if (!string.IsNullOrWhiteSpace(embed.Author.Url))
+                                                    {
+                                                        <a class="chatlog__embed-author-name-link" href="@embed.Author.Url">@embed.Author.Name</a>
+                                                    }
+                                                    else
+                                                    {
+                                                        @embed.Author.Name
+                                                    }
+                                                </span>
+                                            }
+                                        </div>
+                                    }
+
+                                    @if (!string.IsNullOrWhiteSpace(embed.Title))
+                                    {
+                                        <div class="chatlog__embed-title">
+                                            @if (!string.IsNullOrWhiteSpace(embed.Url))
+                                            {
+                                                <a class="chatlog__embed-title-link" href="@embed.Url">
+                                                    <div class="markdown preserve-whitespace">@Raw(FormatEmbedMarkdown(embed.Title))</div>
+                                                </a>
+                                            }
+                                            else
+                                            {
+                                                <div class="markdown preserve-whitespace">@Raw(FormatEmbedMarkdown(embed.Title))</div>
+                                            }
+                                        </div>
+                                    }
+
+                                    @if (!string.IsNullOrWhiteSpace(embed.Description))
+                                    {
+                                        <div class="chatlog__embed-description">
+                                            <div class="markdown preserve-whitespace">@Raw(FormatEmbedMarkdown(embed.Description))</div>
+                                        </div>
+                                    }
+
+                                    @if (embed.Fields.Any())
+                                    {
+                                        <div class="chatlog__embed-fields">
+                                            @foreach (var field in embed.Fields)
+                                            {
+                                                var isInlineStyle = field.IsInline ? "chatlog__embed-field--inline" : null;
+
+                                                <div class="chatlog__embed-field @isInlineStyle">
+                                                    @if (!string.IsNullOrWhiteSpace(field.Name))
+                                                    {
+                                                        <div class="chatlog__embed-field-name">
+                                                            <div class="markdown preserve-whitespace">@Raw(FormatEmbedMarkdown(field.Name))</div>
+                                                        </div>
+                                                    }
+
+                                                    @if (!string.IsNullOrWhiteSpace(field.Value))
+                                                    {
+                                                        <div class="chatlog__embed-field-value">
+                                                            <div class="markdown preserve-whitespace">@Raw(FormatEmbedMarkdown(field.Value))</div>
+                                                        </div>
+                                                    }
+                                                </div>
+                                            }
+                                        </div>
+                                    }
+                                </div>
+
+                                @if (embed.Thumbnail != null)
+                                {
+                                    <div class="chatlog__embed-thumbnail-container">
+                                        <a class="chatlog__embed-thumbnail-link" href="@await ResolveUrlAsync(embed.Thumbnail.Url)">
+                                            <img class="chatlog__embed-thumbnail" src="@await ResolveUrlAsync(embed.Thumbnail.Url)" alt="Thumbnail">
+                                        </a>
+                                    </div>
+                                }
+                            </div>
+
+                            @if (embed.Image != null)
+                            {
+                                <div class="chatlog__embed-image-container">
+                                    <a class="chatlog__embed-image-link" href="@await ResolveUrlAsync(embed.Image.Url)">
+                                        <img class="chatlog__embed-image" src="@await ResolveUrlAsync(embed.Image.Url)" alt="Image">
+                                    </a>
+                                </div>
+                            }
+
+                            @if (embed.Footer != null || embed.Timestamp != null)
+                            {
+                                <div class="chatlog__embed-footer">
+                                    @if (!string.IsNullOrWhiteSpace(embed.Footer?.IconUrl))
+                                    {
+                                        <img class="chatlog__embed-footer-icon" src="@await ResolveUrlAsync(embed.Footer.IconUrl)" alt="Footer icon">
+                                    }
+
+                                    <span class="chatlog__embed-footer-text">
+                                        @if (!string.IsNullOrWhiteSpace(embed.Footer?.Text))
+                                        {
+                                            @embed.Footer.Text
+                                        }
+
+                                        @if (!string.IsNullOrWhiteSpace(embed.Footer?.Text) && embed.Timestamp != null)
+                                        {
+                                            @(" • ")
+                                        }
+
+                                        @if (embed.Timestamp != null)
+                                        {
+                                            @FormatDate(embed.Timestamp.Value)
+                                        }
+                                    </span>
+                                </div>
+                            }
+                        </div>
+                    </div>
+                }
+
+                @if (message.Reactions.Any())
+                {
+                    <div class="chatlog__reactions">
+                        @foreach (var reaction in message.Reactions)
+                        {
+                            <div class="chatlog__reaction">
+                                <img class="emoji emoji--small" alt="@reaction.Emoji.Name" title="@reaction.Emoji.Name" src="@await ResolveUrlAsync(reaction.Emoji.ImageUrl)">
+                                <span class="chatlog__reaction-count">@reaction.Count</span>
+                            </div>
+                        }
+                    </div>
+                }
+            </div>
+        }
+    </div>
+</div>

DiscordChatExporter.Domain/Exporting/Writers/Html/MessageGroupTemplateContext.cs

@@ -0,0 +1,20 @@
+using DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+{
+    internal class MessageGroupTemplateContext
+    {
+        public ExportContext ExportContext { get; }
+
+        public MessageGroup MessageGroup { get; }
+
+        public MessageGroupTemplateContext(ExportContext exportContext, MessageGroup messageGroup)
+        {
+            ExportContext = exportContext;
+            MessageGroup = messageGroup;
+        }
+
+        public string FormatMarkdown(string? markdown, bool isJumboAllowed = true) =>
+            HtmlMarkdownVisitor.Format(ExportContext, markdown ?? "", isJumboAllowed);
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/Html/PostambleTemplate.cshtml

@@ -0,0 +1,12 @@
+@namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+@inherits MiniRazor.TemplateBase<DiscordChatExporter.Domain.Exporting.Writers.Html.LayoutTemplateContext>
+
+</div>
+
+<div class="postamble">
+    <div class="postamble__entry">Exported @Model.MessageCount.ToString("N0") message(s)</div>
+</div>
+
+</body>
+
+</html>

DiscordChatExporter.Domain/Exporting/Writers/Html/PreambleTemplate.cshtml

@@ -0,0 +1,101 @@
+@using System
+@using System.Threading.Tasks
+@using Tyrrrz.Extensions
+@namespace DiscordChatExporter.Domain.Exporting.Writers.Html
+@inherits MiniRazor.TemplateBase<DiscordChatExporter.Domain.Exporting.Writers.Html.LayoutTemplateContext>
+
+@{
+    string FormatDate(DateTimeOffset date) => Model.ExportContext.FormatDate(date);
+
+    ValueTask<string> ResolveUrlAsync(string url) => Model.ExportContext.ResolveMediaUrlAsync(url);
+
+    string GetStyleSheet(string name) => Model.GetType().Assembly.GetManifestResourceString($"DiscordChatExporter.Domain.Exporting.Writers.Html.{name}.css");
+}
+
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <title>@Model.ExportContext.Request.Guild.Name - @Model.ExportContext.Request.Channel.Name</title>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width">
+
+    <style>
+        @Raw(GetStyleSheet("Core"))
+    </style>
+    <style>
+        @Raw(GetStyleSheet(Model.ThemeName))
+    </style>
+
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/styles/solarized-@(Model.ThemeName.ToLowerInvariant()).min.css">
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/highlight.min.js"></script>
+    <script>
+        document.addEventListener('DOMContentLoaded', () => {
+            document.querySelectorAll('.pre--multiline').forEach(block => hljs.highlightBlock(block));
+        });
+    </script>
+
+    <script>
+        function scrollToMessage(event, id) {
+            var element = document.getElementById('message-' + id);
+
+            if (element) {
+                event.preventDefault();
+
+                element.classList.add('chatlog__message--highlighted');
+
+                window.scrollTo({
+                    top: element.getBoundingClientRect().top - document.body.getBoundingClientRect().top - (window.innerHeight / 2),
+                    behavior: 'smooth'
+                });
+
+                window.setTimeout(function() {
+                    element.classList.remove('chatlog__message--highlighted');
+                }, 2000);
+            }
+        }
+
+        function showSpoiler(event, element) {
+            if (element && element.classList.contains('spoiler--hidden')) {
+                event.preventDefault();
+                element.classList.remove('spoiler--hidden');
+            }
+        }
+    </script>
+</head>
+<body>
+
+<div class="preamble">
+    <div class="preamble__guild-icon-container">
+        <img class="preamble__guild-icon" src="@await ResolveUrlAsync(Model.ExportContext.Request.Guild.IconUrl)" alt="Guild icon">
+    </div>
+    <div class="preamble__entries-container">
+        <div class="preamble__entry">@Model.ExportContext.Request.Guild.Name</div>
+        <div class="preamble__entry">@Model.ExportContext.Request.Channel.Category / @Model.ExportContext.Request.Channel.Name</div>
+
+        @if (!string.IsNullOrWhiteSpace(Model.ExportContext.Request.Channel.Topic))
+        {
+            <div class="preamble__entry preamble__entry--small">@Model.ExportContext.Request.Channel.Topic</div>
+        }
+
+        @if (Model.ExportContext.Request.After != null || Model.ExportContext.Request.Before != null)
+        {
+            <div class="preamble__entry preamble__entry--small">
+            @if (Model.ExportContext.Request.After != null && Model.ExportContext.Request.Before != null)
+            {
+                @($"Between {FormatDate(Model.ExportContext.Request.After.Value.ToDate())} and {FormatDate(Model.ExportContext.Request.Before.Value.ToDate())}")
+            }
+            else if (Model.ExportContext.Request.After != null)
+            {
+                @($"After {FormatDate(Model.ExportContext.Request.After.Value.ToDate())}")
+            }
+            else if (Model.ExportContext.Request.Before != null)
+            {
+                @($"Before {FormatDate(Model.ExportContext.Request.Before.Value.ToDate())}")
+            }
+            </div>
+        }
+    </div>
+</div>
+
+<div class="chatlog">

DiscordChatExporter.Domain/Exporting/Writers/HtmlMessageWriter.cs

@@ -0,0 +1,83 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting.Writers.Html;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers
+{
+    internal class HtmlMessageWriter : MessageWriter
+    {
+        private readonly TextWriter _writer;
+        private readonly string _themeName;
+
+        private readonly List<Message> _messageGroupBuffer = new();
+
+        private long _messageCount;
+
+        public HtmlMessageWriter(Stream stream, ExportContext context, string themeName)
+            : base(stream, context)
+        {
+            _writer = new StreamWriter(stream);
+            _themeName = themeName;
+        }
+
+        public override async ValueTask WritePreambleAsync()
+        {
+            var templateContext = new LayoutTemplateContext(Context, _themeName, _messageCount);
+
+            await _writer.WriteLineAsync(
+                await PreambleTemplate.RenderAsync(templateContext)
+            );
+        }
+
+        private async ValueTask WriteMessageGroupAsync(MessageGroup messageGroup)
+        {
+            var templateContext = new MessageGroupTemplateContext(Context, messageGroup);
+
+            await _writer.WriteLineAsync(
+                await MessageGroupTemplate.RenderAsync(templateContext)
+            );
+        }
+
+        public override async ValueTask WriteMessageAsync(Message message)
+        {
+            // If message group is empty or the given message can be grouped, buffer the given message
+            if (!_messageGroupBuffer.Any() || MessageGroup.CanJoin(_messageGroupBuffer.Last(), message))
+            {
+                _messageGroupBuffer.Add(message);
+            }
+            // Otherwise, flush the group and render messages
+            else
+            {
+                await WriteMessageGroupAsync(MessageGroup.Join(_messageGroupBuffer));
+
+                _messageGroupBuffer.Clear();
+                _messageGroupBuffer.Add(message);
+            }
+
+            // Increment message count
+            _messageCount++;
+        }
+
+        public override async ValueTask WritePostambleAsync()
+        {
+            // Flush current message group
+            if (_messageGroupBuffer.Any())
+                await WriteMessageGroupAsync(MessageGroup.Join(_messageGroupBuffer));
+
+            var templateContext = new LayoutTemplateContext(Context, _themeName, _messageCount);
+
+            await _writer.WriteLineAsync(
+                await PostambleTemplate.RenderAsync(templateContext)
+            );
+        }
+
+        public override async ValueTask DisposeAsync()
+        {
+            await _writer.DisposeAsync();
+            await base.DisposeAsync();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/JsonMessageWriter.cs

@@ -0,0 +1,301 @@
+using System.IO;
+using System.Text.Json;
+using System.Threading.Tasks;
+using System.Text.Encodings.Web;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors;
+using DiscordChatExporter.Domain.Internal.Extensions;
+using JsonExtensions.Writing;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers
+{
+    internal class JsonMessageWriter : MessageWriter
+    {
+        private readonly Utf8JsonWriter _writer;
+
+        private long _messageCount;
+
+        public JsonMessageWriter(Stream stream, ExportContext context)
+            : base(stream, context)
+        {
+            _writer = new Utf8JsonWriter(stream, new JsonWriterOptions
+            {
+                Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
+                Indented = true
+            });
+        }
+
+        private string FormatMarkdown(string? markdown) =>
+            PlainTextMarkdownVisitor.Format(Context, markdown ?? "");
+
+        private async ValueTask WriteAttachmentAsync(Attachment attachment)
+        {
+            _writer.WriteStartObject();
+
+            _writer.WriteString("id", attachment.Id.ToString());
+            _writer.WriteString("url", await Context.ResolveMediaUrlAsync(attachment.Url));
+            _writer.WriteString("fileName", attachment.FileName);
+            _writer.WriteNumber("fileSizeBytes", attachment.FileSize.TotalBytes);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedAuthorAsync(EmbedAuthor embedAuthor)
+        {
+            _writer.WriteStartObject("author");
+
+            _writer.WriteString("name", embedAuthor.Name);
+            _writer.WriteString("url", embedAuthor.Url);
+
+            if (!string.IsNullOrWhiteSpace(embedAuthor.IconUrl))
+                _writer.WriteString("iconUrl", await Context.ResolveMediaUrlAsync(embedAuthor.IconUrl));
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedThumbnailAsync(EmbedImage embedThumbnail)
+        {
+            _writer.WriteStartObject("thumbnail");
+
+            if (!string.IsNullOrWhiteSpace(embedThumbnail.Url))
+                _writer.WriteString("url", await Context.ResolveMediaUrlAsync(embedThumbnail.Url));
+
+            _writer.WriteNumber("width", embedThumbnail.Width);
+            _writer.WriteNumber("height", embedThumbnail.Height);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedImageAsync(EmbedImage embedImage)
+        {
+            _writer.WriteStartObject("image");
+
+            if (!string.IsNullOrWhiteSpace(embedImage.Url))
+                _writer.WriteString("url", await Context.ResolveMediaUrlAsync(embedImage.Url));
+
+            _writer.WriteNumber("width", embedImage.Width);
+            _writer.WriteNumber("height", embedImage.Height);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedFooterAsync(EmbedFooter embedFooter)
+        {
+            _writer.WriteStartObject("footer");
+
+            _writer.WriteString("text", embedFooter.Text);
+
+            if (!string.IsNullOrWhiteSpace(embedFooter.IconUrl))
+                _writer.WriteString("iconUrl", await Context.ResolveMediaUrlAsync(embedFooter.IconUrl));
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedFieldAsync(EmbedField embedField)
+        {
+            _writer.WriteStartObject();
+
+            _writer.WriteString("name", FormatMarkdown(embedField.Name));
+            _writer.WriteString("value", FormatMarkdown(embedField.Value));
+            _writer.WriteBoolean("isInline", embedField.IsInline);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteEmbedAsync(Embed embed)
+        {
+            _writer.WriteStartObject();
+
+            _writer.WriteString("title", FormatMarkdown(embed.Title));
+            _writer.WriteString("url", embed.Url);
+            _writer.WriteString("timestamp", embed.Timestamp);
+            _writer.WriteString("description", FormatMarkdown(embed.Description));
+
+            if (embed.Color != null)
+                _writer.WriteString("color", embed.Color.Value.ToHex());
+
+            if (embed.Author != null)
+                await WriteEmbedAuthorAsync(embed.Author);
+
+            if (embed.Thumbnail != null)
+                await WriteEmbedThumbnailAsync(embed.Thumbnail);
+
+            if (embed.Image != null)
+                await WriteEmbedImageAsync(embed.Image);
+
+            if (embed.Footer != null)
+                await WriteEmbedFooterAsync(embed.Footer);
+
+            // Fields
+            _writer.WriteStartArray("fields");
+
+            foreach (var field in embed.Fields)
+                await WriteEmbedFieldAsync(field);
+
+            _writer.WriteEndArray();
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteReactionAsync(Reaction reaction)
+        {
+            _writer.WriteStartObject();
+
+            // Emoji
+            _writer.WriteStartObject("emoji");
+            _writer.WriteString("id", reaction.Emoji.Id);
+            _writer.WriteString("name", reaction.Emoji.Name);
+            _writer.WriteBoolean("isAnimated", reaction.Emoji.IsAnimated);
+            _writer.WriteString("imageUrl", await Context.ResolveMediaUrlAsync(reaction.Emoji.ImageUrl));
+            _writer.WriteEndObject();
+
+            _writer.WriteNumber("count", reaction.Count);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        private async ValueTask WriteMentionAsync(User mentionedUser)
+        {
+            _writer.WriteStartObject();
+
+            _writer.WriteString("id", mentionedUser.Id.ToString());
+            _writer.WriteString("name", mentionedUser.Name);
+            _writer.WriteNumber("discriminator", mentionedUser.Discriminator);
+            _writer.WriteString("nickname", Context.TryGetMember(mentionedUser.Id)?.Nick ?? mentionedUser.Name);
+            _writer.WriteBoolean("isBot", mentionedUser.IsBot);
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        public override async ValueTask WritePreambleAsync()
+        {
+            // Root object (start)
+            _writer.WriteStartObject();
+
+            // Guild
+            _writer.WriteStartObject("guild");
+            _writer.WriteString("id", Context.Request.Guild.Id.ToString());
+            _writer.WriteString("name", Context.Request.Guild.Name);
+            _writer.WriteString("iconUrl", await Context.ResolveMediaUrlAsync(Context.Request.Guild.IconUrl));
+            _writer.WriteEndObject();
+
+            // Channel
+            _writer.WriteStartObject("channel");
+            _writer.WriteString("id", Context.Request.Channel.Id.ToString());
+            _writer.WriteString("type", Context.Request.Channel.Type.ToString());
+            _writer.WriteString("category", Context.Request.Channel.Category);
+            _writer.WriteString("name", Context.Request.Channel.Name);
+            _writer.WriteString("topic", Context.Request.Channel.Topic);
+            _writer.WriteEndObject();
+
+            // Date range
+            _writer.WriteStartObject("dateRange");
+            _writer.WriteString("after", Context.Request.After?.ToDate());
+            _writer.WriteString("before", Context.Request.Before?.ToDate());
+            _writer.WriteEndObject();
+
+            // Message array (start)
+            _writer.WriteStartArray("messages");
+            await _writer.FlushAsync();
+        }
+
+        public override async ValueTask WriteMessageAsync(Message message)
+        {
+            _writer.WriteStartObject();
+
+            // Metadata
+            _writer.WriteString("id", message.Id.ToString());
+            _writer.WriteString("type", message.Type.ToString());
+            _writer.WriteString("timestamp", message.Timestamp);
+            _writer.WriteString("timestampEdited", message.EditedTimestamp);
+            _writer.WriteString("callEndedTimestamp", message.CallEndedTimestamp);
+            _writer.WriteBoolean("isPinned", message.IsPinned);
+
+            // Content
+            _writer.WriteString("content", FormatMarkdown(message.Content));
+
+            // Author
+            _writer.WriteStartObject("author");
+            _writer.WriteString("id", message.Author.Id.ToString());
+            _writer.WriteString("name", message.Author.Name);
+            _writer.WriteString("discriminator", $"{message.Author.Discriminator:0000}");
+            _writer.WriteBoolean("isBot", message.Author.IsBot);
+            _writer.WriteString("avatarUrl", await Context.ResolveMediaUrlAsync(message.Author.AvatarUrl));
+            _writer.WriteEndObject();
+
+            // Attachments
+            _writer.WriteStartArray("attachments");
+
+            foreach (var attachment in message.Attachments)
+                await WriteAttachmentAsync(attachment);
+
+            _writer.WriteEndArray();
+
+            // Embeds
+            _writer.WriteStartArray("embeds");
+
+            foreach (var embed in message.Embeds)
+                await WriteEmbedAsync(embed);
+
+            _writer.WriteEndArray();
+
+            // Reactions
+            _writer.WriteStartArray("reactions");
+
+            foreach (var reaction in message.Reactions)
+                await WriteReactionAsync(reaction);
+
+            _writer.WriteEndArray();
+
+            // Mentions
+            _writer.WriteStartArray("mentions");
+
+            foreach (var mention in message.MentionedUsers)
+                await WriteMentionAsync(mention);
+
+            _writer.WriteEndArray();
+
+            // Message reference
+            if (message.Reference != null)
+            {
+                _writer.WriteStartObject("reference");
+                _writer.WriteString("messageId", message.Reference.MessageId?.ToString());
+                _writer.WriteString("channelId", message.Reference.ChannelId?.ToString());
+                _writer.WriteString("guildId", message.Reference.GuildId?.ToString());
+                _writer.WriteEndObject();
+            }
+
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+
+            _messageCount++;
+        }
+
+        public override async ValueTask WritePostambleAsync()
+        {
+            // Message array (end)
+            _writer.WriteEndArray();
+
+            _writer.WriteNumber("messageCount", _messageCount);
+
+            // Root object (end)
+            _writer.WriteEndObject();
+            await _writer.FlushAsync();
+        }
+
+        public override async ValueTask DisposeAsync()
+        {
+            await _writer.DisposeAsync();
+            await base.DisposeAsync();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/MarkdownVisitors/HtmlMarkdownVisitor.cs

@@ -0,0 +1,180 @@
+using System;
+using System.Linq;
+using System.Net;
+using System.Text;
+using System.Text.RegularExpressions;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Markdown;
+using DiscordChatExporter.Domain.Markdown.Ast;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors
+{
+    internal partial class HtmlMarkdownVisitor : MarkdownVisitor
+    {
+        private readonly ExportContext _context;
+        private readonly StringBuilder _buffer;
+        private readonly bool _isJumbo;
+
+        public HtmlMarkdownVisitor(ExportContext context, StringBuilder buffer, bool isJumbo)
+        {
+            _context = context;
+            _buffer = buffer;
+            _isJumbo = isJumbo;
+        }
+
+        protected override MarkdownNode VisitText(TextNode text)
+        {
+            _buffer.Append(HtmlEncode(text.Text));
+            return base.VisitText(text);
+        }
+
+        protected override MarkdownNode VisitFormatted(FormattedNode formatted)
+        {
+            var (tagOpen, tagClose) = formatted.Formatting switch
+            {
+                TextFormatting.Bold => ("<strong>", "</strong>"),
+                TextFormatting.Italic => ("<em>", "</em>"),
+                TextFormatting.Underline => ("<u>", "</u>"),
+                TextFormatting.Strikethrough => ("<s>", "</s>"),
+                TextFormatting.Spoiler => (
+                    "<span class=\"spoiler spoiler--hidden\" onclick=\"showSpoiler(event, this)\"><span class=\"spoiler-text\">", "</span></span>"),
+                TextFormatting.Quote => ("<div class=\"quote\">", "</div>"),
+                _ => throw new ArgumentOutOfRangeException(nameof(formatted.Formatting))
+            };
+
+            _buffer.Append(tagOpen);
+            var result = base.VisitFormatted(formatted);
+            _buffer.Append(tagClose);
+
+            return result;
+        }
+
+        protected override MarkdownNode VisitInlineCodeBlock(InlineCodeBlockNode inlineCodeBlock)
+        {
+            _buffer
+                .Append("<span class=\"pre pre--inline\">")
+                .Append(HtmlEncode(inlineCodeBlock.Code))
+                .Append("</span>");
+
+            return base.VisitInlineCodeBlock(inlineCodeBlock);
+        }
+
+        protected override MarkdownNode VisitMultiLineCodeBlock(MultiLineCodeBlockNode multiLineCodeBlock)
+        {
+            var highlightCssClass = !string.IsNullOrWhiteSpace(multiLineCodeBlock.Language)
+                ? $"language-{multiLineCodeBlock.Language}"
+                : "nohighlight";
+
+            _buffer
+                .Append($"<div class=\"pre pre--multiline {highlightCssClass}\">")
+                .Append(HtmlEncode(multiLineCodeBlock.Code))
+                .Append("</div>");
+
+            return base.VisitMultiLineCodeBlock(multiLineCodeBlock);
+        }
+
+        protected override MarkdownNode VisitMention(MentionNode mention)
+        {
+            if (mention.Type == MentionType.Meta)
+            {
+                _buffer
+                    .Append("<span class=\"mention\">")
+                    .Append("@").Append(HtmlEncode(mention.Id))
+                    .Append("</span>");
+            }
+            else if (mention.Type == MentionType.User)
+            {
+                var member = _context.TryGetMember(Snowflake.Parse(mention.Id));
+                var fullName = member?.User.FullName ?? "Unknown";
+                var nick = member?.Nick ?? "Unknown";
+
+                _buffer
+                    .Append($"<span class=\"mention\" title=\"{HtmlEncode(fullName)}\">")
+                    .Append("@").Append(HtmlEncode(nick))
+                    .Append("</span>");
+            }
+            else if (mention.Type == MentionType.Channel)
+            {
+                var channel = _context.TryGetChannel(Snowflake.Parse(mention.Id));
+                var name = channel?.Name ?? "deleted-channel";
+
+                _buffer
+                    .Append("<span class=\"mention\">")
+                    .Append("#").Append(HtmlEncode(name))
+                    .Append("</span>");
+            }
+            else if (mention.Type == MentionType.Role)
+            {
+                var role = _context.TryGetRole(Snowflake.Parse(mention.Id));
+                var name = role?.Name ?? "deleted-role";
+                var color = role?.Color;
+
+                var style = color != null
+                    ? $"color: rgb({color?.R}, {color?.G}, {color?.B}); background-color: rgba({color?.R}, {color?.G}, {color?.B}, 0.1);"
+                    : "";
+
+                _buffer
+                    .Append($"<span class=\"mention\" style=\"{style}\">")
+                    .Append("@").Append(HtmlEncode(name))
+                    .Append("</span>");
+            }
+
+            return base.VisitMention(mention);
+        }
+
+        protected override MarkdownNode VisitEmoji(EmojiNode emoji)
+        {
+            var emojiImageUrl = Emoji.GetImageUrl(emoji.Id, emoji.Name, emoji.IsAnimated);
+            var jumboClass = _isJumbo ? "emoji--large" : "";
+
+            _buffer
+                .Append($"<img class=\"emoji {jumboClass}\" alt=\"{emoji.Name}\" title=\"{emoji.Name}\" src=\"{emojiImageUrl}\">");
+
+            return base.VisitEmoji(emoji);
+        }
+
+        protected override MarkdownNode VisitLink(LinkNode link)
+        {
+            // Extract message ID if the link points to a Discord message
+            var linkedMessageId = Regex.Match(link.Url, "^https?://(?:discord|discordapp).com/channels/.*?/(\\d+)/?$").Groups[1].Value;
+
+            if (!string.IsNullOrWhiteSpace(linkedMessageId))
+            {
+                _buffer
+                    .Append($"<a href=\"{Uri.EscapeUriString(link.Url)}\" onclick=\"scrollToMessage(event, '{linkedMessageId}')\">")
+                    .Append(HtmlEncode(link.Title))
+                    .Append("</a>");
+            }
+            else
+            {
+                _buffer
+                    .Append($"<a href=\"{Uri.EscapeUriString(link.Url)}\">")
+                    .Append(HtmlEncode(link.Title))
+                    .Append("</a>");
+            }
+
+            return base.VisitLink(link);
+        }
+    }
+
+    internal partial class HtmlMarkdownVisitor
+    {
+        private static string HtmlEncode(string text) => WebUtility.HtmlEncode(text);
+
+        public static string Format(ExportContext context, string markdown, bool isJumboAllowed = true)
+        {
+            var nodes = MarkdownParser.Parse(markdown);
+
+            var isJumbo =
+                isJumboAllowed &&
+                nodes.All(n => n is EmojiNode || n is TextNode textNode && string.IsNullOrWhiteSpace(textNode.Text));
+
+            var buffer = new StringBuilder();
+
+            new HtmlMarkdownVisitor(context, buffer, isJumbo).Visit(nodes);
+
+            return buffer.ToString();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/MarkdownVisitors/PlainTextMarkdownVisitor.cs

@@ -0,0 +1,80 @@
+using System.Text;
+using DiscordChatExporter.Domain.Discord;
+using DiscordChatExporter.Domain.Markdown;
+using DiscordChatExporter.Domain.Markdown.Ast;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors
+{
+    internal partial class PlainTextMarkdownVisitor : MarkdownVisitor
+    {
+        private readonly ExportContext _context;
+        private readonly StringBuilder _buffer;
+
+        public PlainTextMarkdownVisitor(ExportContext context, StringBuilder buffer)
+        {
+            _context = context;
+            _buffer = buffer;
+        }
+
+        protected override MarkdownNode VisitText(TextNode text)
+        {
+            _buffer.Append(text.Text);
+            return base.VisitText(text);
+        }
+
+        protected override MarkdownNode VisitMention(MentionNode mention)
+        {
+            if (mention.Type == MentionType.Meta)
+            {
+                _buffer.Append($"@{mention.Id}");
+            }
+            else if (mention.Type == MentionType.User)
+            {
+                var member = _context.TryGetMember(Snowflake.Parse(mention.Id));
+                var name = member?.User.Name ?? "Unknown";
+
+                _buffer.Append($"@{name}");
+            }
+            else if (mention.Type == MentionType.Channel)
+            {
+                var channel = _context.TryGetChannel(Snowflake.Parse(mention.Id));
+                var name = channel?.Name ?? "deleted-channel";
+
+                _buffer.Append($"#{name}");
+            }
+            else if (mention.Type == MentionType.Role)
+            {
+                var role = _context.TryGetRole(Snowflake.Parse(mention.Id));
+                var name = role?.Name ?? "deleted-role";
+
+                _buffer.Append($"@{name}");
+            }
+
+            return base.VisitMention(mention);
+        }
+
+        protected override MarkdownNode VisitEmoji(EmojiNode emoji)
+        {
+            _buffer.Append(
+                emoji.IsCustomEmoji
+                    ? $":{emoji.Name}:"
+                    : emoji.Name
+            );
+
+            return base.VisitEmoji(emoji);
+        }
+    }
+
+    internal partial class PlainTextMarkdownVisitor
+    {
+        public static string Format(ExportContext context, string markdown)
+        {
+            var nodes = MarkdownParser.ParseMinimal(markdown);
+            var buffer = new StringBuilder();
+
+            new PlainTextMarkdownVisitor(context, buffer).Visit(nodes);
+
+            return buffer.ToString();
+        }
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/MessageWriter.cs

@@ -0,0 +1,28 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers
+{
+    internal abstract class MessageWriter : IAsyncDisposable
+    {
+        protected Stream Stream { get; }
+
+        protected ExportContext Context { get; }
+
+        protected MessageWriter(Stream stream, ExportContext context)
+        {
+            Stream = stream;
+            Context = context;
+        }
+
+        public virtual ValueTask WritePreambleAsync() => default;
+
+        public abstract ValueTask WriteMessageAsync(Message message);
+
+        public virtual ValueTask WritePostambleAsync() => default;
+
+        public virtual async ValueTask DisposeAsync() => await Stream.DisposeAsync();
+    }
+}

DiscordChatExporter.Domain/Exporting/Writers/PlainTextMessageWriter.cs

@@ -0,0 +1,162 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Domain.Discord.Models;
+using DiscordChatExporter.Domain.Exporting.Writers.MarkdownVisitors;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Domain.Exporting.Writers
+{
+    internal class PlainTextMessageWriter : MessageWriter
+    {
+        private readonly TextWriter _writer;
+
+        private long _messageCount;
+
+        public PlainTextMessageWriter(Stream stream, ExportContext context)
+            : base(stream, context)
+        {
+            _writer = new StreamWriter(stream);
+        }
+
+        private string FormatMarkdown(string? markdown) =>
+            PlainTextMarkdownVisitor.Format(Context, markdown ?? "");
+
+        private async ValueTask WriteMessageHeaderAsync(Message message)
+        {
+            // Timestamp & author
+            await _writer.WriteAsync($"[{Context.FormatDate(message.Timestamp)}]");
+            await _writer.WriteAsync($" {message.Author.FullName}");
+
+            // Whether the message is pinned
+            if (message.IsPinned)
+                await _writer.WriteAsync(" (pinned)");
+
+            await _writer.WriteLineAsync();
+        }
+
+        private async ValueTask WriteAttachmentsAsync(IReadOnlyList<Attachment> attachments)
+        {
+            if (!attachments.Any())
+                return;
+
+            await _writer.WriteLineAsync("{Attachments}");
+
+            foreach (var attachment in attachments)
+                await _writer.WriteLineAsync(await Context.ResolveMediaUrlAsync(attachment.Url));
+
+            await _writer.WriteLineAsync();
+        }
+
+        private async ValueTask WriteEmbedsAsync(IReadOnlyList<Embed> embeds)
+        {
+            foreach (var embed in embeds)
+            {
+                await _writer.WriteLineAsync("{Embed}");
+
+                if (!string.IsNullOrWhiteSpace(embed.Author?.Name))
+                    await _writer.WriteLineAsync(embed.Author.Name);
+
+                if (!string.IsNullOrWhiteSpace(embed.Url))
+                    await _writer.WriteLineAsync(embed.Url);
+
+                if (!string.IsNullOrWhiteSpace(embed.Title))
+                    await _writer.WriteLineAsync(FormatMarkdown(embed.Title));
+
+                if (!string.IsNullOrWhiteSpace(embed.Description))
+                    await _writer.WriteLineAsync(FormatMarkdown(embed.Description));
+
+                foreach (var field in embed.Fields)
+                {
+                    if (!string.IsNullOrWhiteSpace(field.Name))
+                        await _writer.WriteLineAsync(FormatMarkdown(field.Name));
+
+                    if (!string.IsNullOrWhiteSpace(field.Value))
+                        await _writer.WriteLineAsync(FormatMarkdown(field.Value));
+                }
+
+                if (!string.IsNullOrWhiteSpace(embed.Thumbnail?.Url))
+                    await _writer.WriteLineAsync(await Context.ResolveMediaUrlAsync(embed.Thumbnail.Url));
+
+                if (!string.IsNullOrWhiteSpace(embed.Image?.Url))
+                    await _writer.WriteLineAsync(await Context.ResolveMediaUrlAsync(embed.Image.Url));
+
+                if (!string.IsNullOrWhiteSpace(embed.Footer?.Text))
+                    await _writer.WriteLineAsync(embed.Footer.Text);
+
+                await _writer.WriteLineAsync();
+            }
+        }
+
+        private async ValueTask WriteReactionsAsync(IReadOnlyList<Reaction> reactions)
+        {
+            if (!reactions.Any())
+                return;
+
+            await _writer.WriteLineAsync("{Reactions}");
+
+            foreach (var reaction in reactions)
+            {
+                await _writer.WriteAsync(reaction.Emoji.Name);
+
+                if (reaction.Count > 1)
+                    await _writer.WriteAsync($" ({reaction.Count})");
+
+                await _writer.WriteAsync(' ');
+            }
+
+            await _writer.WriteLineAsync();
+        }
+
+        public override async ValueTask WritePreambleAsync()
+        {
+            await _writer.WriteLineAsync('='.Repeat(62));
+            await _writer.WriteLineAsync($"Guild: {Context.Request.Guild.Name}");
+            await _writer.WriteLineAsync($"Channel: {Context.Request.Channel.Category} / {Context.Request.Channel.Name}");
+
+            if (!string.IsNullOrWhiteSpace(Context.Request.Channel.Topic))
+                await _writer.WriteLineAsync($"Topic: {Context.Request.Channel.Topic}");
+
+            if (Context.Request.After != null)
+                await _writer.WriteLineAsync($"After: {Context.FormatDate(Context.Request.After.Value.ToDate())}");
+
+            if (Context.Request.Before != null)
+                await _writer.WriteLineAsync($"Before: {Context.FormatDate(Context.Request.Before.Value.ToDate())}");
+
+            await _writer.WriteLineAsync('='.Repeat(62));
+            await _writer.WriteLineAsync();
+        }
+
+        public override async ValueTask WriteMessageAsync(Message message)
+        {
+            await WriteMessageHeaderAsync(message);
+
+            if (!string.IsNullOrWhiteSpace(message.Content))
+                await _writer.WriteLineAsync(FormatMarkdown(message.Content));
+
+            await _writer.WriteLineAsync();
+
+            await WriteAttachmentsAsync(message.Attachments);
+            await WriteEmbedsAsync(message.Embeds);
+            await WriteReactionsAsync(message.Reactions);
+
+            await _writer.WriteLineAsync();
+
+            _messageCount++;
+        }
+
+        public override async ValueTask WritePostambleAsync()
+        {
+            await _writer.WriteLineAsync('='.Repeat(62));
+            await _writer.WriteLineAsync($"Exported {_messageCount:N0} message(s)");
+            await _writer.WriteLineAsync('='.Repeat(62));
+        }
+
+        public override async ValueTask DisposeAsync()
+        {
+            await _writer.DisposeAsync();
+            await base.DisposeAsync();
+        }
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/BinaryExtensions.cs

@@ -0,0 +1,19 @@
+using System.Text;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class BinaryExtensions
+    {
+        public static string ToHex(this byte[] data)
+        {
+            var buffer = new StringBuilder();
+
+            foreach (var t in data)
+            {
+                buffer.Append(t.ToString("X2"));
+            }
+
+            return buffer.ToString();
+        }
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/ColorExtensions.cs

@@ -0,0 +1,15 @@
+using System.Drawing;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class ColorExtensions
+    {
+        public static Color WithAlpha(this Color color, int alpha) => Color.FromArgb(alpha, color);
+
+        public static Color ResetAlpha(this Color color) => color.WithAlpha(255);
+
+        public static int ToRgb(this Color color) => color.ToArgb() & 0xffffff;
+
+        public static string ToHex(this Color color) => $"#{color.R:X2}{color.G:X2}{color.B:X2}";
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/DateExtensions.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Globalization;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class DateExtensions
+    {
+        public static string ToLocalString(this DateTimeOffset dateTime, string format) =>
+            dateTime.ToLocalTime().ToString(format, CultureInfo.InvariantCulture);
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/GenericExtensions.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class GenericExtensions
+    {
+        public static T? NullIf<T>(this T value, Func<T, bool> predicate) where T : struct =>
+            !predicate(value)
+                ? value
+                : (T?) null;
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/HttpExtensions.cs

@@ -0,0 +1,12 @@
+using System.Net.Http.Headers;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class HttpExtensions
+    {
+        public static string? TryGetValue(this HttpContentHeaders headers, string name) =>
+            headers.TryGetValues(name, out var values)
+                ? string.Concat(values)
+                : null;
+    }
+}

DiscordChatExporter.Domain/Internal/Extensions/StringExtensions.cs

@@ -0,0 +1,17 @@
+using System.Text;
+
+namespace DiscordChatExporter.Domain.Internal.Extensions
+{
+    internal static class StringExtensions
+    {
+        public static string Truncate(this string str, int charCount) =>
+            str.Length > charCount
+                ? str.Substring(0, charCount)
+                : str;
+
+        public static StringBuilder AppendIfNotEmpty(this StringBuilder builder, char value) =>
+            builder.Length > 0
+                ? builder.Append(value)
+                : builder;
+    }
+}

DiscordChatExporter.Domain/Internal/Http.cs

@@ -0,0 +1,61 @@
+using System;
+using System.Globalization;
+using System.IO;
+using System.Net;
+using System.Net.Http;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Polly;
+
+namespace DiscordChatExporter.Domain.Internal
+{
+    internal static class Http
+    {
+        public static HttpClient Client { get; } = new();
+
+        public static IAsyncPolicy<HttpResponseMessage> ResponsePolicy { get; } =
+            Policy
+                .Handle<IOException>()
+                .Or<HttpRequestException>()
+                .OrResult<HttpResponseMessage>(m => m.StatusCode == HttpStatusCode.TooManyRequests)
+                .OrResult(m => m.StatusCode == HttpStatusCode.RequestTimeout)
+                .OrResult(m => m.StatusCode >= HttpStatusCode.InternalServerError)
+                .WaitAndRetryAsync(8,
+                    (i, result, _) =>
+                    {
+                        // If rate-limited, use retry-after as a guide
+                        if (result.Result?.StatusCode == HttpStatusCode.TooManyRequests)
+                        {
+                            // Only start respecting retry-after after a few attempts.
+                            // The reason is that Discord often sends unreasonable (20+ minutes) retry-after
+                            // on the very first request.
+                            if (i > 3)
+                            {
+                                var retryAfterDelay = result.Result.Headers.RetryAfter.Delta;
+                                if (retryAfterDelay != null)
+                                    return retryAfterDelay.Value + TimeSpan.FromSeconds(1); // margin just in case
+                            }
+                        }
+
+                        return TimeSpan.FromSeconds(Math.Pow(2, i) + 1);
+                    },
+                    (_, _, _, _) => Task.CompletedTask);
+
+        private static HttpStatusCode? TryGetStatusCodeFromException(HttpRequestException ex)
+        {
+            // This is extremely frail, but there's no other way
+            var statusCodeRaw = Regex.Match(ex.Message, @": (\d+) \(").Groups[1].Value;
+            return !string.IsNullOrWhiteSpace(statusCodeRaw)
+                ? (HttpStatusCode) int.Parse(statusCodeRaw, CultureInfo.InvariantCulture)
+                : (HttpStatusCode?) null;
+        }
+
+        public static IAsyncPolicy ExceptionPolicy { get; } =
+            Policy
+                .Handle<IOException>() // dangerous
+                .Or<HttpRequestException>(ex => TryGetStatusCodeFromException(ex) == HttpStatusCode.TooManyRequests)
+                .Or<HttpRequestException>(ex => TryGetStatusCodeFromException(ex) == HttpStatusCode.RequestTimeout)
+                .Or<HttpRequestException>(ex => TryGetStatusCodeFromException(ex) >= HttpStatusCode.InternalServerError)
+                .WaitAndRetryAsync(4, i => TimeSpan.FromSeconds(Math.Pow(2, i) + 1));
+    }
+}

DiscordChatExporter.Domain/Internal/PathEx.cs

@@ -0,0 +1,18 @@
+using System.IO;
+using System.Text;
+
+namespace DiscordChatExporter.Domain.Internal
+{
+    internal static class PathEx
+    {
+        public static StringBuilder EscapePath(StringBuilder pathBuffer)
+        {
+            foreach (var invalidChar in Path.GetInvalidFileNameChars())
+                pathBuffer.Replace(invalidChar, '_');
+
+            return pathBuffer;
+        }
+
+        public static string EscapePath(string path) => EscapePath(new StringBuilder(path)).ToString();
+    }
+}

DiscordChatExporter.Domain/Internal/UrlBuilder.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Text;
+
+namespace DiscordChatExporter.Domain.Internal
+{
+    internal class UrlBuilder
+    {
+        private string _path = "";
+
+        private readonly Dictionary<string, string?> _queryParameters = new(StringComparer.OrdinalIgnoreCase);
+
+        public UrlBuilder SetPath(string path)
+        {
+            _path = path;
+            return this;
+        }
+
+        public UrlBuilder SetQueryParameter(string key, string? value, bool ignoreUnsetValue = true)
+        {
+            if (ignoreUnsetValue && string.IsNullOrWhiteSpace(value))
+                return this;
+
+            var keyEncoded = WebUtility.UrlEncode(key);
+            var valueEncoded = WebUtility.UrlEncode(value);
+            _queryParameters[keyEncoded] = valueEncoded;
+
+            return this;
+        }
+
+        public string Build()
+        {
+            var buffer = new StringBuilder();
+
+            buffer.Append(_path);
+
+            if (_queryParameters.Any())
+                buffer.Append('?').AppendJoin('&', _queryParameters.Select(kvp => $"{kvp.Key}={kvp.Value}"));
+
+            return buffer.ToString();
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/EmojiNode.cs

@@ -0,0 +1,27 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal class EmojiNode : MarkdownNode
+    {
+        public string? Id { get; }
+
+        public string Name { get; }
+
+        public bool IsAnimated { get; }
+
+        public bool IsCustomEmoji => !string.IsNullOrWhiteSpace(Id);
+
+        public EmojiNode(string? id, string name, bool isAnimated)
+        {
+            Id = id;
+            Name = name;
+            IsAnimated = isAnimated;
+        }
+
+        public EmojiNode(string name)
+            : this(null, name, false)
+        {
+        }
+
+        public override string ToString() => $"<Emoji> {Name}";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/FormattedNode.cs

@@ -0,0 +1,29 @@
+using System.Collections.Generic;
+
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal enum TextFormatting
+    {
+        Bold,
+        Italic,
+        Underline,
+        Strikethrough,
+        Spoiler,
+        Quote
+    }
+
+    internal class FormattedNode : MarkdownNode
+    {
+        public TextFormatting Formatting { get; }
+
+        public IReadOnlyList<MarkdownNode> Children { get; }
+
+        public FormattedNode(TextFormatting formatting, IReadOnlyList<MarkdownNode> children)
+        {
+            Formatting = formatting;
+            Children = children;
+        }
+
+        public override string ToString() => $"<{Formatting}> (+{Children.Count})";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/InlineCodeBlockNode.cs

@@ -0,0 +1,14 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal class InlineCodeBlockNode : MarkdownNode
+    {
+        public string Code { get; }
+
+        public InlineCodeBlockNode(string code)
+        {
+            Code = code;
+        }
+
+        public override string ToString() => $"<Code> {Code}";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/LinkNode.cs

@@ -0,0 +1,22 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal class LinkNode : MarkdownNode
+    {
+        public string Url { get; }
+
+        public string Title { get; }
+
+        public LinkNode(string url, string title)
+        {
+            Url = url;
+            Title = title;
+        }
+
+        public LinkNode(string url)
+            : this(url, url)
+        {
+        }
+
+        public override string ToString() => $"<Link> {Title}";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/MarkdownNode.cs

@@ -0,0 +1,6 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal abstract class MarkdownNode
+    {
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/MentionNode.cs

@@ -0,0 +1,25 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal enum MentionType
+    {
+        Meta,
+        User,
+        Channel,
+        Role
+    }
+
+    internal class MentionNode : MarkdownNode
+    {
+        public string Id { get; }
+
+        public MentionType Type { get; }
+
+        public MentionNode(string id, MentionType type)
+        {
+            Id = id;
+            Type = type;
+        }
+
+        public override string ToString() => $"<{Type} mention> {Id}";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/MultiLineCodeBlockNode.cs

@@ -0,0 +1,17 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal class MultiLineCodeBlockNode : MarkdownNode
+    {
+        public string Language { get; }
+
+        public string Code { get; }
+
+        public MultiLineCodeBlockNode(string language, string code)
+        {
+            Language = language;
+            Code = code;
+        }
+
+        public override string ToString() => $"<{Language}> {Code}";
+    }
+}

DiscordChatExporter.Domain/Markdown/Ast/TextNode.cs

@@ -0,0 +1,14 @@
+namespace DiscordChatExporter.Domain.Markdown.Ast
+{
+    internal class TextNode : MarkdownNode
+    {
+        public string Text { get; }
+
+        public TextNode(string text)
+        {
+            Text = text;
+        }
+
+        public override string ToString() => Text;
+    }
+}

DiscordChatExporter.Domain/Markdown/MarkdownParser.cs

@@ -0,0 +1,291 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using DiscordChatExporter.Domain.Markdown.Ast;
+using DiscordChatExporter.Domain.Markdown.Matching;
+
+namespace DiscordChatExporter.Domain.Markdown
+{
+    // The following parsing logic is meant to replicate Discord's markdown grammar as close as possible
+    internal static partial class MarkdownParser
+    {
+        private const RegexOptions DefaultRegexOptions =
+            RegexOptions.Compiled |
+            RegexOptions.CultureInvariant |
+            RegexOptions.Multiline;
+
+        /* Formatting */
+
+        // Capture any character until the earliest double asterisk not followed by an asterisk
+        private static readonly IMatcher<MarkdownNode> BoldFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\*\\*(.+?)\\*\\*(?!\\*)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Bold, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Capture any character until the earliest single asterisk not preceded or followed by an asterisk
+        // Opening asterisk must not be followed by whitespace
+        // Closing asterisk must not be preceded by whitespace
+        private static readonly IMatcher<MarkdownNode> ItalicFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\*(?!\\s)(.+?)(?<!\\s|\\*)\\*(?!\\*)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Italic, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Capture any character until the earliest triple asterisk not followed by an asterisk
+        private static readonly IMatcher<MarkdownNode> ItalicBoldFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\*(\\*\\*.+?\\*\\*)\\*(?!\\*)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Italic, Parse(p.Slice(m.Groups[1]), BoldFormattedNodeMatcher))
+        );
+
+        // Capture any character except underscore until an underscore
+        // Closing underscore must not be followed by a word character
+        private static readonly IMatcher<MarkdownNode> ItalicAltFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("_([^_]+)_(?!\\w)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Italic, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Capture any character until the earliest double underscore not followed by an underscore
+        private static readonly IMatcher<MarkdownNode> UnderlineFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("__(.+?)__(?!_)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Underline, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Capture any character until the earliest triple underscore not followed by an underscore
+        private static readonly IMatcher<MarkdownNode> ItalicUnderlineFormattedNodeMatcher =
+            new RegexMatcher<MarkdownNode>(
+                new Regex("_(__.+?__)_(?!_)", DefaultRegexOptions | RegexOptions.Singleline),
+                (p, m) => new FormattedNode(TextFormatting.Italic,
+                    Parse(p.Slice(m.Groups[1]), UnderlineFormattedNodeMatcher))
+            );
+
+        // Capture any character until the earliest double tilde
+        private static readonly IMatcher<MarkdownNode> StrikethroughFormattedNodeMatcher =
+            new RegexMatcher<MarkdownNode>(
+                new Regex("~~(.+?)~~", DefaultRegexOptions | RegexOptions.Singleline),
+                (p, m) => new FormattedNode(TextFormatting.Strikethrough, Parse(p.Slice(m.Groups[1])))
+            );
+
+        // Capture any character until the earliest double pipe
+        private static readonly IMatcher<MarkdownNode> SpoilerFormattedNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\|\\|(.+?)\\|\\|", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Spoiler, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Capture any character until the end of the line
+        // Opening 'greater than' character must be followed by whitespace
+        private static readonly IMatcher<MarkdownNode> SingleLineQuoteNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("^>\\s(.+\n?)", DefaultRegexOptions),
+            (p, m) => new FormattedNode(TextFormatting.Quote, Parse(p.Slice(m.Groups[1])))
+        );
+
+        // Repeatedly capture any character until the end of the line
+        // This one is tricky as it ends up producing multiple separate captures which need to be joined
+        private static readonly IMatcher<MarkdownNode> RepeatedSingleLineQuoteNodeMatcher =
+            new RegexMatcher<MarkdownNode>(
+                new Regex("(?:^>\\s(.+\n?)){2,}", DefaultRegexOptions),
+                (_, m) =>
+                {
+                    var content = string.Concat(m.Groups[1].Captures.Select(c => c.Value));
+                    return new FormattedNode(TextFormatting.Quote, Parse(content));
+                }
+            );
+
+        // Capture any character until the end of the input
+        // Opening 'greater than' characters must be followed by whitespace
+        private static readonly IMatcher<MarkdownNode> MultiLineQuoteNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("^>>>\\s(.+)", DefaultRegexOptions | RegexOptions.Singleline),
+            (p, m) => new FormattedNode(TextFormatting.Quote, Parse(p.Slice(m.Groups[1])))
+        );
+
+        /* Code blocks */
+
+        // Capture any character except backtick until a backtick
+        // Blank lines at the beginning and end of content are trimmed
+        // There can be either one or two backticks, but equal number on both sides
+        private static readonly IMatcher<MarkdownNode> InlineCodeBlockNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("(`{1,2})([^`]+)\\1", DefaultRegexOptions | RegexOptions.Singleline),
+            m => new InlineCodeBlockNode(m.Groups[2].Value.Trim('\r', '\n'))
+        );
+
+        // Capture language identifier and then any character until the earliest triple backtick
+        // Language identifier is one word immediately after opening backticks, followed immediately by newline
+        // Blank lines at the beginning and end of content are trimmed
+        private static readonly IMatcher<MarkdownNode> MultiLineCodeBlockNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("```(?:(\\w*)\\n)?(.+?)```", DefaultRegexOptions | RegexOptions.Singleline),
+            m => new MultiLineCodeBlockNode(m.Groups[1].Value, m.Groups[2].Value.Trim('\r', '\n'))
+        );
+
+        /* Mentions */
+
+        // Capture @everyone
+        private static readonly IMatcher<MarkdownNode> EveryoneMentionNodeMatcher = new StringMatcher<MarkdownNode>(
+            "@everyone",
+            _ => new MentionNode("everyone", MentionType.Meta)
+        );
+
+        // Capture @here
+        private static readonly IMatcher<MarkdownNode> HereMentionNodeMatcher = new StringMatcher<MarkdownNode>(
+            "@here",
+            _ => new MentionNode("here", MentionType.Meta)
+        );
+
+        // Capture <@123456> or <@!123456>
+        private static readonly IMatcher<MarkdownNode> UserMentionNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("<@!?(\\d+)>", DefaultRegexOptions),
+            m => new MentionNode(m.Groups[1].Value, MentionType.User)
+        );
+
+        // Capture <#123456>
+        private static readonly IMatcher<MarkdownNode> ChannelMentionNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("<#(\\d+)>", DefaultRegexOptions),
+            m => new MentionNode(m.Groups[1].Value, MentionType.Channel)
+        );
+
+        // Capture <@&123456>
+        private static readonly IMatcher<MarkdownNode> RoleMentionNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("<@&(\\d+)>", DefaultRegexOptions),
+            m => new MentionNode(m.Groups[1].Value, MentionType.Role)
+        );
+
+        /* Emojis */
+
+        // Capture any country flag emoji (two regional indicator surrogate pairs)
+        // ... or "miscellaneous symbol" character
+        // ... or surrogate pair
+        // ... or digit followed by enclosing mark
+        // (this does not match all emojis in Discord but it's reasonably accurate enough)
+        private static readonly IMatcher<MarkdownNode> StandardEmojiNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("((?:[\\uD83C][\\uDDE6-\\uDDFF]){2}|[\\u2600-\\u26FF]|\\p{Cs}{2}|\\d\\p{Me})",
+                DefaultRegexOptions),
+            m => new EmojiNode(m.Groups[1].Value)
+        );
+
+        // Capture <:lul:123456> or <a:lul:123456>
+        private static readonly IMatcher<MarkdownNode> CustomEmojiNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("<(a)?:(.+?):(\\d+?)>", DefaultRegexOptions),
+            m => new EmojiNode(m.Groups[3].Value, m.Groups[2].Value, !string.IsNullOrWhiteSpace(m.Groups[1].Value))
+        );
+
+        /* Links */
+
+        // Capture [title](link)
+        private static readonly IMatcher<MarkdownNode> TitledLinkNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\[(.+?)\\]\\((.+?)\\)", DefaultRegexOptions),
+            m => new LinkNode(m.Groups[2].Value, m.Groups[1].Value)
+        );
+
+        // Capture any non-whitespace character after http:// or https:// until the last punctuation character or whitespace
+        private static readonly IMatcher<MarkdownNode> AutoLinkNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("(https?://\\S*[^\\.,:;\"\'\\s])", DefaultRegexOptions),
+            m => new LinkNode(m.Groups[1].Value)
+        );
+
+        // Same as auto link but also surrounded by angular brackets
+        private static readonly IMatcher<MarkdownNode> HiddenLinkNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("<(https?://\\S*[^\\.,:;\"\'\\s])>", DefaultRegexOptions),
+            m => new LinkNode(m.Groups[1].Value)
+        );
+
+        /* Text */
+
+        // Capture the shrug emoticon
+        // This escapes it from matching for formatting
+        private static readonly IMatcher<MarkdownNode> ShrugTextNodeMatcher = new StringMatcher<MarkdownNode>(
+            @"¯\_(ツ)_/¯",
+            p => new TextNode(p.ToString())
+        );
+
+        // Capture some specific emojis that don't get rendered
+        // This escapes it from matching for emoji
+        private static readonly IMatcher<MarkdownNode> IgnoredEmojiTextNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("(\\u26A7|\\u2640|\\u2642|\\u2695|\\u267E|\\u00A9|\\u00AE|\\u2122)", DefaultRegexOptions),
+            m => new TextNode(m.Groups[1].Value)
+        );
+
+        // Capture any "symbol/other" character or surrogate pair preceded by a backslash
+        // This escapes it from matching for emoji
+        private static readonly IMatcher<MarkdownNode> EscapedSymbolTextNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\\\(\\p{So}|\\p{Cs}{2})", DefaultRegexOptions),
+            m => new TextNode(m.Groups[1].Value)
+        );
+
+        // Capture any non-whitespace, non latin alphanumeric character preceded by a backslash
+        // This escapes it from matching for formatting or other tokens
+        private static readonly IMatcher<MarkdownNode> EscapedCharacterTextNodeMatcher = new RegexMatcher<MarkdownNode>(
+            new Regex("\\\\([^a-zA-Z0-9\\s])", DefaultRegexOptions),
+            m => new TextNode(m.Groups[1].Value)
+        );
+
+        // Combine all matchers into one
+        // Matchers that have similar patterns are ordered from most specific to least specific
+        private static readonly IMatcher<MarkdownNode> AggregateNodeMatcher = new AggregateMatcher<MarkdownNode>(
+            // Escaped text
+            ShrugTextNodeMatcher,
+            IgnoredEmojiTextNodeMatcher,
+            EscapedSymbolTextNodeMatcher,
+            EscapedCharacterTextNodeMatcher,
+
+            // Formatting
+            ItalicBoldFormattedNodeMatcher,
+            ItalicUnderlineFormattedNodeMatcher,
+            BoldFormattedNodeMatcher,
+            ItalicFormattedNodeMatcher,
+            UnderlineFormattedNodeMatcher,
+            ItalicAltFormattedNodeMatcher,
+            StrikethroughFormattedNodeMatcher,
+            SpoilerFormattedNodeMatcher,
+            MultiLineQuoteNodeMatcher,
+            RepeatedSingleLineQuoteNodeMatcher,
+            SingleLineQuoteNodeMatcher,
+
+            // Code blocks
+            MultiLineCodeBlockNodeMatcher,
+            InlineCodeBlockNodeMatcher,
+
+            // Mentions
+            EveryoneMentionNodeMatcher,
+            HereMentionNodeMatcher,
+            UserMentionNodeMatcher,
+            ChannelMentionNodeMatcher,
+            RoleMentionNodeMatcher,
+
+            // Links
+            TitledLinkNodeMatcher,
+            AutoLinkNodeMatcher,
+            HiddenLinkNodeMatcher,
+
+            // Emoji
+            StandardEmojiNodeMatcher,
+            CustomEmojiNodeMatcher
+        );
+
+        // Minimal set of matchers for non-multimedia formats (e.g. plain text)
+        private static readonly IMatcher<MarkdownNode> MinimalAggregateNodeMatcher = new AggregateMatcher<MarkdownNode>(
+            // Mentions
+            EveryoneMentionNodeMatcher,
+            HereMentionNodeMatcher,
+            UserMentionNodeMatcher,
+            ChannelMentionNodeMatcher,
+            RoleMentionNodeMatcher,
+
+            // Emoji
+            CustomEmojiNodeMatcher
+        );
+
+        private static IReadOnlyList<MarkdownNode> Parse(StringPart stringPart, IMatcher<MarkdownNode> matcher) =>
+            matcher
+                .MatchAll(stringPart, p => new TextNode(p.ToString()))
+                .Select(r => r.Value)
+                .ToArray();
+    }
+
+    internal static partial class MarkdownParser
+    {
+        private static IReadOnlyList<MarkdownNode> Parse(StringPart stringPart) => Parse(stringPart, AggregateNodeMatcher);
+
+        private static IReadOnlyList<MarkdownNode> ParseMinimal(StringPart stringPart) => Parse(stringPart, MinimalAggregateNodeMatcher);
+
+        public static IReadOnlyList<MarkdownNode> Parse(string input) => Parse(new StringPart(input));
+
+        public static IReadOnlyList<MarkdownNode> ParseMinimal(string input) => ParseMinimal(new StringPart(input));
+    }
+}

DiscordChatExporter.Domain/Markdown/MarkdownVisitor.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using DiscordChatExporter.Domain.Markdown.Ast;
+
+namespace DiscordChatExporter.Domain.Markdown
+{
+    internal abstract class MarkdownVisitor
+    {
+        protected virtual MarkdownNode VisitText(TextNode text) => text;
+
+        protected virtual MarkdownNode VisitFormatted(FormattedNode formatted)
+        {
+            Visit(formatted.Children);
+            return formatted;
+        }
+
+        protected virtual MarkdownNode VisitInlineCodeBlock(InlineCodeBlockNode inlineCodeBlock) => inlineCodeBlock;
+
+        protected virtual MarkdownNode VisitMultiLineCodeBlock(MultiLineCodeBlockNode multiLineCodeBlock) => multiLineCodeBlock;
+
+        protected virtual MarkdownNode VisitLink(LinkNode link) => link;
+
+        protected virtual MarkdownNode VisitEmoji(EmojiNode emoji) => emoji;
+
+        protected virtual MarkdownNode VisitMention(MentionNode mention) => mention;
+
+        public MarkdownNode Visit(MarkdownNode node) => node switch
+        {
+            TextNode text => VisitText(text),
+            FormattedNode formatted => VisitFormatted(formatted),
+            InlineCodeBlockNode inlineCodeBlock => VisitInlineCodeBlock(inlineCodeBlock),
+            MultiLineCodeBlockNode multiLineCodeBlock => VisitMultiLineCodeBlock(multiLineCodeBlock),
+            LinkNode link => VisitLink(link),
+            EmojiNode emoji => VisitEmoji(emoji),
+            MentionNode mention => VisitMention(mention),
+            _ => throw new ArgumentOutOfRangeException(nameof(node))
+        };
+
+        public void Visit(IEnumerable<MarkdownNode> nodes)
+        {
+            foreach (var node in nodes)
+                Visit(node);
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/AggregateMatcher.cs

@@ -0,0 +1,46 @@
+using System.Collections.Generic;
+
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal class AggregateMatcher<T> : IMatcher<T>
+    {
+        private readonly IReadOnlyList<IMatcher<T>> _matchers;
+
+        public AggregateMatcher(IReadOnlyList<IMatcher<T>> matchers)
+        {
+            _matchers = matchers;
+        }
+
+        public AggregateMatcher(params IMatcher<T>[] matchers)
+            : this((IReadOnlyList<IMatcher<T>>) matchers)
+        {
+        }
+
+        public ParsedMatch<T>? TryMatch(StringPart stringPart)
+        {
+            ParsedMatch<T>? earliestMatch = null;
+
+            // Try to match the input with each matcher and get the match with the lowest start index
+            foreach (var matcher in _matchers)
+            {
+                // Try to match
+                var match = matcher.TryMatch(stringPart);
+
+                // If there's no match - continue
+                if (match == null)
+                    continue;
+
+                // If this match is earlier than previous earliest - replace
+                if (earliestMatch == null || match.StringPart.StartIndex < earliestMatch.StringPart.StartIndex)
+                    earliestMatch = match;
+
+                // If the earliest match starts at the very beginning - break,
+                // because it's impossible to find a match earlier than that
+                if (earliestMatch.StringPart.StartIndex == stringPart.StartIndex)
+                    break;
+            }
+
+            return earliestMatch;
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/IMatcher.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal interface IMatcher<T>
+    {
+        ParsedMatch<T>? TryMatch(StringPart stringPart);
+    }
+
+    internal static class MatcherExtensions
+    {
+        public static IEnumerable<ParsedMatch<T>> MatchAll<T>(this IMatcher<T> matcher,
+            StringPart stringPart, Func<StringPart, T> transformFallback)
+        {
+            // Loop through segments divided by individual matches
+            var currentIndex = stringPart.StartIndex;
+            while (currentIndex < stringPart.EndIndex)
+            {
+                // Find a match within this segment
+                var match = matcher.TryMatch(stringPart.Slice(currentIndex, stringPart.EndIndex - currentIndex));
+
+                // If there's no match - break
+                if (match == null)
+                    break;
+
+                // If this match doesn't start immediately at current index - transform and yield fallback first
+                if (match.StringPart.StartIndex > currentIndex)
+                {
+                    var fallbackPart = stringPart.Slice(currentIndex, match.StringPart.StartIndex - currentIndex);
+                    yield return new ParsedMatch<T>(fallbackPart, transformFallback(fallbackPart));
+                }
+
+                // Yield match
+                yield return match;
+
+                // Shift current index to the end of the match
+                currentIndex = match.StringPart.StartIndex + match.StringPart.Length;
+            }
+
+            // If EOL wasn't reached - transform and yield remaining part as fallback
+            if (currentIndex < stringPart.EndIndex)
+            {
+                var fallbackPart = stringPart.Slice(currentIndex);
+                yield return new ParsedMatch<T>(fallbackPart, transformFallback(fallbackPart));
+            }
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/ParsedMatch.cs

@@ -0,0 +1,15 @@
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal class ParsedMatch<T>
+    {
+        public StringPart StringPart { get; }
+
+        public T Value { get; }
+
+        public ParsedMatch(StringPart stringPart, T value)
+        {
+            StringPart = stringPart;
+            Value = value;
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/RegexMatcher.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal class RegexMatcher<T> : IMatcher<T>
+    {
+        private readonly Regex _regex;
+        private readonly Func<StringPart, Match, T> _transform;
+
+        public RegexMatcher(Regex regex, Func<StringPart, Match, T> transform)
+        {
+            _regex = regex;
+            _transform = transform;
+        }
+
+        public RegexMatcher(Regex regex, Func<Match, T> transform)
+            : this(regex, (p, m) => transform(m))
+        {
+        }
+
+        public ParsedMatch<T>? TryMatch(StringPart stringPart)
+        {
+            var match = _regex.Match(stringPart.Target, stringPart.StartIndex, stringPart.Length);
+            if (!match.Success)
+                return null;
+
+            // Overload regex.Match(string, int, int) doesn't take the whole string into account,
+            // it effectively functions as a match check on a substring.
+            // Which is super weird because regex.Match(string, int) takes the whole input in context.
+            // So in order to properly account for ^/$ regex tokens, we need to make sure that
+            // the expression also matches on the bigger part of the input.
+            if (!_regex.IsMatch(stringPart.Target.Substring(0, stringPart.EndIndex), stringPart.StartIndex))
+                return null;
+
+            var stringPartMatch = stringPart.Slice(match.Index, match.Length);
+            return new ParsedMatch<T>(stringPartMatch, _transform(stringPartMatch, match));
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/StringMatcher.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal class StringMatcher<T> : IMatcher<T>
+    {
+        private readonly string _needle;
+        private readonly StringComparison _comparison;
+        private readonly Func<StringPart, T> _transform;
+
+        public StringMatcher(string needle, StringComparison comparison, Func<StringPart, T> transform)
+        {
+            _needle = needle;
+            _comparison = comparison;
+            _transform = transform;
+        }
+
+        public StringMatcher(string needle, Func<StringPart, T> transform)
+            : this(needle, StringComparison.Ordinal, transform)
+        {
+        }
+
+        public ParsedMatch<T>? TryMatch(StringPart stringPart)
+        {
+            var index = stringPart.Target.IndexOf(_needle, stringPart.StartIndex, stringPart.Length, _comparison);
+
+            if (index >= 0)
+            {
+                var stringPartMatch = stringPart.Slice(index, _needle.Length);
+                return new ParsedMatch<T>(stringPartMatch, _transform(stringPartMatch));
+            }
+
+            return null;
+        }
+    }
+}

DiscordChatExporter.Domain/Markdown/Matching/StringPart.cs

@@ -0,0 +1,36 @@
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Domain.Markdown.Matching
+{
+    internal readonly struct StringPart
+    {
+        public string Target { get; }
+
+        public int StartIndex { get; }
+
+        public int Length { get; }
+
+        public int EndIndex { get; }
+
+        public StringPart(string target, int startIndex, int length)
+        {
+            Target = target;
+            StartIndex = startIndex;
+            Length = length;
+            EndIndex = startIndex + length;
+        }
+
+        public StringPart(string target)
+            : this(target, 0, target.Length)
+        {
+        }
+
+        public StringPart Slice(int newStartIndex, int newLength) => new(Target, newStartIndex, newLength);
+
+        public StringPart Slice(int newStartIndex) => Slice(newStartIndex, EndIndex - newStartIndex);
+
+        public StringPart Slice(Capture capture) => Slice(capture.Index, capture.Length);
+
+        public override string ToString() => Target.Substring(StartIndex, Length);
+    }
+}

DiscordChatExporter.Domain/Utilities/AsyncExtensions.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace DiscordChatExporter.Domain.Utilities
+{
+    public static class AsyncExtensions
+    {
+        private static async ValueTask<IReadOnlyList<T>> AggregateAsync<T>(
+            this IAsyncEnumerable<T> asyncEnumerable)
+        {
+            var list = new List<T>();
+
+            await foreach (var i in asyncEnumerable)
+                list.Add(i);
+
+            return list;
+        }
+
+        public static ValueTaskAwaiter<IReadOnlyList<T>> GetAwaiter<T>(
+            this IAsyncEnumerable<T> asyncEnumerable) =>
+            asyncEnumerable.AggregateAsync().GetAwaiter();
+
+        public static async ValueTask ParallelForEachAsync<T>(
+            this IEnumerable<T> source,
+            Func<T, ValueTask> handleAsync,
+            int degreeOfParallelism)
+        {
+            using var semaphore = new SemaphoreSlim(degreeOfParallelism);
+
+            await Task.WhenAll(source.Select(async item =>
+            {
+                // ReSharper disable once AccessToDisposedClosure
+                await semaphore.WaitAsync();
+
+                try
+                {
+                    await handleAsync(item);
+                }
+                finally
+                {
+                    // ReSharper disable once AccessToDisposedClosure
+                    semaphore.Release();
+                }
+            }));
+        }
+    }
+}

DiscordChatExporter.Domain/Utilities/GeneralExtensions.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace DiscordChatExporter.Domain.Utilities
+{
+    public static class GeneralExtensions
+    {
+        public static TOut Pipe<TIn, TOut>(this TIn input, Func<TIn, TOut> transform) => transform(input);
+    }
+}

DiscordChatExporter.Gui/App.xaml

@@ -0,0 +1,168 @@
+<Application
+    x:Class="DiscordChatExporter.Gui.App"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="clr-namespace:DiscordChatExporter.Gui"
+    xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
+    xmlns:s="https://github.com/canton7/Stylet">
+    <Application.Resources>
+        <s:ApplicationLoader>
+            <!--  Bootstrapper  -->
+            <s:ApplicationLoader.Bootstrapper>
+                <local:Bootstrapper />
+            </s:ApplicationLoader.Bootstrapper>
+
+            <!--  Merged dictionaries  -->
+            <ResourceDictionary.MergedDictionaries>
+                <!--  Colors are irrelevant because they are overriden in runtime  -->
+                <materialDesign:BundledTheme
+                    BaseTheme="Light"
+                    PrimaryColor="Blue"
+                    SecondaryColor="Blue" />
+
+                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+
+            <!--  Styles  -->
+            <Style x:Key="MaterialDesignRoot" TargetType="{x:Type Control}">
+                <Setter Property="FontFamily" Value="{DynamicResource MaterialDesignFont}" />
+                <Setter Property="RenderOptions.BitmapScalingMode" Value="HighQuality" />
+                <Setter Property="SnapsToDevicePixels" Value="True" />
+                <Setter Property="TextElement.FontSize" Value="13" />
+                <Setter Property="TextElement.FontWeight" Value="Regular" />
+                <Setter Property="TextElement.Foreground" Value="{DynamicResource MaterialDesignBody}" />
+                <Setter Property="TextOptions.TextFormattingMode" Value="Ideal" />
+                <Setter Property="TextOptions.TextRenderingMode" Value="Auto" />
+                <Setter Property="UseLayoutRounding" Value="True" />
+            </Style>
+
+            <Style BasedOn="{StaticResource MaterialDesignScrollBarMinimal}" TargetType="{x:Type ScrollBar}" />
+
+            <Style BasedOn="{StaticResource MaterialDesignLinearProgressBar}" TargetType="{x:Type ProgressBar}">
+                <Setter Property="BorderThickness" Value="0" />
+                <Setter Property="Background" Value="Transparent" />
+                <Setter Property="Foreground" Value="{DynamicResource SecondaryAccentBrush}" />
+                <Setter Property="Height" Value="2" />
+                <Setter Property="Maximum" Value="1" />
+                <Setter Property="Minimum" Value="0" />
+            </Style>
+
+            <Style BasedOn="{StaticResource MaterialDesignTextBox}" TargetType="{x:Type TextBox}" />
+
+            <Style BasedOn="{StaticResource MaterialDesignComboBox}" TargetType="{x:Type ComboBox}" />
+
+            <Style BasedOn="{StaticResource MaterialDesignDatePicker}" TargetType="{x:Type DatePicker}" />
+
+            <Style BasedOn="{StaticResource MaterialDesignTimePicker}" TargetType="{x:Type materialDesign:TimePicker}" />
+
+            <Style
+                x:Key="MaterialDesignFlatDarkButton"
+                BasedOn="{StaticResource MaterialDesignFlatButton}"
+                TargetType="{x:Type Button}">
+                <Style.Resources>
+                    <SolidColorBrush x:Key="MaterialDesignFlatButtonClick" Color="#4C4C4C" />
+                </Style.Resources>
+
+                <Setter Property="Foreground" Value="{DynamicResource PrimaryHueMidForegroundBrush}" />
+            </Style>
+
+            <Style
+                x:Key="MaterialDesignFlatActionToggleButton"
+                BasedOn="{StaticResource MaterialDesignActionToggleButton}"
+                TargetType="{x:Type ToggleButton}">
+                <Setter Property="Background" Value="Transparent" />
+                <Setter Property="Foreground" Value="{DynamicResource PrimaryHueMidBrush}" />
+
+                <Style.Triggers>
+                    <Trigger Property="IsMouseOver" Value="True">
+                        <Setter Property="Background" Value="{DynamicResource MaterialDesignFlatButtonClick}" />
+                        <Setter Property="BorderBrush" Value="{DynamicResource MaterialDesignFlatButtonClick}" />
+                    </Trigger>
+                </Style.Triggers>
+            </Style>
+
+            <!--  Default MD Expander is incredibly slow (https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/issues/1307)  -->
+            <Style BasedOn="{StaticResource MaterialDesignExpander}" TargetType="{x:Type Expander}">
+                <Setter Property="Template">
+                    <Setter.Value>
+                        <ControlTemplate TargetType="Expander">
+                            <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}">
+                                <DockPanel Background="{TemplateBinding Background}">
+                                    <ToggleButton
+                                        Name="HeaderSite"
+                                        BorderThickness="0"
+                                        Content="{TemplateBinding Header}"
+                                        ContentStringFormat="{TemplateBinding HeaderStringFormat}"
+                                        ContentTemplate="{TemplateBinding HeaderTemplate}"
+                                        ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}"
+                                        Cursor="Hand"
+                                        DockPanel.Dock="Top"
+                                        Focusable="False"
+                                        Foreground="{TemplateBinding Foreground}"
+                                        IsChecked="{Binding Path=IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
+                                        IsTabStop="False"
+                                        Opacity=".87"
+                                        Style="{StaticResource MaterialDesignExpanderDownHeaderStyle}"
+                                        TextElement.FontSize="15" />
+                                    <Border
+                                        Name="ContentSite"
+                                        DockPanel.Dock="Bottom"
+                                        Visibility="Collapsed">
+                                        <StackPanel
+                                            Name="ContentPanel"
+                                            Margin="{TemplateBinding Padding}"
+                                            HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                                            VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
+                                            <ContentPresenter
+                                                Name="PART_Content"
+                                                ContentStringFormat="{TemplateBinding ContentStringFormat}"
+                                                ContentTemplate="{TemplateBinding ContentTemplate}"
+                                                ContentTemplateSelector="{TemplateBinding ContentTemplateSelector}"
+                                                Focusable="False" />
+                                        </StackPanel>
+                                    </Border>
+                                </DockPanel>
+                            </Border>
+                            <ControlTemplate.Triggers>
+                                <Trigger Property="IsExpanded" Value="true">
+                                    <Setter TargetName="ContentSite" Property="Visibility" Value="Visible" />
+                                </Trigger>
+                                <Trigger Property="ExpandDirection" Value="Right">
+                                    <Setter TargetName="HeaderSite" Property="DockPanel.Dock" Value="Left" />
+                                    <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Right" />
+                                    <Setter TargetName="ContentPanel" Property="Orientation" Value="Horizontal" />
+                                    <Setter TargetName="ContentPanel" Property="Height" Value="Auto" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderRightHeaderStyle}" />
+                                </Trigger>
+
+                                <Trigger Property="ExpandDirection" Value="Left">
+                                    <Setter TargetName="HeaderSite" Property="DockPanel.Dock" Value="Right" />
+                                    <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Left" />
+                                    <Setter TargetName="ContentPanel" Property="Orientation" Value="Horizontal" />
+                                    <Setter TargetName="ContentPanel" Property="Height" Value="Auto" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderLeftHeaderStyle}" />
+                                </Trigger>
+
+                                <Trigger Property="ExpandDirection" Value="Up">
+                                    <Setter TargetName="HeaderSite" Property="DockPanel.Dock" Value="Bottom" />
+                                    <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Top" />
+                                    <Setter TargetName="ContentPanel" Property="Orientation" Value="Vertical" />
+                                    <Setter TargetName="ContentPanel" Property="Width" Value="Auto" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderUpHeaderStyle}" />
+                                </Trigger>
+
+                                <Trigger Property="ExpandDirection" Value="Down">
+                                    <Setter TargetName="HeaderSite" Property="DockPanel.Dock" Value="Top" />
+                                    <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Bottom" />
+                                    <Setter TargetName="ContentPanel" Property="Orientation" Value="Vertical" />
+                                    <Setter TargetName="ContentPanel" Property="Width" Value="Auto" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderDownHeaderStyle}" />
+                                </Trigger>
+                            </ControlTemplate.Triggers>
+                        </ControlTemplate>
+                    </Setter.Value>
+                </Setter>
+            </Style>
+        </s:ApplicationLoader>
+    </Application.Resources>
+</Application>

DiscordChatExporter.Gui/App.xaml.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Reflection;
+using DiscordChatExporter.Gui.Internal;
+using MaterialDesignThemes.Wpf;
+
+namespace DiscordChatExporter.Gui
+{
+    public partial class App
+    {
+        private static Assembly Assembly { get; } = typeof(App).Assembly;
+
+        public static string Name { get; } = Assembly.GetName().Name!;
+
+        public static Version Version { get; } = Assembly.GetName().Version!;
+
+        public static string VersionString { get; } = Version.ToString(3);
+
+        public static string GitHubProjectUrl { get; } = "https://github.com/Tyrrrz/DiscordChatExporter";
+
+        public static string GitHubProjectWikiUrl { get; } = GitHubProjectUrl + "/wiki";
+    }
+
+    public partial class App
+    {
+        private static Theme LightTheme { get; } = Theme.Create(
+            new MaterialDesignLightTheme(),
+            MediaColor.FromHex("#343838"),
+            MediaColor.FromHex("#F9A825")
+        );
+
+        private static Theme DarkTheme { get; } = Theme.Create(
+            new MaterialDesignDarkTheme(),
+            MediaColor.FromHex("#E8E8E8"),
+            MediaColor.FromHex("#F9A825")
+        );
+
+        public static void SetLightTheme()
+        {
+            var paletteHelper = new PaletteHelper();
+            paletteHelper.SetTheme(LightTheme);
+        }
+
+        public static void SetDarkTheme()
+        {
+            var paletteHelper = new PaletteHelper();
+            paletteHelper.SetTheme(DarkTheme);
+        }
+    }
+}

DiscordChatExporter.Gui/Behaviors/ChannelMultiSelectionListBoxBehavior.cs

@@ -0,0 +1,8 @@
+using DiscordChatExporter.Domain.Discord.Models;
+
+namespace DiscordChatExporter.Gui.Behaviors
+{
+    public class ChannelMultiSelectionListBoxBehavior : MultiSelectionListBoxBehavior<Channel>
+    {
+    }
+}

DiscordChatExporter.Gui/Behaviors/MultiSelectionListBoxBehavior.cs

@@ -0,0 +1,92 @@
+using System.Collections;
+using System.Collections.Specialized;
+using System.Linq;
+using System.Windows;
+using System.Windows.Controls;
+using Microsoft.Xaml.Behaviors;
+
+namespace DiscordChatExporter.Gui.Behaviors
+{
+    public class MultiSelectionListBoxBehavior<T> : Behavior<ListBox>
+    {
+        public static readonly DependencyProperty SelectedItemsProperty =
+            DependencyProperty.Register(nameof(SelectedItems), typeof(IList),
+                typeof(MultiSelectionListBoxBehavior<T>),
+                new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
+                    OnSelectedItemsChanged));
+
+        private static void OnSelectedItemsChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
+        {
+            var behavior = (MultiSelectionListBoxBehavior<T>) sender;
+            if (behavior._modelHandled) return;
+
+            if (behavior.AssociatedObject == null)
+                return;
+
+            behavior._modelHandled = true;
+            behavior.SelectItems();
+            behavior._modelHandled = false;
+        }
+
+        private bool _viewHandled;
+        private bool _modelHandled;
+
+        public IList? SelectedItems
+        {
+            get => (IList?) GetValue(SelectedItemsProperty);
+            set => SetValue(SelectedItemsProperty, value);
+        }
+
+        // Propagate selected items from model to view
+        private void SelectItems()
+        {
+            _viewHandled = true;
+
+            AssociatedObject.SelectedItems.Clear();
+            if (SelectedItems != null)
+            {
+                foreach (var item in SelectedItems)
+                    AssociatedObject.SelectedItems.Add(item);
+            }
+
+            _viewHandled = false;
+        }
+
+        // Propagate selected items from view to model
+        private void OnListBoxSelectionChanged(object sender, SelectionChangedEventArgs args)
+        {
+            if (_viewHandled) return;
+            if (AssociatedObject.Items.SourceCollection == null) return;
+
+            SelectedItems = AssociatedObject.SelectedItems.Cast<T>().ToArray();
+        }
+
+        // Re-select items when the set of items changes
+        private void OnListBoxItemsChanged(object sender, NotifyCollectionChangedEventArgs args)
+        {
+            if (_viewHandled) return;
+            if (AssociatedObject.Items.SourceCollection == null) return;
+            SelectItems();
+        }
+
+        protected override void OnAttached()
+        {
+            base.OnAttached();
+
+            AssociatedObject.SelectionChanged += OnListBoxSelectionChanged;
+            ((INotifyCollectionChanged) AssociatedObject.Items).CollectionChanged += OnListBoxItemsChanged;
+        }
+
+        /// <inheritdoc />
+        protected override void OnDetaching()
+        {
+            base.OnDetaching();
+
+            if (AssociatedObject != null)
+            {
+                AssociatedObject.SelectionChanged -= OnListBoxSelectionChanged;
+                ((INotifyCollectionChanged) AssociatedObject.Items).CollectionChanged -= OnListBoxItemsChanged;
+            }
+        }
+    }
+}