Update version

Fixes #747

.config/dotnet-tools.json

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

.github/FUNDING.yml

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

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -1,25 +1,31 @@
-name: "\U0001F41E Bug report"
+name: 🐞 Bug report
 description: Report broken functionality.
 labels: [bug]
+
 body:
 - type: markdown
   attributes:
     value: |
-      - Please check existing issues (both opened and closed) to ensure that this bug hasn't been reported before.
-      - Refer to the [contribution guidelines](https://github.com/Tyrrrz/DiscordChatExporter/blob/master/Contributing.md) for info on how to file a good issue.
-      - If you want to ask a question instead of reporting a bug, use [**discussions**](https://github.com/Tyrrrz/DiscordChatExporter/discussions/new) instead.
+      🧐 **Guidelines:**
+
+      - Search through [existing issues](https://github.com/Tyrrrz/DiscordChatExporter/issues?q=is%3Aissue) first to ensure that this bug has not been reported before.
+      - Write a descriptive title for your issue. Avoid generic or vague titles such as "Something's not working" or "A couple of problems".
+      - Keep your issue focused on one single problem. If you have multiple bug reports, please create separate issues for each of them.
+      - Provide as much context as possible in the details section. Include screenshots, screen recordings, links, references, or anything else you may consider relevant.
+      - If you want to ask a question instead of reporting a bug, please use [discussions](https://github.com/Tyrrrz/DiscordChatExporter/discussions/new) instead.
 
 - type: input
   attributes:
     label: Version
-    description: "Which version(s) of DiscordChatExporter does this bug affect?"
+    description: Which version of DiscordChatExporter does this bug affect?
+    placeholder: ver X.Y.Z
   validations:
     required: true
 
 - type: dropdown
   attributes:
     label: Flavor
-    description: "Which flavor(s) of DiscordChatExporter does this bug affect?"
+    description: Does this bug affect the GUI version, the CLI version, or both?
     multiple: true
     options:
     - GUI (Graphical User Interface)
@@ -27,16 +33,32 @@ body:
   validations:
     required: true
 
+- type: dropdown
+  attributes:
+    label: Export format
+    description: Does this bug affect specific export format(s)? If not applicable, leave this field blank.
+    multiple: true
+    options:
+    - HTML
+    - TXT
+    - JSON
+    - CSV
+
 - type: textarea
   attributes:
     label: Details
-    description: "Clear and thorough explanation of the bug. If relevant, include screenshots or screen recordings."
+    description: Clear and thorough explanation of the bug.
+    placeholder: I was doing X expecting Y to happen, but Z happened instead.
   validations:
     required: true
 
 - type: textarea
   attributes:
     label: Steps to reproduce
-    description: "Minimum steps required to reproduce the bug."
+    description: Minimum steps required to reproduce the bug.
+    placeholder: |
+      - Step 1
+      - Step 2
+      - Step 3
   validations:
     required: true

.github/ISSUE_TEMPLATE/config.yml

@@ -1,8 +1,11 @@
 blank_issues_enabled: false
 contact_links:
-  - name: "\U0001F4D6 Read the wiki"
+  - name: 💬 Discord server
+    url: https://discord.gg/2SUWKFnHSm
+    about: Chat with the project community.
+  - name: 📖 Wiki
     url: https://github.com/Tyrrrz/DiscordChatExporter/wiki
-    about: Find answers to most common questions.
-  - name: "\U0001F5E8 Ask a question"
+    about: Find usage guides and frequently asked questions.
+  - name: 🗨 Discussions
     url: https://github.com/Tyrrrz/DiscordChatExporter/discussions/new
-    about: Please ask and answer questions here.
+    about: Ask and answer questions.

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -1,26 +1,42 @@
-name: "\U00002728 Feature request"
+name: ✨ Feature request
 description: Request a new feature.
 labels: [enhancement]
+
 body:
 - type: markdown
   attributes:
     value: |
-      - Please check existing issues (both opened and closed) to ensure that this feature hasn't been requested before.
-      - Refer to the [contribution guidelines](https://github.com/Tyrrrz/DiscordChatExporter/blob/master/Contributing.md) for info on how to file a good issue.
-      - If you want to ask a question instead of requesting a feature, use [**discussions**](https://github.com/Tyrrrz/DiscordChatExporter/discussions/new) instead.
+      🧐 **Guidelines:**
+
+      - Search through [existing issues](https://github.com/Tyrrrz/DiscordChatExporter/issues?q=is%3Aissue) first to ensure that this feature has not been requested before.
+      - Write a descriptive title for your issue. Avoid generic or vague titles such as "Some suggestions" or "Ideas for improvement".
+      - Keep your issue focused on one single problem. If you have multiple feature requests, please create separate issues for each of them.
+      - Provide as much context as possible in the details section. Include screenshots, screen recordings, links, references, or anything else you may consider relevant.
+      - If you want to ask a question instead of requesting a feature, please use [discussions](https://github.com/Tyrrrz/DiscordChatExporter/discussions/new) instead.
 
 - type: dropdown
   attributes:
     label: Flavor
-    description: "Which flavor(s) of DiscordChatExporter does this feature request apply to?"
+    description: Is this feature request related to specific flavor(s) of DiscordChatExporter? If not applicable, leave this field blank.
     multiple: true
     options:
     - GUI (Graphical User Interface)
     - CLI (Command Line Interface)
 
+- type: dropdown
+  attributes:
+    label: Export format
+    description: Is this feature request related to specific export format(s)? If not applicable, leave this field blank.
+    multiple: true
+    options:
+    - HTML
+    - TXT
+    - JSON
+    - CSV
+
 - type: textarea
   attributes:
     label: Details
-    description: "Clear and thorough explanation of the feature you have in mind."
+    description: Clear and thorough explanation of the feature you have in mind.
   validations:
     required: true

.github/workflows/CD-Docker.yml

@@ -0,0 +1,30 @@
+name: Docker CD
+
+on:
+  push:
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2.3.3
+
+      - name: Get release version
+        id: get_version
+        uses: dawidd6/action-get-tag@v1
+
+      - name: Login
+        run: docker login -u tyrrrz -p ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Build
+        run: docker build -t tyrrrz/discordchatexporter:${{ steps.get_version.outputs.tag }} -t tyrrrz/discordchatexporter:stable .
+
+      - name: Deploy (version)
+        run: docker push tyrrrz/discordchatexporter:${{ steps.get_version.outputs.tag }}
+
+      - name: Deploy (stable)
+        run: docker push tyrrrz/discordchatexporter:stable

.github/workflows/CD.yml

@@ -13,15 +13,14 @@ jobs:
       - 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: Get release version
+        id: get_version
+        uses: dawidd6/action-get-tag@v1
 
-      - name: Install .NET (v5.0)
+      - name: Install .NET
         uses: actions/setup-dotnet@v1.7.2
         with:
-          dotnet-version: 5.0.x
+          dotnet-version: 6.0.x
 
       - name: Build & publish (CLI)
         run: dotnet publish DiscordChatExporter.Cli/ -o DiscordChatExporter.Cli/bin/Publish/ --configuration Release
@@ -69,3 +68,17 @@ jobs:
           asset_path: DiscordChatExporter.Gui/bin/Publish/Archive.zip
           asset_name: DiscordChatExporter.zip
           asset_content_type: application/zip
+
+      - name: Notify Discord
+        uses: satak/webrequest-action@v1.2.4
+        with:
+          url: ${{ secrets.DISCORD_WEBHOOK }}
+          method: POST
+          headers: |
+            {
+              "ContentType": "application/json; charset=UTF-8"
+            }
+          payload: |
+            {
+              "content": "**DiscordChatExporter** new version released!\nVersion: `${{ steps.get_version.outputs.tag }}`\nChangelog: <https://github.com/Tyrrrz/DiscordChatExporter/blob/${{ steps.get_version.outputs.tag }}/Changelog.md>"
+            }

.github/workflows/CI-Docker.yml

@@ -0,0 +1,23 @@
+name: Docker CI
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2.3.3
+
+      - name: Login
+        run: docker login -u tyrrrz -p ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Build
+        run: docker build -t tyrrrz/discordchatexporter:latest .
+
+      - name: Deploy (latest)
+        run: docker push tyrrrz/discordchatexporter:latest

.github/workflows/CI.yml

@@ -10,15 +10,23 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2.3.3
 
-      - name: Install .NET (v3.1)
+      - name: Install .NET
         uses: actions/setup-dotnet@v1.7.2
         with:
-          dotnet-version: 3.1.x
+          dotnet-version: 6.0.x
 
-      - name: Install .NET (v5.0)
-        uses: actions/setup-dotnet@v1.7.2
+      - name: Build & test
+        # Tests need access to secrets, so we can't run them against PRs because of limited trust
+        if: ${{ github.event_name != 'pull_request' }}
+        run: dotnet test --configuration Release --logger GitHubActions
+        env:
+          DISCORD_TOKEN: ${{ secrets.DISCORD_TOKEN }}
+          DISCORD_TOKEN_BOT: true
+
+      - name: Upload coverage
+        uses: codecov/codecov-action@v1.0.5
         with:
-          dotnet-version: 5.0.x
+          token: ${{ secrets.CODECOV_TOKEN }}
 
       - name: Build & publish (CLI)
         run: dotnet publish DiscordChatExporter.Cli/ -o DiscordChatExporter.Cli/bin/Publish/ --configuration Release
@@ -36,4 +44,4 @@ jobs:
         uses: actions/upload-artifact@v1
         with:
           name: DiscordChatExporter
-          path: DiscordChatExporter.Gui/bin/Publish/
+          path: DiscordChatExporter.Gui/bin/Publish/

.gitignore

@@ -19,4 +19,7 @@ bld/
 [Oo]bj/
 
 # Coverage
-*.opencover.xml
+*.opencover.xml
+
+# Secrets
+*.secret

Changelog.md

@@ -1,3 +1,72 @@
+### v2.31.1 (15-Dec-2021)
+
+- Fixed an issue which caused an exception when parsing certain custom emoji reactions.
+- [GUI] Improved user interface.
+
+### v2.31 (06-Dec-2021)
+
+- Changed target runtime of the application (both GUI and CLI) from .NET 3.1 to .NET 6. Those using the GUI version will not need to take any action as the application should install the necessary prerequisites automatically. Those using the CLI version will need to download and install .NET 6 runtime manually [from here](https://dotnet.microsoft.com/download/dotnet/6.0) (look for ".NET Runtime 6.0.x" section on the right and choose the distribution appropriate for your system).
+- [HTML] Updated layout design to match Discord more closely. (Thanks [@Artem](https://github.com/Scarg))
+- [HTML] Fixed an issue where markdown inside channel topic was not rendered correctly. (Thanks [@Emily](https://github.com/emillly-b))
+- [HTML] Fixed an issue where the layout was broken for messages containing text in right-to-left languages. (Thanks [@Emily](https://github.com/emillly-b))
+- Fixed an issue where text filters weren't matching content inside of embeds.
+- [GUI] Fixed a multitude of issues related to the bootstrapper.
+
+### v2.30.1 (28-Aug-2021)
+
+- [HTML] Changed user avatars to render using higher resolution images. (Thanks [@Chris Helder](https://github.com/TheDude53))
+- Fixed an issue where `has:file` message filter was not recognized. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- Fixed an issue where a unix timestamp marker with an invalid offset crashed the export process.
+
+### v2.30 (08-Aug-2021)
+
+- [HTML] Added special casing for Spotify track embeds to render them directly using an embedded player.
+- [HTML] Added special casing for plain image embeds to render them like image attachments.
+- [HTML] Added tooltip text for unix timestamp markers which shows the full date represented by the timestamp, regardless of configured date format. 
+- [HTML] Updated the fallback text shown when the referenced message could not be loaded to make it more explicit.
+- [HTML] Updated styling of quoted text in markdown to more closely resemble how it looks in Discord.
+- [HTML] Fixed an issue where some file formats were not correctly recognized as image or video attachments, which affected how they were rendered.
+- [HTML] Fixed an issue where formatting inside named links (e.g. `[**Bold link**](https://example.com)`) was not being parsed.
+- [HTML] Fixed an issue where inline embed fields were missing horizontal spacing between columns.
+- [HTML] Fixed other minor styling issues.
+
+### v2.29 (19-Jul-2021)
+
+- Added support for message filtering, which is accessible as an additional export parameter in the GUI and as the `--filter` option in the CLI. Message filters use a special syntax similar to Discord's search query syntax to allow specifying which messages should be included in the export. For example, you can limit the export to only include messages that contain image attachments (`has:image`) or messages from a certain user (`from:Tyrrrz`) or messages containing certain words (`hello world`), etc. You can also combine filters together (`hi mentions:Tyrrrz`, `from:Tyrrrz | from:96-LB`, `(mentions:Tyrrrz | from:Tyrrrz) has:image`) or negate them (`-has:link`). More thorough documentation coming soon. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- Added support for rendering mentions of voice channels, in addition to text channels.
+- Added support for rendering unix timestamp markers. Currently, style markers are ignored and timestamps are always rendered with the format configured in settings (or provided via `--date-format` option).
+- Updated in-app instructions for obtaining a user token. (Thanks [@Yudi](https://github.com/Yudi) and [@virtuallyvlad](https://github.com/virtuallyvlad))
+- [HTML] Improved visual appearance of the reference symbol (Г-shaped line in replies) to make it more closely resemble Discord's styling.
+- [HTML] Added more specific fallback text used when rendering referenced messages that contain no text content but have attachments or embeds.
+- [HTML] Fixed an issue where a broken embed author icon occupied visual space, ruining the embed layout. (Thanks [@Cliff J.](https://github.com/CliffJameston))
+- [GUI] Improved handling for fatal errors that may occur when attempting to export a channel. These errors are now displayed in a popup, allowing the user to try again instead of having the application crash completely.
+- [CLI] Fixed an issue where an attempt to export a channel resulted in `NotSupportedException` when the default encoding was set to `UTF8`.
+- [CLI] Fixed an issue where providing an incorrectly formatted partition limit via `-p|--partition` option resulted in a non-descriptive and unhelpful error.
+- Improved "Requested resource does not exist" error message by including the ID of the requested resource.
+
+### v2.28 (19-Jun-2021)
+
+- [HTML] Added special casing for YouTube video embeds to render them directly using an embedded player. (Thanks [@quentinmay](https://github.com/quentinmay))
+- [HTML] Added support for rendering standard emoji by code. Such emoji may sometimes be found in messages sent by bots or through webhooks. (Thanks [@CanePlayz](https://github.com/CanePlayz) and [@Lucas LaBuff](https://github.com/96-LB))
+- [HTML] Changed tooltips on standard emoji to show emoji code instead of their raw string representations. (Thanks [@CanePlayz](https://github.com/CanePlayz) and [@Lucas LaBuff](https://github.com/96-LB))
+- [HTML] Added tooltips on individual messages to show when those messages were sent. 
+- [HTML] Updated colors and minor styling elements to match Discord's new style direction after rebranding.
+- [HTML] Updated Twemoji URLs to use SVG image variants for better rendering quality.
+- [HTML] Changed user avatar URLs to include predetermined size query parameter for better rendering quality.
+- Changed embed rendering logic to prefer Discord-proxied URLs for external content, in order to avoid unnecessary HTTP requests to third parties.
+- Fixed an issue where exporting with media sometimes resulted in a crash due to lack of permissions to change file attributes. These errors are now ignored, which means that the creation, write, and access dates of downloaded files may sometimes not match the dates provided by Discord's CDN.
+- [HTML] Fixed styling issues when rendering embed footers.
+- [HTML] Fixed an issue where links didn't render properly inside referenced messages.
+- [HTML] Fixed an issue where standalone emoji were incorrectly enlarged inside referenced messages.
+- [HTML] Fixed an issue where clicking on a referenced message revealed spoilers inside of it.
+- [GUI] Fixed an issue where the list of missing components, reported by the prerequisite check at application startup, included Windows updates that were not applicable to the user's system due to the fact that other superseding updates have already been installed. This issue only affected users running DiscordChatExporter on Windows 7.
+- [GUI] Fixed a few other minor issues related to the prerequisite installation window.
+
+### v2.27.1 (08-Jun-2021)
+
+- [GUI] Application will now detect if the required .NET Runtime or any of its prerequisites are missing and prompt the user to download and install them automatically. **Experimental feature, please test it out and report any issues you may find!**
+- [CLI] Fixed an issue where the application crashed when exporting a channel that had square brackets as part of its name or category name. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+
 ### v2.27 (24-Apr-2021)
 
 - Added partitioning by file size. You can now use values such as `10mb` to indicate a size-based cut off point, in addition to values like `10` to indicate a number of messages. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
@@ -73,7 +142,7 @@
 
 ### 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.
+- 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 emoji. 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. 
@@ -112,7 +181,7 @@ Note that all existing and current HTML exports will likely not render accuratel
 
 - 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.
+- [HTML] Fixed an issue where some emoji 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)
@@ -125,7 +194,7 @@ Note that all existing and current HTML exports will likely not render accuratel
 - 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] Changed emoji parser to be less greedy. As a result it should match fewer character sequences that look like emoji but really aren't, but on the other hand it might miss some actual emoji. This means that some standard emoji (i.e. not custom server emoji) may not look like in Discord. This is a compromise I'm willing to take because detecting emoji 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.
 
@@ -166,8 +235,8 @@ Please note that CSV export is most likely not going to receive future updates a
 ### 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.
+- [HTML] Fixed an issue where some of the emoji were rendered via Twemoji while Discord renders them as plain text.
+- [HTML] Fixed an issue where emoji weren't jumbo if there were more than one of them.
 
 ### v2.12 (11-Apr-2019)
 
@@ -189,15 +258,15 @@ Please note that CSV export is most likely not going to receive future updates a
 
 ### 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 multiple emoji 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] Added support for animated emoji.
+- [HTML] Standard emoji 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.
@@ -257,7 +326,7 @@ Please note that CSV export is most likely not going to receive future updates a
 - 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 support for jumbo emoji (custom emoji 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.
@@ -281,7 +350,7 @@ Please note that CSV export is most likely not going to receive future updates a
 
 - 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 custom emoji.
 - Added support for user and role mentions.
 - Added support for channel mentions.
 - Fixed text in pre blocks not being wrapped correctly.

Contributing.md

@@ -1,56 +0,0 @@
-# Contributing
-
-DiscordChatExporter accepts contributions in the form of issues and pull requests.
-
-## Creating issues
-
-If you have a feature suggestion or want to report a bug, you are welcome to create an issue.
-
-Guidelines:
-
-- Avoid creating an issue if a similar one already exists. Look through existing open and closed issues first.
-- Keep your issue focused on one specific problem. If you have multiple suggestions or bug reports, please create separate issues for them.
-- Provide a descriptive title for your issue. Don't use generic titles like "A couple suggestions" or "Not working".
-- Provide more context in the body of the issue. If relevant, attach screenshots or screen recordings.
-- Remain civil and respectful when participating in discussions.
-
-## Creating pull requests
-
-If you want to contribute code to the project, you can do so by creating a pull request.
-
-Guidelines:
-
-- Make sure that there is an existing issue that describes the problem solved by your pull request. If there isn't one, please create it first.
-- Add a comment to the issue indicating that you want to submit a pull request for it. This can be a good opportunity to discuss possible solutions, finalize requirements, or ask questions.
-- Keep your pull request focused and as small as possible. If you want to contribute multiple unrelated changes, please create separate pull requests for them.
-- Follow the coding style and conventions already established by the project. When in doubt which style to use, ask in comments to your pull request.
-- If you want to start a discussion regarding a specific change you made, add a review comment to your own code. This can be used to highlight something important or to seek input from others.
-
-## Building the project locally
-
-Prerequisites:
-
-- [.NET 5.0 SDK](https://dotnet.microsoft.com/download/dotnet/5.0)
-- [.NET 3.1 SDK](https://dotnet.microsoft.com/download/dotnet/3.1) (temporarily as the app still targets .NET 3.1, but requires .NET 5.0 to build)
-- _(Optional)_ C#/.NET IDE, such as [JetBrains Rider](https://www.jetbrains.com/rider), [VS Code](https://code.visualstudio.com/docs/languages/csharp), or [Visual Studio](https://visualstudio.microsoft.com).
-
-To build the entire solution run the following command in the root of the repository:
-
-```sh
-> dotnet build
-```
-
-This will generate runtime artifacts for each project:
-
-```plaintext
-./DiscordChatExporter.Gui/bin/[Debug|Release]/[runtime]/*
-./DiscordChatExporter.Cli/bin/[Debug|Release]/[runtime]/*
-```
-
-You can also build and run a specific project directly.
-To do that, navigate to its directory and use `dotnet run`:
-
-```sh
-> cd DiscordChatExporter.Gui
-> dotnet run
-```

Directory.Build.props

@@ -1,8 +1,8 @@
 <Project>
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
-    <Version>2.27</Version>
+    <TargetFramework>net6.0</TargetFramework>
+    <Version>2.31.1</Version>
     <Company>Tyrrrz</Company>
     <Copyright>Copyright (c) Alexey Golub</Copyright>
     <LangVersion>preview</LangVersion>
@@ -10,4 +10,4 @@
     <WarningsAsErrors>nullable</WarningsAsErrors>
   </PropertyGroup>
 
-</Project>
+</Project>

DiscordChatExporter.Cli.Tests/DiscordChatExporter.Cli.Tests.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  
+  <PropertyGroup>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+    <CollectCoverage>true</CollectCoverage>
+    <CoverletOutputFormat>opencover</CoverletOutputFormat>
+    <NoWarn>$(NoWarn);xUnit1013</NoWarn>
+  </PropertyGroup>
+  
+  <ItemGroup>
+    <Content Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
+    <None Include="*.secret" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <PackageReference Include="AngleSharp" Version="0.16.1" />
+    <PackageReference Include="FluentAssertions" Version="6.2.0" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="1.2.0" />
+    <PackageReference Include="JsonExtensions" Version="1.2.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
+    <PackageReference Include="coverlet.msbuild" Version="3.1.0" PrivateAssets="all" />
+    <PackageReference Include="System.Reactive" Version="5.0.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DiscordChatExporter.Cli\DiscordChatExporter.Cli.csproj" />
+  </ItemGroup>
+
+</Project>

DiscordChatExporter.Cli.Tests/Fixtures/ExportWrapperFixture.cs

@@ -0,0 +1,131 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text.Json;
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using AngleSharp.Html.Dom;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
+using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.Utils;
+using DiscordChatExporter.Core.Discord;
+using DiscordChatExporter.Core.Exporting;
+using JsonExtensions;
+
+namespace DiscordChatExporter.Cli.Tests.Fixtures;
+
+public class ExportWrapperFixture : IDisposable
+{
+    private string DirPath { get; } = Path.Combine(
+        Path.GetDirectoryName(typeof(ExportWrapperFixture).Assembly.Location) ?? Directory.GetCurrentDirectory(),
+        "ExportCache",
+        Guid.NewGuid().ToString()
+    );
+
+    public ExportWrapperFixture() => DirectoryEx.Reset(DirPath);
+
+    private async ValueTask<string> ExportAsync(Snowflake channelId, ExportFormat format)
+    {
+        var fileName = channelId.ToString() + '.' + format.GetFileExtension();
+        var filePath = Path.Combine(DirPath, fileName);
+
+        // Perform export only if it hasn't been done before
+        if (!File.Exists(filePath))
+        {
+            await new ExportChannelsCommand
+            {
+                TokenValue = Secrets.DiscordToken,
+                IsBotToken = Secrets.IsDiscordTokenBot,
+                ChannelIds = new[] { channelId },
+                ExportFormat = format,
+                OutputPath = filePath
+            }.ExecuteAsync(new FakeConsole());
+        }
+
+        return await File.ReadAllTextAsync(filePath);
+    }
+
+    public async ValueTask<IHtmlDocument> ExportAsHtmlAsync(Snowflake channelId)
+    {
+        var data = await ExportAsync(channelId, ExportFormat.HtmlDark);
+        return Html.Parse(data);
+    }
+
+    public async ValueTask<JsonElement> ExportAsJsonAsync(Snowflake channelId)
+    {
+        var data = await ExportAsync(channelId, ExportFormat.Json);
+        return Json.Parse(data);
+    }
+
+    public async ValueTask<string> ExportAsPlainTextAsync(Snowflake channelId)
+    {
+        var data = await ExportAsync(channelId, ExportFormat.PlainText);
+        return data;
+    }
+
+    public async ValueTask<string> ExportAsCsvAsync(Snowflake channelId)
+    {
+        var data = await ExportAsync(channelId, ExportFormat.Csv);
+        return data;
+    }
+
+    public async ValueTask<IReadOnlyList<IElement>> GetMessagesAsHtmlAsync(Snowflake channelId)
+    {
+        var document = await ExportAsHtmlAsync(channelId);
+        return document.QuerySelectorAll("[data-message-id]").ToArray();
+    }
+
+    public async ValueTask<IReadOnlyList<JsonElement>> GetMessagesAsJsonAsync(Snowflake channelId)
+    {
+        var document = await ExportAsJsonAsync(channelId);
+        return document.GetProperty("messages").EnumerateArray().ToArray();
+    }
+
+    public async ValueTask<IElement> GetMessageAsHtmlAsync(Snowflake channelId, Snowflake messageId)
+    {
+        var messages = await GetMessagesAsHtmlAsync(channelId);
+
+        var message = messages.SingleOrDefault(e =>
+            string.Equals(
+                e.GetAttribute("data-message-id"),
+                messageId.ToString(),
+                StringComparison.OrdinalIgnoreCase
+            )
+        );
+
+        if (message is null)
+        {
+            throw new InvalidOperationException(
+                $"Message '{messageId}' does not exist in export of channel '{channelId}'."
+            );
+        }
+
+        return message;
+    }
+
+    public async ValueTask<JsonElement> GetMessageAsJsonAsync(Snowflake channelId, Snowflake messageId)
+    {
+        var messages = await GetMessagesAsJsonAsync(channelId);
+
+        var message = messages.FirstOrDefault(j =>
+            string.Equals(
+                j.GetProperty("id").GetString(),
+                messageId.ToString(),
+                StringComparison.OrdinalIgnoreCase
+            )
+        );
+
+        if (message.ValueKind == JsonValueKind.Undefined)
+        {
+            throw new InvalidOperationException(
+                $"Message '{messageId}' does not exist in export of channel '{channelId}'."
+            );
+        }
+
+        return message;
+    }
+
+    public void Dispose() => DirectoryEx.DeleteIfExists(DirPath);
+}

DiscordChatExporter.Cli.Tests/Fixtures/TempOutputFixture.cs

@@ -0,0 +1,22 @@
+using System;
+using System.IO;
+using DiscordChatExporter.Cli.Tests.Utils;
+
+namespace DiscordChatExporter.Cli.Tests.Fixtures;
+
+public class TempOutputFixture : IDisposable
+{
+    public string DirPath { get; } = Path.Combine(
+        Path.GetDirectoryName(typeof(TempOutputFixture).Assembly.Location) ?? Directory.GetCurrentDirectory(),
+        "Temp",
+        Guid.NewGuid().ToString()
+    );
+
+    public TempOutputFixture() => DirectoryEx.Reset(DirPath);
+
+    public string GetTempFilePath(string fileName) => Path.Combine(DirPath, fileName);
+
+    public string GetTempFilePath() => GetTempFilePath(Guid.NewGuid() + ".tmp");
+
+    public void Dispose() => DirectoryEx.DeleteIfExists(DirPath);
+}

DiscordChatExporter.Cli.Tests/Infra/Secrets.cs

@@ -0,0 +1,45 @@
+using System;
+using System.IO;
+
+namespace DiscordChatExporter.Cli.Tests.Infra;
+
+internal static class Secrets
+{
+    private static readonly Lazy<string> DiscordTokenLazy = new(() =>
+    {
+        var fromEnvironment = Environment.GetEnvironmentVariable("DISCORD_TOKEN");
+        if (!string.IsNullOrWhiteSpace(fromEnvironment))
+            return fromEnvironment;
+
+        var secretFilePath = Path.Combine(
+            Path.GetDirectoryName(typeof(Secrets).Assembly.Location) ?? Directory.GetCurrentDirectory(),
+            "DiscordToken.secret"
+        );
+
+        if (File.Exists(secretFilePath))
+            return File.ReadAllText(secretFilePath);
+
+        throw new InvalidOperationException("Discord token not provided for tests.");
+    });
+
+    private static readonly Lazy<bool> IsDiscordTokenBotLazy = new(() =>
+    {
+        var fromEnvironment = Environment.GetEnvironmentVariable("DISCORD_TOKEN_BOT");
+        if (!string.IsNullOrWhiteSpace(fromEnvironment))
+            return string.Equals(fromEnvironment, "true", StringComparison.OrdinalIgnoreCase);
+
+        var secretFilePath = Path.Combine(
+            Path.GetDirectoryName(typeof(Secrets).Assembly.Location) ?? Directory.GetCurrentDirectory(),
+            "DiscordTokenBot.secret"
+        );
+
+        if (File.Exists(secretFilePath))
+            return true;
+
+        return false;
+    });
+
+    public static string DiscordToken => DiscordTokenLazy.Value;
+
+    public static bool IsDiscordTokenBot => IsDiscordTokenBotLazy.Value;
+}

DiscordChatExporter.Cli.Tests/Readme.md

@@ -0,0 +1,14 @@
+# DiscordChatExporter Tests
+
+This test suite runs against a real Discord server, specifically created to exercise different behaviors required by the test scenarios.
+In order to run these tests locally, you need to join the test server and configure your authentication token.
+
+1. Join the server: https://discord.gg/eRV8Vap5bm
+2. Locate your Discord authentication token
+3. Specify your token using a file or an environment variable:
+    - **Using a file**: put your token in a new `DiscordToken.secret` file created in this directory
+    - **Using an environment variable**: set `DISCORD_TOKEN` variable to your token
+4. Run the tests: `dotnet test`
+
+> If you want to have a new test case or a scenario added, please let me know in your pull request.
+Currently, it's not possible to add them by yourself.

DiscordChatExporter.Cli.Tests/Specs/CsvWriting/ContentSpecs.cs

@@ -0,0 +1,30 @@
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.CsvWriting;
+
+public record ContentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Messages_are_exported_correctly()
+    {
+        // Act
+        var document = await ExportWrapper.ExportAsCsvAsync(ChannelIds.DateRangeTestCases);
+
+        // Assert
+        document.Should().ContainAll(
+            "Tyrrrz#5447",
+            "Hello world",
+            "Goodbye world",
+            "Foo bar",
+            "Hurdle Durdle",
+            "One",
+            "Two",
+            "Three",
+            "Yeet"
+        );
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/DateRangeSpecs.cs

@@ -0,0 +1,159 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using DiscordChatExporter.Core.Exporting;
+using FluentAssertions;
+using JsonExtensions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs;
+
+public record DateRangeSpecs(TempOutputFixture TempOutput) : IClassFixture<TempOutputFixture>
+{
+    [Fact]
+    public async Task Messages_filtered_after_specific_date_only_include_messages_sent_after_that_date()
+    {
+        // Arrange
+        var after = new DateTimeOffset(2021, 07, 24, 0, 0, 0, TimeSpan.Zero);
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            After = Snowflake.FromDate(after)
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        var timestamps = document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        // Assert
+        timestamps.All(t => t > after).Should().BeTrue();
+
+        timestamps.Should().BeEquivalentTo(new[]
+        {
+            new DateTimeOffset(2021, 07, 24, 13, 49, 13, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 38, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 39, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 40, TimeSpan.Zero),
+            new DateTimeOffset(2021, 09, 08, 14, 26, 35, TimeSpan.Zero)
+        }, o =>
+        {
+            return o
+                .Using<DateTimeOffset>(ctx =>
+                    ctx.Subject.Should().BeCloseTo(ctx.Expectation, TimeSpan.FromSeconds(1))
+                )
+                .WhenTypeIs<DateTimeOffset>();
+        });
+    }
+
+    [Fact]
+    public async Task Messages_filtered_before_specific_date_only_include_messages_sent_before_that_date()
+    {
+        // Arrange
+        var before = new DateTimeOffset(2021, 07, 24, 0, 0, 0, TimeSpan.Zero);
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            Before = Snowflake.FromDate(before)
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        var timestamps = document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        // Assert
+        timestamps.All(t => t < before).Should().BeTrue();
+
+        timestamps.Should().BeEquivalentTo(new[]
+        {
+            new DateTimeOffset(2021, 07, 19, 13, 34, 18, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 19, 15, 58, 48, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 19, 17, 23, 58, TimeSpan.Zero)
+        }, o =>
+        {
+            return o
+                .Using<DateTimeOffset>(ctx =>
+                    ctx.Subject.Should().BeCloseTo(ctx.Expectation, TimeSpan.FromSeconds(1))
+                )
+                .WhenTypeIs<DateTimeOffset>();
+        });
+    }
+
+    [Fact]
+    public async Task Messages_filtered_between_specific_dates_only_include_messages_sent_between_those_dates()
+    {
+        // Arrange
+        var after = new DateTimeOffset(2021, 07, 24, 0, 0, 0, TimeSpan.Zero);
+        var before = new DateTimeOffset(2021, 08, 01, 0, 0, 0, TimeSpan.Zero);
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            Before = Snowflake.FromDate(before),
+            After = Snowflake.FromDate(after)
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        var timestamps = document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        // Assert
+        timestamps.All(t => t < before && t > after).Should().BeTrue();
+
+        timestamps.Should().BeEquivalentTo(new[]
+        {
+            new DateTimeOffset(2021, 07, 24, 13, 49, 13, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 38, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 39, TimeSpan.Zero),
+            new DateTimeOffset(2021, 07, 24, 14, 52, 40, TimeSpan.Zero)
+        }, o =>
+        {
+            return o
+                .Using<DateTimeOffset>(ctx =>
+                    ctx.Subject.Should().BeCloseTo(ctx.Expectation, TimeSpan.FromSeconds(1))
+                )
+                .WhenTypeIs<DateTimeOffset>();
+        });
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/FilterSpecs.cs

@@ -0,0 +1,134 @@
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Exporting;
+using DiscordChatExporter.Core.Exporting.Filtering;
+using FluentAssertions;
+using JsonExtensions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs;
+
+public record FilterSpecs(TempOutputFixture TempOutput) : IClassFixture<TempOutputFixture>
+{
+    [Fact]
+    public async Task Messages_filtered_by_text_only_include_messages_that_contain_that_text()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("some text")
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        // Assert
+        document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("Some random text");
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_author_only_include_messages_sent_by_that_author()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("from:Tyrrrz")
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        // Assert
+        document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("author").GetProperty("name").GetString())
+            .Should()
+            .AllBe("Tyrrrz");
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_content_only_include_messages_that_have_that_content()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("has:image")
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        // Assert
+        document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("This has image");
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_mention_only_include_messages_that_have_that_mention()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("mentions:Tyrrrz")
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Json.Parse(data);
+
+        // Assert
+        document
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("This has mention");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/HtmlWriting/AttachmentSpecs.cs

@@ -0,0 +1,92 @@
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.HtmlWriting;
+
+public record AttachmentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Message_with_a_generic_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885587844989612074")
+        );
+
+        var fileUrl = message.QuerySelector("a")?.GetAttribute("href");
+
+        // Assert
+        message.Text().Should().ContainAll(
+            "Generic file attachment",
+            "Test.txt",
+            "11 bytes"
+        );
+
+        fileUrl.Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885587844964417596/Test.txt"
+        );
+    }
+
+    [Fact]
+    public async Task Message_with_an_image_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885654862656843786")
+        );
+
+        var imageUrl = message.QuerySelector("img")?.GetAttribute("src");
+
+        // Assert
+        message.Text().Should().Contain("Image attachment");
+
+        imageUrl.Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885654862430359613/bird-thumbnail.png"
+        );
+    }
+
+    [Fact]
+    public async Task Message_with_a_video_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885655761919836171")
+        );
+
+        var videoUrl = message.QuerySelector("video source")?.GetAttribute("src");
+
+        // Assert
+        message.Text().Should().Contain("Video attachment");
+
+        videoUrl.Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885655761512968233/file_example_MP4_640_3MG.mp4"
+        );
+    }
+
+    [Fact]
+    public async Task Message_with_an_audio_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885656175620808734")
+        );
+
+        var audioUrl = message.QuerySelector("audio source")?.GetAttribute("src");
+
+        // Assert
+        message.Text().Should().Contain("Audio attachment");
+
+        audioUrl.Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885656175348187146/file_example_MP3_1MG.mp3"
+        );
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/HtmlWriting/ContentSpecs.cs

@@ -0,0 +1,42 @@
+using System.Linq;
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.HtmlWriting;
+
+public record ContentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Messages_are_exported_correctly()
+    {
+        // Act
+        var messages = await ExportWrapper.GetMessagesAsHtmlAsync(ChannelIds.DateRangeTestCases);
+
+        // Assert
+        messages.Select(e => e.GetAttribute("data-message-id")).Should().Equal(
+            "866674314627121232",
+            "866710679758045195",
+            "866732113319428096",
+            "868490009366396958",
+            "868505966528835604",
+            "868505969821364245",
+            "868505973294268457",
+            "885169254029213696"
+        );
+
+        messages.Select(e => e.QuerySelector(".chatlog__content")?.Text().Trim()).Should().Equal(
+            "Hello world",
+            "Goodbye world",
+            "Foo bar",
+            "Hurdle Durdle",
+            "One",
+            "Two",
+            "Three",
+            "Yeet"
+        );
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/HtmlWriting/EmbedSpecs.cs

@@ -0,0 +1,63 @@
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.HtmlWriting;
+
+public record EmbedSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Message_with_an_embed_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("866769910729146400")
+        );
+
+        // Assert
+        message.Text().Should().ContainAll(
+            "Embed author",
+            "Embed title",
+            "Embed description",
+            "Field 1", "Value 1",
+            "Field 2", "Value 2",
+            "Field 3", "Value 3",
+            "Embed footer"
+        );
+    }
+
+    [Fact]
+    public async Task Message_with_a_Spotify_track_is_rendered_using_an_iframe()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("867886632203976775")
+        );
+
+        var iframeSrc = message.QuerySelector("iframe")?.GetAttribute("src");
+
+        // Assert
+        iframeSrc.Should().StartWithEquivalentOf("https://open.spotify.com/embed/track/1LHZMWefF9502NPfArRfvP");
+    }
+
+    [Fact]
+    public async Task Message_with_a_YouTube_video_is_rendered_using_an_iframe()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("866472508588294165")
+        );
+
+        var iframeSrc = message.QuerySelector("iframe")?.GetAttribute("src");
+
+        // Assert
+        iframeSrc.Should().StartWithEquivalentOf("https://www.youtube.com/embed/qOWW4OlgbvE");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/HtmlWriting/MentionSpecs.cs

@@ -0,0 +1,65 @@
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.HtmlWriting;
+
+public record MentionSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task User_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866458840245076028")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("User mention: @Tyrrrz");
+        message.InnerHtml.Should().Contain("Tyrrrz#5447");
+    }
+
+    [Fact]
+    public async Task Text_channel_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459040480624680")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("Text channel mention: #mention-tests");
+    }
+
+    [Fact]
+    public async Task Voice_channel_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459175462633503")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("Voice channel mention: 🔊chaos-vc");
+    }
+
+    [Fact]
+    public async Task Role_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459254693429258")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("Role mention: @Role 1");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/HtmlWriting/ReplySpecs.cs

@@ -0,0 +1,56 @@
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.HtmlWriting;
+
+public record ReplySpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Reply_to_a_normal_message_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.ReplyTestCases,
+            Snowflake.Parse("866460738239725598")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("reply to original");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Trim().Should().Be("original");
+    }
+
+    [Fact]
+    public async Task Reply_to_a_deleted_message_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.ReplyTestCases,
+            Snowflake.Parse("866460975388819486")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("reply to deleted");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Trim().Should()
+            .Be("Original message was deleted or could not be loaded.");
+    }
+
+    [Fact]
+    public async Task Reply_to_a_empty_message_with_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.ReplyTestCases,
+            Snowflake.Parse("866462470335627294")
+        );
+
+        // Assert
+        message.Text().Trim().Should().Be("reply to attachment");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Trim().Should()
+            .Be("Click to see attachment 🖼️");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/JsonWriting/AttachmentSpecs.cs

@@ -0,0 +1,100 @@
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.JsonWriting;
+
+public record AttachmentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Message_with_a_generic_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885587844989612074")
+        );
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Generic file attachment");
+
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885587844964417596/Test.txt"
+        );
+        attachments.Single().GetProperty("fileName").GetString().Should().Be("Test.txt");
+        attachments.Single().GetProperty("fileSizeBytes").GetInt64().Should().Be(11);
+    }
+
+    [Fact]
+    public async Task Message_with_an_image_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885654862656843786")
+        );
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Image attachment");
+
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885654862430359613/bird-thumbnail.png"
+        );
+        attachments.Single().GetProperty("fileName").GetString().Should().Be("bird-thumbnail.png");
+        attachments.Single().GetProperty("fileSizeBytes").GetInt64().Should().Be(466335);
+    }
+
+    [Fact]
+    public async Task Message_with_a_video_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885655761919836171")
+        );
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Video attachment");
+
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885655761512968233/file_example_MP4_640_3MG.mp4"
+        );
+        attachments.Single().GetProperty("fileName").GetString().Should().Be("file_example_MP4_640_3MG.mp4");
+        attachments.Single().GetProperty("fileSizeBytes").GetInt64().Should().Be(3114374);
+    }
+
+    [Fact]
+    public async Task Message_with_an_audio_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885656175620808734")
+        );
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Audio attachment");
+
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().StartWithEquivalentOf(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885656175348187146/file_example_MP3_1MG.mp3"
+        );
+        attachments.Single().GetProperty("fileName").GetString().Should().Be("file_example_MP3_1MG.mp3");
+        attachments.Single().GetProperty("fileSizeBytes").GetInt64().Should().Be(1087849);
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/JsonWriting/ContentSpecs.cs

@@ -0,0 +1,41 @@
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.JsonWriting;
+
+public record ContentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Messages_are_exported_correctly()
+    {
+        // Act
+        var messages = await ExportWrapper.GetMessagesAsJsonAsync(ChannelIds.DateRangeTestCases);
+
+        // Assert
+        messages.Select(j => j.GetProperty("id").GetString()).Should().Equal(
+            "866674314627121232",
+            "866710679758045195",
+            "866732113319428096",
+            "868490009366396958",
+            "868505966528835604",
+            "868505969821364245",
+            "868505973294268457",
+            "885169254029213696"
+        );
+
+        messages.Select(j => j.GetProperty("content").GetString()).Should().Equal(
+            "Hello world",
+            "Goodbye world",
+            "Foo bar",
+            "Hurdle Durdle",
+            "One",
+            "Two",
+            "Three",
+            "Yeet"
+        );
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/JsonWriting/EmbedSpecs.cs

@@ -0,0 +1,57 @@
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.JsonWriting;
+
+public record EmbedSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Message_with_an_embed_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("866769910729146400")
+        );
+
+        var embed = message
+            .GetProperty("embeds")
+            .EnumerateArray()
+            .Single();
+
+        var embedAuthor = embed.GetProperty("author");
+        var embedThumbnail = embed.GetProperty("thumbnail");
+        var embedFooter = embed.GetProperty("footer");
+        var embedFields = embed.GetProperty("fields").EnumerateArray().ToArray();
+
+        // Assert
+        embed.GetProperty("title").GetString().Should().Be("Embed title");
+        embed.GetProperty("url").GetString().Should().Be("https://example.com");
+        embed.GetProperty("timestamp").GetString().Should().Be("2021-07-14T21:00:00+00:00");
+        embed.GetProperty("description").GetString().Should().Be("**Embed** _description_");
+        embed.GetProperty("color").GetString().Should().Be("#58B9FF");
+        embedAuthor.GetProperty("name").GetString().Should().Be("Embed author");
+        embedAuthor.GetProperty("url").GetString().Should().Be("https://example.com/author");
+        embedAuthor.GetProperty("iconUrl").GetString().Should().NotBeNullOrWhiteSpace();
+        embedThumbnail.GetProperty("url").GetString().Should().NotBeNullOrWhiteSpace();
+        embedThumbnail.GetProperty("width").GetInt32().Should().Be(120);
+        embedThumbnail.GetProperty("height").GetInt32().Should().Be(120);
+        embedFooter.GetProperty("text").GetString().Should().Be("Embed footer");
+        embedFooter.GetProperty("iconUrl").GetString().Should().NotBeNullOrWhiteSpace();
+        embedFields.Should().HaveCount(3);
+        embedFields[0].GetProperty("name").GetString().Should().Be("Field 1");
+        embedFields[0].GetProperty("value").GetString().Should().Be("Value 1");
+        embedFields[0].GetProperty("isInline").GetBoolean().Should().BeTrue();
+        embedFields[1].GetProperty("name").GetString().Should().Be("Field 2");
+        embedFields[1].GetProperty("value").GetString().Should().Be("Value 2");
+        embedFields[1].GetProperty("isInline").GetBoolean().Should().BeTrue();
+        embedFields[2].GetProperty("name").GetString().Should().Be("Field 3");
+        embedFields[2].GetProperty("value").GetString().Should().Be("Value 3");
+        embedFields[2].GetProperty("isInline").GetBoolean().Should().BeTrue();
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/JsonWriting/MentionSpecs.cs

@@ -0,0 +1,70 @@
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Discord;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.JsonWriting;
+
+public record MentionSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task User_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866458840245076028")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("User mention: @Tyrrrz");
+
+        message
+            .GetProperty("mentions")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("id").GetString())
+            .Should().Contain("128178626683338752");
+    }
+
+    [Fact]
+    public async Task Text_channel_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459040480624680")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Text channel mention: #mention-tests");
+    }
+
+    [Fact]
+    public async Task Voice_channel_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459175462633503")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Voice channel mention: #chaos-vc [voice]");
+    }
+
+    [Fact]
+    public async Task Role_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await ExportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866459254693429258")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Role mention: @Role 1");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/PartitioningSpecs.cs

@@ -0,0 +1,66 @@
+using System.IO;
+using System.Threading.Tasks;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Core.Exporting;
+using DiscordChatExporter.Core.Exporting.Partitioning;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs;
+
+public record PartitioningSpecs(TempOutputFixture TempOutput) : IClassFixture<TempOutputFixture>
+{
+    [Fact]
+    public async Task Messages_partitioned_by_count_are_split_into_multiple_files_correctly()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+        var fileNameWithoutExt = Path.GetFileNameWithoutExtension(filePath);
+        var dirPath = Path.GetDirectoryName(filePath) ?? Directory.GetCurrentDirectory();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath,
+            PartitionLimit = PartitionLimit.Parse("3")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Directory.EnumerateFiles(dirPath, fileNameWithoutExt + "*")
+            .Should()
+            .HaveCount(3);
+    }
+
+    [Fact]
+    public async Task Messages_partitioned_by_file_size_are_split_into_multiple_files_correctly()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+        var fileNameWithoutExt = Path.GetFileNameWithoutExtension(filePath);
+        var dirPath = Path.GetDirectoryName(filePath) ?? Directory.GetCurrentDirectory();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath,
+            PartitionLimit = PartitionLimit.Parse("20kb")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Directory.EnumerateFiles(dirPath, fileNameWithoutExt + "*")
+            .Should()
+            .HaveCount(2);
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/PlainTextWriting/ContentSpecs.cs

@@ -0,0 +1,30 @@
+using System.Threading.Tasks;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.TestData;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs.PlainTextWriting;
+
+public record ContentSpecs(ExportWrapperFixture ExportWrapper) : IClassFixture<ExportWrapperFixture>
+{
+    [Fact]
+    public async Task Messages_are_exported_correctly()
+    {
+        // Act
+        var document = await ExportWrapper.ExportAsPlainTextAsync(ChannelIds.DateRangeTestCases);
+
+        // Assert
+        document.Should().ContainAll(
+            "Tyrrrz#5447",
+            "Hello world",
+            "Goodbye world",
+            "Foo bar",
+            "Hurdle Durdle",
+            "One",
+            "Two",
+            "Three",
+            "Yeet"
+        );
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/SelfContainedSpecs.cs

@@ -0,0 +1,48 @@
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
+using DiscordChatExporter.Cli.Tests.Fixtures;
+using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.TestData;
+using DiscordChatExporter.Cli.Tests.Utils;
+using DiscordChatExporter.Core.Exporting;
+using FluentAssertions;
+using Xunit;
+
+namespace DiscordChatExporter.Cli.Tests.Specs;
+
+public record SelfContainedSpecs(TempOutputFixture TempOutput) : IClassFixture<TempOutputFixture>
+{
+    [Fact]
+    public async Task Messages_in_self_contained_export_only_reference_local_file_resources()
+    {
+        // Arrange
+        var filePath = TempOutput.GetTempFilePath();
+        var dirPath = Path.GetDirectoryName(filePath) ?? Directory.GetCurrentDirectory();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            TokenValue = Secrets.DiscordToken,
+            IsBotToken = Secrets.IsDiscordTokenBot,
+            ChannelIds = new[] { ChannelIds.SelfContainedTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath,
+            ShouldDownloadMedia = true
+        }.ExecuteAsync(new FakeConsole());
+
+        var data = await File.ReadAllTextAsync(filePath);
+        var document = Html.Parse(data);
+
+        // Assert
+        document
+            .QuerySelectorAll("body [src]")
+            .Select(e => e.GetAttribute("src")!)
+            .Select(f => Path.GetFullPath(f, dirPath))
+            .All(File.Exists)
+            .Should()
+            .BeTrue();
+    }
+}

DiscordChatExporter.Cli.Tests/TestData/ChannelIds.cs

@@ -0,0 +1,20 @@
+using DiscordChatExporter.Core.Discord;
+
+namespace DiscordChatExporter.Cli.Tests.TestData;
+
+public static class ChannelIds
+{
+    public static Snowflake AttachmentTestCases { get; } = Snowflake.Parse("885587741654536192");
+
+    public static Snowflake DateRangeTestCases { get; } = Snowflake.Parse("866674248747319326");
+
+    public static Snowflake EmbedTestCases { get; } = Snowflake.Parse("866472452459462687");
+
+    public static Snowflake FilterTestCases { get; } = Snowflake.Parse("866744075033641020");
+
+    public static Snowflake MentionTestCases { get; } = Snowflake.Parse("866458801389174794");
+
+    public static Snowflake ReplyTestCases { get; } = Snowflake.Parse("866459871934677052");
+
+    public static Snowflake SelfContainedTestCases { get; } = Snowflake.Parse("887441432678379560");
+}

DiscordChatExporter.Cli.Tests/Utils/DirectoryEx.cs

@@ -0,0 +1,23 @@
+using System.IO;
+
+namespace DiscordChatExporter.Cli.Tests.Utils;
+
+internal static class DirectoryEx
+{
+    public static void DeleteIfExists(string dirPath, bool recursive = true)
+    {
+        try
+        {
+            Directory.Delete(dirPath, recursive);
+        }
+        catch (DirectoryNotFoundException)
+        {
+        }
+    }
+
+    public static void Reset(string dirPath)
+    {
+        DeleteIfExists(dirPath);
+        Directory.CreateDirectory(dirPath);
+    }
+}

DiscordChatExporter.Cli.Tests/Utils/Html.cs

@@ -0,0 +1,11 @@
+using AngleSharp.Html.Dom;
+using AngleSharp.Html.Parser;
+
+namespace DiscordChatExporter.Cli.Tests.Utils;
+
+internal static class Html
+{
+    private static readonly IHtmlParser Parser = new HtmlParser();
+
+    public static IHtmlDocument Parse(string source) => Parser.ParseDocument(source);
+}

DiscordChatExporter.Cli.Tests/xunit.runner.json

@@ -0,0 +1,5 @@
+{
+  "$schema": "https://xunit.net/schema/current/xunit.runner.schema.json",
+  "methodDisplayOptions": "all",
+  "methodDisplay": "method"
+}

DiscordChatExporter.Cli/Commands/Base/ExportCommandBase.cs

@@ -12,134 +12,154 @@ using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Discord.Data;
 using DiscordChatExporter.Core.Exceptions;
 using DiscordChatExporter.Core.Exporting;
+using DiscordChatExporter.Core.Exporting.Filtering;
 using DiscordChatExporter.Core.Exporting.Partitioning;
-using DiscordChatExporter.Core.Utils.Extensions;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands.Base
+namespace DiscordChatExporter.Cli.Commands.Base;
+
+public abstract class ExportCommandBase : TokenCommandBase
 {
-    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, each limited to this number of messages (e.g. '100') or file size (e.g. '10mb').")]
+    public PartitionLimit PartitionLimit { get; init; } = PartitionLimit.Null;
+
+    [CommandOption("filter", Description = "Only include messages that satisfy this filter (e.g. 'from:foo#1234' or 'has:image').")]
+    public MessageFilter MessageFilter { get; init; } = MessageFilter.Null;
+
+    [CommandOption("parallel", Description = "Limits how many channels can be exported in parallel.")]
+    public int ParallelLimit { get; init; } = 1;
+
+    [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";
+
+    private ChannelExporter? _channelExporter;
+    protected ChannelExporter Exporter => _channelExporter ??= new ChannelExporter(Discord);
+
+    protected async ValueTask ExecuteAsync(IConsole console, IReadOnlyList<Channel> channels)
     {
-        [CommandOption("output", 'o', Description = "Output file or directory path.")]
-        public string OutputPath { get; init; } = Directory.GetCurrentDirectory();
+        var cancellationToken = console.RegisterCancellationHandler();
 
-        [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, each limited to this number of messages (e.g. 100) or file size (e.g. 10mb).")]
-        public PartitionLimit PartitionLimit { get; init; } = NullPartitionLimit.Instance;
-
-        [CommandOption("parallel", Description = "Limits how many channels can be exported in parallel.")]
-        public int ParallelLimit { get; init; } = 1;
-
-        [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";
-
-        private ChannelExporter? _channelExporter;
-        protected ChannelExporter Exporter => _channelExporter ??= new ChannelExporter(Discord);
-
-        protected async ValueTask ExportAsync(IConsole console, IReadOnlyList<Channel> channels)
+        if (ShouldReuseMedia && !ShouldDownloadMedia)
         {
-            await console.Output.WriteLineAsync($"Exporting {channels.Count} channel(s)...");
+            throw new CommandException("Option --reuse-media cannot be used without --media.");
+        }
 
-            var errors = new ConcurrentDictionary<Channel, string>();
+        var errors = new ConcurrentDictionary<Channel, string>();
 
-            // Wrap everything in a progress ticker
-            await console.CreateProgressTicker().StartAsync(async progressContext =>
-            {
-                await channels.ParallelForEachAsync(async channel =>
+        // Export
+        await console.Output.WriteLineAsync($"Exporting {channels.Count} channel(s)...");
+        await console.CreateProgressTicker().StartAsync(async progressContext =>
+        {
+            await Parallel.ForEachAsync(
+                channels,
+                new ParallelOptions
+                {
+                    MaxDegreeOfParallelism = Math.Max(1, ParallelLimit),
+                    CancellationToken = cancellationToken
+                },
+                async (channel, innerCancellationToken) =>
                 {
-                    // Export
                     try
                     {
-                        await progressContext.StartTaskAsync($"{channel.Category} / {channel.Name}", async progress =>
-                        {
-                            var guild = await Discord.GetGuildAsync(channel.GuildId);
+                        await progressContext.StartTaskAsync(
+                            $"{channel.Category.Name} / {channel.Name}",
+                            async progress =>
+                            {
+                                var guild = await Discord.GetGuildAsync(channel.GuildId, innerCancellationToken);
 
-                            var request = new ExportRequest(
-                                guild,
-                                channel,
-                                OutputPath,
-                                ExportFormat,
-                                After,
-                                Before,
-                                PartitionLimit,
-                                ShouldDownloadMedia,
-                                ShouldReuseMedia,
-                                DateFormat
-                            );
+                                var request = new ExportRequest(
+                                    guild,
+                                    channel,
+                                    OutputPath,
+                                    ExportFormat,
+                                    After,
+                                    Before,
+                                    PartitionLimit,
+                                    MessageFilter,
+                                    ShouldDownloadMedia,
+                                    ShouldReuseMedia,
+                                    DateFormat
+                                );
 
-                            await Exporter.ExportChannelAsync(request, progress);
-                        });
+                                await Exporter.ExportChannelAsync(request, progress, innerCancellationToken);
+                            }
+                        );
                     }
-                    catch (DiscordChatExporterException ex) when (!ex.IsCritical)
+                    catch (DiscordChatExporterException ex) when (!ex.IsFatal)
                     {
                         errors[channel] = ex.Message;
                     }
-                }, ParallelLimit.ClampMin(1));
-            });
+                }
+            );
+        });
 
-            // Print result
-            using (console.WithForegroundColor(ConsoleColor.White))
+        // Print result
+        using (console.WithForegroundColor(ConsoleColor.White))
+        {
+            await console.Output.WriteLineAsync(
+                $"Successfully exported {channels.Count - errors.Count} channel(s)."
+            );
+        }
+
+        // Print errors
+        if (errors.Any())
+        {
+            await console.Output.WriteLineAsync();
+
+            using (console.WithForegroundColor(ConsoleColor.Red))
             {
                 await console.Output.WriteLineAsync(
-                    $"Successfully exported {channels.Count - errors.Count} channel(s)."
+                    $"Failed to export {errors.Count} channel(s):"
                 );
             }
 
-            // Print errors
-            if (errors.Any())
+            foreach (var (channel, error) in errors)
             {
-                await console.Output.WriteLineAsync();
+                await console.Output.WriteAsync($"{channel.Category.Name} / {channel.Name}: ");
 
                 using (console.WithForegroundColor(ConsoleColor.Red))
-                {
-                    await console.Output.WriteLineAsync(
-                        $"Failed to export {errors.Count} channel(s):"
-                    );
-                }
-
-                foreach (var (channel, error) in errors)
-                {
-                    await console.Output.WriteAsync($"{channel.Category} / {channel.Name}: ");
-
-                    using (console.WithForegroundColor(ConsoleColor.Red))
-                        await console.Output.WriteLineAsync(error);
-                }
-
-                await console.Output.WriteLineAsync();
+                    await console.Output.WriteLineAsync(error);
             }
 
-            // Fail the command if ALL channels failed to export.
-            // Having some of the channels fail to export is fine and expected.
-            if (errors.Count >= channels.Count)
-            {
-                throw new CommandException("Export failed.");
-            }
-
-            await console.Output.WriteLineAsync("Done.");
+            await console.Output.WriteLineAsync();
         }
 
-        public override ValueTask ExecuteAsync(IConsole console)
+        // Fail the command only if ALL channels failed to export.
+        // Having some of the channels fail to export is expected.
+        if (errors.Count >= channels.Count)
         {
-            if (ShouldReuseMedia && !ShouldDownloadMedia)
-            {
-                throw new CommandException("Option --reuse-media cannot be used without --media.");
-            }
-
-            return default;
+            throw new CommandException("Export failed.");
         }
     }
+
+    protected async ValueTask ExecuteAsync(IConsole console, IReadOnlyList<Snowflake> channelIds)
+    {
+        var cancellationToken = console.RegisterCancellationHandler();
+        var channels = new List<Channel>();
+
+        foreach (var channelId in channelIds)
+        {
+            var channel = await Discord.GetChannelAsync(channelId, cancellationToken);
+            channels.Add(channel);
+        }
+
+        await ExecuteAsync(console, channels);
+    }
 }

DiscordChatExporter.Cli/Commands/Base/TokenCommandBase.cs

@@ -4,26 +4,26 @@ using CliFx.Attributes;
 using CliFx.Infrastructure;
 using DiscordChatExporter.Core.Discord;
 
-namespace DiscordChatExporter.Cli.Commands.Base
+namespace DiscordChatExporter.Cli.Commands.Base;
+
+public abstract class TokenCommandBase : ICommand
 {
-    public abstract class TokenCommandBase : ICommand
-    {
-        [CommandOption("token", 't', IsRequired = true, EnvironmentVariable = "DISCORD_TOKEN", Description = "Authentication token.")]
-        public string TokenValue { get; init; } = "";
+    [CommandOption("token", 't', IsRequired = true, EnvironmentVariable = "DISCORD_TOKEN", Description = "Authentication token.")]
+    public string TokenValue { get; init; } = "";
 
-        [CommandOption("bot", 'b', EnvironmentVariable = "DISCORD_TOKEN_BOT", Description = "Authenticate as a bot.")]
-        public bool IsBotToken { get; init; }
+    [CommandOption("bot", 'b', EnvironmentVariable = "DISCORD_TOKEN_BOT", Description = "Authenticate as a bot.")]
+    public bool IsBotToken { get; init; }
 
-        private AuthToken GetAuthToken() => new(
-            IsBotToken
-                ? AuthTokenType.Bot
-                : AuthTokenType.User,
-            TokenValue
-        );
+    private AuthToken? _authToken;
+    private AuthToken AuthToken => _authToken ??= new AuthToken(
+        IsBotToken
+            ? AuthTokenKind.Bot
+            : AuthTokenKind.User,
+        TokenValue
+    );
 
-        private DiscordClient? _discordClient;
-        protected DiscordClient Discord => _discordClient ??= new DiscordClient(GetAuthToken());
+    private DiscordClient? _discordClient;
+    protected DiscordClient Discord => _discordClient ??= new DiscordClient(AuthToken);
 
-        public abstract ValueTask ExecuteAsync(IConsole console);
-    }
+    public abstract ValueTask ExecuteAsync(IConsole console);
 }

DiscordChatExporter.Cli/Commands/ExportAllCommand.cs

@@ -5,38 +5,36 @@ using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord.Data;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("exportall", Description = "Export all accessible channels.")]
+public class ExportAllCommand : ExportCommandBase
 {
-    [Command("exportall", Description = "Export all accessible channels.")]
-    public class ExportAllCommand : ExportCommandBase
+    [CommandOption("include-dm", Description = "Include direct message channels.")]
+    public bool IncludeDirectMessages { get; init; } = true;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        [CommandOption("include-dm", Description = "Include direct message channels.")]
-        public bool IncludeDirectMessages { get; init; } = true;
+        var cancellationToken = console.RegisterCancellationHandler();
+        var channels = new List<Channel>();
 
-        public override async ValueTask ExecuteAsync(IConsole console)
+        await console.Output.WriteLineAsync("Fetching channels...");
+        await foreach (var guild in Discord.GetUserGuildsAsync(cancellationToken))
         {
-            await base.ExecuteAsync(console);
+            // Skip DMs if instructed to
+            if (!IncludeDirectMessages && guild.Id == Guild.DirectMessages.Id)
+                continue;
 
-            // Get channel metadata
-            await console.Output.WriteLineAsync("Fetching channels...");
-
-            var channels = new List<Channel>();
-
-            // Aggregate channels from all guilds
-            await foreach (var guild in Discord.GetUserGuildsAsync())
+            await foreach (var channel in Discord.GetGuildChannelsAsync(guild.Id, cancellationToken))
             {
-                // Skip DMs if instructed to
-                if (!IncludeDirectMessages && guild.Id == Guild.DirectMessages.Id)
+                // Skip non-text channels
+                if (!channel.IsTextChannel)
                     continue;
 
-                await foreach (var channel in Discord.GetGuildChannelsAsync(guild.Id))
-                {
-                    channels.Add(channel);
-                }
+                channels.Add(channel);
             }
-
-            // Export
-            await ExportAsync(console, channels);
         }
+
+        await base.ExecuteAsync(console, channels);
     }
 }

DiscordChatExporter.Cli/Commands/ExportChannelsCommand.cs

@@ -5,34 +5,16 @@ using CliFx.Attributes;
 using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord;
-using DiscordChatExporter.Core.Discord.Data;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("export", Description = "Export one or multiple channels.")]
+public class ExportChannelsCommand : ExportCommandBase
 {
-    [Command("export", Description = "Export one or multiple channels.")]
-    public class ExportChannelsCommand : ExportCommandBase
-    {
-        // TODO: change this to plural (breaking change)
-        [CommandOption("channel", 'c', IsRequired = true, Description = "Channel ID(s).")]
-        public IReadOnlyList<Snowflake> ChannelIds { get; init; } = Array.Empty<Snowflake>();
+    // TODO: change this to plural (breaking change)
+    [CommandOption("channel", 'c', IsRequired = true, Description = "Channel ID(s).")]
+    public IReadOnlyList<Snowflake> ChannelIds { get; init; } = Array.Empty<Snowflake>();
 
-        public override async ValueTask ExecuteAsync(IConsole console)
-        {
-            await base.ExecuteAsync(console);
-
-            // Get channel metadata
-            await console.Output.WriteLineAsync("Fetching channel(s)...");
-
-            var channels = new List<Channel>();
-
-            foreach (var channelId in ChannelIds)
-            {
-                var channel = await Discord.GetChannelAsync(channelId);
-                channels.Add(channel);
-            }
-
-            // Export
-            await ExportAsync(console, channels);
-        }
-    }
+    public override async ValueTask ExecuteAsync(IConsole console) =>
+        await base.ExecuteAsync(console, ChannelIds);
 }

DiscordChatExporter.Cli/Commands/ExportDirectMessagesCommand.cs

@@ -1,25 +1,24 @@
-using System.Threading.Tasks;
+using System.Linq;
+using System.Threading.Tasks;
 using CliFx.Attributes;
 using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord.Data;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("exportdm", Description = "Export all direct message channels.")]
+public class ExportDirectMessagesCommand : ExportCommandBase
 {
-    [Command("exportdm", Description = "Export all direct message channels.")]
-    public class ExportDirectMessagesCommand : ExportCommandBase
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        public override async ValueTask ExecuteAsync(IConsole console)
-        {
-            await base.ExecuteAsync(console);
+        var cancellationToken = console.RegisterCancellationHandler();
 
-            // Get channel metadata
-            await console.Output.WriteLineAsync("Fetching channels...");
-            var channels = await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id);
+        await console.Output.WriteLineAsync("Fetching channels...");
+        var channels = await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id, cancellationToken);
+        var textChannels = channels.Where(c => c.IsTextChannel).ToArray();
 
-            // Export
-            await ExportAsync(console, channels);
-        }
+        await base.ExecuteAsync(console, textChannels);
     }
 }

DiscordChatExporter.Cli/Commands/ExportGuildCommand.cs

@@ -1,28 +1,27 @@
-using System.Threading.Tasks;
+using System.Linq;
+using System.Threading.Tasks;
 using CliFx.Attributes;
 using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("exportguild", Description = "Export all channels within specified guild.")]
+public class ExportGuildCommand : ExportCommandBase
 {
-    [Command("exportguild", Description = "Export all channels within specified guild.")]
-    public class ExportGuildCommand : ExportCommandBase
+    [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
+    public Snowflake GuildId { get; init; }
+
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
-        public Snowflake GuildId { get; init; }
+        var cancellationToken = console.RegisterCancellationHandler();
 
-        public override async ValueTask ExecuteAsync(IConsole console)
-        {
-            await base.ExecuteAsync(console);
+        await console.Output.WriteLineAsync("Fetching channels...");
+        var channels = await Discord.GetGuildChannelsAsync(GuildId, cancellationToken);
+        var textChannels = channels.Where(c => c.IsTextChannel).ToArray();
 
-            // Get channel metadata
-            await console.Output.WriteLineAsync("Fetching channels...");
-            var channels = await Discord.GetGuildChannelsAsync(GuildId);
-
-            // Export
-            await ExportAsync(console, channels);
-        }
+        await base.ExecuteAsync(console, textChannels);
     }
 }

DiscordChatExporter.Cli/Commands/GetChannelsCommand.cs

@@ -7,33 +7,38 @@ using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("channels", Description = "Get the list of channels in a guild.")]
+public class GetChannelsCommand : TokenCommandBase
 {
-    [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)
     {
-        [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
-        public Snowflake GuildId { get; init; }
+        var cancellationToken = console.RegisterCancellationHandler();
 
-        public override async ValueTask ExecuteAsync(IConsole console)
+        var channels = await Discord.GetGuildChannelsAsync(GuildId, cancellationToken);
+
+        var textChannels = channels
+            .Where(c => c.IsTextChannel)
+            .OrderBy(c => c.Category.Position)
+            .ThenBy(c => c.Name)
+            .ToArray();
+
+        foreach (var channel in textChannels)
         {
-            var channels = await Discord.GetGuildChannelsAsync(GuildId);
+            // Channel ID
+            await console.Output.WriteAsync(channel.Id.ToString());
 
-            foreach (var channel in channels.OrderBy(c => c.Category.Position).ThenBy(c => c.Name))
-            {
-                // Channel ID
-                await console.Output.WriteAsync(channel.Id.ToString());
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
 
-                // Separator
-                using (console.WithForegroundColor(ConsoleColor.DarkGray))
-                    await console.Output.WriteAsync(" | ");
-
-                // Channel category / name
-                using (console.WithForegroundColor(ConsoleColor.White))
-                    await console.Output.WriteAsync($"{channel.Category} / {channel.Name}");
-
-                await console.Output.WriteLineAsync();
-            }
+            // Channel category / name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync($"{channel.Category.Name} / {channel.Name}");
         }
     }
 }

DiscordChatExporter.Cli/Commands/GetDirectMessageChannelsCommand.cs

@@ -7,30 +7,35 @@ using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Discord.Data;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("dm", Description = "Get the list of direct message channels.")]
+public class GetDirectMessageChannelsCommand : TokenCommandBase
 {
-    [Command("dm", Description = "Get the list of direct message channels.")]
-    public class GetDirectMessageChannelsCommand : TokenCommandBase
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        public override async ValueTask ExecuteAsync(IConsole console)
+        var cancellationToken = console.RegisterCancellationHandler();
+
+        var channels = await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id, cancellationToken);
+
+        var textChannels = channels
+            .Where(c => c.IsTextChannel)
+            .OrderBy(c => c.Category.Position)
+            .ThenBy(c => c.Name)
+            .ToArray();
+
+        foreach (var channel in textChannels)
         {
-            var channels = await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id);
+            // Channel ID
+            await console.Output.WriteAsync(channel.Id.ToString());
 
-            foreach (var channel in channels.OrderBy(c => c.Name))
-            {
-                // Channel ID
-                await console.Output.WriteAsync(channel.Id.ToString());
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
 
-                // Separator
-                using (console.WithForegroundColor(ConsoleColor.DarkGray))
-                    await console.Output.WriteAsync(" | ");
-
-                // Channel category / name
-                using (console.WithForegroundColor(ConsoleColor.White))
-                    await console.Output.WriteAsync($"{channel.Category} / {channel.Name}");
-
-                await console.Output.WriteLineAsync();
-            }
+            // Channel category / name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync($"{channel.Category.Name} / {channel.Name}");
         }
     }
 }

DiscordChatExporter.Cli/Commands/GetGuildsCommand.cs

@@ -6,30 +6,29 @@ using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("guilds", Description = "Get the list of accessible guilds.")]
+public class GetGuildsCommand : TokenCommandBase
 {
-    [Command("guilds", Description = "Get the list of accessible guilds.")]
-    public class GetGuildsCommand : TokenCommandBase
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        public override async ValueTask ExecuteAsync(IConsole console)
+        var cancellationToken = console.RegisterCancellationHandler();
+
+        var guilds = await Discord.GetUserGuildsAsync(cancellationToken);
+
+        foreach (var guild in guilds.OrderBy(g => g.Name))
         {
-            var guilds = await Discord.GetUserGuildsAsync();
+            // Guild ID
+            await console.Output.WriteAsync(guild.Id.ToString());
 
-            foreach (var guild in guilds.OrderBy(g => g.Name))
-            {
-                // Guild ID
-                await console.Output.WriteAsync(guild.Id.ToString());
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
 
-                // Separator
-                using (console.WithForegroundColor(ConsoleColor.DarkGray))
-                    await console.Output.WriteAsync(" | ");
-
-                // Guild name
-                using (console.WithForegroundColor(ConsoleColor.White))
-                    await console.Output.WriteAsync(guild.Name);
-
-                await console.Output.WriteLineAsync();
-            }
+            // Guild name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync(guild.Name);
         }
     }
 }

DiscordChatExporter.Cli/Commands/GuideCommand.cs

@@ -1,65 +1,70 @@
-using System;
+using System;
 using System.Threading.Tasks;
 using CliFx;
 using CliFx.Attributes;
 using CliFx.Infrastructure;
 
-namespace DiscordChatExporter.Cli.Commands
+namespace DiscordChatExporter.Cli.Commands;
+
+[Command("guide", Description = "Explains how to obtain token, guild or channel ID.")]
+public class GuideCommand : ICommand
 {
-    [Command("guide", Description = "Explains how to obtain token, guild or channel ID.")]
-    public class GuideCommand : ICommand
+    public ValueTask ExecuteAsync(IConsole console)
     {
-        public ValueTask ExecuteAsync(IConsole console)
-        {
-            using (console.WithForegroundColor(ConsoleColor.White))
-                console.Output.WriteLine("To get user token:");
+        // User token
+        using (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.Output.WriteLine(" 1. Open Discord");
+        console.Output.WriteLine(" 2. Press Ctrl+Shift+I to show developer tools");
+        console.Output.WriteLine(" 3. Press Ctrl+Shift+M to toggle device toolbar");
+        console.Output.WriteLine(" 4. Navigate to the Application tab");
+        console.Output.WriteLine(" 5. On the left, expand Local Storage and select https://discord.com");
+        console.Output.WriteLine(" 6. Type \"token\" into the Filter box");
+        console.Output.WriteLine(" 7. If the token key does not appear, press Ctrl+R to reload");
+        console.Output.WriteLine(" 8. Copy the value of the token key");
+        console.Output.WriteLine(" *  Automating user accounts is technically against TOS, use at your own risk.");
+        console.Output.WriteLine();
 
-            using (console.WithForegroundColor(ConsoleColor.White))
-                console.Output.WriteLine("To get bot token:");
+        // Bot token
+        using (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.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();
 
-            using (console.WithForegroundColor(ConsoleColor.White))
-                console.Output.WriteLine("To get guild ID or guild channel ID:");
+        // Guild or channel ID
+        using (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.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();
 
-            using (console.WithForegroundColor(ConsoleColor.White))
-                console.Output.WriteLine("To get direct message channel ID:");
+        // Direct message channel ID
+        using (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.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();
 
-            using (console.WithForegroundColor(ConsoleColor.White))
-                console.Output.WriteLine("For more information, check out the wiki:");
+        // Wiki link
+        using (console.WithForegroundColor(ConsoleColor.White))
+            console.Output.WriteLine("For more information, check out the wiki:");
+        using (console.WithForegroundColor(ConsoleColor.DarkCyan))
+            console.Output.WriteLine("https://github.com/Tyrrrz/DiscordChatExporter/wiki");
 
-            using (console.WithForegroundColor(ConsoleColor.DarkCyan))
-                console.Output.WriteLine("https://github.com/Tyrrrz/DiscordChatExporter/wiki");
-
-            return default;
-        }
+        return default;
     }
 }

DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj

@@ -6,10 +6,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CliFx" Version="2.0.4" />
-    <PackageReference Include="Spectre.Console" Version="0.39.0" />
+    <PackageReference Include="CliFx" Version="2.0.6" />
+    <PackageReference Include="Spectre.Console" Version="0.43.0" />
     <PackageReference Include="Gress" Version="1.2.0" />
-    <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
   </ItemGroup>
 
   <ItemGroup>

DiscordChatExporter.Cli/Program.cs

@@ -1,14 +1,6 @@
-using System.Threading.Tasks;
-using CliFx;
+using CliFx;
 
-namespace DiscordChatExporter.Cli
-{
-    public static class Program
-    {
-        public static async Task<int> Main(string[] args) =>
-            await new CliApplicationBuilder()
-                .AddCommandsFromThisAssembly()
-                .Build()
-                .RunAsync(args);
-    }
-}
+return await new CliApplicationBuilder()
+    .AddCommandsFromThisAssembly()
+    .Build()
+    .RunAsync(args);

DiscordChatExporter.Cli/Utils/Extensions/ConsoleExtensions.cs

@@ -3,46 +3,48 @@ using System.Threading.Tasks;
 using CliFx.Infrastructure;
 using Spectre.Console;
 
-namespace DiscordChatExporter.Cli.Utils.Extensions
+namespace DiscordChatExporter.Cli.Utils.Extensions;
+
+internal static class ConsoleExtensions
 {
-    internal static class ConsoleExtensions
-    {
-        public static IAnsiConsole CreateAnsiConsole(this IConsole console) => AnsiConsole.Create(
-            new AnsiConsoleSettings
-            {
-                Ansi = AnsiSupport.Detect,
-                ColorSystem = ColorSystemSupport.Detect,
-                Out = new AnsiConsoleOutput(console.Output)
-            }
+    public static IAnsiConsole CreateAnsiConsole(this IConsole console) =>
+        AnsiConsole.Create(new AnsiConsoleSettings
+        {
+            Ansi = AnsiSupport.Detect,
+            ColorSystem = ColorSystemSupport.Detect,
+            Out = new AnsiConsoleOutput(console.Output)
+        });
+
+    public static Progress CreateProgressTicker(this IConsole console) => console
+        .CreateAnsiConsole()
+        .Progress()
+        .AutoClear(false)
+        .AutoRefresh(true)
+        .HideCompleted(false)
+        .Columns(
+            new TaskDescriptionColumn {Alignment = Justify.Left},
+            new ProgressBarColumn(),
+            new PercentageColumn()
         );
 
-        public static Progress CreateProgressTicker(this IConsole console) => console
-            .CreateAnsiConsole()
-            .Progress()
-            .AutoClear(false)
-            .AutoRefresh(true)
-            .HideCompleted(false)
-            .Columns(
-                new TaskDescriptionColumn {Alignment = Justify.Left},
-                new ProgressBarColumn(),
-                new PercentageColumn()
-            );
+    public static async ValueTask StartTaskAsync(
+        this ProgressContext progressContext,
+        string description,
+        Func<ProgressTask, ValueTask> performOperationAsync)
+    {
+        var progressTask = progressContext.AddTask(
+            // Don't recognize random square brackets as style tags
+            Markup.Escape(description),
+            new ProgressTaskSettings {MaxValue = 1}
+        );
 
-        public static async ValueTask StartTaskAsync(
-            this ProgressContext progressContext,
-            string description,
-            Func<ProgressTask, ValueTask> performOperationAsync)
+        try
         {
-            var progressTask = progressContext.AddTask(description, new ProgressTaskSettings {MaxValue = 1});
-
-            try
-            {
-                await performOperationAsync(progressTask);
-            }
-            finally
-            {
-                progressTask.StopTask();
-            }
+            await performOperationAsync(progressTask);
+        }
+        finally
+        {
+            progressTask.StopTask();
         }
     }
 }

DiscordChatExporter.Cli/Utils/Pollyfills.cs

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

DiscordChatExporter.Core/Discord/AuthToken.cs

@@ -1,27 +1,12 @@
 using System.Net.Http.Headers;
 
-namespace DiscordChatExporter.Core.Discord
+namespace DiscordChatExporter.Core.Discord;
+
+public record AuthToken(AuthTokenKind Kind, string Value)
 {
-    public enum AuthTokenType { User, Bot }
-
-    public class AuthToken
+    public AuthenticationHeaderValue GetAuthenticationHeader() => Kind switch
     {
-        public AuthTokenType Type { get; }
-
-        public string Value { get; }
-
-        public AuthToken(AuthTokenType type, string value)
-        {
-            Type = type;
-            Value = value;
-        }
-
-        public AuthenticationHeaderValue GetAuthenticationHeader() => Type switch
-        {
-            AuthTokenType.Bot => new AuthenticationHeaderValue("Bot", Value),
-            _ => new AuthenticationHeaderValue(Value)
-        };
-
-        public override string ToString() => Value;
-    }
+        AuthTokenKind.Bot => new AuthenticationHeaderValue("Bot", Value),
+        _ => new AuthenticationHeaderValue(Value)
+    };
 }

DiscordChatExporter.Core/Discord/AuthTokenKind.cs

@@ -0,0 +1,7 @@
+namespace DiscordChatExporter.Core.Discord;
+
+public enum AuthTokenKind
+{
+    User,
+    Bot
+}

DiscordChatExporter.Core/Discord/Data/Attachment.cs

@@ -1,77 +1,44 @@
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Text.Json;
 using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#attachment-object
+public partial record Attachment(
+    Snowflake Id,
+    string Url,
+    string FileName,
+    int? Width,
+    int? Height,
+    FileSize FileSize) : IHasId
 {
-    // https://discord.com/developers/docs/resources/channel#attachment-object
-    public partial class Attachment : IHasId
+    public string FileExtension => Path.GetExtension(FileName);
+
+    public bool IsImage => FileFormat.IsImage(FileExtension);
+
+    public bool IsVideo => FileFormat.IsVideo(FileExtension);
+
+    public bool IsAudio => FileFormat.IsAudio(FileExtension);
+
+    public bool IsSpoiler => FileName.StartsWith("SPOILER_", StringComparison.Ordinal);
+}
+
+public partial record Attachment
+{
+    public static Attachment Parse(JsonElement json)
     {
-        public Snowflake Id { get; }
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var url = json.GetProperty("url").GetNonWhiteSpaceString();
+        var width = json.GetPropertyOrNull("width")?.GetInt32OrNull();
+        var height = json.GetPropertyOrNull("height")?.GetInt32OrNull();
+        var fileName = json.GetProperty("filename").GetNonWhiteSpaceString();
+        var fileSize = json.GetProperty("size").GetInt64().Pipe(FileSize.FromBytes);
 
-        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);
-        }
+        return new Attachment(id, url, fileName, width, height, fileSize);
     }
 }

DiscordChatExporter.Core/Discord/Data/Channel.cs

@@ -3,109 +3,76 @@ using System.Text.Json;
 using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#channel-object
+public partial record Channel(
+    Snowflake Id,
+    ChannelKind Kind,
+    Snowflake GuildId,
+    ChannelCategory Category,
+    string Name,
+    int? Position,
+    string? Topic) : IHasId
 {
-    // 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
-    }
+    public bool IsTextChannel => Kind is
+        ChannelKind.GuildTextChat or
+        ChannelKind.DirectTextChat or
+        ChannelKind.DirectGroupTextChat or
+        ChannelKind.GuildNews or
+        ChannelKind.GuildStore;
 
-    // https://discord.com/developers/docs/resources/channel#channel-object
-    public partial class Channel : IHasId, IHasPosition
-    {
-        public Snowflake Id { get; }
+    public bool IsVoiceChannel => !IsTextChannel;
+}
 
-        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 ChannelCategory Category { get; }
-
-        public string Name { get; }
-
-        public int? Position { get; }
-
-        public string? Topic { get; }
-
-        public Channel(
-            Snowflake id,
-            ChannelType type,
-            Snowflake guildId,
-            ChannelCategory? category,
-            string name,
-            int? position,
-            string? topic)
+public partial record Channel
+{
+    private static ChannelCategory GetFallbackCategory(ChannelKind channelKind) => new(
+        Snowflake.Zero,
+        channelKind switch
         {
-            Id = id;
-            Type = type;
-            GuildId = guildId;
-            Category = category ?? GetFallbackCategory(type);
-            Name = name;
-            Position = position;
-            Topic = topic;
-        }
+            ChannelKind.GuildTextChat => "Text",
+            ChannelKind.DirectTextChat => "Private",
+            ChannelKind.DirectGroupTextChat => "Group",
+            ChannelKind.GuildNews => "News",
+            ChannelKind.GuildStore => "Store",
+            _ => "Default"
+        },
+        null
+    );
 
-        public override string ToString() => Name;
-
-    }
-
-    public partial class Channel
+    public static Channel Parse(JsonElement json, ChannelCategory? category = null, int? positionHint = null)
     {
-        private static ChannelCategory GetFallbackCategory(ChannelType channelType) => new(
-            Snowflake.Zero,
-            channelType switch
-            {
-                ChannelType.GuildTextChat => "Text",
-                ChannelType.DirectTextChat => "Private",
-                ChannelType.DirectGroupTextChat => "Group",
-                ChannelType.GuildNews => "News",
-                ChannelType.GuildStore => "Store",
-                _ => "Default"
-            },
-            0
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var guildId = json.GetPropertyOrNull("guild_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+        var topic = json.GetPropertyOrNull("topic")?.GetStringOrNull();
+        var kind = (ChannelKind)json.GetProperty("type").GetInt32();
+
+        var name =
+            // Guild channel
+            json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull() ??
+
+            // DM channel
+            json.GetPropertyOrNull("recipients")?
+                .EnumerateArrayOrNull()?
+                .Select(User.Parse)
+                .Select(u => u.Name)
+                .Pipe(s => string.Join(", ", s)) ??
+
+            // Fallback
+            id.ToString();
+
+        var position = positionHint ?? json.GetPropertyOrNull("position")?.GetInt32OrNull();
+
+        return new Channel(
+            id,
+            kind,
+            guildId ?? Guild.DirectMessages.Id,
+            category ?? GetFallbackCategory(kind),
+            name,
+            position,
+            topic
         );
-
-        public static Channel Parse(JsonElement json, ChannelCategory? category = null, int? position = 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();
-
-            position ??= json.GetPropertyOrNull("position")?.GetInt32();
-
-            return new Channel(
-                id,
-                type,
-                guildId ?? Guild.DirectMessages.Id,
-                category ?? GetFallbackCategory(type),
-                name,
-                position,
-                topic
-            );
-        }
     }
 }

DiscordChatExporter.Core/Discord/Data/ChannelCategory.cs

@@ -1,49 +1,23 @@
-using System.Linq;
-using System.Text.Json;
+using System.Text.Json;
 using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+public record ChannelCategory(Snowflake Id, string Name, int? Position) : IHasId
 {
-    public partial class ChannelCategory : IHasId, IHasPosition
+    public static ChannelCategory Unknown { get; } = new(Snowflake.Zero, "<unknown category>", 0);
+
+    public static ChannelCategory Parse(JsonElement json, int? positionHint = null)
     {
-        public Snowflake Id { get; }
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var position = positionHint ?? json.GetPropertyOrNull("position")?.GetInt32OrNull();
 
-        public string Name { get; }
-
-        public int? Position { get; }
-
-        public ChannelCategory(Snowflake id, string name, int? position)
-        {
-            Id = id;
-            Name = name;
-            Position = position;
-        }
-
-        public override string ToString() => Name;
+        var name =
+            json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull() ??
+            id.ToString();
 
+        return new ChannelCategory(id, name, position);
     }
-
-    public partial class ChannelCategory
-    {
-        public static ChannelCategory Parse(JsonElement json, int? position = null)
-        {
-            var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
-            position ??= json.GetPropertyOrNull("position")?.GetInt32();
-
-            var name = json.GetPropertyOrNull("name")?.GetString() ??
-                json.GetPropertyOrNull("recipients")?.EnumerateArray().Select(User.Parse).Select(u => u.Name).JoinToString(", ") ??
-                id.ToString();
-
-            return new ChannelCategory(
-                id,
-                name,
-                position
-            );
-        }
-
-        public static ChannelCategory Empty { get; } = new(Snowflake.Zero, "<unknown category>", 0);
-    }
-}
+}

DiscordChatExporter.Core/Discord/Data/ChannelKind.cs

@@ -0,0 +1,14 @@
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// 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 ChannelKind
+{
+    GuildTextChat = 0,
+    DirectTextChat,
+    GuildVoiceChat,
+    DirectGroupTextChat,
+    GuildCategory,
+    GuildNews,
+    GuildStore
+}

DiscordChatExporter.Core/Discord/Data/Common/FileSize.cs

@@ -1,51 +1,48 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 
-namespace DiscordChatExporter.Core.Discord.Data.Common
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+// Loosely based on https://github.com/omar/ByteSize (MIT license)
+public readonly partial record struct FileSize(long TotalBytes)
 {
-    // Loosely based on https://github.com/omar/ByteSize (MIT license)
-    public readonly partial struct FileSize
+    public double TotalKiloBytes => TotalBytes / 1024.0;
+    public double TotalMegaBytes => TotalKiloBytes / 1024.0;
+    public double TotalGigaBytes => TotalMegaBytes / 1024.0;
+
+    private double GetLargestWholeNumberValue()
     {
-        public long TotalBytes { get; }
+        if (Math.Abs(TotalGigaBytes) >= 1)
+            return TotalGigaBytes;
 
-        public double TotalKiloBytes => TotalBytes / 1024.0;
-        public double TotalMegaBytes => TotalKiloBytes / 1024.0;
-        public double TotalGigaBytes => TotalMegaBytes / 1024.0;
+        if (Math.Abs(TotalMegaBytes) >= 1)
+            return TotalMegaBytes;
 
-        public FileSize(long bytes) => TotalBytes = bytes;
+        if (Math.Abs(TotalKiloBytes) >= 1)
+            return TotalKiloBytes;
 
-        private double GetLargestWholeNumberValue()
-        {
-            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(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()}";
+        return TotalBytes;
     }
 
-    public partial struct FileSize
+    private string GetLargestWholeNumberSymbol()
     {
-        public static FileSize FromBytes(long bytes) => new(bytes);
+        if (Math.Abs(TotalGigaBytes) >= 1)
+            return "GB";
+
+        if (Math.Abs(TotalMegaBytes) >= 1)
+            return "MB";
+
+        if (Math.Abs(TotalKiloBytes) >= 1)
+            return "KB";
+
+        return "bytes";
     }
+
+    [ExcludeFromCodeCoverage]
+    public override string ToString() => $"{GetLargestWholeNumberValue():0.##} {GetLargestWholeNumberSymbol()}";
+}
+
+public partial record struct FileSize
+{
+    public static FileSize FromBytes(long bytes) => new(bytes);
 }

DiscordChatExporter.Core/Discord/Data/Common/IHasId.cs

@@ -1,7 +1,6 @@
-namespace DiscordChatExporter.Core.Discord.Data.Common
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+public interface IHasId
 {
-    public interface IHasId
-    {
-        Snowflake Id { get; }
-    }
+    Snowflake Id { get; }
 }

DiscordChatExporter.Core/Discord/Data/Common/IHasPosition.cs

@@ -1,7 +0,0 @@
-namespace DiscordChatExporter.Core.Discord.Data.Common
-{
-    public interface IHasPosition
-    {
-        int? Position { get; }
-    }
-}

DiscordChatExporter.Core/Discord/Data/Common/IdBasedEqualityComparer.cs

@@ -1,16 +1,12 @@
 using System.Collections.Generic;
 
-namespace DiscordChatExporter.Core.Discord.Data.Common
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+public class IdBasedEqualityComparer : IEqualityComparer<IHasId>
 {
-    public partial class IdBasedEqualityComparer : IEqualityComparer<IHasId>
-    {
-        public bool Equals(IHasId? x, IHasId? y) => x?.Id == y?.Id;
+    public static IdBasedEqualityComparer Instance { get; } = new();
 
-        public int GetHashCode(IHasId obj) => obj.Id.GetHashCode();
-    }
+    public bool Equals(IHasId? x, IHasId? y) => x?.Id == y?.Id;
 
-    public partial class IdBasedEqualityComparer
-    {
-        public static IdBasedEqualityComparer Instance { get; } = new();
-    }
+    public int GetHashCode(IHasId obj) => obj.Id.GetHashCode();
 }

DiscordChatExporter.Core/Discord/Data/Embed.cs

@@ -1,94 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Drawing;
-using System.Linq;
-using System.Text.Json;
-using DiscordChatExporter.Core.Utils.Extensions;
-using JsonExtensions.Reading;
-
-namespace DiscordChatExporter.Core.Discord.Data
-{
-    // 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.Core/Discord/Data/EmbedAuthor.cs

@@ -1,36 +0,0 @@
-using System.Text.Json;
-using JsonExtensions.Reading;
-
-namespace DiscordChatExporter.Core.Discord.Data
-{
-    // 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.Core/Discord/Data/EmbedField.cs

@@ -1,36 +0,0 @@
-using System.Text.Json;
-using JsonExtensions.Reading;
-
-namespace DiscordChatExporter.Core.Discord.Data
-{
-    // 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.Core/Discord/Data/EmbedFooter.cs

@@ -1,32 +0,0 @@
-using System.Text.Json;
-using JsonExtensions.Reading;
-
-namespace DiscordChatExporter.Core.Discord.Data
-{
-    // 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.Core/Discord/Data/EmbedImage.cs

@@ -1,34 +0,0 @@
-using System.Text.Json;
-using JsonExtensions.Reading;
-
-namespace DiscordChatExporter.Core.Discord.Data
-{
-    // 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.Core/Discord/Data/Embeds/Embed.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object
+public partial record Embed(
+    string? Title,
+    string? Url,
+    DateTimeOffset? Timestamp,
+    Color? Color,
+    EmbedAuthor? Author,
+    string? Description,
+    IReadOnlyList<EmbedField> Fields,
+    EmbedImage? Thumbnail,
+    EmbedImage? Image,
+    EmbedFooter? Footer)
+{
+    public PlainImageEmbedProjection? TryGetPlainImage() =>
+        PlainImageEmbedProjection.TryResolve(this);
+
+    public SpotifyTrackEmbedProjection? TryGetSpotifyTrack() =>
+        SpotifyTrackEmbedProjection.TryResolve(this);
+
+    public YouTubeVideoEmbedProjection? TryGetYouTubeVideo() =>
+        YouTubeVideoEmbedProjection.TryResolve(this);
+}
+
+public partial record Embed
+{
+    public static Embed Parse(JsonElement json)
+    {
+        var title = json.GetPropertyOrNull("title")?.GetStringOrNull();
+        var url = json.GetPropertyOrNull("url")?.GetNonWhiteSpaceStringOrNull();
+        var timestamp = json.GetPropertyOrNull("timestamp")?.GetDateTimeOffset();
+        var color = json.GetPropertyOrNull("color")?.GetInt32OrNull()?.Pipe(System.Drawing.Color.FromArgb).ResetAlpha();
+        var description = json.GetPropertyOrNull("description")?.GetStringOrNull();
+
+        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")?.EnumerateArrayOrNull()?.Select(EmbedField.Parse).ToArray() ??
+            Array.Empty<EmbedField>();
+
+        return new Embed(
+            title,
+            url,
+            timestamp,
+            color,
+            author,
+            description,
+            fields,
+            thumbnail,
+            image,
+            footer
+        );
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/EmbedAuthor.cs

@@ -0,0 +1,22 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-author-structure
+public record EmbedAuthor(
+    string? Name,
+    string? Url,
+    string? IconUrl,
+    string? IconProxyUrl)
+{
+    public static EmbedAuthor Parse(JsonElement json)
+    {
+        var name = json.GetPropertyOrNull("name")?.GetStringOrNull();
+        var url = json.GetPropertyOrNull("url")?.GetNonWhiteSpaceStringOrNull();
+        var iconUrl = json.GetPropertyOrNull("icon_url")?.GetNonWhiteSpaceStringOrNull();
+        var iconProxyUrl = json.GetPropertyOrNull("proxy_icon_url")?.GetNonWhiteSpaceStringOrNull();
+
+        return new EmbedAuthor(name, url, iconUrl, iconProxyUrl);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/EmbedField.cs

@@ -0,0 +1,20 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-field-structure
+public record EmbedField(
+    string Name,
+    string Value,
+    bool IsInline)
+{
+    public static EmbedField Parse(JsonElement json)
+    {
+        var name = json.GetProperty("name").GetNonWhiteSpaceString();
+        var value = json.GetProperty("value").GetNonWhiteSpaceString();
+        var isInline = json.GetPropertyOrNull("inline")?.GetBooleanOrNull() ?? false;
+
+        return new EmbedField(name, value, isInline);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/EmbedFooter.cs

@@ -0,0 +1,20 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-footer-structure
+public record EmbedFooter(
+    string Text,
+    string? IconUrl,
+    string? IconProxyUrl)
+{
+    public static EmbedFooter Parse(JsonElement json)
+    {
+        var text = json.GetProperty("text").GetNonNullString();
+        var iconUrl = json.GetPropertyOrNull("icon_url")?.GetNonWhiteSpaceStringOrNull();
+        var iconProxyUrl = json.GetPropertyOrNull("proxy_icon_url")?.GetNonWhiteSpaceStringOrNull();
+
+        return new EmbedFooter(text, iconUrl, iconProxyUrl);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/EmbedImage.cs

@@ -0,0 +1,22 @@
+using System.Text.Json;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-image-structure
+public record EmbedImage(
+    string? Url,
+    string? ProxyUrl,
+    int? Width,
+    int? Height)
+{
+    public static EmbedImage Parse(JsonElement json)
+    {
+        var url = json.GetPropertyOrNull("url")?.GetNonWhiteSpaceStringOrNull();
+        var proxyUrl = json.GetPropertyOrNull("proxy_url")?.GetNonWhiteSpaceStringOrNull();
+        var width = json.GetPropertyOrNull("width")?.GetInt32OrNull();
+        var height = json.GetPropertyOrNull("height")?.GetInt32OrNull();
+
+        return new EmbedImage(url, proxyUrl, width, height);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/PlainImageEmbedProjection.cs

@@ -0,0 +1,33 @@
+using System.IO;
+using System.Linq;
+using System.Text.RegularExpressions;
+using DiscordChatExporter.Core.Utils;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+public record PlainImageEmbedProjection(string Url)
+{
+    public static PlainImageEmbedProjection? TryResolve(Embed embed)
+    {
+        if (string.IsNullOrWhiteSpace(embed.Url))
+            return null;
+
+        // Has to be an embed without any data (except URL and image)
+        if (!string.IsNullOrWhiteSpace(embed.Title) ||
+            embed.Timestamp is not null ||
+            embed.Author is not null ||
+            !string.IsNullOrWhiteSpace(embed.Description) ||
+            embed.Fields.Any() ||
+            embed.Footer is not null)
+        {
+            return null;
+        }
+
+        // Has to be an image file
+        var fileName = Regex.Match(embed.Url, @".+/([^?]*)").Groups[1].Value;
+        if (string.IsNullOrWhiteSpace(fileName) || !FileFormat.IsImage(Path.GetExtension(fileName)))
+            return null;
+
+        return new PlainImageEmbedProjection(embed.Url);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/SpotifyTrackEmbedProjection.cs

@@ -0,0 +1,33 @@
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+public partial record SpotifyTrackEmbedProjection(string TrackId)
+{
+    public string Url => $"https://open.spotify.com/embed/track/{TrackId}";
+}
+
+public partial record SpotifyTrackEmbedProjection
+{
+    private static string? TryParseTrackId(string embedUrl)
+    {
+        // https://open.spotify.com/track/1LHZMWefF9502NPfArRfvP?si=3efac6ce9be04f0a
+        var trackId = Regex.Match(embedUrl, @"spotify\.com/track/(.*?)(?:\?|&|/|$)").Groups[1].Value;
+        if (!string.IsNullOrWhiteSpace(trackId))
+            return trackId;
+
+        return null;
+    }
+
+    public static SpotifyTrackEmbedProjection? TryResolve(Embed embed)
+    {
+        if (string.IsNullOrWhiteSpace(embed.Url))
+            return null;
+
+        var trackId = TryParseTrackId(embed.Url);
+        if (string.IsNullOrWhiteSpace(trackId))
+            return null;
+
+        return new SpotifyTrackEmbedProjection(trackId);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Embeds/YouTubeVideoEmbedProjection.cs

@@ -0,0 +1,48 @@
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+public partial record YouTubeVideoEmbedProjection(string VideoId)
+{
+    public string Url => $"https://www.youtube.com/embed/{VideoId}";
+}
+
+public partial record YouTubeVideoEmbedProjection
+{
+    // Adapted from YoutubeExplode
+    // https://github.com/Tyrrrz/YoutubeExplode/blob/5be164be20019783913f76fcc98f18c65aebe9f0/YoutubeExplode/Videos/VideoId.cs#L34-L64
+    private static string? TryParseVideoId(string embedUrl)
+    {
+        // Regular URL
+        // https://www.youtube.com/watch?v=yIVRs6YSbOM
+        var regularMatch = Regex.Match(embedUrl, @"youtube\..+?/watch.*?v=(.*?)(?:&|/|$)").Groups[1].Value;
+        if (!string.IsNullOrWhiteSpace(regularMatch))
+            return regularMatch;
+
+        // Short URL
+        // https://youtu.be/yIVRs6YSbOM
+        var shortMatch = Regex.Match(embedUrl, @"youtu\.be/(.*?)(?:\?|&|/|$)").Groups[1].Value;
+        if (!string.IsNullOrWhiteSpace(shortMatch))
+            return shortMatch;
+
+        // Embed URL
+        // https://www.youtube.com/embed/yIVRs6YSbOM
+        var embedMatch = Regex.Match(embedUrl, @"youtube\..+?/embed/(.*?)(?:\?|&|/|$)").Groups[1].Value;
+        if (!string.IsNullOrWhiteSpace(embedMatch))
+            return embedMatch;
+
+        return null;
+    }
+
+    public static YouTubeVideoEmbedProjection? TryResolve(Embed embed)
+    {
+        if (string.IsNullOrWhiteSpace(embed.Url))
+            return null;
+
+        var videoId = TryParseVideoId(embed.Url);
+        if (string.IsNullOrWhiteSpace(videoId))
+            return null;
+
+        return new YouTubeVideoEmbedProjection(videoId);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Emoji.cs

@@ -1,79 +1,72 @@
-using System.Collections.Generic;
+using System;
 using System.Linq;
-using System.Text;
 using System.Text.Json;
+using DiscordChatExporter.Core.Utils;
+using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/emoji#emoji-object
+public partial record Emoji(
+    // Only present on custom emoji
+    string? Id,
+    // Name of custom emoji (e.g. LUL) or actual representation of standard emoji (e.g. 🙂)
+    string Name,
+    bool IsAnimated,
+    string ImageUrl)
 {
-    // https://discord.com/developers/docs/resources/emoji#emoji-object
-    public partial class Emoji
+    // Name of custom emoji (e.g. LUL) or name of standard emoji (e.g. slight_smile)
+    public string Code => !string.IsNullOrWhiteSpace(Id)
+        ? Name
+        : EmojiIndex.TryGetCode(Name) ?? Name;
+}
+
+public partial record Emoji
+{
+    private static string GetTwemojiName(string name) => string.Join("-",
+        name
+            .GetRunes()
+            // Variant selector rune is skipped in Twemoji names
+            .Where(r => r.Value != 0xfe0f)
+            .Select(r => r.Value.ToString("x"))
+    );
+
+    private static string GetImageUrl(string id, bool isAnimated) => isAnimated
+        ? $"https://cdn.discordapp.com/emojis/{id}.gif"
+        : $"https://cdn.discordapp.com/emojis/{id}.png";
+
+    private static string GetImageUrl(string name) =>
+        $"https://twemoji.maxcdn.com/2/svg/{GetTwemojiName(name)}.svg";
+
+    public static string GetImageUrl(string? id, string? name, bool isAnimated)
     {
-        public string? Id { get; }
+        // Custom emoji
+        if (!string.IsNullOrWhiteSpace(id))
+            return GetImageUrl(id, isAnimated);
 
-        public string Name { get; }
+        // Standard emoji
+        if (!string.IsNullOrWhiteSpace(name))
+            return GetImageUrl(name);
 
-        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;
+        // Either ID or name should be set
+        throw new ApplicationException("Emoji has neither ID nor name set.");
     }
 
-    public partial class Emoji
+    public static Emoji Parse(JsonElement json)
     {
-        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;
+        var id = json.GetPropertyOrNull("id")?.GetNonWhiteSpaceStringOrNull();
+        var name = json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull();
+        var isAnimated = json.GetPropertyOrNull("animated")?.GetBooleanOrNull() ?? false;
 
-                lastIndex += rune.Utf16SequenceLength;
-            }
-        }
+        var imageUrl = GetImageUrl(id, name, isAnimated);
 
-        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);
-        }
+        return new Emoji(
+            id,
+            // Name may be missing if it's an emoji inside a reaction
+            name ?? "<unknown emoji>",
+            isAnimated,
+            imageUrl
+        );
     }
 }

DiscordChatExporter.Core/Discord/Data/Guild.cs

@@ -1,53 +1,35 @@
 using System.Text.Json;
 using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/guild#guild-object
+public record Guild(Snowflake Id, string Name, string IconUrl) : IHasId
 {
-    // https://discord.com/developers/docs/resources/guild#guild-object
-    public partial class Guild : IHasId
+    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)
     {
-        public Snowflake Id { get; }
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonWhiteSpaceString();
+        var iconHash = json.GetPropertyOrNull("icon")?.GetNonWhiteSpaceStringOrNull();
 
-        public string Name { get; }
+        var iconUrl = !string.IsNullOrWhiteSpace(iconHash)
+            ? GetIconUrl(id, iconHash)
+            : GetDefaultIconUrl();
 
-        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);
-        }
+        return new Guild(id, name, iconUrl);
     }
 }

DiscordChatExporter.Core/Discord/Data/Member.cs

@@ -6,51 +6,41 @@ using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/guild#guild-member-object
+public partial record Member(
+    User User,
+    string Nick,
+    IReadOnlyList<Snowflake> RoleIds) : IHasId
 {
-    // https://discord.com/developers/docs/resources/guild#guild-member-object
-    public partial class Member : IHasId
+    public Snowflake Id => User.Id;
+}
+
+public partial record Member
+{
+    public static Member CreateForUser(User user) => new(
+        user,
+        user.Name,
+        Array.Empty<Snowflake>()
+    );
+
+    public static Member Parse(JsonElement json)
     {
-        public Snowflake Id => User.Id;
+        var user = json.GetProperty("user").Pipe(User.Parse);
+        var nick = json.GetPropertyOrNull("nick")?.GetNonWhiteSpaceStringOrNull();
 
-        public User User { get; }
+        var roleIds = json
+            .GetPropertyOrNull("roles")?
+            .EnumerateArray()
+            .Select(j => j.GetNonWhiteSpaceString())
+            .Select(Snowflake.Parse)
+            .ToArray() ?? Array.Empty<Snowflake>();
 
-        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(
+        return new Member(
             user,
-            null,
-            Array.Empty<Snowflake>()
+            nick ?? user.Name,
+            roleIds
         );
-
-        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.Core/Discord/Data/Message.cs

@@ -3,150 +3,86 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
 using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Discord.Data.Embeds;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#message-object
+public record Message(
+    Snowflake Id,
+    MessageKind Kind,
+    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? Reference,
+    Message? ReferencedMessage) : IHasId
 {
-    // https://discord.com/developers/docs/resources/channel#message-object-message-types
-    public enum MessageType
+    public static Message Parse(JsonElement json)
     {
-        Default = 0,
-        RecipientAdd = 1,
-        RecipientRemove = 2,
-        Call = 3,
-        ChannelNameChange = 4,
-        ChannelIconChange = 5,
-        ChannelPinnedMessage = 6,
-        GuildMemberJoin = 7,
-        Reply = 19
-    }
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().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 kind = (MessageKind)json.GetProperty("type").GetInt32();
+        var isPinned = json.GetPropertyOrNull("pinned")?.GetBooleanOrNull() ?? false;
+        var messageReference = json.GetPropertyOrNull("message_reference")?.Pipe(MessageReference.Parse);
+        var referencedMessage = json.GetPropertyOrNull("referenced_message")?.Pipe(Parse);
 
-    // 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)
+        var content = kind switch
         {
-            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;
-        }
+            MessageKind.RecipientAdd => "Added a recipient.",
+            MessageKind.RecipientRemove => "Removed a recipient.",
+            MessageKind.Call =>
+                $"Started a call that lasted {callEndedTimestamp?.Pipe(t => t - timestamp).Pipe(t => (int)t.TotalMinutes) ?? 0} minutes.",
+            MessageKind.ChannelNameChange => "Changed the channel name.",
+            MessageKind.ChannelIconChange => "Changed the channel icon.",
+            MessageKind.ChannelPinnedMessage => "Pinned a message.",
+            MessageKind.GuildMemberJoin => "Joined the server.",
+            _ => json.GetPropertyOrNull("content")?.GetStringOrNull() ?? ""
+        };
 
-        public override string ToString() => Content;
-    }
+        var attachments =
+            json.GetPropertyOrNull("attachments")?.EnumerateArrayOrNull()?.Select(Attachment.Parse).ToArray() ??
+            Array.Empty<Attachment>();
 
-    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 embeds =
+            json.GetPropertyOrNull("embeds")?.EnumerateArrayOrNull()?.Select(Embed.Parse).ToArray() ??
+            Array.Empty<Embed>();
 
-            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 reactions =
+            json.GetPropertyOrNull("reactions")?.EnumerateArrayOrNull()?.Select(Reaction.Parse).ToArray() ??
+            Array.Empty<Reaction>();
 
-            var attachments =
-                json.GetPropertyOrNull("attachments")?.EnumerateArray().Select(Attachment.Parse).ToArray() ??
-                Array.Empty<Attachment>();
+        var mentionedUsers =
+            json.GetPropertyOrNull("mentions")?.EnumerateArrayOrNull()?.Select(User.Parse).ToArray() ??
+            Array.Empty<User>();
 
-            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
-            );
-        }
+        return new Message(
+            id,
+            kind,
+            author,
+            timestamp,
+            editedTimestamp,
+            callEndedTimestamp,
+            isPinned,
+            content,
+            attachments,
+            embeds,
+            reactions,
+            mentionedUsers,
+            messageReference,
+            referencedMessage
+        );
     }
 }

DiscordChatExporter.Core/Discord/Data/MessageKind.cs

@@ -0,0 +1,15 @@
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#message-object-message-types
+public enum MessageKind
+{
+    Default = 0,
+    RecipientAdd = 1,
+    RecipientRemove = 2,
+    Call = 3,
+    ChannelNameChange = 4,
+    ChannelIconChange = 5,
+    ChannelPinnedMessage = 6,
+    GuildMemberJoin = 7,
+    Reply = 19
+}

DiscordChatExporter.Core/Discord/Data/MessageReference.cs

@@ -2,36 +2,17 @@ using System.Text.Json;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#message-object-message-reference-structure
+public record MessageReference(Snowflake? MessageId, Snowflake? ChannelId, Snowflake? GuildId)
 {
-    // https://discord.com/developers/docs/resources/channel#message-object-message-reference-structure
-    public partial class MessageReference
+    public static MessageReference Parse(JsonElement json)
     {
-        public Snowflake? MessageId { get; }
+        var messageId = json.GetPropertyOrNull("message_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+        var channelId = json.GetPropertyOrNull("channel_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+        var guildId = json.GetPropertyOrNull("guild_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
 
-        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);
-        }
+        return new MessageReference(messageId, channelId, guildId);
     }
 }

DiscordChatExporter.Core/Discord/Data/Reaction.cs

@@ -1,32 +1,16 @@
 using System.Text.Json;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#reaction-object
+public record Reaction(Emoji Emoji, int Count)
 {
-    // https://discord.com/developers/docs/resources/channel#reaction-object
-    public partial class Reaction
+    public static Reaction Parse(JsonElement json)
     {
-        public Emoji Emoji { get; }
+        var emoji = json.GetProperty("emoji").Pipe(Emoji.Parse);
+        var count = json.GetProperty("count").GetInt32();
 
-        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);
-        }
+        return new Reaction(emoji, count);
     }
 }

DiscordChatExporter.Core/Discord/Data/Role.cs

@@ -4,49 +4,24 @@ using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/topics/permissions#role-object
+public record Role(Snowflake Id, string Name, int Position, Color? Color) : IHasId
 {
-    // https://discord.com/developers/docs/topics/permissions#role-object
-    public partial class Role : IHasId
+    public static Role Parse(JsonElement json)
     {
-        public Snowflake Id { get; }
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonWhiteSpaceString();
+        var position = json.GetProperty("position").GetInt32();
 
-        public string Name { get; }
+        var color = json
+            .GetPropertyOrNull("color")?
+            .GetInt32()
+            .Pipe(System.Drawing.Color.FromArgb)
+            .ResetAlpha()
+            .NullIf(c => c.ToRgb() <= 0);
 
-        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);
-        }
+        return new Role(id, name, position, color);
     }
 }

DiscordChatExporter.Core/Discord/Data/User.cs

@@ -4,70 +4,47 @@ using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Reading;
 
-namespace DiscordChatExporter.Core.Discord.Data
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/user#user-object
+public partial record User(
+    Snowflake Id,
+    bool IsBot,
+    int Discriminator,
+    string Name,
+    string AvatarUrl) : IHasId
 {
-    // https://discord.com/developers/docs/resources/user#user-object
-    public partial class User : IHasId
+    public string DiscriminatorFormatted => $"{Discriminator:0000}";
+
+    public string FullName => $"{Name}#{DiscriminatorFormatted}";
+}
+
+public partial record User
+{
+    private static string GetDefaultAvatarUrl(int discriminator) =>
+        $"https://cdn.discordapp.com/embed/avatars/{discriminator % 5}.png";
+
+    private static string GetAvatarUrl(Snowflake id, string avatarHash)
     {
-        public Snowflake Id { get; }
+        var extension = avatarHash.StartsWith("a_", StringComparison.Ordinal)
+            ? "gif"
+            : "png";
 
-        public bool IsBot { get; }
-
-        public int Discriminator { get; }
-
-        public string DiscriminatorFormatted => $"{Discriminator:0000}";
-
-        public string Name { get; }
-
-        public string FullName => $"{Name}#{DiscriminatorFormatted}";
-
-        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;
+        return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.{extension}?size=128";
     }
 
-    public partial class User
+    public static User Parse(JsonElement json)
     {
-        private static string GetDefaultAvatarUrl(int discriminator) =>
-            $"https://cdn.discordapp.com/embed/avatars/{discriminator % 5}.png";
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var isBot = json.GetPropertyOrNull("bot")?.GetBooleanOrNull() ?? false;
+        var discriminator = json.GetProperty("discriminator").GetNonWhiteSpaceString().Pipe(int.Parse);
+        var name = json.GetProperty("username").GetNonWhiteSpaceString();
+        var avatarHash = json.GetPropertyOrNull("avatar")?.GetNonWhiteSpaceStringOrNull();
 
-        private static string GetAvatarUrl(Snowflake id, string avatarHash)
-        {
-            // Animated
-            if (avatarHash.StartsWith("a_", StringComparison.Ordinal))
-                return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.gif";
+        var avatarUrl = !string.IsNullOrWhiteSpace(avatarHash)
+            ? GetAvatarUrl(id, avatarHash)
+            : GetDefaultAvatarUrl(discriminator);
 
-            // 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);
-        }
+        return new User(id, isBot, discriminator, name, avatarUrl);
     }
 }

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -3,7 +3,9 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Runtime.CompilerServices;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using DiscordChatExporter.Core.Discord.Data;
 using DiscordChatExporter.Core.Exceptions;
@@ -11,277 +13,290 @@ using DiscordChatExporter.Core.Utils;
 using DiscordChatExporter.Core.Utils.Extensions;
 using JsonExtensions.Http;
 using JsonExtensions.Reading;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Core.Discord
+namespace DiscordChatExporter.Core.Discord;
+
+public class DiscordClient
 {
-    public class DiscordClient
+    private readonly AuthToken _token;
+    private readonly Uri _baseUri = new("https://discord.com/api/v8/", UriKind.Absolute);
+
+    public DiscordClient(AuthToken token) => _token = token;
+
+    private async ValueTask<HttpResponseMessage> GetResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
     {
-        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)
+        return await Http.ResponsePolicy.ExecuteAsync(async innerCancellationToken =>
         {
-            _httpClient = httpClient;
-            _token = token;
-        }
+            using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));
+            request.Headers.Authorization = _token.GetAuthenticationHeader();
 
-        public DiscordClient(AuthToken token)
-            : this(Http.Client, token) {}
+            return await Http.Client.SendAsync(
+                request,
+                HttpCompletionOption.ResponseHeadersRead,
+                innerCancellationToken
+            );
+        }, cancellationToken);
+    }
 
-        private async ValueTask<HttpResponseMessage> GetResponseAsync(string url) =>
-            await Http.ResponsePolicy.ExecuteAsync(async () =>
+    private async ValueTask<JsonElement> GetJsonResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
+    {
+        using var response = await GetResponseAsync(url, cancellationToken);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            throw response.StatusCode switch
             {
-                using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));
-                request.Headers.Authorization = _token.GetAuthenticationHeader();
-
-                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();
+                HttpStatusCode.Unauthorized => DiscordChatExporterException.Unauthorized(),
+                HttpStatusCode.Forbidden => DiscordChatExporterException.Forbidden(),
+                HttpStatusCode.NotFound => DiscordChatExporterException.NotFound(url),
+                _ => DiscordChatExporterException.FailedHttpRequest(response)
+            };
         }
 
-        private async ValueTask<JsonElement?> TryGetJsonResponseAsync(string url)
-        {
-            using var response = await GetResponseAsync(url);
+        return await response.Content.ReadAsJsonAsync(cancellationToken);
+    }
 
-            return response.IsSuccessStatusCode
-                ? await response.Content.ReadAsJsonAsync()
-                : (JsonElement?) null;
-        }
+    private async ValueTask<JsonElement?> TryGetJsonResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
+    {
+        using var response = await GetResponseAsync(url, cancellationToken);
 
-        public async IAsyncEnumerable<Guild> GetUserGuildsAsync()
-        {
-            yield return Guild.DirectMessages;
+        return response.IsSuccessStatusCode
+            ? await response.Content.ReadAsJsonAsync(cancellationToken)
+            : null;
+    }
 
-            var currentAfter = Snowflake.Zero;
+    public async IAsyncEnumerable<Guild> GetUserGuildsAsync(
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        yield return Guild.DirectMessages;
 
-            while (true)
-            {
-                var url = new UrlBuilder()
-                    .SetPath("users/@me/guilds")
-                    .SetQueryParameter("limit", "100")
-                    .SetQueryParameter("after", currentAfter.ToString())
-                    .Build();
+        var currentAfter = Snowflake.Zero;
 
-                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 orderedResponse = response
-                    .EnumerateArray()
-                    .OrderBy(j => j.GetProperty("position").GetInt32())
-                    .ThenBy(j => ulong.Parse(j.GetProperty("id").GetString()))
-                    .ToArray();
-
-                var categories = orderedResponse
-                    .Where(j => j.GetProperty("type").GetInt32() == (int)ChannelType.GuildCategory)
-                    .Select((j, index) => ChannelCategory.Parse(j, index + 1))
-                    .ToDictionary(j => j.Id.ToString());
-
-                var position = 0;
-
-                foreach (var channelJson in orderedResponse)
-                {
-                    var parentId = channelJson.GetPropertyOrNull("parent_id")?.GetString();
-                    var category = !string.IsNullOrWhiteSpace(parentId)
-                        ? categories.GetValueOrDefault(parentId)
-                        : null;
-
-                    var channel = Channel.Parse(channelJson, category, position);
-
-                    // Skip non-text channels
-                    if (!channel.IsTextChannel)
-                        continue;
-
-                    position++;
-
-                    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);
-        }
-
-        public async ValueTask<ChannelCategory> GetChannelCategoryAsync(Snowflake channelId)
-        {
-            try
-            {
-                var response = await GetJsonResponseAsync($"channels/{channelId}");
-                return ChannelCategory.Parse(response);
-            }
-            /***
-             * In some cases, the Discord API returns an empty body when requesting some channel category info.
-             * Instead, we use an empty channel category as a fallback.
-             */
-            catch (DiscordChatExporterException)
-            {
-                return ChannelCategory.Empty;
-            }
-
-        }
-
-        public async ValueTask<Channel> GetChannelAsync(Snowflake channelId)
-        {
-            var response = await GetJsonResponseAsync($"channels/{channelId}");
-
-            var parentId = response.GetPropertyOrNull("parent_id")?.GetString().Pipe(Snowflake.Parse);
-
-            var category = parentId is not null
-                ? await GetChannelCategoryAsync(parentId.Value)
-                : null;
-
-            return Channel.Parse(response, category);
-        }
-
-        private async ValueTask<Message?> TryGetLastMessageAsync(Snowflake channelId, Snowflake? before = null)
+        while (true)
         {
             var url = new UrlBuilder()
-                .SetPath($"channels/{channelId}/messages")
-                .SetQueryParameter("limit", "1")
-                .SetQueryParameter("before", before?.ToString())
+                .SetPath("users/@me/guilds")
+                .SetQueryParameter("limit", "100")
+                .SetQueryParameter("after", currentAfter.ToString())
                 .Build();
 
-            var response = await GetJsonResponseAsync(url);
-            return response.EnumerateArray().Select(Message.Parse).LastOrDefault();
-        }
+            var response = await GetJsonResponseAsync(url, cancellationToken);
 
-        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 is 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 isEmpty = true;
+            foreach (var guild in response.EnumerateArray().Select(Guild.Parse))
             {
-                var url = new UrlBuilder()
-                    .SetPath($"channels/{channelId}/messages")
-                    .SetQueryParameter("limit", "100")
-                    .SetQueryParameter("after", currentAfter.ToString())
-                    .Build();
+                yield return guild;
 
-                var response = await GetJsonResponseAsync(url);
+                currentAfter = guild.Id;
+                isEmpty = false;
+            }
 
-                var messages = response
-                    .EnumerateArray()
-                    .Select(Message.Parse)
-                    .Reverse() // reverse because messages appear newest first
-                    .ToArray();
+            if (isEmpty)
+                yield break;
+        }
+    }
 
-                // Break if there are no messages (can happen if messages are deleted during execution)
-                if (!messages.Any())
-                    yield break;
+    public async ValueTask<Guild> GetGuildAsync(
+        Snowflake guildId,
+        CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+            return Guild.DirectMessages;
 
-                foreach (var message in messages)
-                {
-                    firstMessage ??= message;
+        var response = await GetJsonResponseAsync($"guilds/{guildId}", cancellationToken);
+        return Guild.Parse(response);
+    }
 
-                    // Ensure messages are in range (take into account that last message could have been deleted)
-                    if (message.Timestamp > lastMessage.Timestamp)
-                        yield break;
+    public async IAsyncEnumerable<Channel> GetGuildChannelsAsync(
+        Snowflake guildId,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+        {
+            var response = await GetJsonResponseAsync("users/@me/channels", cancellationToken);
+            foreach (var channelJson in response.EnumerateArray())
+                yield return Channel.Parse(channelJson);
+        }
+        else
+        {
+            var response = await GetJsonResponseAsync($"guilds/{guildId}/channels", cancellationToken);
 
-                    // Report progress based on the duration of exported messages divided by total
-                    if (progress is not null)
-                    {
-                        var exportedDuration = (message.Timestamp - firstMessage.Timestamp).Duration();
-                        var totalDuration = (lastMessage.Timestamp - firstMessage.Timestamp).Duration();
+            var responseOrdered = response
+                .EnumerateArray()
+                .OrderBy(j => j.GetProperty("position").GetInt32())
+                .ThenBy(j => j.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse))
+                .ToArray();
 
-                        if (totalDuration > TimeSpan.Zero)
-                        {
-                            progress.Report(exportedDuration / totalDuration);
-                        }
-                        // Avoid division by zero if all messages have the exact same timestamp
-                        // (which can happen easily if there's only one message in the channel)
-                        else
-                        {
-                            progress.Report(1);
-                        }
-                    }
+            var categories = responseOrdered
+                .Where(j => j.GetProperty("type").GetInt32() == (int) ChannelKind.GuildCategory)
+                .Select((j, index) => ChannelCategory.Parse(j, index + 1))
+                .ToDictionary(j => j.Id.ToString(), StringComparer.Ordinal);
 
-                    yield return message;
-                    currentAfter = message.Id;
-                }
+            var position = 0;
+
+            foreach (var channelJson in responseOrdered)
+            {
+                var parentId = channelJson.GetPropertyOrNull("parent_id")?.GetNonWhiteSpaceStringOrNull();
+
+                var category = !string.IsNullOrWhiteSpace(parentId)
+                    ? categories.GetValueOrDefault(parentId)
+                    : null;
+
+                var channel = Channel.Parse(channelJson, category, position);
+
+                position++;
+
+                yield return channel;
             }
         }
     }
-}
+
+    public async IAsyncEnumerable<Role> GetGuildRolesAsync(
+        Snowflake guildId,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+            yield break;
+
+        var response = await GetJsonResponseAsync($"guilds/{guildId}/roles", cancellationToken);
+
+        foreach (var roleJson in response.EnumerateArray())
+            yield return Role.Parse(roleJson);
+    }
+
+    public async ValueTask<Member> GetGuildMemberAsync(
+        Snowflake guildId,
+        User user,
+        CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+            return Member.CreateForUser(user);
+
+        var response = await TryGetJsonResponseAsync($"guilds/{guildId}/members/{user.Id}", cancellationToken);
+        return response?.Pipe(Member.Parse) ?? Member.CreateForUser(user);
+    }
+
+    public async ValueTask<ChannelCategory> GetChannelCategoryAsync(
+        Snowflake channelId,
+        CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            var response = await GetJsonResponseAsync($"channels/{channelId}", cancellationToken);
+            return ChannelCategory.Parse(response);
+        }
+        // In some cases, the Discord API returns an empty body when requesting channel category.
+        // Instead, we use an empty channel category as a fallback.
+        catch (DiscordChatExporterException)
+        {
+            return ChannelCategory.Unknown;
+        }
+    }
+
+    public async ValueTask<Channel> GetChannelAsync(
+        Snowflake channelId,
+        CancellationToken cancellationToken = default)
+    {
+        var response = await GetJsonResponseAsync($"channels/{channelId}", cancellationToken);
+
+        var parentId = response.GetPropertyOrNull("parent_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+
+        var category = parentId is not null
+            ? await GetChannelCategoryAsync(parentId.Value, cancellationToken)
+            : null;
+
+        return Channel.Parse(response, category);
+    }
+
+    private async ValueTask<Message?> TryGetLastMessageAsync(
+        Snowflake channelId,
+        Snowflake? before = null,
+        CancellationToken cancellationToken = default)
+    {
+        var url = new UrlBuilder()
+            .SetPath($"channels/{channelId}/messages")
+            .SetQueryParameter("limit", "1")
+            .SetQueryParameter("before", before?.ToString())
+            .Build();
+
+        var response = await GetJsonResponseAsync(url, cancellationToken);
+        return response.EnumerateArray().Select(Message.Parse).LastOrDefault();
+    }
+
+    public async IAsyncEnumerable<Message> GetMessagesAsync(
+        Snowflake channelId,
+        Snowflake? after = null,
+        Snowflake? before = null,
+        IProgress<double>? progress = null,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        // Get the last message in the specified range.
+        // This snapshots the boundaries, which means that messages posted after the export started
+        // will not appear in the output.
+        // Additionally, it provides the date of the last message, which is used to calculate progress.
+        var lastMessage = await TryGetLastMessageAsync(channelId, before, cancellationToken);
+        if (lastMessage is null || lastMessage.Timestamp < after?.ToDate())
+            yield break;
+
+        // Keep track of first message in range in order to calculate progress
+        var firstMessage = default(Message);
+        var currentAfter = after ?? Snowflake.Zero;
+
+        while (true)
+        {
+            var url = new UrlBuilder()
+                .SetPath($"channels/{channelId}/messages")
+                .SetQueryParameter("limit", "100")
+                .SetQueryParameter("after", currentAfter.ToString())
+                .Build();
+
+            var response = await GetJsonResponseAsync(url, cancellationToken);
+
+            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 exported messages divided by total
+                if (progress is not null)
+                {
+                    var exportedDuration = (message.Timestamp - firstMessage.Timestamp).Duration();
+                    var totalDuration = (lastMessage.Timestamp - firstMessage.Timestamp).Duration();
+
+                    if (totalDuration > TimeSpan.Zero)
+                    {
+                        progress.Report(exportedDuration / totalDuration);
+                    }
+                    // Avoid division by zero if all messages have the exact same timestamp
+                    // (which may be the case if there's only one message in the channel)
+                    else
+                    {
+                        progress.Report(1);
+                    }
+                }
+
+                yield return message;
+                currentAfter = message.Id;
+            }
+        }
+    }
+}

DiscordChatExporter.Core/Discord/Snowflake.cs

@@ -1,68 +1,55 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Text.RegularExpressions;
 
-namespace DiscordChatExporter.Core.Discord
+namespace DiscordChatExporter.Core.Discord;
+
+public readonly partial record struct Snowflake(ulong Value)
 {
-    public readonly partial struct Snowflake
+    public DateTimeOffset ToDate() => DateTimeOffset.FromUnixTimeMilliseconds(
+        (long)((Value >> 22) + 1420070400000UL)
+    ).ToLocalTime();
+
+    [ExcludeFromCodeCoverage]
+    public override string ToString() => Value.ToString(CultureInfo.InvariantCulture);
+}
+
+public partial record struct Snowflake
+{
+    public static Snowflake Zero { get; } = new(0);
+
+    public static Snowflake FromDate(DateTimeOffset date) => new(
+        ((ulong)date.ToUnixTimeMilliseconds() - 1420070400000UL) << 22
+    );
+
+    public static Snowflake? TryParse(string? str, IFormatProvider? formatProvider = null)
     {
-        public ulong Value { get; }
+        if (string.IsNullOrWhiteSpace(str))
+            return null;
 
-        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)
+        // As number
+        if (Regex.IsMatch(str, @"^\d+$") && ulong.TryParse(str, NumberStyles.Number, formatProvider, out var value))
         {
-            var value = ((ulong) date.ToUnixTimeMilliseconds() - 1420070400000UL) << 22;
             return new Snowflake(value);
         }
 
-        public static Snowflake? TryParse(string? str, IFormatProvider? formatProvider = null)
+        // As date
+        if (DateTimeOffset.TryParse(str, formatProvider, DateTimeStyles.None, out var date))
         {
-            if (string.IsNullOrWhiteSpace(str))
-                return null;
-
-            // As number
-            if (Regex.IsMatch(str, @"^\d+$") &&
-                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;
+            return FromDate(date);
         }
 
-        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);
+        return null;
     }
 
-    public partial struct Snowflake : IEquatable<Snowflake>
-    {
-        public bool Equals(Snowflake other) => Value == other.Value;
+    public static Snowflake Parse(string str, IFormatProvider? formatProvider) =>
+        TryParse(str, formatProvider) ?? throw new FormatException($"Invalid snowflake '{str}'.");
 
-        public override bool Equals(object? obj) => obj is Snowflake other && Equals(other);
+    public static Snowflake Parse(string str) => Parse(str, null);
+}
 
-        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);
-    }
+public partial record struct Snowflake : IComparable<Snowflake>
+{
+    public int CompareTo(Snowflake other) => Value.CompareTo(other.Value);
 }

DiscordChatExporter.Core/DiscordChatExporter.Core.csproj

@@ -5,19 +5,14 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="JsonExtensions" Version="1.0.1" />
-    <PackageReference Include="MiniRazor.CodeGen" Version="2.1.2" />
+    <PackageReference Include="JsonExtensions" Version="1.2.0" />
+    <PackageReference Include="MiniRazor.CodeGen" Version="2.2.0" />
     <PackageReference Include="Polly" Version="7.2.2" />
-    <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
+    <PackageReference Include="Superpower" Version="3.0.0" />
   </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" />
+    <AdditionalFiles Include="Exporting\Writers\Html\*.cshtml" IsRazorTemplate="true" />
   </ItemGroup>
 
 </Project>

DiscordChatExporter.Core/Exceptions/DiscordChatExporterException.cs

@@ -1,24 +1,24 @@
 using System;
 using System.Net.Http;
 
-namespace DiscordChatExporter.Core.Exceptions
+namespace DiscordChatExporter.Core.Exceptions;
+
+public partial class DiscordChatExporterException : Exception
 {
-    public partial class DiscordChatExporterException : Exception
-    {
-        public bool IsCritical { get; }
+    public bool IsFatal { get; }
 
-        public DiscordChatExporterException(string message, bool isCritical = false)
-            : base(message)
-        {
-            IsCritical = isCritical;
-        }
+    public DiscordChatExporterException(string message, bool isFatal = false)
+        : base(message)
+    {
+        IsFatal = isFatal;
     }
+}
 
-    public partial class DiscordChatExporterException
+public partial class DiscordChatExporterException
+{
+    internal static DiscordChatExporterException FailedHttpRequest(HttpResponseMessage response)
     {
-        internal static DiscordChatExporterException FailedHttpRequest(HttpResponseMessage response)
-        {
-            var message = $@"
+        var message = $@"
 Failed to perform an HTTP request.
 
 [Request]
@@ -27,19 +27,18 @@ Failed to perform an HTTP request.
 [Response]
 {response}";
 
-            return new DiscordChatExporterException(message.Trim(), true);
-        }
-
-        internal static DiscordChatExporterException Unauthorized() =>
-            new("Authentication token is invalid.");
-
-        internal static DiscordChatExporterException Forbidden() =>
-            new("Access is forbidden.");
-
-        internal static DiscordChatExporterException NotFound() =>
-            new("Requested resource does not exist.");
-
-        internal static DiscordChatExporterException ChannelIsEmpty() =>
-            new("No messages found for the specified period.");
+        return new DiscordChatExporterException(message.Trim(), true);
     }
+
+    internal static DiscordChatExporterException Unauthorized() =>
+        new("Authentication token is invalid.", true);
+
+    internal static DiscordChatExporterException Forbidden() =>
+        new("Access is forbidden.");
+
+    internal static DiscordChatExporterException NotFound(string resourceId) =>
+        new($"Requested resource ({resourceId}) does not exist.");
+
+    internal static DiscordChatExporterException ChannelIsEmpty() =>
+        new("No messages found for the specified period.");
 }

DiscordChatExporter.Core/Exporting/ChannelExporter.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Discord.Data;
@@ -8,58 +9,74 @@ using DiscordChatExporter.Core.Discord.Data.Common;
 using DiscordChatExporter.Core.Exceptions;
 using DiscordChatExporter.Core.Utils.Extensions;
 
-namespace DiscordChatExporter.Core.Exporting
+namespace DiscordChatExporter.Core.Exporting;
+
+public class ChannelExporter
 {
-    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,
+        CancellationToken cancellationToken = default)
     {
-        private readonly DiscordClient _discord;
+        // Build context
+        var contextMembers = new HashSet<Member>(IdBasedEqualityComparer.Instance);
+        var contextChannels = await _discord.GetGuildChannelsAsync(request.Guild.Id, cancellationToken);
+        var contextRoles = await _discord.GetGuildRolesAsync(request.Guild.Id, cancellationToken);
 
-        public ChannelExporter(DiscordClient discord) => _discord = discord;
+        var context = new ExportContext(
+            request,
+            contextMembers,
+            contextChannels,
+            contextRoles
+        );
 
-        public ChannelExporter(AuthToken token) : this(new DiscordClient(token)) {}
+        // Export messages
+        await using var messageExporter = new MessageExporter(context);
 
-        public async ValueTask ExportChannelAsync(ExportRequest request, IProgress<double>? progress = null)
+        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,
+                           cancellationToken))
         {
-            // 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);
+            cancellationToken.ThrowIfCancellationRequested();
 
-            var context = new ExportContext(
-                request,
-                contextMembers,
-                contextChannels,
-                contextRoles
-            );
+            // Skips any messages that fail to pass the supplied filter
+            if (!request.MessageFilter.IsMatch(message))
+                continue;
 
-            // 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))
             {
-                // Resolve members for referenced users
-                foreach (var referencedUser in message.MentionedUsers.Prepend(message.Author))
-                {
-                    if (!encounteredUsers.Add(referencedUser))
-                        continue;
+                if (!encounteredUsers.Add(referencedUser))
+                    continue;
 
-                    var member =
-                        await _discord.TryGetGuildMemberAsync(request.Guild.Id, referencedUser) ??
-                        Member.CreateForUser(referencedUser);
+                var member = await _discord.GetGuildMemberAsync(
+                    request.Guild.Id,
+                    referencedUser,
+                    cancellationToken
+                );
 
-                    contextMembers.Add(member);
-                }
-
-                // Export message
-                await messageExporter.ExportMessageAsync(message);
-                exportedAnything = true;
+                contextMembers.Add(member);
             }
 
-            // Throw if no messages were exported
-            if (!exportedAnything)
-                throw DiscordChatExporterException.ChannelIsEmpty();
+            // Export message
+            await messageExporter.ExportMessageAsync(message, cancellationToken);
+            exportedAnything = true;
         }
+
+        // Throw if no messages were exported
+        if (!exportedAnything)
+            throw DiscordChatExporterException.ChannelIsEmpty();
     }
 }

DiscordChatExporter.Core/Exporting/ExportContext.cs

@@ -4,101 +4,102 @@ using System.Drawing;
 using System.IO;
 using System.Linq;
 using System.Net.Http;
+using System.Threading;
 using System.Threading.Tasks;
 using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Discord.Data;
 using DiscordChatExporter.Core.Utils.Extensions;
-using Tyrrrz.Extensions;
 
-namespace DiscordChatExporter.Core.Exporting
+namespace DiscordChatExporter.Core.Exporting;
+
+internal class ExportContext
 {
-    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)
     {
-        private readonly MediaDownloader _mediaDownloader;
+        Request = request;
+        Members = members;
+        Channels = channels;
+        Roles = roles;
 
-        public ExportRequest Request { get; }
+        _mediaDownloader = new MediaDownloader(request.OutputMediaDirPath, request.ShouldReuseMedia);
+    }
 
-        public IReadOnlyCollection<Member> Members { get; }
+    public string FormatDate(DateTimeOffset date) => Request.DateFormat switch
+    {
+        "unix" => date.ToUnixTimeSeconds().ToString(),
+        "unixms" => date.ToUnixTimeMilliseconds().ToString(),
+        var dateFormat => date.ToLocalString(dateFormat)
+    };
 
-        public IReadOnlyCollection<Channel> Channels { get; }
+    public Member? TryGetMember(Snowflake id) => Members.FirstOrDefault(m => m.Id == id);
 
-        public IReadOnlyCollection<Role> Roles { get; }
+    public Channel? TryGetChannel(Snowflake id) => Channels.FirstOrDefault(c => c.Id == id);
 
-        public ExportContext(
-            ExportRequest request,
-            IReadOnlyCollection<Member> members,
-            IReadOnlyCollection<Channel> channels,
-            IReadOnlyCollection<Role> roles)
+    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 is not null)
+            .OrderByDescending(r => r.Position)
+            .Select(r => r.Color)
+            .FirstOrDefault();
+    }
+
+    public async ValueTask<string> ResolveMediaUrlAsync(string url, CancellationToken cancellationToken = default)
+    {
+        if (!Request.ShouldDownloadMedia)
+            return url;
+
+        try
         {
-            Request = request;
-            Members = members;
-            Channels = channels;
-            Roles = roles;
+            var filePath = await _mediaDownloader.DownloadAsync(url, cancellationToken);
 
-            _mediaDownloader = new MediaDownloader(request.OutputMediaDirPath, request.ShouldReuseMedia);
-        }
+            // 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;
 
-        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 is not null)
-                .OrderByDescending(r => r.Position)
-                .Select(r => r.Color)
-                .FirstOrDefault();
-        }
-
-        public async ValueTask<string> ResolveMediaUrlAsync(string url)
-        {
-            if (!Request.ShouldDownloadMedia)
-                return url;
-
-            try
+            // HACK: for HTML, we need to format the URL properly
+            if (Request.Format is ExportFormat.HtmlDark or ExportFormat.HtmlLight)
             {
-                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
+                // Need to escape each path segment while keeping the directory separators intact
+                return string.Join(
+                    Path.AltDirectorySeparatorChar,
+                    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;
-            }
+            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 or 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.Core/Exporting/ExportFormat.cs

@@ -1,36 +1,35 @@
 using System;
 
-namespace DiscordChatExporter.Core.Exporting
+namespace DiscordChatExporter.Core.Exporting;
+
+public enum ExportFormat
 {
-    public enum ExportFormat
-    {
-        PlainText,
-        HtmlDark,
-        HtmlLight,
-        Csv,
-        Json
-    }
+    PlainText,
+    HtmlDark,
+    HtmlLight,
+    Csv,
+    Json
+}
 
-    public static class ExportFormatExtensions
+public static class ExportFormatExtensions
+{
+    public static string GetFileExtension(this ExportFormat format) => format switch
     {
-        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))
-        };
+        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))
-        };
-    }
+    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.Core/Exporting/ExportRequest.cs

@@ -4,160 +4,119 @@ using System.Text;
 using System.Text.RegularExpressions;
 using DiscordChatExporter.Core.Discord;
 using DiscordChatExporter.Core.Discord.Data;
+using DiscordChatExporter.Core.Exporting.Filtering;
 using DiscordChatExporter.Core.Exporting.Partitioning;
 using DiscordChatExporter.Core.Utils;
 
-namespace DiscordChatExporter.Core.Exporting
+namespace DiscordChatExporter.Core.Exporting;
+
+public partial record ExportRequest(
+    Guild Guild,
+    Channel Channel,
+    string OutputPath,
+    ExportFormat Format,
+    Snowflake? After,
+    Snowflake? Before,
+    PartitionLimit PartitionLimit,
+    MessageFilter MessageFilter,
+    bool ShouldDownloadMedia,
+    bool ShouldReuseMedia,
+    string DateFormat)
 {
-    public partial class ExportRequest
+    private string? _outputBaseFilePath;
+    public string OutputBaseFilePath => _outputBaseFilePath ??= GetOutputBaseFilePath(
+        Guild,
+        Channel,
+        OutputPath,
+        Format,
+        After,
+        Before
+    );
+
+    public string OutputBaseDirPath => Path.GetDirectoryName(OutputBaseFilePath) ?? OutputPath;
+
+    public string OutputMediaDirPath => $"{OutputBaseFilePath}_Files{Path.DirectorySeparatorChar}";
+}
+
+public partial record ExportRequest
+{
+    private static string GetOutputBaseFilePath(
+        Guild guild,
+        Channel channel,
+        string outputPath,
+        ExportFormat format,
+        Snowflake? after = null,
+        Snowflake? before = null)
     {
-        public Guild Guild { get; }
+        // Formats path
+        outputPath = Regex.Replace(outputPath, "%.", m =>
+            PathEx.EscapeFileName(m.Value switch
+            {
+                "%g" => guild.Id.ToString(),
+                "%G" => guild.Name,
+                "%t" => channel.Category.Id.ToString(),
+                "%T" => channel.Category.Name,
+                "%c" => channel.Id.ToString(),
+                "%C" => channel.Name,
+                "%p" => channel.Position?.ToString() ?? "0",
+                "%P" => channel.Category.Position?.ToString() ?? "0",
+                "%a" => (after ?? Snowflake.Zero).ToDate().ToString("yyyy-MM-dd"),
+                "%b" => (before?.ToDate() ?? DateTime.Now).ToString("yyyy-MM-dd"),
+                "%%" => "%",
+                _ => m.Value
+            })
+        );
 
-        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 PartitionLimit 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,
-            PartitionLimit partitionLimit,
-            bool shouldDownloadMedia,
-            bool shouldReuseMedia,
-            string dateFormat)
+        // Output is a directory
+        if (Directory.Exists(outputPath) || string.IsNullOrWhiteSpace(Path.GetExtension(outputPath)))
         {
-            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}";
+            var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);
+            return Path.Combine(outputPath, fileName);
         }
+
+        // Output is a file
+        return outputPath;
     }
 
-    public partial class ExportRequest
+    public static string GetDefaultOutputFileName(
+        Guild guild,
+        Channel channel,
+        ExportFormat format,
+        Snowflake? after = null,
+        Snowflake? before = null)
     {
-        private static string GetOutputBaseFilePath(
-            Guild guild,
-            Channel channel,
-            string outputPath,
-            ExportFormat format,
-            Snowflake? after = null,
-            Snowflake? before = null)
+        var buffer = new StringBuilder();
+
+        // Guild and channel names
+        buffer.Append($"{guild.Name} - {channel.Category.Name} - {channel.Name} [{channel.Id}]");
+
+        // Date range
+        if (after is not null || before is not null)
         {
+            buffer.Append(" (");
 
-            // Formats path
-            outputPath = Regex.Replace(outputPath, "%.", m =>
-                PathEx.EscapePath(m.Value switch
-                {
-                    "%g" => guild.Id.ToString(),
-                    "%G" => guild.Name,
-                    "%t" => channel.Category.Id.ToString(),
-                    "%T" => channel.Category.Name,
-                    "%c" => channel.Id.ToString(),
-                    "%C" => channel.Name,
-                    "%p" => channel.Position?.ToString() ?? "0",
-                    "%P" => channel.Category.Position?.ToString() ?? "0",
-                    "%a" => (after ?? Snowflake.Zero).ToDate().ToString("yyyy-MM-dd"),
-                    "%b" => (before?.ToDate() ?? DateTime.Now).ToString("yyyy-MM-dd"),
-                    "%%" => "%",
-                    _ => m.Value
-                })
-            );
-
-            // Output is a directory
-            if (Directory.Exists(outputPath) || string.IsNullOrWhiteSpace(Path.GetExtension(outputPath)))
+            // Both 'after' and 'before' are set
+            if (after is not null && before is not null)
             {
-                var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);
-                return Path.Combine(outputPath, fileName);
+                buffer.Append($"{after.Value.ToDate():yyyy-MM-dd} to {before.Value.ToDate():yyyy-MM-dd}");
+            }
+            // Only 'after' is set
+            else if (after is not null)
+            {
+                buffer.Append($"after {after.Value.ToDate():yyyy-MM-dd}");
+            }
+            // Only 'before' is set
+            else if (before is not null)
+            {
+                buffer.Append($"before {before.Value.ToDate():yyyy-MM-dd}");
             }
 
-            // Output is a file
-            return outputPath;
+            buffer.Append(")");
         }
 
-        public static string GetDefaultOutputFileName(
-            Guild guild,
-            Channel channel,
-            ExportFormat format,
-            Snowflake? after = null,
-            Snowflake? before = null)
-        {
-            var buffer = new StringBuilder();
+        // File extension
+        buffer.Append($".{format.GetFileExtension()}");
 
-            // Guild and channel names
-            buffer.Append($"{guild.Name} - {channel.Category.Name} - {channel.Name} [{channel.Id}]");
-
-            // Date range
-            if (after is not null || before is not null)
-            {
-                buffer.Append(" (");
-
-                // Both 'after' and 'before' are set
-                if (after is not null && before is not null)
-                {
-                    buffer.Append($"{after?.ToDate():yyyy-MM-dd} to {before?.ToDate():yyyy-MM-dd}");
-                }
-                // Only 'after' is set
-                else if (after is not 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();
-        }
+        return PathEx.EscapeFileName(buffer.ToString());
     }
 }

DiscordChatExporter.Core/Exporting/Filtering/BinaryExpressionKind.cs

@@ -0,0 +1,7 @@
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal enum BinaryExpressionKind
+{
+    Or,
+    And
+}

DiscordChatExporter.Core/Exporting/Filtering/BinaryExpressionMessageFilter.cs

@@ -0,0 +1,25 @@
+using System;
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class BinaryExpressionMessageFilter : MessageFilter
+{
+    private readonly MessageFilter _first;
+    private readonly MessageFilter _second;
+    private readonly BinaryExpressionKind _kind;
+
+    public BinaryExpressionMessageFilter(MessageFilter first, MessageFilter second, BinaryExpressionKind kind)
+    {
+        _first = first;
+        _second = second;
+        _kind = kind;
+    }
+
+    public override bool IsMatch(Message message) => _kind switch
+    {
+        BinaryExpressionKind.Or => _first.IsMatch(message) || _second.IsMatch(message),
+        BinaryExpressionKind.And => _first.IsMatch(message) && _second.IsMatch(message),
+        _ => throw new InvalidOperationException($"Unknown binary expression kind '{_kind}'.")
+    };
+}

DiscordChatExporter.Core/Exporting/Filtering/ContainsMessageFilter.cs

@@ -0,0 +1,33 @@
+using System.Linq;
+using System.Text.RegularExpressions;
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class ContainsMessageFilter : MessageFilter
+{
+    private readonly string _text;
+
+    public ContainsMessageFilter(string text) => _text = text;
+
+    private bool IsMatch(string? content) =>
+        !string.IsNullOrWhiteSpace(content) &&
+        Regex.IsMatch(
+            content,
+            "\\b" + Regex.Escape(_text) + "\\b",
+            RegexOptions.IgnoreCase | RegexOptions.CultureInvariant
+        );
+
+    public override bool IsMatch(Message message) =>
+        IsMatch(message.Content) ||
+        message.Embeds.Any(e =>
+            IsMatch(e.Title) ||
+            IsMatch(e.Author?.Name) ||
+            IsMatch(e.Description) ||
+            IsMatch(e.Footer?.Text) ||
+            e.Fields.Any(f =>
+                IsMatch(f.Name) ||
+                IsMatch(f.Value)
+            )
+        );
+}

DiscordChatExporter.Core/Exporting/Filtering/FromMessageFilter.cs

@@ -0,0 +1,16 @@
+using System;
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class FromMessageFilter : MessageFilter
+{
+    private readonly string _value;
+
+    public FromMessageFilter(string value) => _value = value;
+
+    public override bool IsMatch(Message message) =>
+        string.Equals(_value, message.Author.Name, StringComparison.OrdinalIgnoreCase) ||
+        string.Equals(_value, message.Author.FullName, StringComparison.OrdinalIgnoreCase) ||
+        string.Equals(_value, message.Author.Id.ToString(), StringComparison.OrdinalIgnoreCase);
+}

DiscordChatExporter.Core/Exporting/Filtering/HasMessageFilter.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Linq;
+using System.Text.RegularExpressions;
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class HasMessageFilter : MessageFilter
+{
+    private readonly MessageContentMatchKind _kind;
+
+    public HasMessageFilter(MessageContentMatchKind kind) => _kind = kind;
+
+    public override bool IsMatch(Message message) => _kind switch
+    {
+        MessageContentMatchKind.Link => Regex.IsMatch(message.Content, "https?://\\S*[^\\.,:;\"\'\\s]"),
+        MessageContentMatchKind.Embed => message.Embeds.Any(),
+        MessageContentMatchKind.File => message.Attachments.Any(),
+        MessageContentMatchKind.Video => message.Attachments.Any(file => file.IsVideo),
+        MessageContentMatchKind.Image => message.Attachments.Any(file => file.IsImage),
+        MessageContentMatchKind.Sound => message.Attachments.Any(file => file.IsAudio),
+        _ => throw new InvalidOperationException($"Unknown message content match kind '{_kind}'.")
+    };
+}

DiscordChatExporter.Core/Exporting/Filtering/MentionsMessageFilter.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Linq;
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class MentionsMessageFilter : MessageFilter
+{
+    private readonly string _value;
+
+    public MentionsMessageFilter(string value) => _value = value;
+
+    public override bool IsMatch(Message message) => message.MentionedUsers.Any(user =>
+        string.Equals(_value, user.Name, StringComparison.OrdinalIgnoreCase) ||
+        string.Equals(_value, user.FullName, StringComparison.OrdinalIgnoreCase) ||
+        string.Equals(_value, user.Id.ToString(), StringComparison.OrdinalIgnoreCase)
+    );
+}

DiscordChatExporter.Core/Exporting/Filtering/MessageContentMatchKind.cs

@@ -0,0 +1,11 @@
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal enum MessageContentMatchKind
+{
+    Link,
+    Embed,
+    File,
+    Video,
+    Image,
+    Sound
+}

DiscordChatExporter.Core/Exporting/Filtering/MessageFilter.cs

@@ -0,0 +1,17 @@
+using DiscordChatExporter.Core.Discord.Data;
+using DiscordChatExporter.Core.Exporting.Filtering.Parsing;
+using Superpower;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+public abstract partial class MessageFilter
+{
+    public abstract bool IsMatch(Message message);
+}
+
+public partial class MessageFilter
+{
+    public static MessageFilter Null { get; } = new NullMessageFilter();
+
+    public static MessageFilter Parse(string value) => FilterGrammar.Filter.Parse(value);
+}

DiscordChatExporter.Core/Exporting/Filtering/NegatedMessageFilter.cs

@@ -0,0 +1,12 @@
+using DiscordChatExporter.Core.Discord.Data;
+
+namespace DiscordChatExporter.Core.Exporting.Filtering;
+
+internal class NegatedMessageFilter : MessageFilter
+{
+    private readonly MessageFilter _filter;
+
+    public NegatedMessageFilter(MessageFilter filter) => _filter = filter;
+
+    public override bool IsMatch(Message message) => !_filter.IsMatch(message);
+}