Update version

Closes #936

.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

@@ -0,0 +1,64 @@
+name: 🐞 Bug report
+description: Report broken functionality.
+labels: [bug]
+
+body:
+- type: markdown
+  attributes:
+    value: |
+      🧐 **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 of DiscordChatExporter does this bug affect?
+    placeholder: ver X.Y.Z
+  validations:
+    required: true
+
+- type: dropdown
+  attributes:
+    label: Flavor
+    description: Does this bug affect the GUI version, the CLI version, or both?
+    multiple: true
+    options:
+    - GUI (Graphical User Interface)
+    - CLI (Command Line Interface)
+  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.
+    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.
+    placeholder: |
+      - Step 1
+      - Step 2
+      - Step 3
+  validations:
+    required: true

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,14 @@
+blank_issues_enabled: false
+contact_links:
+  - name: ⚠ Feature request
+    url: https://github.com/Tyrrrz/.github/blob/master/docs/project-status.md
+    about: Sorry, but this project is in maintenance mode and no longer accepts new feature requests.
+  - 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 usage guides and frequently asked questions.
+  - name: 🗨 Discussions
+    url: https://github.com/Tyrrrz/DiscordChatExporter/discussions/new
+    about: Ask and answer questions.

.github/workflows/CD.yml

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

.github/workflows/CI.yml

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

.github/workflows/docker.yml

@@ -0,0 +1,55 @@
+name: docker
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Build container
+        run: docker build -f DiscordChatExporter.Cli.dockerfile .
+
+  deploy-latest:
+    if: ${{ github.event_name == 'push' && github.ref_type == 'branch' && github.ref_name == 'master' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Login to DockerHub
+        run: docker login -u tyrrrz -p ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Build container
+        run: docker build -f DiscordChatExporter.Cli.dockerfile -t tyrrrz/discordchatexporter:latest .
+
+      - name: Push container
+        run: docker push tyrrrz/discordchatexporter:latest
+
+  deploy-stable:
+    if: ${{ github.event_name == 'push' && github.ref_type == 'tag' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Get release version
+        id: get_version
+        uses: dawidd6/action-get-tag@v1
+
+      - name: Login to DockerHub
+        run: docker login -u tyrrrz -p ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Build container
+        run: docker build -f DiscordChatExporter.Cli.dockerfile -t tyrrrz/discordchatexporter:stable -t tyrrrz/discordchatexporter:${{ steps.get_version.outputs.tag }} .
+
+      - name: Push container (stable)
+        run: docker push tyrrrz/discordchatexporter:stable
+
+      - name: Push container (${{ steps.get_version.outputs.tag }})
+        run: docker push tyrrrz/discordchatexporter:${{ steps.get_version.outputs.tag }}

.github/workflows/main.yml

@@ -0,0 +1,152 @@
+name: main
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: windows-latest
+
+    env:
+      DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
+      DOTNET_NOLOGO: true
+      DOTNET_CLI_TELEMETRY_OPTOUT: true
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Install .NET
+        uses: actions/setup-dotnet@v2
+        with:
+          dotnet-version: 6.0.x
+
+      - name: Run tests
+        # 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 --collect:"XPlat Code Coverage" -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=opencover
+        env:
+          DISCORD_TOKEN: ${{ secrets.DISCORD_TOKEN }}
+          DISCORD_TOKEN_BOT: true
+
+      - name: Upload coverage
+        uses: codecov/codecov-action@v3
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+
+  package:
+    needs: test
+    runs-on: windows-latest
+
+    env:
+      DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
+      DOTNET_NOLOGO: true
+      DOTNET_CLI_TELEMETRY_OPTOUT: true
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Install .NET
+        uses: actions/setup-dotnet@v2
+        with:
+          dotnet-version: 6.0.x
+
+      - name: Publish (CLI)
+        run: dotnet publish DiscordChatExporter.Cli/ -o DiscordChatExporter.Cli/bin/Publish/ --configuration Release
+
+      - name: Publish (GUI)
+        run: dotnet publish DiscordChatExporter.Gui/ -o DiscordChatExporter.Gui/bin/Publish/ --configuration Release
+
+      - name: Upload artifacts (CLI)
+        uses: actions/upload-artifact@v3
+        with:
+          name: DiscordChatExporter.Cli
+          path: DiscordChatExporter.Cli/bin/Publish/
+
+      - name: Upload artifacts (GUI)
+        uses: actions/upload-artifact@v3
+        with:
+          name: DiscordChatExporter
+          path: DiscordChatExporter.Gui/bin/Publish/
+
+  deploy:
+    if: ${{ github.event_name == 'push' && github.ref_type == 'tag' }}
+    needs: package
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Download artifacts (CLI)
+        uses: actions/download-artifact@v3
+        with:
+          name: DiscordChatExporter.Cli
+          path: DiscordChatExporter.Cli
+
+      - name: Download artifacts (GUI)
+        uses: actions/download-artifact@v3
+        with:
+          name: DiscordChatExporter
+          path: DiscordChatExporter.Gui
+
+      - name: Create package (CLI)
+        run: Compress-Archive -Path DiscordChatExporter.Cli/* -DestinationPath DiscordChatExporter.Cli.zip -Force
+        shell: pwsh
+
+      - name: Create package (GUI)
+        run: Compress-Archive -Path DiscordChatExporter.Gui/* -DestinationPath DiscordChatExporter.Gui.zip -Force
+        shell: pwsh
+
+      - name: Create release
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ github.ref }}
+          body: |
+            [Changelog](https://github.com/Tyrrrz/DiscordChatExporter/blob/master/Changelog.md)
+          draft: false
+          prerelease: false
+
+      - name: Upload release asset (CLI)
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_name: DiscordChatExporter.Cli.zip
+          asset_path: DiscordChatExporter.Cli.zip
+          asset_content_type: application/zip
+
+      - name: Upload release asset (GUI)
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_name: DiscordChatExporter.zip
+          asset_path: DiscordChatExporter.Gui.zip
+          asset_content_type: application/zip
+
+  notify:
+    needs: deploy
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Get release version
+        id: get_version
+        uses: dawidd6/action-get-tag@v1
+
+      - 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>"
+            }

.gitignore

@@ -4,6 +4,8 @@
 *.userosscache
 *.sln.docstates
 .idea/
+.vs/
+.vscode/
 
 # Build results
 [Dd]ebug/
@@ -18,4 +20,7 @@ bld/
 [Oo]bj/
 
 # Coverage
-*.opencover.xml
+*.opencover.xml
+
+# Secrets
+*.secret

Changelog.md

@@ -1,3 +1,181 @@
+### v2.36.1 (24-Sep-2022)
+
+- Added a check which will trigger an error if the provided bot account does not have the message content intent enabled. Note, however, that this check is based on heuristics which may result in false negatives.
+- Fixed an issue where certain transient HTTP errors were not retried.
+- Fixed an issue which caused the export process to fail with the `IndexOutOfRangeException` exception on certain automated messages.
+- Fixed an issue which caused the export process to fail on unrecognized embed types.
+
+### v2.36 (16-Sep-2022)
+
+- [HTML] Added support for rendering GIFV embeds. They will now render as videos that automatically play when you hover your mouse over them. (Thanks [@gan-of-culture](https://github.com/gan-of-culture))
+- [HTML] Added support for rendering system notification messages, such as when a user joins a server or when a messages gets pinned. Previously, such messages were rendered as regular text messages, but now they look similar to how they're presented in the Discord client. (Thanks [@gan-of-culture](https://github.com/gan-of-culture))
+- [CLI] Improved the wording of the error message that's shown when exporting multiple channels and the provided output path is ambiguous. It now mentions that you can resolve the ambiguity by adding a slash at the end of the path.
+
+### v2.35.2 (08-Sep-2022)
+
+- Updated usage guide to mention the need to enable "Message Content Intent" to use a bot as a medium for exporting messages.
+- [CLI] Fixed an issue where passing an existing directory as the output path failed when exporting multiple channels (for example, when running `exportdm`). An ambiguous output path will now always be treated as a directory path if that directory already exists. If it doesn't exist, it will be treated as a file path, matching the previous behavior.
+
+### v2.35.1 (26-Aug-2022)
+
+- Added `~` character as an alias for `-` when negating a message filter. This should make it easier to use negated filters from CLI where the dash character already has other meanings.
+- Extended retry logic to encompass all server-side errors from Discord API, instead of only `500 Internal Server Error`.
+- [CLI] Attempt to export multiple channels will now fail if provided with an output path that is neither a directory, nor a file name template. Previously, this resulted in all channels being exported to the same file, overwriting each other.
+- Fixed an issue where a text message filter didn't work if it started with a character that's also the first character in one of the named filters (e.g. `from` or `mentions`).
+- Fixed an issue where a text message filter didn't work correctly if it was enclosed in parentheses.
+- Fixed an issue where categories were displayed alongside regular channels in the channel list, both in GUI and in CLI (when using the `guild` command).
+- [CLI] Fixed an issue where an output path starting with a tilde on Linux was not expanded properly into a full path. (Thanks [@TSRBerry](https://github.com/TSRBerry))
+
+### v2.35 (02-Jul-2022)
+
+- Added support for exporting text chat in voice channels. These channels are now also displayed when browsing in the GUI and in the CLI when executing the `channels` command.
+- [GUI] Direct message channels are now sorted by the timestamp of their last message, similarly to how they appear in the Discord client.
+- [GUI] Removed artificial grouping of direct message channels into "Private" and "Group".
+- [CLI] Added runtime bootstrapper capabilities to the CLI flavor of DiscordChatExporter on Windows. Now, if you attempt to run the application without the required prerequisites installed, you will be provided with an option to install them automatically.
+- [CLI] Fixed outdated information in the usage guide. (Thanks [@Clint Herron](https://github.com/HanClinto))
+- [CLI] Added whitespace padding to the output of `guilds`, `channels`, and `dm` to make the tables look more uniform.
+- [HTML] Added hyperlinks to message timestamps, which allows you to quickly copy a link to a specific message in the export. (Thanks [@Philipp C. Heckel](https://github.com/binwiederhier))
+- [HTML] Added minification. Chat exports in HTML format are now 30-35% smaller than before.
+- [HTML] Added support for rendering embeds of Twitter posts that contain multiple images. Previously, this resulted in multiple separate embeds instead of one.
+- [HTML] Added support for rendering embeds of YouTube Shorts videos.
+- [HTML] Text content is now hidden if the message only contains a link to an image and nothing else. The link itself is resolved as an image embed.
+- [HTML] Fixed an issue where some emoji that included a zero-width-joiner rune were not rendered correctly due to a wrong Twemoji URL being generated. (Thanks [@Ethan](https://github.com/ethanndickson))
+- [HTML] Fixed an issue where replies to a message that contained a quote (i.e. `>`) were not rendered correctly.
+- [HTML] Fixed an issue where code blocks with language highlighting did not have the correct background color.
+- Added file name template token that resolves to the current date (`%d`). (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- Updated the usage guide to replace the instructions for retrieving the user token with those that appear to work for more people.
+- Updated the usage guide to feature the TOS warning more prominently.
+- [Docker] Changed internal working directory from `/app/out` to `/out`. This was an unintended breaking change. Please update your volume binding configuration from `-v /path/on/machine:/app/out` to `-v /path/on/machine:/out`.
+
+### v2.34.1 (01-Jun-2022)
+
+- Improved retry policy to handle more transient errors. This should result in fewer errors exporting a channel due to timeout.
+- Added `has:pin` message filter. You can use it to limit exported messages to those that have been pinned. (Thanks [@Andrew Kolos](https://github.com/andrewkolos))
+- Fixed an issue which caused the export to fail when processing stickers that have no name.
+
+### v2.34 (10-Apr-2022)
+
+- [HTML] Reworked layout to be more consistent with Discord.
+- [HTML] Changed user profile picture dimensions from `128x128` to `512x512`. (Thanks [@Chris Helder](https://github.com/TheDude53))
+- [HTML] Improved image scaling for Chromium-based browsers. This should result in higher quality images across the entire export.
+- [HTML] Hovering over messages will now show short timestamps on the left, indicating the time that the individual messages of the group were sent.
+- [HTML] Using "download media" option will now also download scripts, styles, fonts, and other similar resources used by the export.
+- [HTML] Image attachments will now use the provided description as alt text.
+- [HTML] Fixed a few layout inconsistencies related to embeds.
+- [GUI] Added a few clickable links to the usage guide to make the process of locating tokens easier.
+
+### v2.33.2 (07-Mar-2022)
+
+- Actually fixed it this time.
+
+### v2.33.1 (07-Mar-2022)
+
+- Fixed an issue where the application silently failed to run if the system didn't have .NET Runtime 6.0.2 installed. If you continue seeing this issue, please uninstall all existing .NET runtimes from your computer and then try running the application again.
+
+### v2.33 (06-Mar-2022)
+
+- Added messages informing about war in Ukraine and available ways to help.
+- Added support for rendering stickers in HTML and JSON. Lottie-based stickers currently cannot be displayed in HTML exports (see [#803](https://github.com/Tyrrrz/DiscordChatExporter/issues/803)).
+- Added a new `reaction:` message filter which can be used to check if someone reacted to a message with a specific emoji. You can either pass the emoji name (e.g. `reaction:LUL`) or its ID (e.g. `reaction:41771983429993937`).
+- [GUI] Added auto-detection for dark mode. If your system is configured to prefer dark mode in applications, DiscordChatExporter will use it by default instead of light mode.
+- Fixed an issue which caused the export process to crash when downloading media files with extremely long file extensions. (Thanks [@Tomlacko](https://github.com/Tomlacko))
+- Fixed an issue which caused the export process to crash on invalid mentions.
+- [GUI] Fixed an issue where the time pickers used to specify export ranges always displayed time in 12-hour format, instead of respecting the system locale.
+
+### v2.32 (27-Jan-2022)
+
+- Token kind (user or bot) is now detected automatically. Removed the button to switch token kind in GUI. Option `-b|--bot` in CLI is now deprecated and does nothing.
+- Updated user token extraction guide to reflect the fact that devtools are no longer accessible in the desktop version of Discord client. The recommended workaround is to open Discord in browser. (Thanks [@Dhananjay-JSR](https://github.com/Dhananjay-JSR))
+- Fixed an issue which caused an error when parsing invalid date timestamps. Such timestamps are now rendered as "Invalid date", similarly to how the Discord client does it.
+- Fixed an issue which caused an error when parsing certain embed fields.
+- Fixed an issue which caused an error when parsing a mention to a user that has no username.
+- [GUI] Minor visual fixes.
+
+### v2.31.1 (15-Dec-2021)
+
+- Fixed an issue which caused an error 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))
+- [CLI] Improved formatting and progress reporting.
+- [CLI] Changed `export` command so that it can accept multiple channel IDs passed to `-c|--channel` option. This makes it possible to export multiple channels at once while benefiting from parallelization.
+- [JSON] Added `color` field to message author. This is a hex string that represents user's color, inherited from their roles. (Thanks [@rtm516](https://github.com/rtm516))
+- [JSON] Added `categoryId` field to the root. This represents the ID of the category channel that the currently exported channel belongs to. (Thanks [@rtm516](https://github.com/rtm516))
+- [JSON] Fixed an issue where user discriminator was written without leading zeroes. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- [JSON] Fixed an issue where the application sometimes crashed with an error saying `']' invalid without a matching open`, which was just a validation message that masked the actual error behind the failure. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- Fixed an issue where progress was not reported correctly if the channel didn't have any messages in the specified time range.
+
+### v2.26.1 (06-Feb-2021)
+
+- [CLI] Added support for file name templates, which allow you to dynamically generate output file names based on channel and guild metadata. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+- Fixed an issue where the application sometimes crashed with `Invalid snowflake` message when exporting chat logs that contained invalid or outdated mentions. (Thanks [@Lucas LaBuff](https://github.com/96-LB))
+
 ### v2.26 (29-Dec-2020)
 
 - [HTML] Added support for replies. (Thanks [@Sanqui](https://github.com/Sanqui))
@@ -57,10 +235,10 @@
 
 ### 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. 
+Note that all existing and current HTML exports will likely not render accurately because Discord enabled CORS for their font resources, which prevents them from loading locally. Please refer to [issue #322](https://github.com/Tyrrrz/DiscordChatExporter/issues/322) for discussion on this topic.
 
 ### v2.20 (27-Apr-2020)
 
@@ -96,7 +274,7 @@ 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)
@@ -109,7 +287,7 @@ 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.
 
@@ -150,8 +328,8 @@ 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)
 
@@ -173,15 +351,15 @@ 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.
@@ -241,7 +419,7 @@ 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.
@@ -265,7 +443,7 @@ 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.

Directory.Build.props

@@ -1,13 +1,13 @@
 <Project>
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
-    <Version>2.26</Version>
+    <TargetFramework>net6.0</TargetFramework>
+    <Version>2.36.1</Version>
     <Company>Tyrrrz</Company>
-    <Copyright>Copyright (c) Alexey Golub</Copyright>
+    <Copyright>Copyright (c) Oleksii Holub</Copyright>
     <LangVersion>preview</LangVersion>
     <Nullable>enable</Nullable>
     <WarningsAsErrors>nullable</WarningsAsErrors>
   </PropertyGroup>
 
-</Project>
+</Project>

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

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Content Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
+    <None Include="*.secret" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="AngleSharp" Version="0.17.1" />
+    <PackageReference Include="FluentAssertions" Version="6.7.0" />
+    <PackageReference Include="GitHubActionsTestLogger" Version="2.0.1" PrivateAssets="all" />
+    <PackageReference Include="JsonExtensions" Version="1.2.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.3.0" />
+    <PackageReference Include="System.Reactive" Version="5.0.0" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="all" />
+    <PackageReference Include="coverlet.collector" Version="3.1.2" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DiscordChatExporter.Cli\DiscordChatExporter.Cli.csproj" />
+  </ItemGroup>
+
+</Project>

DiscordChatExporter.Cli.Tests/Fixtures/ExportWrapperFixture.cs

@@ -0,0 +1,117 @@
+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
+            {
+                Token = Secrets.DiscordToken,
+                ChannelIds = new[] { channelId },
+                ExportFormat = format,
+                OutputPath = filePath
+            }.ExecuteAsync(new FakeConsole());
+        }
+
+        return await File.ReadAllTextAsync(filePath);
+    }
+
+    public async ValueTask<IHtmlDocument> ExportAsHtmlAsync(Snowflake channelId) => Html.Parse(
+        await ExportAsync(channelId, ExportFormat.HtmlDark)
+    );
+
+    public async ValueTask<JsonElement> ExportAsJsonAsync(Snowflake channelId) => Json.Parse(
+        await ExportAsync(channelId, ExportFormat.Json)
+    );
+
+    public async ValueTask<string> ExportAsPlainTextAsync(Snowflake channelId) =>
+        await ExportAsync(channelId, ExportFormat.PlainText);
+
+    public async ValueTask<string> ExportAsCsvAsync(Snowflake channelId) =>
+        await ExportAsync(channelId, ExportFormat.Csv);
+
+    public async ValueTask<IReadOnlyList<IElement>> GetMessagesAsHtmlAsync(Snowflake channelId) =>
+        (await ExportAsHtmlAsync(channelId))
+        .QuerySelectorAll("[data-message-id]")
+        .ToArray();
+
+    public async ValueTask<IReadOnlyList<JsonElement>> GetMessagesAsJsonAsync(Snowflake channelId) =>
+        (await ExportAsJsonAsync(channelId))
+        .GetProperty("messages")
+        .EnumerateArray()
+        .ToArray();
+
+    public async ValueTask<IElement> GetMessageAsHtmlAsync(Snowflake channelId, Snowflake messageId)
+    {
+        var message = (await GetMessagesAsHtmlAsync(channelId))
+            .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 the export of channel '{channelId}'."
+            );
+        }
+
+        return message;
+    }
+
+    public async ValueTask<JsonElement> GetMessageAsJsonAsync(Snowflake channelId, Snowflake messageId)
+    {
+        var message = (await GetMessagesAsJsonAsync(channelId))
+            .SingleOrDefault(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 the 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 +1,26 @@
+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.");
+    });
+
+    public static string DiscordToken => DiscordTokenLazy.Value;
+}

DiscordChatExporter.Cli.Tests/Readme.md

@@ -0,0 +1,13 @@
+# 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 test 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 add a new test case, please let me know and I will give you the required permissions

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

@@ -0,0 +1,37 @@
+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 class ContentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public ContentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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 +1,157 @@
+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 class DateRangeSpecs : IClassFixture<TempOutputFixture>
+{
+    private readonly TempOutputFixture _tempOutput;
+
+    public DateRangeSpecs(TempOutputFixture tempOutput)
+    {
+        _tempOutput = tempOutput;
+    }
+
+    [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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            After = Snowflake.FromDate(after)
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        var timestamps = Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            Before = Snowflake.FromDate(before)
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        var timestamps = Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            Before = Snowflake.FromDate(before),
+            After = Snowflake.FromDate(after)
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        var timestamps = Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("timestamp").GetDateTimeOffset())
+            .ToArray();
+
+        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 +1,155 @@
+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 class FilterSpecs : IClassFixture<TempOutputFixture>
+{
+    private readonly TempOutputFixture _tempOutput;
+
+    public FilterSpecs(TempOutputFixture tempOutput)
+    {
+        _tempOutput = tempOutput;
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_text_only_include_messages_that_contain_that_text()
+    {
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("some text")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("from:Tyrrrz")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("has:image")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("This has image");
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_pin_only_include_messages_that_have_been_pinned()
+    {
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("has:pin")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("This is pinned");
+    }
+
+    [Fact]
+    public async Task Messages_filtered_by_mention_only_include_messages_that_have_that_mention()
+    {
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.FilterTestCases },
+            ExportFormat = ExportFormat.Json,
+            OutputPath = filePath,
+            MessageFilter = MessageFilter.Parse("mentions:Tyrrrz")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Json
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .GetProperty("messages")
+            .EnumerateArray()
+            .Select(j => j.GetProperty("content").GetString())
+            .Should()
+            .ContainSingle("This has mention");
+    }
+}

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

@@ -0,0 +1,106 @@
+using System.Linq;
+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 class AttachmentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public AttachmentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task Message_with_a_generic_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885587844989612074")
+        );
+
+        // Assert
+        message.Text().Should().ContainAll(
+            "Generic file attachment",
+            "Test.txt",
+            "11 bytes"
+        );
+
+        message
+            .QuerySelectorAll("a")
+            .Select(e => e.GetAttribute("href"))
+            .Should()
+            .Contain(
+                "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")
+        );
+
+        // Assert
+        message.Text().Should().Contain("Image attachment");
+
+        message
+            .QuerySelectorAll("img")
+            .Select(e => e.GetAttribute("src"))
+            .Should()
+            .Contain(
+                "https://cdn.discordapp.com/attachments/885587741654536192/885654862430359613/bird-thumbnail.png"
+            );
+    }
+
+    [Fact]
+    public async Task Message_with_a_video_attachment_is_rendered_correctly()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/333
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885655761919836171")
+        );
+
+        // Assert
+        message.Text().Should().Contain("Video attachment");
+
+        var videoUrl = message.QuerySelector("video source")?.GetAttribute("src");
+        videoUrl.Should().Be(
+            "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()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/333
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885656175620808734")
+        );
+
+        // Assert
+        message.Text().Should().Contain("Audio attachment");
+
+        var audioUrl = message.QuerySelector("audio source")?.GetAttribute("src");
+        audioUrl.Should().Be(
+            "https://cdn.discordapp.com/attachments/885587741654536192/885656175348187146/file_example_MP3_1MG.mp3"
+        );
+    }
+}

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

@@ -0,0 +1,49 @@
+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 class ContentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public ContentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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.SelectMany(e => e.Text()).Should().ContainInOrder(
+            "Hello world",
+            "Goodbye world",
+            "Foo bar",
+            "Hurdle Durdle",
+            "One",
+            "Two",
+            "Three",
+            "Yeet"
+        );
+    }
+}

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

@@ -0,0 +1,167 @@
+using System.Linq;
+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 class EmbedSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public EmbedSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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_containing_an_image_link_is_rendered_with_an_image_embed()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/537
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("991768701126852638")
+        );
+
+        // Assert
+        message
+            .QuerySelectorAll("img")
+            .Select(e => e.GetAttribute("src"))
+            .Where(s => s?.EndsWith("i.redd.it/f8w05ja8s4e61.png") ?? false)
+            .Should()
+            .ContainSingle();
+    }
+
+    [Fact]
+    public async Task Message_containing_an_image_link_and_nothing_else_is_rendered_without_text_content()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/682
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("991768701126852638")
+        );
+
+        // Assert
+        var content = message.QuerySelector(".chatlog__content")?.Text();
+        content.Should().BeNullOrEmpty();
+    }
+
+    [Fact]
+    public async Task Message_containing_a_gifv_link_is_rendered_with_a_video_embed()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("1019234520349814794")
+        );
+
+        // Assert
+        message
+            .QuerySelectorAll("source")
+            .Select(e => e.GetAttribute("src"))
+            .Where(s => s?.EndsWith("media.tenor.com/DDAJeW6BQKkAAAPo/tooncasm-test-copy.mp4") ?? false)
+            .Should()
+            .ContainSingle();
+    }
+
+    [Fact]
+    public async Task Message_containing_a_gifv_link_and_nothing_else_is_rendered_without_text_content()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("1019234520349814794")
+        );
+
+        // Assert
+        var content = message.QuerySelector(".chatlog__content")?.Text();
+        content.Should().BeNullOrEmpty();
+    }
+
+    [Fact]
+    public async Task Message_containing_a_Spotify_track_link_is_rendered_with_a_track_embed()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/657
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("867886632203976775")
+        );
+
+        // Assert
+        var iframeUrl = message.QuerySelector("iframe")?.GetAttribute("src");
+        iframeUrl.Should().Be("https://open.spotify.com/embed/track/1LHZMWefF9502NPfArRfvP");
+    }
+
+    [Fact]
+    public async Task Message_containing_a_YouTube_video_link_is_rendered_with_a_video_embed()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/570
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("866472508588294165")
+        );
+
+        // Assert
+        var iframeUrl = message.QuerySelector("iframe")?.GetAttribute("src");
+        iframeUrl.Should().Be("https://www.youtube.com/embed/qOWW4OlgbvE");
+    }
+
+    [Fact]
+    public async Task Message_containing_a_Twitter_post_link_with_multiple_images_is_rendered_as_a_single_embed()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/695
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("991757444017557665")
+        );
+
+        // Assert
+        message
+            .QuerySelectorAll("img")
+            .Select(e => e.GetAttribute("src"))
+            .Should()
+            .ContainInOrder(
+                "https://images-ext-1.discordapp.net/external/-n--xW3EHH_3jlrheVkMXHCM7T86b5Ty4-MzXCT4m1Q/https/pbs.twimg.com/media/FVYIzYPWAAAMBqZ.png",
+                "https://images-ext-2.discordapp.net/external/z5nEmGeEldV-kswydGLhqUsFHbb5AWHtdvc9XT6N5rE/https/pbs.twimg.com/media/FVYJBWJWAAMNAx2.png",
+                "https://images-ext-2.discordapp.net/external/gnip03SawMB6uZLagN5sRDpA_1Ap1CcEhMbJfK1z6WQ/https/pbs.twimg.com/media/FVYJHiRX0AANZcz.png",
+                "https://images-ext-2.discordapp.net/external/jl1v6cCbLaGmiwmKU-ZkXnF4cFsJ39f9A3-oEdqPdZs/https/pbs.twimg.com/media/FVYJNZNXwAAPnVG.png"
+            );
+
+        message.QuerySelectorAll(".chatlog__embed").Should().ContainSingle();
+    }
+}

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

@@ -0,0 +1,79 @@
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using AngleSharp.Dom;
+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.HtmlWriting;
+
+public class GroupingSpecs : IClassFixture<TempOutputFixture>
+{
+    private readonly TempOutputFixture _tempOutput;
+
+    public GroupingSpecs(TempOutputFixture tempOutput)
+    {
+        _tempOutput = tempOutput;
+    }
+
+    [Fact]
+    public async Task Messages_are_grouped_correctly()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/152
+
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.GroupingTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        var messageGroups = Html
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .QuerySelectorAll(".chatlog__message-group");
+
+        messageGroups.Should().HaveCount(2);
+
+        messageGroups[0]
+            .QuerySelectorAll(".chatlog__content")
+            .Select(e => e.Text())
+            .Should()
+            .ContainInOrder(
+                "First",
+                "Second",
+                "Third",
+                "Fourth",
+                "Fifth",
+                "Sixth",
+                "Seventh",
+                "Eighth",
+                "Ninth",
+                "Tenth"
+            );
+
+        messageGroups[1]
+            .QuerySelectorAll(".chatlog__content")
+            .Select(e => e.Text())
+            .Should()
+            .ContainInOrder(
+                "Eleventh",
+                "Twelveth",
+                "Thirteenth",
+                "Fourteenth",
+                "Fifteenth"
+            );
+    }
+}

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

@@ -0,0 +1,72 @@
+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 class MentionSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public MentionSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task User_mention_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.MentionTestCases,
+            Snowflake.Parse("866458840245076028")
+        );
+
+        // Assert
+        message.Text().Should().Contain("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().Should().Contain("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().Should().Contain("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().Should().Contain("Role mention: @Role 1");
+    }
+}

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

@@ -0,0 +1,67 @@
+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 class ReplySpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public ReplySpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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().Should().Contain("reply to original");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Should().Contain("original");
+    }
+
+    [Fact]
+    public async Task Reply_to_a_deleted_message_is_rendered_correctly()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/645
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.ReplyTestCases,
+            Snowflake.Parse("866460975388819486")
+        );
+
+        // Assert
+        message.Text().Should().Contain("reply to deleted");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Should().Contain(
+            "Original message was deleted or could not be loaded."
+        );
+    }
+
+    [Fact]
+    public async Task Reply_to_an_empty_message_with_attachment_is_rendered_correctly()
+    {
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/634
+
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.ReplyTestCases,
+            Snowflake.Parse("866462470335627294")
+        );
+
+        // Assert
+        message.Text().Should().Contain("reply to attachment");
+        message.QuerySelector(".chatlog__reference-link")?.Text().Should().Contain("Click to see attachment");
+    }
+}

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

@@ -0,0 +1,46 @@
+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.HtmlWriting;
+
+public class StickerSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public StickerSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task Message_with_a_PNG_based_sticker_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.StickerTestCases,
+            Snowflake.Parse("939670623158943754")
+        );
+
+        // Assert
+        var stickerUrl = message.QuerySelector("[title='rock'] img")?.GetAttribute("src");
+        stickerUrl.Should().Be("https://discord.com/stickers/904215665597120572.png");
+    }
+
+    [Fact]
+    public async Task Message_with_a_Lottie_based_sticker_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsHtmlAsync(
+            ChannelIds.StickerTestCases,
+            Snowflake.Parse("939670526517997590")
+        );
+
+        // Assert
+        var stickerUrl = message.QuerySelector("[title='Yikes'] [data-source]")?.GetAttribute("data-source");
+        stickerUrl.Should().Be("https://discord.com/stickers/816087132447178774.json");
+    }
+}

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

@@ -0,0 +1,103 @@
+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 class AttachmentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public AttachmentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task Message_with_a_generic_attachment_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.AttachmentTestCases,
+            Snowflake.Parse("885587844989612074")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Generic file attachment");
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().Be(
+            "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")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Image attachment");
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().Be(
+            "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")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Video attachment");
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().Be(
+            "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")
+        );
+
+        // Assert
+        message.GetProperty("content").GetString().Should().Be("Audio attachment");
+
+        var attachments = message.GetProperty("attachments").EnumerateArray().ToArray();
+        attachments.Should().HaveCount(1);
+        attachments.Single().GetProperty("url").GetString().Should().Be(
+            "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 +1,48 @@
+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 class ContentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public ContentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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 +1,63 @@
+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 class EmbedSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public EmbedSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task Message_with_an_embed_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.EmbedTestCases,
+            Snowflake.Parse("866769910729146400")
+        );
+
+        // Assert
+        var embed = message.GetProperty("embeds").EnumerateArray().Single();
+        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");
+
+        var embedAuthor = embed.GetProperty("author");
+        embedAuthor.GetProperty("name").GetString().Should().Be("Embed author");
+        embedAuthor.GetProperty("url").GetString().Should().Be("https://example.com/author");
+        embedAuthor.GetProperty("iconUrl").GetString().Should().NotBeNullOrWhiteSpace();
+
+        var embedThumbnail = embed.GetProperty("thumbnail");
+        embedThumbnail.GetProperty("url").GetString().Should().NotBeNullOrWhiteSpace();
+        embedThumbnail.GetProperty("width").GetInt32().Should().Be(120);
+        embedThumbnail.GetProperty("height").GetInt32().Should().Be(120);
+
+        var embedFooter = embed.GetProperty("footer");
+        embedFooter.GetProperty("text").GetString().Should().Be("Embed footer");
+        embedFooter.GetProperty("iconUrl").GetString().Should().NotBeNullOrWhiteSpace();
+
+        var embedFields = embed.GetProperty("fields").EnumerateArray().ToArray();
+        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 +1,78 @@
+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 class MentionSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public MentionSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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/JsonWriting/StickerSpecs.cs

@@ -0,0 +1,61 @@
+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 class StickerSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public StickerSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [Fact]
+    public async Task Message_with_a_PNG_based_sticker_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.StickerTestCases,
+            Snowflake.Parse("939670623158943754")
+        );
+
+        // Assert
+        var sticker = message
+            .GetProperty("stickers")
+            .EnumerateArray()
+            .Single();
+
+        sticker.GetProperty("id").GetString().Should().Be("904215665597120572");
+        sticker.GetProperty("name").GetString().Should().Be("rock");
+        sticker.GetProperty("format").GetString().Should().Be("PngAnimated");
+        sticker.GetProperty("sourceUrl").GetString().Should().Be("https://discord.com/stickers/904215665597120572.png");
+    }
+
+    [Fact]
+    public async Task Message_with_a_Lottie_based_sticker_is_rendered_correctly()
+    {
+        // Act
+        var message = await _exportWrapper.GetMessageAsJsonAsync(
+            ChannelIds.StickerTestCases,
+            Snowflake.Parse("939670526517997590")
+        );
+
+        // Assert
+        var sticker = message
+            .GetProperty("stickers")
+            .EnumerateArray()
+            .Single();
+
+        sticker.GetProperty("id").GetString().Should().Be("816087132447178774");
+        sticker.GetProperty("name").GetString().Should().Be("Yikes");
+        sticker.GetProperty("format").GetString().Should().Be("Lottie");
+        sticker.GetProperty("sourceUrl").GetString().Should().Be("https://discord.com/stickers/816087132447178774.json");
+    }
+}

DiscordChatExporter.Cli.Tests/Specs/PartitioningSpecs.cs

@@ -0,0 +1,71 @@
+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 class PartitioningSpecs : IClassFixture<TempOutputFixture>
+{
+    private readonly TempOutputFixture _tempOutput;
+
+    public PartitioningSpecs(TempOutputFixture tempOutput)
+    {
+        _tempOutput = tempOutput;
+    }
+
+    [Fact]
+    public async Task Messages_partitioned_by_count_are_split_into_a_corresponding_number_of_files()
+    {
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+        var fileNameWithoutExt = Path.GetFileNameWithoutExtension(filePath);
+        var dirPath = Path.GetDirectoryName(filePath) ?? Directory.GetCurrentDirectory();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            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_a_corresponding_number_of_files()
+    {
+        // Arrange
+        var filePath = _tempOutput.GetTempFilePath();
+        var fileNameWithoutExt = Path.GetFileNameWithoutExtension(filePath);
+        var dirPath = Path.GetDirectoryName(filePath) ?? Directory.GetCurrentDirectory();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.DateRangeTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath,
+            PartitionLimit = PartitionLimit.Parse("1kb")
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Directory.EnumerateFiles(dirPath, fileNameWithoutExt + "*")
+            .Should()
+            .HaveCount(8);
+    }
+}

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

@@ -0,0 +1,37 @@
+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 class ContentSpecs : IClassFixture<ExportWrapperFixture>
+{
+    private readonly ExportWrapperFixture _exportWrapper;
+
+    public ContentSpecs(ExportWrapperFixture exportWrapper)
+    {
+        _exportWrapper = exportWrapper;
+    }
+
+    [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 +1,52 @@
+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 class SelfContainedSpecs : IClassFixture<TempOutputFixture>
+{
+    private readonly TempOutputFixture _tempOutput;
+
+    public SelfContainedSpecs(TempOutputFixture tempOutput)
+    {
+        _tempOutput = tempOutput;
+    }
+
+    [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
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = new[] { ChannelIds.SelfContainedTestCases },
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = filePath,
+            ShouldDownloadMedia = true
+        }.ExecuteAsync(new FakeConsole());
+
+        // Assert
+        Html
+            .Parse(await File.ReadAllTextAsync(filePath))
+            .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 +1,24 @@
+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 GroupingTestCases { get; } = Snowflake.Parse("992092091545034842");
+
+    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");
+
+    public static Snowflake StickerTestCases { get; } = Snowflake.Parse("939668868253769729");
+}

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.dockerfile

@@ -0,0 +1,18 @@
+# Build
+FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
+
+COPY favicon.ico ./
+COPY NuGet.config ./
+COPY Directory.Build.props ./
+COPY DiscordChatExporter.Core ./DiscordChatExporter.Core
+COPY DiscordChatExporter.Cli ./DiscordChatExporter.Cli
+
+RUN dotnet publish DiscordChatExporter.Cli -c Release -o ./publish
+
+# Run
+FROM mcr.microsoft.com/dotnet/runtime:6.0 AS run
+
+COPY --from=build ./publish ./
+
+WORKDIR ./out
+ENTRYPOINT ["dotnet", "/DiscordChatExporter.Cli.dll"]

DiscordChatExporter.Cli/Commands/Base/ExportCommandBase.cs

@@ -1,87 +1,246 @@
-using System.IO;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
-using CliFx;
 using CliFx.Attributes;
 using CliFx.Exceptions;
-using CliFx.Utilities;
-using DiscordChatExporter.Domain.Discord;
-using DiscordChatExporter.Domain.Discord.Models;
-using DiscordChatExporter.Domain.Exporting;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Utils.Extensions;
+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;
+using Gress;
 
-namespace DiscordChatExporter.Cli.Commands.Base
+namespace DiscordChatExporter.Cli.Commands.Base;
+
+public abstract class ExportCommandBase : TokenCommandBase
 {
-    public abstract class ExportCommandBase : TokenCommandBase
+    private readonly string _outputPath = Directory.GetCurrentDirectory();
+
+    [CommandOption(
+        "output",
+        'o',
+        Description = "Output file or directory path. Directory path should end in a slash."
+    )]
+    public string OutputPath
     {
-        [CommandOption("output", 'o', Description = "Output file or directory path.")]
-        public string OutputPath { get; init; } = Directory.GetCurrentDirectory();
+        get => _outputPath;
+        // Handle ~/ in paths on *nix systems
+        // https://github.com/Tyrrrz/DiscordChatExporter/pull/903
+        init => _outputPath = Path.GetFullPath(value);
+    }
 
-        [CommandOption("format", 'f', Description = "Export format.")]
-        public ExportFormat ExportFormat { get; init; } = ExportFormat.HtmlDark;
+    [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(
+        "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(
+        "before",
+        Description = "Only include messages sent before this date or message ID."
+    )]
+    public Snowflake? Before { get; init; }
 
-        [CommandOption("partition", 'p', Description = "Split output into partitions limited to this number of messages.")]
-        public int? PartitionLimit { get; init; }
+    [CommandOption(
+        "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("media", Description = "Download referenced media content.")]
-        public bool ShouldDownloadMedia { get; init; }
+    [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("reuse-media", Description = "Reuse already existing media content to skip redundant downloads.")]
-        public bool ShouldReuseMedia { get; init; }
+    [CommandOption(
+        "parallel",
+        Description = "Limits how many channels can be exported in parallel."
+    )]
+    public int ParallelLimit { get; init; } = 1;
 
-        [CommandOption("dateformat", Description = "Format used when writing dates.")]
-        public string DateFormat { get; init; } = "dd-MMM-yy hh:mm tt";
+    [CommandOption(
+        "media",
+        Description = "Download referenced media content."
+    )]
+    public bool ShouldDownloadMedia { get; init; }
 
-        protected ChannelExporter GetChannelExporter() => new(GetDiscordClient());
+    [CommandOption(
+        "reuse-media",
+        Description = "Reuse already existing media content to skip redundant downloads."
+    )]
+    public bool ShouldReuseMedia { get; init; }
 
-        protected async ValueTask ExportAsync(IConsole console, Guild guild, Channel channel)
+    [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)
+    {
+        // Reuse media option should only be used when the media option is set.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/425
+        if (ShouldReuseMedia && !ShouldDownloadMedia)
         {
-            console.Output.Write($"Exporting channel '{channel.Category} / {channel.Name}'... ");
-            var progress = console.CreateProgressTicker();
-
-            var request = new ExportRequest(
-                guild,
-                channel,
-                OutputPath,
-                ExportFormat,
-                After,
-                Before,
-                PartitionLimit,
-                ShouldDownloadMedia,
-                ShouldReuseMedia,
-                DateFormat
+            throw new CommandException(
+                "Option --reuse-media cannot be used without --media."
             );
-
-            await GetChannelExporter().ExportChannelAsync(request, progress);
-
-            console.Output.WriteLine();
-            console.Output.WriteLine("Done.");
         }
 
-        protected async ValueTask ExportAsync(IConsole console, Channel channel)
+        // Make sure the user does not try to export all channels into a single file.
+        // Output path must either be a directory, or contain template tokens.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/799
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/917
+        var isValidOutputPath =
+            // Anything is valid when exporting a single channel
+            channels.Count <= 1 ||
+            // When using template tokens, assume the user knows what they're doing
+            OutputPath.Contains('%') ||
+            // Otherwise, require an existing directory or an unambiguous directory path
+            Directory.Exists(OutputPath) || PathEx.IsDirectoryPath(OutputPath);
+
+        if (!isValidOutputPath)
         {
-            var guild = await GetDiscordClient().GetGuildAsync(channel.GuildId);
-            await ExportAsync(console, guild, channel);
+            throw new CommandException(
+                "Attempted to export multiple channels, but the output path is neither a directory nor a template. " +
+                "If the provided output path is meant to be treated as a directory, make sure it ends with a slash."
+            );
         }
 
-        protected async ValueTask ExportAsync(IConsole console, Snowflake channelId)
+        var cancellationToken = console.RegisterCancellationHandler();
+        var errors = new ConcurrentDictionary<Channel, string>();
+
+        // Export
+        await console.Output.WriteLineAsync($"Exporting {channels.Count} channel(s)...");
+        await console.CreateProgressTicker().StartAsync(async progressContext =>
         {
-            var channel = await GetDiscordClient().GetChannelAsync(channelId);
-            await ExportAsync(console, channel);
+            await Parallel.ForEachAsync(
+                channels,
+                new ParallelOptions
+                {
+                    MaxDegreeOfParallelism = Math.Max(1, ParallelLimit),
+                    CancellationToken = cancellationToken
+                },
+                async (channel, innerCancellationToken) =>
+                {
+                    try
+                    {
+                        await progressContext.StartTaskAsync($"{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,
+                                    MessageFilter,
+                                    ShouldDownloadMedia,
+                                    ShouldReuseMedia,
+                                    DateFormat
+                                );
+
+                                await Exporter.ExportChannelAsync(
+                                    request,
+                                    progress.ToPercentageBased(),
+                                    innerCancellationToken
+                                );
+                            }
+                        );
+                    }
+                    catch (DiscordChatExporterException ex) when (!ex.IsFatal)
+                    {
+                        errors[channel] = ex.Message;
+                    }
+                }
+            );
+        });
+
+        // Print result
+        using (console.WithForegroundColor(ConsoleColor.White))
+        {
+            await console.Output.WriteLineAsync(
+                $"Successfully exported {channels.Count - errors.Count} channel(s)."
+            );
         }
 
-        public override ValueTask ExecuteAsync(IConsole console)
+        // Print errors
+        if (errors.Any())
         {
-            if (ShouldReuseMedia && !ShouldDownloadMedia)
+            await console.Output.WriteLineAsync();
+
+            using (console.WithForegroundColor(ConsoleColor.Red))
             {
-                throw new CommandException("The --reuse-media option cannot be used without the --media option.");
+                await console.Output.WriteLineAsync(
+                    $"Failed to export {errors.Count} channel(s):"
+                );
             }
 
-            return default;
+            foreach (var (channel, error) in errors)
+            {
+                await console.Output.WriteAsync($"{channel.Category.Name} / {channel.Name}: ");
+
+                using (console.WithForegroundColor(ConsoleColor.Red))
+                    await console.Output.WriteLineAsync(error);
+            }
+
+            await console.Output.WriteLineAsync();
+        }
+
+        // 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)
+        {
+            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);
+    }
+
+    public override ValueTask ExecuteAsync(IConsole console)
+    {
+        // War in Ukraine message
+        console.Output.WriteLine("========================================================================");
+        console.Output.WriteLine("||   Ukraine is at war! Support my country in its fight for freedom~  ||");
+        console.Output.WriteLine("||   Learn more on my website: https://tyrrrz.me                      ||");
+        console.Output.WriteLine("========================================================================");
+        console.Output.WriteLine("");
+
+        return default;
+    }
 }

DiscordChatExporter.Cli/Commands/Base/ExportMultipleCommandBase.cs

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

DiscordChatExporter.Cli/Commands/Base/TokenCommandBase.cs

@@ -1,27 +1,34 @@
-using System.Threading.Tasks;
+using System;
+using System.Threading.Tasks;
 using CliFx;
 using CliFx.Attributes;
-using DiscordChatExporter.Domain.Discord;
+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, EnvironmentVariableName = "DISCORD_TOKEN", Description = "Authorization token.")]
-        public string TokenValue { get; init; } = "";
+    [CommandOption(
+        "token",
+        't',
+        IsRequired = true,
+        EnvironmentVariable = "DISCORD_TOKEN",
+        Description = "Authentication token."
+    )]
+    public string Token { get; init; } = "";
 
-        [CommandOption("bot", 'b', EnvironmentVariableName = "DISCORD_TOKEN_BOT", Description = "Authorize as a bot.")]
-        public bool IsBotToken { get; init; }
+    [Obsolete("This option doesn't do anything. Kept for backwards compatibility.")]
+    [CommandOption(
+        "bot",
+        'b',
+        EnvironmentVariable = "DISCORD_TOKEN_BOT",
+        Description = "This option doesn't do anything. Kept for backwards compatibility."
+    )]
+    public bool IsBotToken { get; init; }
 
-        protected AuthToken GetAuthToken() => new(
-            IsBotToken
-                ? AuthTokenType.Bot
-                : AuthTokenType.User,
-            TokenValue
-        );
+    private DiscordClient? _discordClient;
+    protected DiscordClient Discord => _discordClient ??= new DiscordClient(Token);
 
-        protected DiscordClient GetDiscordClient() => new(GetAuthToken());
-
-        public abstract ValueTask ExecuteAsync(IConsole console);
-    }
+    public abstract ValueTask ExecuteAsync(IConsole console);
 }

DiscordChatExporter.Cli/Commands/ExportAllCommand.cs

@@ -1,36 +1,39 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using CliFx;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Discord.Models;
+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 : ExportMultipleCommandBase
+    [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;
+        await base.ExecuteAsync(console);
 
-        public override async ValueTask ExecuteAsync(IConsole console)
+        var cancellationToken = console.RegisterCancellationHandler();
+        var channels = new List<Channel>();
+
+        await console.Output.WriteLineAsync("Fetching channels...");
+        await foreach (var guild in Discord.GetUserGuildsAsync(cancellationToken))
         {
-            var channels = new List<Channel>();
+            // Skip DMs if instructed to
+            if (!IncludeDirectMessages && guild.Id == Guild.DirectMessages.Id)
+                continue;
 
-            // Aggregate channels from all guilds
-            await foreach (var guild in GetDiscordClient().GetUserGuildsAsync())
-            {
-                // Skip DMs if instructed to
-                if (!IncludeDirectMessages && guild.Id == Guild.DirectMessages.Id)
-                    continue;
-
-                await foreach (var channel in GetDiscordClient().GetGuildChannelsAsync(guild.Id))
-                {
-                    channels.Add(channel);
-                }
-            }
-
-            await ExportMultipleAsync(console, channels);
+            await foreach (var channel in Discord.GetGuildChannelsAsync(guild.Id, cancellationToken))
+                channels.Add(channel);
         }
+
+        await base.ExecuteAsync(console, channels);
     }
 }

DiscordChatExporter.Cli/Commands/ExportChannelCommand.cs

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

DiscordChatExporter.Cli/Commands/ExportChannelsCommand.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands.Base;
+using DiscordChatExporter.Core.Discord;
+
+namespace DiscordChatExporter.Cli.Commands;
+
+[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>();
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        await base.ExecuteAsync(console);
+        await base.ExecuteAsync(console, ChannelIds);
+    }
+}

DiscordChatExporter.Cli/Commands/ExportDirectMessagesCommand.cs

@@ -1,19 +1,28 @@
-using System.Threading.Tasks;
-using CliFx;
+using System.Linq;
+using System.Threading.Tasks;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Discord.Models;
-using DiscordChatExporter.Domain.Utilities;
+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 : ExportMultipleCommandBase
+    public override async ValueTask ExecuteAsync(IConsole console)
     {
-        public override async ValueTask ExecuteAsync(IConsole console)
-        {
-            var channels = await GetDiscordClient().GetGuildChannelsAsync(Guild.DirectMessages.Id);
-            await ExportMultipleAsync(console, channels);
-        }
+        await base.ExecuteAsync(console);
+
+        var cancellationToken = console.RegisterCancellationHandler();
+
+        await console.Output.WriteLineAsync("Fetching channels...");
+
+        var channels = (await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id, cancellationToken))
+            .Where(c => c.Kind != ChannelKind.GuildCategory)
+            .ToArray();
+
+        await base.ExecuteAsync(console, channels);
     }
 }

DiscordChatExporter.Cli/Commands/ExportGuildCommand.cs

@@ -1,22 +1,37 @@
-using System.Threading.Tasks;
-using CliFx;
+using System.Linq;
+using System.Threading.Tasks;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Discord;
-using DiscordChatExporter.Domain.Utilities;
+using DiscordChatExporter.Core.Discord;
+using DiscordChatExporter.Core.Discord.Data;
+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 : ExportMultipleCommandBase
-    {
-        [CommandOption("guild", 'g', IsRequired = true, Description = "Guild ID.")]
-        public Snowflake GuildId { get; init; }
+    [CommandOption(
+        "guild",
+        'g',
+        IsRequired = true,
+        Description = "Guild ID."
+    )]
+    public Snowflake GuildId { get; init; }
 
-        public override async ValueTask ExecuteAsync(IConsole console)
-        {
-            var channels = await GetDiscordClient().GetGuildChannelsAsync(GuildId);
-            await ExportMultipleAsync(console, channels);
-        }
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        await base.ExecuteAsync(console);
+
+        var cancellationToken = console.RegisterCancellationHandler();
+
+        await console.Output.WriteLineAsync("Fetching channels...");
+
+        var channels = (await Discord.GetGuildChannelsAsync(GuildId, cancellationToken))
+            .Where(c => c.Kind != ChannelKind.GuildCategory)
+            .ToArray();
+
+        await base.ExecuteAsync(console, channels);
     }
 }

DiscordChatExporter.Cli/Commands/GetChannelsCommand.cs

@@ -1,25 +1,50 @@
-using System.Linq;
+using System;
+using System.Linq;
 using System.Threading.Tasks;
-using CliFx;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Discord;
-using DiscordChatExporter.Domain.Utilities;
+using DiscordChatExporter.Core.Discord;
+using DiscordChatExporter.Core.Discord.Data;
+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))
+            .Where(c => c.Kind != ChannelKind.GuildCategory)
+            .OrderBy(c => c.Category.Position)
+            .ThenBy(c => c.Name)
+            .ToArray();
+
+        foreach (var channel in channels)
         {
-            var channels = await GetDiscordClient().GetGuildChannelsAsync(GuildId);
+            // Channel ID
+            await console.Output.WriteAsync(
+                channel.Id.ToString().PadRight(18, ' ')
+            );
 
-            foreach (var channel in channels.OrderBy(c => c.Category).ThenBy(c => c.Name))
-                console.Output.WriteLine($"{channel.Id} | {channel.Category} / {channel.Name}");
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
+
+            // Channel category / name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync($"{channel.Category.Name} / {channel.Name}");
         }
     }
 }

DiscordChatExporter.Cli/Commands/GetDirectMessageChannelsCommand.cs

@@ -1,22 +1,41 @@
-using System.Linq;
+using System;
+using System.Linq;
 using System.Threading.Tasks;
-using CliFx;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Discord.Models;
-using DiscordChatExporter.Domain.Utilities;
+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 channels = await GetDiscordClient().GetGuildChannelsAsync(Guild.DirectMessages.Id);
+        var cancellationToken = console.RegisterCancellationHandler();
 
-            foreach (var channel in channels.OrderBy(c => c.Category).ThenBy(c => c.Name))
-                console.Output.WriteLine($"{channel.Id} | {channel.Category} / {channel.Name}");
+        var channels = (await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id, cancellationToken))
+            .Where(c => c.Kind != ChannelKind.GuildCategory)
+            .OrderByDescending(c => c.LastMessageId)
+            .ThenBy(c => c.Name)
+            .ToArray();
+
+        foreach (var channel in channels)
+        {
+            // Channel ID
+            await console.Output.WriteAsync(
+                channel.Id.ToString().PadRight(18, ' ')
+            );
+
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
+
+            // Channel category / name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync($"{channel.Category.Name} / {channel.Name}");
         }
     }
 }

DiscordChatExporter.Cli/Commands/GetGuildsCommand.cs

@@ -1,21 +1,40 @@
-using System.Linq;
+using System;
+using System.Linq;
 using System.Threading.Tasks;
-using CliFx;
 using CliFx.Attributes;
+using CliFx.Infrastructure;
 using DiscordChatExporter.Cli.Commands.Base;
-using DiscordChatExporter.Domain.Utilities;
+using DiscordChatExporter.Core.Discord.Data;
+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 guilds = await GetDiscordClient().GetUserGuildsAsync();
+        var cancellationToken = console.RegisterCancellationHandler();
 
-            foreach (var guild in guilds.OrderBy(g => g.Name))
-                console.Output.WriteLine($"{guild.Id} | {guild.Name}");
+        var guilds = (await Discord.GetUserGuildsAsync(cancellationToken))
+            // Show direct messages first
+            .OrderByDescending(g => g.Id == Guild.DirectMessages.Id)
+            .ThenBy(g => g.Name);
+
+        foreach (var guild in guilds)
+        {
+            // Guild ID
+            await console.Output.WriteAsync(
+                guild.Id.ToString().PadRight(18, ' ')
+            );
+
+            // Separator
+            using (console.WithForegroundColor(ConsoleColor.DarkGray))
+                await console.Output.WriteAsync(" | ");
+
+            // Guild name
+            using (console.WithForegroundColor(ConsoleColor.White))
+                await console.Output.WriteLineAsync(guild.Name);
         }
     }
 }

DiscordChatExporter.Cli/Commands/GuideCommand.cs

@@ -1,65 +1,72 @@
-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)
-        {
-            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();
+        // User token
+        using (console.WithForegroundColor(ConsoleColor.White))
+            console.Output.WriteLine("To get user token:");
 
-            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(" *  Automating user accounts is technically against TOS — USE AT YOUR OWN RISK!");
+        console.Output.WriteLine(" 1. Open Discord in your web browser and login");
+        console.Output.WriteLine(" 2. Open any server or direct message channel");
+        console.Output.WriteLine(" 3. Press Ctrl+Shift+I to show developer tools");
+        console.Output.WriteLine(" 4. Navigate to the Network tab");
+        console.Output.WriteLine(" 5. Press Ctrl+R to reload");
+        console.Output.WriteLine(" 6. Search for a request containing \"messages?limit=50\" or similar");
+        console.Output.WriteLine(" 7. Select the Headers tab on the right");
+        console.Output.WriteLine(" 8. Scroll down to the Request Headers section");
+        console.Output.WriteLine(" 9. Copy the value of the \"authorization\" header");
+        console.Output.WriteLine();
 
-            console.WithForegroundColor(ConsoleColor.White, () =>
-                console.Output.WriteLine("To get guild ID or guild channel ID:")
-            );
-            console.Output.WriteLine(" 1. Open Discord");
-            console.Output.WriteLine(" 2. Open Settings");
-            console.Output.WriteLine(" 3. Go to Appearance section");
-            console.Output.WriteLine(" 4. Enable Developer Mode");
-            console.Output.WriteLine(" 5. Right click on the desired guild or channel and click Copy ID");
-            console.Output.WriteLine();
+        // Bot token
+        using (console.WithForegroundColor(ConsoleColor.White))
+            console.Output.WriteLine("To get bot token:");
 
-            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. 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(" *  Your bot needs to have Message Content Intent enabled to read messages");
+        console.Output.WriteLine();
 
-            console.WithForegroundColor(ConsoleColor.White,
-                () => console.Output.WriteLine("For more information, check out the wiki:")
-            );
-            console.WithForegroundColor(ConsoleColor.Blue,
-                () => console.Output.WriteLine("https://github.com/Tyrrrz/DiscordChatExporter/wiki")
-            );
+        // Guild or channel ID
+        using (console.WithForegroundColor(ConsoleColor.White))
+            console.Output.WriteLine("To get guild ID or guild channel ID:");
 
-            return default;
-        }
+        console.Output.WriteLine(" 1. Open Discord");
+        console.Output.WriteLine(" 2. Open Settings");
+        console.Output.WriteLine(" 3. Go to Advanced 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();
+
+        // 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();
+
+        // Wiki link
+        using (console.WithForegroundColor(ConsoleColor.White))
+            console.Output.WriteLine("If you have questions or issues, please refer to the wiki:");
+        using (console.WithForegroundColor(ConsoleColor.DarkCyan))
+            console.Output.WriteLine("https://github.com/Tyrrrz/DiscordChatExporter/wiki");
+
+        return default;
     }
 }

DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj

@@ -6,13 +6,14 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CliFx" Version="1.6.0" />
-    <PackageReference Include="Gress" Version="1.2.0" />
-    <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
+    <PackageReference Include="CliFx" Version="2.3.0" />
+    <PackageReference Include="Spectre.Console" Version="0.44.0" />
+    <PackageReference Include="Gress" Version="2.0.1" />
+    <PackageReference Include="DotnetRuntimeBootstrapper" Version="2.3.1" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\DiscordChatExporter.Domain\DiscordChatExporter.Domain.csproj" />
+    <ProjectReference Include="..\DiscordChatExporter.Core\DiscordChatExporter.Core.csproj" />
   </ItemGroup>
 
 </Project>

DiscordChatExporter.Cli/Internal/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.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

@@ -0,0 +1,50 @@
+using System;
+using System.Threading.Tasks;
+using CliFx.Infrastructure;
+using Spectre.Console;
+
+namespace DiscordChatExporter.Cli.Utils.Extensions;
+
+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 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}
+        );
+
+        try
+        {
+            await performOperationAsync(progressTask);
+        }
+        finally
+        {
+            progressTask.StopTask();
+        }
+    }
+}

DiscordChatExporter.Core/Discord/Data/Attachment.cs

@@ -0,0 +1,46 @@
+using System;
+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;
+
+// https://discord.com/developers/docs/resources/channel#attachment-object
+public partial record Attachment(
+    Snowflake Id,
+    string Url,
+    string FileName,
+    string? Description,
+    int? Width,
+    int? Height,
+    FileSize FileSize) : 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)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var url = json.GetProperty("url").GetNonWhiteSpaceString();
+        var fileName = json.GetProperty("filename").GetNonNullString();
+        var description = json.GetPropertyOrNull("description")?.GetNonWhiteSpaceStringOrNull();
+        var width = json.GetPropertyOrNull("width")?.GetInt32OrNull();
+        var height = json.GetPropertyOrNull("height")?.GetInt32OrNull();
+        var fileSize = json.GetProperty("size").GetInt64().Pipe(FileSize.FromBytes);
+
+        return new Attachment(id, url, fileName, description, width, height, fileSize);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Channel.cs

@@ -0,0 +1,80 @@
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+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,
+    Snowflake? LastMessageId) : IHasId
+{
+    public bool SupportsVoice => Kind is ChannelKind.GuildVoiceChat or ChannelKind.GuildStageVoice;
+}
+
+public partial record Channel
+{
+    private static ChannelCategory GetFallbackCategory(ChannelKind channelKind) => new(
+        Snowflake.Zero,
+        channelKind switch
+        {
+            ChannelKind.GuildTextChat => "Text",
+            ChannelKind.DirectTextChat => "Private",
+            ChannelKind.DirectGroupTextChat => "Group",
+            ChannelKind.GuildNews => "News",
+            _ => "Default"
+        },
+        null
+    );
+
+    public static Channel Parse(JsonElement json, ChannelCategory? category = null, int? positionHint = null)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var kind = (ChannelKind)json.GetProperty("type").GetInt32();
+        var guildId = json.GetPropertyOrNull("guild_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+
+        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();
+
+        var topic = json.GetPropertyOrNull("topic")?.GetStringOrNull();
+
+        var lastMessageId = json
+            .GetPropertyOrNull("last_message_id")?
+            .GetNonWhiteSpaceStringOrNull()?
+            .Pipe(Snowflake.Parse);
+
+        return new Channel(
+            id,
+            kind,
+            guildId ?? Guild.DirectMessages.Id,
+            category ?? GetFallbackCategory(kind),
+            name,
+            position,
+            topic,
+            lastMessageId
+        );
+    }
+}

DiscordChatExporter.Core/Discord/Data/ChannelCategory.cs

@@ -0,0 +1,26 @@
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+public record ChannelCategory(Snowflake Id, string Name, int? Position) : IHasId
+{
+    public static ChannelCategory Unknown { get; } = new(Snowflake.Zero, "<unknown category>", 0);
+
+    public static ChannelCategory Parse(JsonElement json, int? positionHint = null)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+
+        var name =
+            json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull() ??
+            id.ToString();
+
+        var position =
+            positionHint ??
+            json.GetPropertyOrNull("position")?.GetInt32OrNull();
+
+        return new ChannelCategory(id, name, position);
+    }
+}

DiscordChatExporter.Core/Discord/Data/ChannelKind.cs

@@ -0,0 +1,19 @@
+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 = 1,
+    GuildVoiceChat = 2,
+    DirectGroupTextChat = 3,
+    GuildCategory = 4,
+    GuildNews = 5,
+    GuildNewsThread = 10,
+    GuildPublicThread = 11,
+    GuildPrivateThread = 12,
+    GuildStageVoice = 13,
+    GuildDirectory = 14,
+    GuildForum = 15
+}

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

@@ -0,0 +1,48 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+// Loosely based on https://github.com/omar/ByteSize (MIT license)
+public readonly partial record struct FileSize(long TotalBytes)
+{
+    public double TotalKiloBytes => TotalBytes / 1024.0;
+    public double TotalMegaBytes => TotalKiloBytes / 1024.0;
+    public double TotalGigaBytes => TotalMegaBytes / 1024.0;
+
+    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";
+    }
+
+    [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

@@ -0,0 +1,6 @@
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+public interface IHasId
+{
+    Snowflake Id { get; }
+}

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

@@ -0,0 +1,12 @@
+using System.Collections.Generic;
+
+namespace DiscordChatExporter.Core.Discord.Data.Common;
+
+public class IdBasedEqualityComparer : IEqualityComparer<IHasId>
+{
+    public static IdBasedEqualityComparer Instance { get; } = new();
+
+    public bool Equals(IHasId? x, IHasId? y) => x?.Id == y?.Id;
+
+    public int GetHashCode(IHasId obj) => obj.Id.GetHashCode();
+}

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

@@ -0,0 +1,91 @@
+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,
+    EmbedKind Kind,
+    string? Url,
+    DateTimeOffset? Timestamp,
+    Color? Color,
+    EmbedAuthor? Author,
+    string? Description,
+    IReadOnlyList<EmbedField> Fields,
+    EmbedImage? Thumbnail,
+    IReadOnlyList<EmbedImage> Images,
+    EmbedVideo? Video,
+    EmbedFooter? Footer)
+{
+    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 kind =
+            json.GetPropertyOrNull("type")?.GetStringOrNull()?.ParseEnumOrNull<EmbedKind>() ??
+            EmbedKind.Rich;
+
+        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 author = json.GetPropertyOrNull("author")?.Pipe(EmbedAuthor.Parse);
+        var description = json.GetPropertyOrNull("description")?.GetStringOrNull();
+
+        var fields =
+            json.GetPropertyOrNull("fields")?.EnumerateArrayOrNull()?.Select(EmbedField.Parse).ToArray() ??
+            Array.Empty<EmbedField>();
+
+        var thumbnail = json.GetPropertyOrNull("thumbnail")?.Pipe(EmbedImage.Parse);
+
+        // Under the Discord API model, embeds can only have at most one image.
+        // Because of that, embeds that are rendered with multiple images on the client
+        // (e.g. tweet embeds), are exposed from the API as multiple separate embeds.
+        // Our embed model is consistent with the user-facing side of Discord, so images
+        // are stored as an array. The API will only ever return one image, but we deal
+        // with this by merging related embeds at the end of the message parsing process.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/695
+        var images =
+            json.GetPropertyOrNull("image")?.Pipe(EmbedImage.Parse).Enumerate().ToArray() ??
+            Array.Empty<EmbedImage>();
+
+        var video = json.GetPropertyOrNull("video")?.Pipe(EmbedVideo.Parse);
+
+        var footer = json.GetPropertyOrNull("footer")?.Pipe(EmbedFooter.Parse);
+
+        return new Embed(
+            title,
+            kind,
+            url,
+            timestamp,
+            color,
+            author,
+            description,
+            fields,
+            thumbnail,
+            images,
+            video,
+            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").GetNonNullString();
+        var value = json.GetProperty("value").GetNonNullString();
+        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/EmbedKind.cs

@@ -0,0 +1,11 @@
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-types
+public enum EmbedKind
+{
+    Rich,
+    Image,
+    Video,
+    Gifv,
+    Link
+}

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

@@ -0,0 +1,22 @@
+using JsonExtensions.Reading;
+using System.Text.Json;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+// https://discord.com/developers/docs/resources/channel#embed-object-embed-video-structure
+public record EmbedVideo(
+    string? Url,
+    string? ProxyUrl,
+    int? Width,
+    int? Height)
+{
+    public static EmbedVideo 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 EmbedVideo(url, proxyUrl, width, height);
+    }
+}

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

@@ -0,0 +1,36 @@
+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 (embed.Kind != EmbedKind.Link)
+            return null;
+
+        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 +1,57 @@
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Core.Discord.Data.Embeds;
+
+public partial record YouTubeVideoEmbedProjection(string VideoId)
+{
+    public string Url => $"https://www.youtube.com/embed/{VideoId}";
+}
+
+public partial record YouTubeVideoEmbedProjection
+{
+    // Adapted from YoutubeExplode
+    // https://github.com/Tyrrrz/YoutubeExplode/blob/bc700b631bd105d0be208a88116347034bdca88b/YoutubeExplode/Videos/VideoId.cs#L40-L62
+    private static string? TryParseVideoId(string embedUrl)
+    {
+        // Regular URL
+        // https://www.youtube.com/watch?v=yIVRs6YSbOM
+        var regularMatch = Regex.Match(embedUrl, @"youtube\..+?/watch.*?v=(.*?)(?:&|/|$)").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;
+
+        // Shorts URL
+        // https://www.youtube.com/shorts/sKL1vjP0tIo
+        var shortsMatch = Regex.Match(embedUrl, @"youtube\..+?/shorts/(.*?)(?:\?|&|/|$)").Groups[1].Value;
+        if (!string.IsNullOrWhiteSpace(shortsMatch))
+            return shortsMatch;
+
+        return null;
+    }
+
+    public static YouTubeVideoEmbedProjection? TryResolve(Embed embed)
+    {
+        if (embed.Kind != EmbedKind.Video)
+            return null;
+
+        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

@@ -0,0 +1,79 @@
+using System;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/emoji#emoji-object
+public partial record Emoji(
+    // Only present on custom emoji
+    Snowflake? Id,
+    // Name of a custom emoji (e.g. LUL) or actual representation of a standard emoji (e.g. 🙂)
+    string Name,
+    bool IsAnimated,
+    string ImageUrl)
+{
+    // Name of a custom emoji (e.g. LUL) or name of a standard emoji (e.g. slight_smile)
+    public string Code => Id is not null
+        ? Name
+        : EmojiIndex.TryGetCode(Name) ?? Name;
+}
+
+public partial record Emoji
+{
+    private static string GetTwemojiId(string name)
+    {
+        var runes = name.GetRunes().ToArray();
+
+        // Variant selector rune is skipped in Twemoji names, except when the emoji also contains a zero-width joiner.
+        // VS = 0xfe0f; ZWJ = 0x200d.
+        var filteredRunes = runes.Any(r => r.Value == 0x200d)
+            ? runes
+            : runes.Where(r => r.Value != 0xfe0f);
+
+        return string.Join(
+            "-",
+            filteredRunes.Select(r => r.Value.ToString("x"))
+        );
+    }
+
+    private static string GetImageUrl(Snowflake 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/v/latest/svg/{GetTwemojiId(name)}.svg";
+
+    public static string GetImageUrl(Snowflake? id, string? name, bool isAnimated)
+    {
+        // Custom emoji
+        if (id is not null)
+            return GetImageUrl(id.Value, isAnimated);
+
+        // Standard emoji
+        if (!string.IsNullOrWhiteSpace(name))
+            return GetImageUrl(name);
+
+        // Either ID or name should be set
+        throw new ApplicationException("Emoji has neither ID nor name set.");
+    }
+
+    public static Emoji Parse(JsonElement json)
+    {
+        var id = json.GetPropertyOrNull("id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse);
+        var name = json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull();
+        var isAnimated = json.GetPropertyOrNull("animated")?.GetBooleanOrNull() ?? false;
+        var imageUrl = GetImageUrl(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

@@ -0,0 +1,42 @@
+using System;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/guild#guild-object
+public record Guild(Snowflake Id, string Name, string IconUrl) : 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)
+    {
+        var extension = iconHash.StartsWith("a_", StringComparison.Ordinal)
+            ? "gif"
+            : "png";
+
+        return $"https://cdn.discordapp.com/icons/{id}/{iconHash}.{extension}";
+    }
+
+    public static Guild Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonNullString();
+
+        var iconHash = json.GetPropertyOrNull("icon")?.GetNonWhiteSpaceStringOrNull();
+        var iconUrl = !string.IsNullOrWhiteSpace(iconHash)
+            ? GetIconUrl(id, iconHash)
+            : GetDefaultIconUrl();
+
+        return new Guild(id, name, iconUrl);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Member.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+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
+{
+    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)
+    {
+        var user = json.GetProperty("user").Pipe(User.Parse);
+        var nick = json.GetPropertyOrNull("nick")?.GetNonWhiteSpaceStringOrNull();
+
+        var roleIds = json
+            .GetPropertyOrNull("roles")?
+            .EnumerateArray()
+            .Select(j => j.GetNonWhiteSpaceString())
+            .Select(Snowflake.Parse)
+            .ToArray() ?? Array.Empty<Snowflake>();
+
+        return new Member(
+            user,
+            nick ?? user.Name,
+            roleIds
+        );
+    }
+}

DiscordChatExporter.Core/Discord/Data/Message.cs

@@ -0,0 +1,167 @@
+using System;
+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;
+
+// https://discord.com/developers/docs/resources/channel#message-object
+public partial 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<Sticker> Stickers,
+    IReadOnlyList<Reaction> Reactions,
+    IReadOnlyList<User> MentionedUsers,
+    MessageReference? Reference,
+    Message? ReferencedMessage) : IHasId
+{
+    public bool IsEmpty =>
+        Kind == MessageKind.Default &&
+        string.IsNullOrEmpty(Content) &&
+        !Attachments.Any() &&
+        !Embeds.Any() &&
+        !Stickers.Any();
+}
+
+public partial record Message
+{
+    private static IReadOnlyList<Embed> NormalizeEmbeds(IReadOnlyList<Embed> embeds)
+    {
+        if (embeds.Count <= 1)
+            return embeds;
+
+        // Discord API doesn't support embeds with multiple images, even though the Discord client does.
+        // To work around this, it seems that the API returns multiple consecutive embeds with different images,
+        // which are then merged together on the client. We need to replicate the same behavior ourselves.
+        // Currently, only known case where this workaround is required is Twitter embeds.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/695
+
+        var normalizedEmbeds = new List<Embed>();
+
+        for (var i = 0; i < embeds.Count; i++)
+        {
+            var embed = embeds[i];
+
+            if (embed.Url?.Contains("://twitter.com/", StringComparison.OrdinalIgnoreCase) == true)
+            {
+                // Find embeds with the same URL that only contain a single image and nothing else
+                var trailingEmbeds = embeds
+                    .Skip(i + 1)
+                    .TakeWhile(e =>
+                        e.Url == embed.Url &&
+                        e.Timestamp is null &&
+                        e.Author is null &&
+                        e.Color is null &&
+                        string.IsNullOrWhiteSpace(e.Description) &&
+                        !e.Fields.Any() &&
+                        e.Images.Count == 1 &&
+                        e.Footer is null
+                    )
+                    .ToArray();
+
+                if (trailingEmbeds.Any())
+                {
+                    // Concatenate all images into one embed
+                    var images = embed.Images.Concat(trailingEmbeds.SelectMany(e => e.Images)).ToArray();
+                    normalizedEmbeds.Add(embed with { Images = images });
+
+                    i += trailingEmbeds.Length;
+                }
+                else
+                {
+                    normalizedEmbeds.Add(embed);
+                }
+            }
+            else
+            {
+                normalizedEmbeds.Add(embed);
+            }
+        }
+
+        return normalizedEmbeds;
+    }
+
+    public static Message Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var kind = (MessageKind)json.GetProperty("type").GetInt32();
+        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 isPinned = json.GetPropertyOrNull("pinned")?.GetBooleanOrNull() ?? false;
+
+        var content = kind switch
+        {
+            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.ThreadCreated => "Started a thread.",
+            MessageKind.GuildMemberJoin => "Joined the server.",
+            _ => json.GetPropertyOrNull("content")?.GetStringOrNull() ?? ""
+        };
+
+        var attachments =
+            json.GetPropertyOrNull("attachments")?.EnumerateArrayOrNull()?.Select(Attachment.Parse).ToArray() ??
+            Array.Empty<Attachment>();
+
+        var embeds = NormalizeEmbeds(
+            json.GetPropertyOrNull("embeds")?.EnumerateArrayOrNull()?.Select(Embed.Parse).ToArray() ??
+            Array.Empty<Embed>()
+        );
+
+        var stickers =
+            json.GetPropertyOrNull("sticker_items")?.EnumerateArrayOrNull()?.Select(Sticker.Parse).ToArray() ??
+            Array.Empty<Sticker>();
+
+        var reactions =
+            json.GetPropertyOrNull("reactions")?.EnumerateArrayOrNull()?.Select(Reaction.Parse).ToArray() ??
+            Array.Empty<Reaction>();
+
+        var mentionedUsers =
+            json.GetPropertyOrNull("mentions")?.EnumerateArrayOrNull()?.Select(User.Parse).ToArray() ??
+            Array.Empty<User>();
+
+        var messageReference = json.GetPropertyOrNull("message_reference")?.Pipe(MessageReference.Parse);
+        var referencedMessage = json.GetPropertyOrNull("referenced_message")?.Pipe(Parse);
+
+        return new Message(
+            id,
+            kind,
+            author,
+            timestamp,
+            editedTimestamp,
+            callEndedTimestamp,
+            isPinned,
+            content,
+            attachments,
+            embeds,
+            stickers,
+            reactions,
+            mentionedUsers,
+            messageReference,
+            referencedMessage
+        );
+    }
+}

DiscordChatExporter.Core/Discord/Data/MessageKind.cs

@@ -0,0 +1,21 @@
+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,
+    ThreadCreated = 18,
+    Reply = 19
+}
+
+public static class MessageKindExtensions
+{
+    public static bool IsSystemNotification(this MessageKind c) => (int)c is >= 1 and <= 18;
+}

DiscordChatExporter.Core/Discord/Data/MessageReference.cs

@@ -0,0 +1,29 @@
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+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)
+{
+    public static MessageReference Parse(JsonElement json)
+    {
+        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);
+
+        return new MessageReference(messageId, channelId, guildId);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Reaction.cs

@@ -0,0 +1,16 @@
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils.Extensions;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#reaction-object
+public record Reaction(Emoji Emoji, int Count)
+{
+    public static Reaction Parse(JsonElement json)
+    {
+        var emoji = json.GetProperty("emoji").Pipe(Emoji.Parse);
+        var count = json.GetProperty("count").GetInt32();
+
+        return new Reaction(emoji, count);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Role.cs

@@ -0,0 +1,27 @@
+using System.Drawing;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+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
+{
+    public static Role Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonNullString();
+        var position = json.GetProperty("position").GetInt32();
+
+        var color = json
+            .GetPropertyOrNull("color")?
+            .GetInt32()
+            .Pipe(System.Drawing.Color.FromArgb)
+            .ResetAlpha()
+            .NullIf(c => c.ToRgb() <= 0);
+
+        return new Role(id, name, position, color);
+    }
+}

DiscordChatExporter.Core/Discord/Data/Sticker.cs

@@ -0,0 +1,25 @@
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/sticker#sticker-resource
+public record Sticker(Snowflake Id, string Name, StickerFormat Format, string SourceUrl)
+{
+    private static string GetSourceUrl(Snowflake id, StickerFormat format)
+    {
+        var extension = format == StickerFormat.Lottie ? "json" : "png";
+        return $"https://discord.com/stickers/{id}.{extension}";
+    }
+
+    public static Sticker Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonNullString();
+        var format = (StickerFormat)json.GetProperty("format_type").GetInt32();
+        var sourceUrl = GetSourceUrl(id, format);
+
+        return new Sticker(id, name, format, sourceUrl);
+    }
+}

DiscordChatExporter.Core/Discord/Data/StickerFormat.cs

@@ -0,0 +1,8 @@
+namespace DiscordChatExporter.Core.Discord.Data;
+
+public enum StickerFormat
+{
+    Png = 1,
+    PngAnimated = 2,
+    Lottie = 3
+}

DiscordChatExporter.Core/Discord/Data/User.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+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
+{
+    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)
+    {
+        var extension = avatarHash.StartsWith("a_", StringComparison.Ordinal)
+            ? "gif"
+            : "png";
+
+        return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.{extension}?size=512";
+    }
+
+    public static User Parse(JsonElement json)
+    {
+        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").GetNonNullString();
+
+        var avatarHash = json.GetPropertyOrNull("avatar")?.GetNonWhiteSpaceStringOrNull();
+        var avatarUrl = !string.IsNullOrWhiteSpace(avatarHash)
+            ? GetAvatarUrl(id, avatarHash)
+            : GetDefaultAvatarUrl(discriminator);
+
+        return new User(id, isBot, discriminator, name, avatarUrl);
+    }
+}

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -0,0 +1,351 @@
+using System;
+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;
+using DiscordChatExporter.Core.Utils;
+using DiscordChatExporter.Core.Utils.Extensions;
+using Gress;
+using JsonExtensions.Http;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord;
+
+public class DiscordClient
+{
+    private readonly string _token;
+    private readonly Uri _baseUri = new("https://discord.com/api/v9/", UriKind.Absolute);
+
+    private TokenKind? _resolvedTokenKind;
+
+    public DiscordClient(string token) => _token = token;
+
+    private async ValueTask<HttpResponseMessage> GetResponseAsync(
+        string url,
+        TokenKind tokenKind,
+        CancellationToken cancellationToken = default)
+    {
+        return await Http.ResponseResiliencePolicy.ExecuteAsync(async innerCancellationToken =>
+        {
+            using var request = new HttpRequestMessage(HttpMethod.Get, new Uri(_baseUri, url));
+
+            // Don't validate because token can have invalid characters
+            // https://github.com/Tyrrrz/DiscordChatExporter/issues/828
+            request.Headers.TryAddWithoutValidation(
+                "Authorization",
+                tokenKind == TokenKind.Bot
+                    ? $"Bot {_token}"
+                    : _token
+            );
+
+            return await Http.Client.SendAsync(
+                request,
+                HttpCompletionOption.ResponseHeadersRead,
+                innerCancellationToken
+            );
+        }, cancellationToken);
+    }
+
+    private async ValueTask<TokenKind> GetTokenKindAsync(CancellationToken cancellationToken = default)
+    {
+        // Try authenticating as a user
+        using var userResponse = await GetResponseAsync(
+            "users/@me",
+            TokenKind.User,
+            cancellationToken
+        );
+
+        if (userResponse.StatusCode != HttpStatusCode.Unauthorized)
+            return TokenKind.User;
+
+        // Try authenticating as a bot
+        using var botResponse = await GetResponseAsync(
+            "users/@me",
+            TokenKind.Bot,
+            cancellationToken
+        );
+
+        if (botResponse.StatusCode != HttpStatusCode.Unauthorized)
+            return TokenKind.Bot;
+
+        throw DiscordChatExporterException.Unauthorized();
+    }
+
+    private async ValueTask<HttpResponseMessage> GetResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
+    {
+        var tokenKind = _resolvedTokenKind ??= await GetTokenKindAsync(cancellationToken);
+        return await GetResponseAsync(url, tokenKind, cancellationToken);
+    }
+
+    private async ValueTask<JsonElement> GetJsonResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
+    {
+        using var response = await GetResponseAsync(url, cancellationToken);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            throw response.StatusCode switch
+            {
+                HttpStatusCode.Unauthorized => DiscordChatExporterException.Unauthorized(),
+                HttpStatusCode.Forbidden => DiscordChatExporterException.Forbidden(),
+                HttpStatusCode.NotFound => DiscordChatExporterException.NotFound(url),
+                _ => DiscordChatExporterException.FailedHttpRequest(response)
+            };
+        }
+
+        return await response.Content.ReadAsJsonAsync(cancellationToken);
+    }
+
+    private async ValueTask<JsonElement?> TryGetJsonResponseAsync(
+        string url,
+        CancellationToken cancellationToken = default)
+    {
+        using var response = await GetResponseAsync(url, cancellationToken);
+
+        return response.IsSuccessStatusCode
+            ? await response.Content.ReadAsJsonAsync(cancellationToken)
+            : null;
+    }
+
+    public async IAsyncEnumerable<Guild> GetUserGuildsAsync(
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        yield return Guild.DirectMessages;
+
+        var currentAfter = Snowflake.Zero;
+
+        while (true)
+        {
+            var url = new UrlBuilder()
+                .SetPath("users/@me/guilds")
+                .SetQueryParameter("limit", "100")
+                .SetQueryParameter("after", currentAfter.ToString())
+                .Build();
+
+            var response = await GetJsonResponseAsync(url, cancellationToken);
+
+            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,
+        CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+            return Guild.DirectMessages;
+
+        var response = await GetJsonResponseAsync($"guilds/{guildId}", cancellationToken);
+        return Guild.Parse(response);
+    }
+
+    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($"guilds/{guildId}/channels", cancellationToken);
+
+            var responseOrdered = response
+                .EnumerateArray()
+                .OrderBy(j => j.GetProperty("position").GetInt32())
+                .ThenBy(j => j.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse))
+                .ToArray();
+
+            var categories = responseOrdered
+                .Where(j => j.GetProperty("type").GetInt32() == (int) ChannelKind.GuildCategory)
+                .Select((j, index) => ChannelCategory.Parse(j, index + 1))
+                .ToDictionary(j => j.Id.ToString(), StringComparer.Ordinal);
+
+            // Discord positions are not deterministic, so we need to normalize them
+            // because the user may refer to the channel position via file name template.
+            var position = 0;
+
+            foreach (var channelJson in responseOrdered)
+            {
+                var parentId = channelJson.GetPropertyOrNull("parent_id")?.GetNonWhiteSpaceStringOrNull();
+
+                var category = !string.IsNullOrWhiteSpace(parentId)
+                    ? categories.GetValueOrDefault(parentId)
+                    : null;
+
+                var channel = Channel.Parse(channelJson, category, position);
+
+                position++;
+
+                yield return channel;
+            }
+        }
+    }
+
+    public async IAsyncEnumerable<Role> GetGuildRolesAsync(
+        Snowflake guildId,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        if (guildId == Guild.DirectMessages.Id)
+            yield break;
+
+        var response = await GetJsonResponseAsync($"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<Percentage>? 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;
+
+                // Make sure the messages are not empty when exporting via a bot
+                // https://github.com/Tyrrrz/DiscordChatExporter/issues/918
+                if (_resolvedTokenKind == TokenKind.Bot && message.IsEmpty && !message.Author.IsBot)
+                    throw DiscordChatExporterException.MessageContentIntentMissing();
+
+                // 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();
+
+                    progress.Report(Percentage.FromFraction(
+                        // 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)
+                        totalDuration > TimeSpan.Zero
+                            ? exportedDuration / totalDuration
+                            : 1
+                    ));
+                }
+
+                yield return message;
+                currentAfter = message.Id;
+            }
+        }
+    }
+}

DiscordChatExporter.Core/Discord/Snowflake.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Text.RegularExpressions;
+
+namespace DiscordChatExporter.Core.Discord;
+
+public readonly partial record struct Snowflake(ulong Value)
+{
+    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)
+    {
+        if (string.IsNullOrWhiteSpace(str))
+            return null;
+
+        // As number
+        if (Regex.IsMatch(str, @"^\d+$") && ulong.TryParse(str, NumberStyles.Number, formatProvider, out var value))
+        {
+            return new Snowflake(value);
+        }
+
+        // As date
+        if (DateTimeOffset.TryParse(str, formatProvider, DateTimeStyles.None, out var date))
+        {
+            return FromDate(date);
+        }
+
+        return null;
+    }
+
+    public static Snowflake Parse(string str, IFormatProvider? formatProvider) =>
+        TryParse(str, formatProvider) ?? throw new FormatException($"Invalid snowflake '{str}'.");
+
+    public static Snowflake Parse(string str) => Parse(str, null);
+}
+
+public partial record struct Snowflake : IComparable<Snowflake>, IComparable
+{
+    public int CompareTo(Snowflake other) => Value.CompareTo(other.Value);
+
+    public int CompareTo(object? obj)
+    {
+        if (obj is not Snowflake other)
+            throw new ArgumentException($"Object must be of type {nameof(Snowflake)}.");
+
+        return Value.CompareTo(other.Value);
+    }
+}

DiscordChatExporter.Core/Discord/TokenKind.cs

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

DiscordChatExporter.Core/DiscordChatExporter.Core.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Gress" Version="2.0.1" />
+    <PackageReference Include="JsonExtensions" Version="1.2.0" />
+    <PackageReference Include="MiniRazor.CodeGen" Version="2.2.2" />
+    <PackageReference Include="Polly" Version="7.2.3" />
+    <PackageReference Include="Superpower" Version="3.0.0" />
+    <PackageReference Include="WebMarkupMin.Core" Version="2.12.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <AdditionalFiles Include="Exporting\Writers\Html\*.cshtml" IsRazorTemplate="true" />
+  </ItemGroup>
+
+</Project>

DiscordChatExporter.Core/Exceptions/DiscordChatExporterException.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Net.Http;
+
+namespace DiscordChatExporter.Core.Exceptions;
+
+public partial class DiscordChatExporterException : Exception
+{
+    public bool IsFatal { get; }
+
+    public DiscordChatExporterException(string message, bool isFatal = false)
+        : base(message)
+    {
+        IsFatal = isFatal;
+    }
+}
+
+public partial class DiscordChatExporterException
+{
+    internal static DiscordChatExporterException FailedHttpRequest(HttpResponseMessage response)
+    {
+        var message = $@"
+Failed to perform an HTTP request.
+
+[Request]
+{response.RequestMessage}
+
+[Response]
+{response}";
+
+        return new DiscordChatExporterException(message.Trim(), true);
+    }
+
+    internal static DiscordChatExporterException Unauthorized() =>
+        new("Authentication token is invalid.", true);
+
+    internal static DiscordChatExporterException Forbidden() =>
+        new("Access is forbidden.");
+
+    internal static DiscordChatExporterException NotFound(string resourceId) =>
+        new($"Requested resource ({resourceId}) does not exist.");
+
+    internal static DiscordChatExporterException ChannelIsEmpty() =>
+        new("No messages found for the specified period.");
+
+    internal static DiscordChatExporterException MessageContentIntentMissing() =>
+        new("Failed to retrieve message content because the bot doesn't have the Message Content Intent enabled.");
+}

DiscordChatExporter.Core/Exporting/ChannelExporter.cs

@@ -0,0 +1,81 @@
+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;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Exceptions;
+using DiscordChatExporter.Core.Utils.Extensions;
+using Gress;
+
+namespace DiscordChatExporter.Core.Exporting;
+
+public class ChannelExporter
+{
+    private readonly DiscordClient _discord;
+
+    public ChannelExporter(DiscordClient discord) => _discord = discord;
+
+    public async ValueTask ExportChannelAsync(
+        ExportRequest request,
+        IProgress<Percentage>? progress = null,
+        CancellationToken cancellationToken = default)
+    {
+        // 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);
+
+        var context = new ExportContext(
+            request,
+            contextMembers,
+            contextChannels,
+            contextRoles
+        );
+
+        // Export messages
+        await using var messageExporter = new MessageExporter(context);
+
+        var exportedAnything = false;
+        var encounteredUsers = new HashSet<User>(IdBasedEqualityComparer.Instance);
+
+        await foreach (var message in _discord.GetMessagesAsync(
+                           request.Channel.Id,
+                           request.After,
+                           request.Before,
+                           progress,
+                           cancellationToken))
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+
+            // Skips any messages that fail to pass the supplied filter
+            if (!request.MessageFilter.IsMatch(message))
+                continue;
+
+            // Resolve members for referenced users
+            foreach (var referencedUser in message.MentionedUsers.Prepend(message.Author))
+            {
+                if (!encounteredUsers.Add(referencedUser))
+                    continue;
+
+                var member = await _discord.GetGuildMemberAsync(
+                    request.Guild.Id,
+                    referencedUser,
+                    cancellationToken
+                );
+
+                contextMembers.Add(member);
+            }
+
+            // 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

@@ -0,0 +1,105 @@
+using System;
+using System.Collections.Generic;
+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;
+
+namespace DiscordChatExporter.Core.Exporting;
+
+internal class ExportContext
+{
+    private readonly MediaDownloader _mediaDownloader;
+
+    public ExportRequest Request { get; }
+
+    public IReadOnlyCollection<Member> Members { get; }
+
+    public IReadOnlyCollection<Channel> Channels { get; }
+
+    public IReadOnlyCollection<Role> Roles { get; }
+
+    public ExportContext(
+        ExportRequest request,
+        IReadOnlyCollection<Member> members,
+        IReadOnlyCollection<Channel> channels,
+        IReadOnlyCollection<Role> roles)
+    {
+        Request = request;
+        Members = members;
+        Channels = channels;
+        Roles = roles;
+
+        _mediaDownloader = new MediaDownloader(request.OutputMediaDirPath, request.ShouldReuseMedia);
+    }
+
+    public string FormatDate(DateTimeOffset date) => Request.DateFormat switch
+    {
+        "unix" => date.ToUnixTimeSeconds().ToString(),
+        "unixms" => date.ToUnixTimeMilliseconds().ToString(),
+        var format => date.ToLocalString(format)
+    };
+
+    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, CancellationToken cancellationToken = default)
+    {
+        if (!Request.ShouldDownloadMedia)
+            return url;
+
+        try
+        {
+            var filePath = await _mediaDownloader.DownloadAsync(url, cancellationToken);
+
+            // 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 is ExportFormat.HtmlDark or ExportFormat.HtmlLight)
+            {
+                // 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)
+                );
+            }
+
+            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

@@ -0,0 +1,35 @@
+using System;
+
+namespace DiscordChatExporter.Core.Exporting;
+
+public enum ExportFormat
+{
+    PlainText,
+    HtmlDark,
+    HtmlLight,
+    Csv,
+    Json
+}
+
+public static class ExportFormatExtensions
+{
+    public static string GetFileExtension(this ExportFormat format) => format switch
+    {
+        ExportFormat.PlainText => "txt",
+        ExportFormat.HtmlDark => "html",
+        ExportFormat.HtmlLight => "html",
+        ExportFormat.Csv => "csv",
+        ExportFormat.Json => "json",
+        _ => throw new ArgumentOutOfRangeException(nameof(format))
+    };
+
+    public static string GetDisplayName(this ExportFormat format) => format switch
+    {
+        ExportFormat.PlainText => "TXT",
+        ExportFormat.HtmlDark => "HTML (Dark)",
+        ExportFormat.HtmlLight => "HTML (Light)",
+        ExportFormat.Csv => "CSV",
+        ExportFormat.Json => "JSON",
+        _ => throw new ArgumentOutOfRangeException(nameof(format))
+    };
+}

DiscordChatExporter.Core/Exporting/ExportRequest.cs

@@ -0,0 +1,123 @@
+using System;
+using System.IO;
+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;
+
+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)
+{
+    private string? _outputBaseFilePath;
+    public string OutputBaseFilePath => _outputBaseFilePath ??= GetOutputBaseFilePath(
+        Guild,
+        Channel,
+        OutputPath,
+        Format,
+        After,
+        Before
+    );
+
+    public string OutputBaseDirPath => Path.GetDirectoryName(OutputBaseFilePath) ?? OutputPath;
+
+    public string OutputMediaDirPath => $"{OutputBaseFilePath}_Files{Path.DirectorySeparatorChar}";
+}
+
+public partial record ExportRequest
+{
+    private static string GetOutputBaseFilePath(
+        Guild guild,
+        Channel channel,
+        string outputPath,
+        ExportFormat format,
+        Snowflake? after = null,
+        Snowflake? before = null)
+    {
+        // Formats path
+        outputPath = Regex.Replace(outputPath, "%.", m =>
+            PathEx.EscapeFileName(m.Value switch
+            {
+                "%g" => guild.Id.ToString(),
+                "%G" => guild.Name,
+                "%t" => channel.Category.Id.ToString(),
+                "%T" => channel.Category.Name,
+                "%c" => channel.Id.ToString(),
+                "%C" => channel.Name,
+                "%p" => channel.Position?.ToString() ?? "0",
+                "%P" => channel.Category.Position?.ToString() ?? "0",
+                "%a" => after?.ToDate().ToString("yyyy-MM-dd") ?? "",
+                "%b" => before?.ToDate().ToString("yyyy-MM-dd") ?? "",
+                "%d" => DateTimeOffset.Now.ToString("yyyy-MM-dd"),
+                "%%" => "%",
+                _ => m.Value
+            })
+        );
+
+        // Output is a directory
+        if (Directory.Exists(outputPath) || string.IsNullOrWhiteSpace(Path.GetExtension(outputPath)))
+        {
+            var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);
+            return Path.Combine(outputPath, fileName);
+        }
+
+        // Output is a file
+        return outputPath;
+    }
+
+    public static string GetDefaultOutputFileName(
+        Guild guild,
+        Channel channel,
+        ExportFormat format,
+        Snowflake? after = null,
+        Snowflake? before = null)
+    {
+        var buffer = new StringBuilder();
+
+        // Guild and channel names
+        buffer.Append($"{guild.Name} - {channel.Category.Name} - {channel.Name} [{channel.Id}]");
+
+        // Date range
+        if (after is not null || before is not null)
+        {
+            buffer.Append(' ').Append('(');
+
+            // Both 'after' and 'before' are set
+            if (after is not null && before is not null)
+            {
+                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}");
+            }
+
+            buffer.Append(')');
+        }
+
+        // File extension
+        buffer.Append('.').Append(format.GetFileExtension());
+
+        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 +1,41 @@
+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;
+
+    // Match content within word boundaries, between spaces, or as the whole input.
+    // For example, "max" shouldn't match on content "our maximum effort",
+    // but should match on content "our max effort".
+    // Also, "(max)" should match on content "our (max) effort", even though
+    // parentheses are not considered word characters.
+    // https://github.com/Tyrrrz/DiscordChatExporter/issues/909
+    private bool IsMatch(string? content) =>
+        !string.IsNullOrWhiteSpace(content) &&
+        Regex.IsMatch(
+            content,
+            @"(?:\b|\s|^)" +
+            Regex.Escape(_text) +
+            @"(?:\b|\s|$)",
+            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 +1,25 @@
+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),
+        MessageContentMatchKind.Pin => message.IsPinned,
+        _ => throw new InvalidOperationException($"Unknown message content match kind '{_kind}'.")
+    };
+}