feat(discord): desktop Discord Rich Presence (reading/TTS activity)

[anishgoyal1108]

Description

Adds desktop Discord Rich Presence for reading / TTS activity.

IReader takes on no Discord SDK dependency: it publishes the current activity to
~/.cache/IReader/discord_state.json via a small debounced, atomic-rename file
writer, and a companion standalone bridge (ireader-discord) reads the file and
pushes the actual RPC. Deleting the file on Idle clears presence.

• ActivityStateHolder (common) + nowMillis() expect/actual (android, desktop).
• DiscordStatePublisher (desktop): writer with a 20s heartbeat so a motionless
  reading session doesn't go stale.
• TTSActivityBridge (desktop): mirrors v2 TTSController playback into the holder
  so presence shows "Listening" during TTS.
• AppTab.displayName: stable, locale-independent tab name for the payload.
• Wiring: Koin singles, eager startup init, browsing-tab hook in MainStarterScreen.
• New AppPreferences.discordRichPresenceEnabled() gates startup (default on).

Type of Change

• New feature

Testing

• Compiled successfully (desktop) ← reviewer to confirm
• With the companion bridge running, presence updates on tab change and shows
  "Listening" during TTS; closing IReader clears presence

Additional Notes / open questions

• External bridge: the actual RPC (and the Discord application/client ID) lives
  in the separate ireader-discord Python service, not this repo. Happy to either
  document it as a companion install or reimplement the RPC in-app if preferred.
• Scoped: browsing + TTS presence are wired here; the reading/perusing presence
  hooks (reader + book-detail VMs) and a Settings UI toggle are intended follow-ons.
• iOS actual omitted because upstream removed the iOS target.

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[kazemcodes]

What does this actually do? What's the Idea and need behind this code?

[anishgoyal1108]

What does this actually do? What's the Idea and need behind this code?

It's a toggle that lets users display what they're reading in IReader on Discord via the RPC protocol. I'm not at my computer right now to show what the system service I built in Python looks like, but this is the backend to support anyone who wants to build their own service anyway. In my next reply (likely in a couple of weeks), I will showcase the sample Python service and what the result looks like on Discord.

[kazemcodes]

---

PR #233 Review: Discord Rich Presence
Overall Verdict: Not ready to merge — several issues need addressing.

What's Good

• Clean architecture: File-based IPC keeps IReader SDK-free. Well-thought-out separation.
• Atomic file writes: *.tmp + rename pattern prevents partial reads.
• 300ms debounce + 20s heartbeat: Sensible for presence updates.
• TTS priority lock: Correctly prevents reader from clobbering TTS presence.
• Documentation: DISCORD_RICH_PRESENCE.md is thorough and well-structured.
• Koin registration pattern: Follows existing codebase conventions.

---

Critical Issues

1. CoroutineScope leak in DiscordStatePublisher
   domain/src/desktopMain/kotlin/ireader/domain/services/discord/DiscordStatePublisher.kt creates CoroutineScope(SupervisorJob() + Dispatchers.IO) but:

• stop() cancels jobs but doesn't cancel the scope
• No shutdown hook in Main.kt — exitProcess(0) won't call stop()
• The scope is never cleaned up, leaking coroutines

2. Missing shutdown cleanup in Main.kt
   desktop/src/main/kotlin/ireader/desktop/Main.kt:143 — onCloseRequest just calls exitProcess(0). The publisher never writes the Idle state / cleans up on app exit. The heartbeat will keep running until process death.
3. Hardcoded chapterIndex = 1, chapterCount = 1 in TTSActivityBridge
   domain/src/desktopMain/kotlin/ireader/domain/services/discord/TTSActivityBridge.kt:55-56 — This is a known limitation but produces incorrect presence. If chapter info isn't available, it should probably not publish chapter details at all, or the bridge should observe the reader VM's state instead.

---

Medium Issues
4. Cache directory inconsistency
DiscordStatePublisher uses ~/.cache/IReader but Main.kt:67 uses AppData\Local\IReader (Windows). The existing getCacheDir() at line 351 already handles OS-specific paths. Use it instead of hardcoding.
5. Manual JSON serialization
DiscordStatePublisher.toJson() builds JSON with StringBuilder. This is fragile — a missing escape or field will break the bridge silently. Consider using kotlinx.serialization which the project already has.
6. Default preference value
AppPreferences.discordRichPresenceEnabled() defaults to true, but the feature requires a separate Python bridge most users won't have. Should default to false.
7. ActivityStateHolder in commonMain is wasteful
The holder is registered as a singleton in DomainServices (common), but only desktop has a publisher. Every platform pays the cost of the StateFlow + ttsLocked field. Consider making it desktop-only or using a no-op on other platforms.

Minor Issues
8. AppTab.displayName API change
Adding a constructor parameter to the sealed class changes the API. All subclasses must now pass it. This is fine but should be noted — any external code using AppTab subclasses will break.
9. Swallowed exceptions
Main.kt wraps the eager init in catch (_: Exception) which silently hides Koin resolution failures. At minimum, log a warning.
10. tmpFile.renameTo() fallback isn't atomic
The fallback stateFile.writeText(json) leaves a window where the poller could read a partial file. Minor since the heartbeat rewrites quickly.

Summary
The feature concept is solid but the implementation has lifecycle management issues (scope leak, no shutdown hook), a correctness problem (TTS chapter data), and some design inconsistencies (cache path, default pref). I'd recommend addressing the critical and medium issues before merging.

[kazemcodes]

I research a little about the discord rich peresence, but this feature needs more thinking