Greptile Summary

Implements auto-save draft functionality for message composition with proper race condition handling and database persistence.

Key Implementation Details:

• Database migration (v35→v36) creates drafts table with composite PK (conversationHash, identityHash) and proper FK constraints
• 500ms debounce on onDraftTextChanged prevents excessive database writes during typing
• Race condition fixes (from commits 8a4e9ff and fce3f7a):
  • Re-checks active conversation after debounce delay before saving (line MessagingViewModel.kt:940)
  • Flushes pending draft immediately when switching conversations using lastDraftText tracking
  • Clears lastDraftText after message send to prevent re-saving sent text as draft
  • Keys draftRestored flag to destinationHash for proper restoration on conversation switch
• Draft restoration uses LaunchedEffect keyed to both draftText and destinationHash to restore drafts when opening conversations
• Conversation list displays "Draft:" prefix in italic error color when draft exists
• Repository provides reactive observeDrafts() Flow that maps conversationHash → draft content

Previous review concerns addressed:

• ✅ Draft restoration now works correctly when switching between conversations (draftRestored keyed to destinationHash)
• ✅ Draft saves to correct conversation (re-checks _currentConversation.value after delay)

The implementation follows clean architecture with proper separation of concerns across database, repository, ViewModel, and UI layers.

Confidence Score: 5/5

• This PR is safe to merge with no identified issues
• All race conditions have been properly fixed with conversation re-checks and immediate flushing, database schema is well-designed with proper constraints, and the implementation follows best practices with debouncing and reactive patterns
• No files require special attention

Important Files Changed

Flowchart

flowchart TD
    A[User Types in MessagingScreen] --> B[onDraftTextChanged called]
    B --> C[Save to lastDraftText]
    B --> D[Cancel previous draftSaveJob]
    B --> E[Start new debounced job 500ms]
    E --> F{Still same conversation?}
    F -->|Yes| G[saveDraft to repository]
    F -->|No| H[Discard save]
    G --> I[DraftDao.insertOrReplaceDraft]
    I --> J[Database UPDATE/INSERT]
    
    K[User Switches Conversation] --> L[Cancel draftSaveJob]
    L --> M[Flush lastDraftText immediately]
    M --> N[saveDraftNow for old conversation]
    N --> O[Load new conversation]
    O --> P[getDraft from repository]
    P --> Q[Update _draftText StateFlow]
    Q --> R[LaunchedEffect restores to messageText]
    
    S[User Sends Message] --> T[Clear draft on success]
    T --> U[Cancel draftSaveJob]
    T --> V[Clear lastDraftText]
    T --> W[clearDraft in repository]
    W --> X[DraftDao.deleteDraft]
    
    Y[ChatsViewModel] --> Z[observeDrafts Flow]
    Z --> AA[Map conversation hash to draft text]
    AA --> AB[ChatsScreen displays Draft: prefix]

_{Last reviewed commit: fce3f7a}

Codecov Report

❌ Patch coverage is 48.19277% with 43 lines in your changes missing coverage. Please review.

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