Instruction file imported from codedbykishore/mitra_sense (.github/instructions/history-retrieval.instructions.md). Copyright stays with the author.

MITRA Sense — Feature 2.5: Chat History Retrieval

Goal

Allow users to see their past conversations after logging out/logging in again or when accessing the app from another device.

Requirements

Backend

1. FirestoreService (app/services/firestore.py)

   • Add:

     async def get_messages(conversation_id: str, limit: int = 50) -> List[Dict]

     • Query conversations/{conversation_id}/messages.
     • Order by timestamp ascending (oldest → newest).
     • Apply limit for pagination.

   • Add:

     async def get_user_conversations(user_id: str) -> List[Dict]

     • Returns conversation documents where user_id is a participant.
     • Sort by last_active_at descending.

2. New API Endpoints

   • GET /api/v1/conversations
     • Returns list of conversation_ids + metadata for current_user.
   • GET /api/v1/conversations/{conversation_id}/messages?limit=50
     • Returns messages for a conversation.
     • Verify current_user is in participants list.

3. Access Control

   • Only participants can fetch conversation messages.
   • Validate via get_current_user.

Frontend

1. Chat UI Initialization

   • On login, call /api/v1/conversations to fetch latest conversation_id(s).
   • Then call /api/v1/conversations/{conversation_id}/messages to load chat messages.
   • Hydrate chat state with response.

2. Pagination

   • Implement "Load More" or infinite scroll to fetch older messages.

Testing

• Unit test: tests/test_chat_history.py

  • Insert fake messages into Firestore.
  • Verify get_messages() returns correct order + limit.
  • Verify only participants can fetch conversations.

• Integration test: tests/test_chat_history_real.py

  • Run with real Firestore credentials.
  • Confirm endpoint returns actual saved chat.