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import asyncio
import uuid
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession
from src.db.postgres.connection import get_db
from src.db.postgres.models import ChatMessage, MessageSource
from src.agents.orchestration import orchestrator
from src.agents.chatbot import chatbot
from src.rag.retriever import retriever
from src.rag.base import RetrievalResult
from src.query.query_executor import query_executor
from src.query.base import QueryResult
from src.db.redis.connection import get_redis
from src.config.settings import settings
from src.middlewares.logging import get_logger, log_execution
from sse_starlette.sse import EventSourceResponse
from langchain_core.messages import HumanMessage, AIMessage
from sqlalchemy import select
from pydantic import BaseModel
from typing import List, Dict, Any, Optional
import json
_GREETINGS = frozenset(["hi", "hello", "hey", "halo", "hai", "hei"])
_GOODBYES = frozenset(["bye", "goodbye", "thanks", "thank you", "terima kasih", "sampai jumpa"])
def _fast_intent(message: str) -> Optional[dict]:
"""Bypass LLM orchestrator for obvious greetings and farewells."""
lower = message.lower().strip().rstrip("!.,?")
if lower in _GREETINGS:
return {"intent": "greeting", "needs_search": False,
"direct_response": "Hello! How can I assist you today?", "search_query": ""}
if lower in _GOODBYES:
return {"intent": "goodbye", "needs_search": False,
"direct_response": "Goodbye! Have a great day!", "search_query": ""}
return None
logger = get_logger("chat_api")
router = APIRouter(prefix="/api/v1", tags=["Chat"])
class ChatRequest(BaseModel):
user_id: str
room_id: str
message: str
def _format_context(results: List[Dict[str, Any]]) -> str:
"""Format retrieval results as context string for the LLM."""
lines = []
for result in results:
filename = result["metadata"].get("filename", "Unknown")
page = result["metadata"].get("page_label")
source_label = f"{filename}, p.{page}" if page else filename
lines.append(f"[Source: {source_label}]\n{result['content']}\n")
return "\n".join(lines)
def _extract_sources(results: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
"""Extract deduplicated source references from retrieval results."""
seen = set()
sources = []
for result in results:
if "document_id" in result["metadata"].get("data", {}):
meta = result["metadata"]
key = (meta.get("data", {}).get("document_id"), meta.get("data", {}).get("page_label"))
if key not in seen:
seen.add(key)
sources.append({
"document_id": meta.get("data", {}).get("document_id"),
"filename": meta.get("data", {}).get("filename", "Unknown"),
"page_label": meta.get("data", {}).get("page_label", "Unknown"),
})
else:
meta = result["metadata"]
key = (meta.get("data", {}).get("table_name"), meta.get("data", {}).get("column_name"))
if key not in seen:
seen.add(key)
table_name = meta.get("data", {}).get("table_name")
user_id = meta.get("user_id")
sources.append({
"document_id": f"{user_id}_{table_name}",
"filename": meta.get("data", {}).get("table_name", "Unknown"),
"page_label": meta.get("data", {}).get("column_name", "Unknown"),
})
logger.debug(f"Extracted sources: {sources}")
return sources
def _format_query_results(results: list[QueryResult]) -> str:
if not results:
return ""
lines = []
for r in results:
name = r.metadata.get("client_name", r.source_id)
lines.append(f"[Query result β {name}, tables: {r.table_or_file}]")
lines.append(f"SQL: {r.metadata.get('sql', '')}")
if r.columns and r.rows:
lines.append(" | ".join(r.columns))
for row in r.rows[:20]:
lines.append(" | ".join(str(row.get(c, "")) for c in r.columns))
lines.append(f"({r.row_count} rows total)\n")
return "\n".join(lines)
async def get_cached_response(redis, cache_key: str) -> Optional[str]:
cached = await redis.get(cache_key)
if cached:
return json.loads(cached)
return None
async def cache_response(redis, cache_key: str, response: str):
await redis.setex(cache_key, 86400, json.dumps(response))
async def load_history(db: AsyncSession, room_id: str, limit: int = 10) -> list:
"""Load recent chat messages for a room as LangChain message objects (oldest-first)."""
result = await db.execute(
select(ChatMessage)
.where(ChatMessage.room_id == room_id)
.order_by(ChatMessage.created_at.asc())
.limit(limit)
)
rows = result.scalars().all()
return [
HumanMessage(content=row.content) if row.role == "user" else AIMessage(content=row.content)
for row in rows
]
async def save_messages(
db: AsyncSession,
room_id: str,
user_content: str,
assistant_content: str,
sources: Optional[List[Dict[str, Any]]] = None,
):
"""Persist user and assistant messages, and attach sources to the assistant message."""
db.add(ChatMessage(id=str(uuid.uuid4()), room_id=room_id, role="user", content=user_content))
assistant_id = str(uuid.uuid4())
db.add(ChatMessage(id=assistant_id, room_id=room_id, role="assistant", content=assistant_content))
for src in (sources or []):
page = src.get("page_label")
db.add(MessageSource(
id=str(uuid.uuid4()),
message_id=assistant_id,
document_id=src.get("document_id"),
filename=src.get("filename"),
page_label=str(page) if page is not None else None,
))
await db.commit()
@router.post("/chat/stream")
@log_execution(logger)
async def chat_stream(request: ChatRequest, db: AsyncSession = Depends(get_db)):
"""Chat endpoint with streaming response.
SSE event sequence:
1. sources β JSON array of {document_id, filename, page_label}
2. chunk β text fragments of the answer
3. done β signals end of stream
"""
redis = await get_redis()
cache_key = f"{settings.redis_prefix}chat:{request.room_id}:{request.message}"
cached = await get_cached_response(redis, cache_key)
if cached:
logger.info("Returning cached response")
async def stream_cached():
yield {"event": "sources", "data": json.dumps([])}
for i in range(0, len(cached), 50):
yield {"event": "chunk", "data": cached[i:i + 50]}
yield {"event": "done", "data": ""}
return EventSourceResponse(stream_cached())
try:
# Step 1: Fast local intent check (skips LLM for greetings/farewells)
intent_result = _fast_intent(request.message)
context = ""
sources: List[Dict[str, Any]] = []
if intent_result is None:
# Step 2: Launch retrieval and history loading in parallel, then run orchestrator
retrieval_task = asyncio.create_task(
retriever.retrieve(request.message, request.user_id, db)
)
history_task = asyncio.create_task(
load_history(db, request.room_id, limit=6) # 6 msgs (3 pairs) for orchestrator
)
history = await history_task # fast DB query (<100ms), done before orchestrator finishes
intent_result = await orchestrator.analyze_message(request.message, history)
if not intent_result.get("needs_search"):
retrieval_task.cancel()
try:
await retrieval_task
except asyncio.CancelledError:
pass
raw_results = []
else:
search_query = intent_result.get("search_query", request.message)
logger.info(f"Searching for: {search_query}")
if search_query != request.message:
retrieval_task.cancel()
try:
await retrieval_task
except asyncio.CancelledError:
pass
raw_results = await retriever.retrieve(
query=search_query,
user_id=request.user_id,
db=db,
source_hint=intent_result.get("source_hint", "both"),
)
else:
raw_results = await retrieval_task
context = _format_context(raw_results)
sources = _extract_sources(raw_results)
source_hint = intent_result.get("source_hint", "both")
if source_hint in ("schema", "both"):
retrieval_objects = [
RetrievalResult(
content=r["content"],
metadata=r["metadata"],
score=0.0,
source_type=r["metadata"].get("source_type", ""),
)
for r in raw_results
]
query_results = await query_executor.execute(
results=retrieval_objects,
user_id=request.user_id,
db=db,
question=intent_result.get("search_query") or request.message,
)
query_context = _format_query_results(query_results)
if query_context:
context = query_context + "\n\n" + context
# Step 3: Direct response for greetings / non-document intents
if intent_result.get("direct_response"):
response = intent_result["direct_response"]
await cache_response(redis, cache_key, response)
await save_messages(db, request.room_id, request.message, response, sources=[])
async def stream_direct():
yield {"event": "sources", "data": json.dumps([])}
yield {"event": "message", "data": response}
return EventSourceResponse(stream_direct())
# Step 4: Stream answer token-by-token as LLM generates it
# Load full history (10 msgs) for chatbot β richer context than the 6 used by orchestrator
full_history = await load_history(db, request.room_id, limit=10)
messages = full_history + [HumanMessage(content=request.message)]
async def stream_response():
full_response = ""
yield {"event": "sources", "data": json.dumps(sources)}
async for token in chatbot.astream_response(messages, context):
full_response += token
yield {"event": "chunk", "data": token}
yield {"event": "done", "data": ""}
await cache_response(redis, cache_key, full_response)
await save_messages(db, request.room_id, request.message, full_response, sources=sources)
return EventSourceResponse(stream_response())
except Exception as e:
logger.error("Chat failed", error=str(e))
raise HTTPException(status_code=500, detail=f"Chat failed: {str(e)}")
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