initial_commit

backend/app/api/chat.py

@@ -0,0 +1,91 @@
+import uuid
+from datetime import datetime, timezone
+from fastapi import APIRouter, Depends, HTTPException
+from fastapi.responses import StreamingResponse
+from pydantic import BaseModel
+from sqlalchemy.orm import Session as DBSession
+
+from app.db.database import get_db
+from app.db.models import Session, Message
+from app.core import memory as mem
+from app.core import llm
+from app.core.config import DEFAULT_MODEL
+
+router = APIRouter(prefix="/chat", tags=["chat"])
+
+
+class ChatRequest(BaseModel):
+    session_id: str | None = None
+    message: str
+    model: str | None = None
+
+
+class SessionResponse(BaseModel):
+    id: str
+    title: str
+    model: str
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+@router.get("/sessions", response_model=list[SessionResponse])
+def list_sessions(db: DBSession = Depends(get_db)):
+    return db.query(Session).order_by(Session.updated_at.desc()).all()
+
+
+@router.delete("/sessions/{session_id}", status_code=204)
+def delete_session(session_id: str, db: DBSession = Depends(get_db)):
+    session = db.get(Session, session_id)
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    db.delete(session)
+    db.commit()
+
+
+@router.post("/stream")
+async def stream_chat(req: ChatRequest, db: DBSession = Depends(get_db)):
+    # セッション取得 or 新規作成
+    if req.session_id:
+        session = db.get(Session, req.session_id)
+        if not session:
+            raise HTTPException(status_code=404, detail="Session not found")
+    else:
+        session = Session(
+            id=str(uuid.uuid4()),
+            title=req.message[:40],
+            model=req.model or DEFAULT_MODEL,
+        )
+        db.add(session)
+        db.commit()
+
+    # ユーザーメッセージを保存
+    user_msg = Message(session_id=session.id, role="user", content=req.message)
+    db.add(user_msg)
+    db.commit()
+
+    context = mem.get_context_messages(db, session.id)
+
+    async def generate():
+        # セッションIDをまず返す（新規セッション時にフロントへ通知）
+        yield f"data: {{\"type\":\"session_id\",\"value\":\"{session.id}\"}}\n\n"
+
+        full_response = []
+        async for chunk in llm.stream_chat(context, model=req.model or session.model):
+            full_response.append(chunk)
+            escaped = chunk.replace('"', '\\"').replace('\n', '\\n')
+            yield f"data: {{\"type\":\"chunk\",\"value\":\"{escaped}\"}}\n\n"
+
+        # アシスタントメッセージを保存
+        assistant_content = "".join(full_response)
+        db.add(Message(session_id=session.id, role="assistant", content=assistant_content))
+        session.updated_at = datetime.now(timezone.utc)
+        db.commit()
+
+        # メモリ要約チェック
+        await mem.maybe_summarize(db, session)
+
+        yield "data: {\"type\":\"done\"}\n\n"
+
+    return StreamingResponse(generate(), media_type="text/event-stream")