from fastapi import APIRouter, Depends, HTTPException
from fastapi.responses import StreamingResponse
from sqlalchemy.orm import Session

from app.api.schemas import MessageCreate, MessageOut, SessionCreate, SessionDetailOut, SessionOut
from app.chat.service import ChatService
from app.db.base import get_db

router = APIRouter()


@router.post("/sessions", response_model=SessionOut)
def create_session(payload: SessionCreate, db: Session = Depends(get_db)) -> SessionOut:
    service = ChatService(db)
    return service.create_session(title=payload.title)


@router.get("/sessions", response_model=list[SessionOut])
def list_sessions(db: Session = Depends(get_db)) -> list[SessionOut]:
    service = ChatService(db)
    return service.list_sessions()


@router.get("/sessions/{session_id}", response_model=SessionDetailOut)
def get_session(session_id: int, db: Session = Depends(get_db)) -> SessionDetailOut:
    service = ChatService(db)
    session = service.get_session(session_id)
    if not session:
        raise HTTPException(status_code=404, detail="Session not found")
    return session


@router.delete("/sessions/{session_id}")
def delete_session(session_id: int, db: Session = Depends(get_db)) -> dict[str, bool]:
    service = ChatService(db)
    if not service.delete_session(session_id):
        raise HTTPException(status_code=404, detail="Session not found")
    return {"ok": True}


@router.post("/sessions/{session_id}/messages")
async def send_message(
    session_id: int,
    payload: MessageCreate,
    db: Session = Depends(get_db),
) -> StreamingResponse:
    service = ChatService(db)
    if not service.get_session(session_id):
        raise HTTPException(status_code=404, detail="Session not found")

    async def event_stream():
        async for chunk in service.stream_response(session_id, payload.content):
            yield chunk

    return StreamingResponse(event_stream(), media_type="text/event-stream")