"""Chat router — POST /chat, GET /chat/{job_id}/stream, POST /chat/{job_id}/cancel."""

from __future__ import annotations

import asyncio

from fastapi import APIRouter, HTTPException
from fastapi.responses import StreamingResponse

from models.schemas import CancelResponse, ChatRequest, ChatResponse
from services import worker
from services.job_manager import job_manager
from services.state_stream import state_stream

router = APIRouter(tags=["chat"])


@router.post("/chat", response_model=ChatResponse)
async def create_chat(body: ChatRequest):
    """job_id 즉시 반환 (ACK). 백그라운드에서 EXAONE 처리 시작."""
    job = job_manager.create(body.message)
    state_stream.create(job.id)

    task = asyncio.create_task(worker.run(job))
    job_manager.attach_task(job.id, task)

    return ChatResponse(job_id=job.id)


@router.get("/chat/{job_id}/stream")
async def stream_chat(job_id: str):
    """SSE 스트림으로 상태 + 결과 전달."""
    job = job_manager.get(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")

    return StreamingResponse(
        _stream_with_cleanup(job_id),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "X-Accel-Buffering": "no",
        },
    )


async def _stream_with_cleanup(job_id: str):
    try:
        async for chunk in state_stream.subscribe(job_id):
            yield chunk
    finally:
        state_stream.cleanup(job_id)


@router.post("/chat/{job_id}/cancel", response_model=CancelResponse)
async def cancel_chat(job_id: str):
    """진행 중인 job 취소."""
    success = job_manager.cancel(job_id)
    if not success:
        raise HTTPException(status_code=404, detail="Job not found or already finished")
    return CancelResponse(status="cancelled")