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

from __future__ import annotations

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

from models.schemas import CancelResponse, ChatRequest, ChatResponse, JobStatusResponse
from services.job_manager import job_manager
from services import job_queue as jq_module
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 파이프라인 처리 시작."""
    job = job_manager.create(body.message)
    state_stream.create(job.id)
    await jq_module.job_queue.submit(job)
    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.get("/chat/{job_id}/status", response_model=JobStatusResponse)
async def job_status(job_id: str):
    """job 상태 조회 (SSE 없이)."""
    job = job_manager.get(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")

    return JobStatusResponse(
        job_id=job.id,
        status=job.status,
        created_at=job.created_at,
        pipeline=job.pipeline,
        queue_position=jq_module.job_queue.position(job.id) if jq_module.job_queue else None,
    )


@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")


@router.get("/queue/stats")
async def queue_stats():
    """큐 통계."""
    if jq_module.job_queue:
        return jq_module.job_queue.stats
    return {"pending": 0, "active": 0}