"""
Queue management router.

POST  /queue/jobs          — enqueue a job, return immediately with job metadata
GET   /queue/jobs/{id}     — poll job status / result
DELETE /queue/jobs/{id}    — cancel a pending job

GET   /queue/status        — worker state + queue depth
POST  /queue/pause         — finish current job, stop picking new ones
POST  /queue/resume        — resume from pause
POST  /queue/start         — start (or restart) the worker
POST  /queue/stop          — stop worker immediately (pending jobs stay queued)
"""
from fastapi import APIRouter, HTTPException

from app.schemas.queue import JobStatus, QueueRequest, QueueStatus
from app.services.queue import PRIORITY_MAP, Job, Priority, queue_service

router = APIRouter(prefix="/queue", tags=["queue"])


# ── Job endpoints ─────────────────────────────────────────────────────────────

@router.post("/jobs", response_model=JobStatus, status_code=202)
async def enqueue_job(request: QueueRequest) -> JobStatus:
    priority = PRIORITY_MAP[request.priority]
    job = await queue_service.enqueue(request, priority)
    return _job_to_status(job)


@router.get("/jobs/{job_id}", response_model=JobStatus)
async def get_job(job_id: str) -> JobStatus:
    job = queue_service.get_job(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")
    return _job_to_status(job)


@router.delete("/jobs/{job_id}", status_code=204)
async def cancel_job(job_id: str) -> None:
    if not queue_service.cancel_job(job_id):
        raise HTTPException(status_code=404, detail="Job not found or already started")


# ── Worker control endpoints ──────────────────────────────────────────────────

@router.get("/status", response_model=QueueStatus)
async def get_status() -> QueueStatus:
    cur = queue_service.current_job
    return QueueStatus(
        running=queue_service._running,
        paused=queue_service.is_paused,
        queue_size=queue_service.queue_size,
        current_job_id=cur.id if cur else None,
    )


@router.post("/pause", status_code=204)
async def pause() -> None:
    """Pause after the current job finishes."""
    queue_service.pause()


@router.post("/resume", status_code=204)
async def resume() -> None:
    """Resume from a paused state."""
    queue_service.resume()


@router.post("/start", status_code=204)
async def start() -> None:
    """Start (or restart) the worker task."""
    queue_service.start()


@router.post("/stop", status_code=204)
async def stop() -> None:
    """Stop the worker. Pending jobs remain in queue; POST /queue/start to resume."""
    queue_service.stop()


# ── Helper ────────────────────────────────────────────────────────────────────

def _job_to_status(job: Job) -> JobStatus:
    pos: int | None = None
    if job.status == "pending":
        # Count jobs that are ahead: same or higher priority AND earlier seq
        pos = sum(
            1
            for j in queue_service._jobs.values()
            if j.status == "pending"
            and (int(j.priority), j.seq) < (int(job.priority), job.seq)
        )
    return JobStatus(
        id=job.id,
        status=job.status,
        priority=Priority(job.priority).name.lower(),
        position=pos,
        created_at=job.created_at,
        started_at=job.started_at,
        finished_at=job.finished_at,
        result=job.result,
        error=job.error,
    )