import json
from datetime import datetime, timezone

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session

from app.database import get_db
from app.models import JobModel
from app.schemas import EntityResponse, Job, JobStatus, ListResponse

router = APIRouter(prefix='/jobs', tags=['jobs'])


def _to_job(m: JobModel) -> Job:
    return Job(
        id=m.id, type=m.type, status=m.status,
        progress=m.progress, message=m.message, error=m.error,
        payload=json.loads(m.payload_json or '{}'),
        result=json.loads(m.result_json or 'null'),
        created_at=m.created_at,
        started_at=m.started_at,
        finished_at=m.finished_at,
    )


@router.get('', response_model=ListResponse[Job])
def list_jobs(
    status: JobStatus | None = Query(default=None),
    type: str | None = Query(default=None),
    db: Session = Depends(get_db),
):
    q = db.query(JobModel)
    if status:
        q = q.filter(JobModel.status == status)
    if type:
        q = q.filter(JobModel.type == type)
    rows = q.order_by(JobModel.created_at.desc()).all()
    return ListResponse(count=len(rows), items=[_to_job(r) for r in rows])


@router.get('/{job_id}', response_model=EntityResponse[Job])
def get_job(job_id: str, db: Session = Depends(get_db)):
    row = db.query(JobModel).filter(JobModel.id == job_id).first()
    if not row:
        raise HTTPException(status_code=404, detail='Job not found')
    return EntityResponse(item=_to_job(row))


@router.post('/{job_id}/cancel', response_model=EntityResponse[Job])
def cancel_job(job_id: str, db: Session = Depends(get_db)):
    row = db.query(JobModel).filter(JobModel.id == job_id).first()
    if not row:
        raise HTTPException(status_code=404, detail='Job not found')
    if row.status not in ('pending', 'running'):
        raise HTTPException(
            status_code=409,
            detail=f'Cannot cancel job with status {row.status!r}',
        )
    row.status = 'cancelled'
    row.finished_at = datetime.now(timezone.utc)
    db.commit()
    db.refresh(row)
    return EntityResponse(item=_to_job(row))