"""Celery app + task definitions."""
from celery import Celery
from app.config import get_settings

settings = get_settings()

celery_app = Celery(
    "pdf_accessibility",
    broker=settings.redis_url,
    backend=settings.redis_url,
)
celery_app.conf.update(
    task_serializer="json",
    result_serializer="json",
    accept_content=["json"],
    timezone="UTC",
    task_track_started=True,
    task_acks_late=True,
    worker_prefetch_multiplier=1,  # one PDF at a time per worker
)


@celery_app.task(bind=True, max_retries=2, name="tasks.process_pdf")
def process_pdf_task(self, job_id: str, storage_key: str, filename: str, workspace_id: str):
    """Download PDF from MinIO, run checker, store result, update job status."""
    import asyncio
    from sqlalchemy import text, update
    from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
    from app.services import storage, checker as checker_svc
    from datetime import datetime, timezone

    engine = create_async_engine(settings.database_url)
    Session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)

    async def _run():
        async with Session() as db:
            # Mark processing
            await db.execute(
                text("UPDATE jobs SET status='processing', updated_at=NOW() WHERE id=:id"),
                {"id": job_id},
            )
            await db.commit()

        pdf_bytes = storage.download_bytes(storage_key)

        try:
            result = checker_svc.run_check(pdf_bytes, filename)
            score = result.get("accessibility_score", 0)

            async with Session() as db:
                await db.execute(
                    text("""
                        UPDATE jobs
                        SET status='completed', result=:result::jsonb,
                            accessibility_score=:score, completed_at=NOW(), updated_at=NOW()
                        WHERE id=:id
                    """),
                    {"result": __import__("json").dumps(result), "score": score, "id": job_id},
                )
                await db.execute(
                    text("INSERT INTO usage_events (workspace_id, event_type, job_id) VALUES (:wid, 'pdf_checked', :jid)"),
                    {"wid": workspace_id, "jid": job_id},
                )
                await db.commit()
        except Exception as exc:
            async with Session() as db:
                await db.execute(
                    text("UPDATE jobs SET status='failed', error_message=:err, updated_at=NOW() WHERE id=:id"),
                    {"err": str(exc), "id": job_id},
                )
                await db.commit()
            raise self.retry(exc=exc, countdown=30)

    asyncio.run(_run())