"""Celery tasks for OCR processing of uploaded screenshots."""
import asyncio
import logging
from uuid import UUID

from app.workers.celery_app import celery_app

logger = logging.getLogger(__name__)


def _run_async(coro):
    """Run an async coroutine from synchronous Celery task context."""
    loop = asyncio.new_event_loop()
    try:
        return loop.run_until_complete(coro)
    finally:
        loop.close()


@celery_app.task(name="app.workers.ocr_tasks.process_image_ocr", bind=True, max_retries=3)
def process_image_ocr(self, image_id: str):
    """Process a single image: classify page, extract fields, save to DB."""
    _run_async(_process(image_id))


async def _process(image_id_str: str):
    from app.core.database import async_session_factory
    from app.models.evidence_image import EvidenceImage, OcrStatus
    from app.models.ocr_block import OcrBlock
    from app.services.ocr_service import classify_page, extract_transaction_fields
    from app.services.parser_service import parse_extracted_fields

    image_id = UUID(image_id_str)

    async with async_session_factory() as db:
        image = await db.get(EvidenceImage, image_id)
        if not image:
            logger.error("Image %s not found", image_id)
            return

        image.ocr_status = OcrStatus.processing
        await db.flush()

        try:
            source_app, page_type = await classify_page(image.file_path)
            image.source_app = source_app
            image.page_type = page_type

            raw_fields = await extract_transaction_fields(image.file_path, source_app, page_type)

            # save raw OCR block
            block = OcrBlock(
                image_id=image.id,
                content=str(raw_fields),
                bbox={},
                seq_order=0,
                confidence=raw_fields.get("confidence", 0.5) if isinstance(raw_fields, dict) else 0.5,
            )
            db.add(block)

            # parse into transaction records
            records = parse_extracted_fields(raw_fields, image.case_id, image.id, source_app)
            for r in records:
                db.add(r)

            image.ocr_status = OcrStatus.done
            await db.commit()
            logger.info("Image %s processed: %d transactions", image_id, len(records))

        except Exception as e:
            image.ocr_status = OcrStatus.failed
            await db.commit()
            logger.error("Image %s OCR failed: %s", image_id, e)
            raise