import asyncio
import logging
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
from app.models.call_event import CallEvent
from app.infrastructure.s3 import download_and_upload_stream
from app.infrastructure.database import get_db
from app.config import settings

logger = logging.getLogger(__name__)

BATCH_SIZE = 20
MAX_RETRIES_CALL = 3
async def fetch_pending_calls(session: AsyncSession):
    stmt = (
        select(CallEvent)
        .where(CallEvent.processing_status == "pending")
        .where(CallEvent.retries < MAX_RETRIES_CALL)
        .order_by(CallEvent.id)
        .limit(BATCH_SIZE)
        .with_for_update(skip_locked=True)
    )
    result = await session.execute(stmt)
    calls = result.scalars().all()
    return calls

async def process_pending_calls():
    logger.info("[INFO] Запуск обработки новых записей")

    async for session in get_db():
        calls = await fetch_pending_calls(session)
        if not calls:
            logger.info("[INFO] Нет новых записей для обработки")
            return

        # сразу увеличиваем retries и помечаем processing
        for call in calls:
            call.retries += 1
            call.processing_status = "processing"
        await session.commit()

        # создаём задачи на скачивание/загрузку
        tasks = []
        for call in calls:
            key_name = f"audio/{call.id}.mp3"
            logger.info("Попытка скачать и загрузить запись %s", call.full_record_file_link)
            tasks.append(download_and_upload_stream(call.full_record_file_link, key_name))

        results = await asyncio.gather(*tasks, return_exceptions=True)

        # обновляем статус после обработки
        for call, result in zip(calls, results):
            if isinstance(result, Exception) or result is False:
                call.processing_status = "failed"
            else:
                call.processing_status = "done"
                call.s3_key = f"audio/{call.id}.mp3"

        await session.commit()
        logger.info(f"Обработка пачки из {len(calls)} записей завершена")