"""
Standalone worker: слушает очередь RabbitMQ 'ticket_events',
генерирует PDF-билет через core.pdf_generator, загружает в MinIO,
сохраняет pdf_url в PostgreSQL.
"""
import asyncio
import json
import logging
import os
from typing import Any

import aio_pika
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

from core.minio import ensure_bucket_exists, upload_pdf
from core.pdf_generator import generate_qr_ticket
from database.models import Ticket

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
)
log = logging.getLogger("worker")

RABBITMQ_URL: str = os.getenv("RABBITMQ_URL", "amqp://user:password@rabbitmq/")
DATABASE_URL: str = os.getenv(
    "DATABASE_URL",
    "postgresql+asyncpg://admin:your_strong_password@postgres:5432/ticket_db",
)
QUEUE_NAME: str = "ticket_events"


async def _handle_ticket_paid(
    payload: dict[str, Any],
    db_session: AsyncSession,
) -> None:
    ticket_id: int | None = payload.get("ticket_id")
    if ticket_id is None:
        log.error("Event 'ticket_paid' missing 'ticket_id': %s", payload)
        return

    result = await db_session.execute(select(Ticket).where(Ticket.id == ticket_id))
    ticket: Ticket | None = result.scalar_one_or_none()

    if ticket is None:
        log.error("Ticket %s not found in DB", ticket_id)
        return

    if ticket.pdf_url:
        log.info("Ticket %s already has a PDF, skipping (idempotency guard)", ticket_id)
        return

    log.info("Generating PDF for ticket %s …", ticket_id)
    pdf_bytes = generate_qr_ticket(
        ticket_id=ticket.id,
        user_id=ticket.user_id or 0,
        seat_id=ticket.seat_id,
    )

    object_name = f"tickets/ticket_{ticket_id}.pdf"
    pdf_url = await upload_pdf(object_name, pdf_bytes)
    log.info("PDF uploaded: %s", pdf_url)

    ticket.pdf_url = pdf_url
    await db_session.commit()
    log.info("Ticket %s updated with pdf_url", ticket_id)


async def _process_message(
    message: aio_pika.abc.AbstractIncomingMessage,
    session_factory: async_sessionmaker[AsyncSession],
) -> None:
    async with message.process(requeue=True):
        try:
            payload: dict[str, Any] = json.loads(message.body)
            action: str = payload.get("action", "")

            if action == "ticket_paid":
                async with session_factory() as session:
                    await _handle_ticket_paid(payload, session)
            else:
                log.debug("Unknown action '%s', skipping", action)

        except json.JSONDecodeError:
            log.exception("Failed to decode message body: %r", message.body)
            # Некорректный JSON — не возвращаем в очередь (requeue=False через reject)
            await message.reject(requeue=False)


async def main() -> None:
    engine = create_async_engine(DATABASE_URL, echo=False)
    session_factory = async_sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)

    await ensure_bucket_exists()
    log.info("MinIO bucket ready")

    connection = await aio_pika.connect_robust(RABBITMQ_URL)
    async with connection:
        channel = await connection.channel()
        await channel.set_qos(prefetch_count=10)

        queue = await channel.declare_queue(QUEUE_NAME, durable=True)
        log.info("Worker started. Listening on queue '%s' …", QUEUE_NAME)

        async with queue.iterator() as queue_iter:
            async for message in queue_iter:
                await _process_message(message, session_factory)


if __name__ == "__main__":
    asyncio.run(main())