"""Celery task definitions.

Only the scaffold's ``ping`` task lives here. It proves the whole async path:
API creates ``tk_task`` → queue → worker transitions running → succeeded →
task centre reflects it. Real long-running tasks (report / tryon / matting /
render) follow exactly this shape and additionally call
``billing.commit()``/``refund()`` and ``compliance.publish_asset()``.
"""

from __future__ import annotations

import asyncio
from typing import Any

from apps.worker.celery_app import celery_app
from packages.domain.task.state import TaskStatus
from packages.shared.context import bind_context
from packages.shared.db import get_session_factory
from packages.shared.logging import get_logger
from packages.task.service import TaskService

logger = get_logger(__name__)


async def _run_ping(task_id: int, echo: str | None = None) -> dict[str, Any]:
    factory = get_session_factory()
    async with factory() as session:
        service = TaskService(session)
        task = await service.transition(
            task_id=task_id, target=TaskStatus.RUNNING, stage_text="执行中"
        )
        payload = task.payload or {}
        message = echo or str(payload.get("echo", "pong"))
        await session.commit()

        finished = await service.transition(
            task_id=task_id,
            target=TaskStatus.SUCCEEDED,
            stage_text="已完成",
            result={"echo": message},
        )
        await session.commit()
        return {"task_id": str(finished.task_id), "echo": message}


async def _fail_ping(task_id: int, error: str) -> None:
    factory = get_session_factory()
    async with factory() as session:
        service = TaskService(session)
        await service.transition(
            task_id=task_id,
            target=TaskStatus.FAILED,
            stage_text="执行失败",
            error_message=error,
        )
        await session.commit()


# Celery 的 task 装饰器没有类型标注，会把被装饰函数擦成 untyped
@celery_app.task(name="meida.task.ping", bind=True, max_retries=2)  # type: ignore[untyped-decorator]
def ping_task(self: Any, task_id: int, echo: str | None = None) -> dict[str, Any]:
    bind_context(task_id=task_id)
    try:
        return asyncio.run(_run_ping(task_id, echo))
    except Exception as exc:
        logger.exception("ping_task_failed", task_id=task_id)
        # Real tasks additionally refund the quota reservation here (FR-BILL-05).
        asyncio.run(_fail_ping(task_id, f"{type(exc).__name__}: {exc}"))
        raise