"""Alembic async env：仅用于 MySQL 后端。MongoDB 无 schema 迁移概念。"""

import asyncio
from logging.config import fileConfig

from sqlalchemy.ext.asyncio import async_engine_from_config

from alembic import context

config = context.config
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# 从应用配置注入 DSN + metadata
import src.items.mysql
from src.config import settings
from src.database import Base

config.set_main_option("sqlalchemy.url", settings.MYSQL_DSN)
target_metadata = Base.metadata


def run_migrations_offline() -> None:
    context.configure(
        url=config.get_main_option("sqlalchemy.url"),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )
    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection) -> None:
    context.configure(connection=connection, target_metadata=target_metadata)
    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    connectable = async_engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
    )
    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)
    await connectable.dispose()


if context.is_offline_mode():
    run_migrations_offline()
else:
    asyncio.run(run_migrations_online())