"""MySQL 业务库数据源（同步）"""

from typing import Optional

from sqlalchemy import Engine, create_engine
from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker

from app.config import settings
from app.core.logger import log

# ──────────── 内部变量 ────────────
_mysql_engine: Optional[Engine] = None
_mysql_session_factory: Optional[sessionmaker[Session]] = None


class MysqlBase(DeclarativeBase):
    """MySQL ORM 声明基类"""
    pass


def init_db() -> None:
    """初始化 MySQL 数据源"""
    global _mysql_engine, _mysql_session_factory

    _mysql_engine = create_engine(
        settings.mysql_url,
        pool_size=settings.mysql_pool_size,
        max_overflow=settings.mysql_max_overflow,
        pool_timeout=settings.db_pool_timeout,
        pool_recycle=3600,
        pool_pre_ping=True,
        echo=False,
    )
    _mysql_session_factory = sessionmaker(_mysql_engine, expire_on_commit=False)

    log.info("MySQL 数据源初始化完成: {}", settings.db_host)


def close_db() -> None:
    """关闭 MySQL 数据源"""
    if _mysql_engine:
        _mysql_engine.dispose()
    log.info("MySQL 数据源已关闭")


def MysqlSession() -> Session:
    """获取 MySQL 会话（用作 with MysqlSession() as session）"""
    if _mysql_session_factory is None:
        raise RuntimeError("数据库未初始化，请先调用 init_db()")
    return _mysql_session_factory()