"""
从配置文件读取数据引擎连接信息，连接数据库。
"""

from typing import Union

from sqlalchemy import create_engine
from sqlalchemy.engine import Engine
from sqlalchemy.engine.mock import MockConnection
from sqlalchemy.ext.asyncio import create_async_engine, AsyncEngine

from paste.core import config

ASYNC_CONNECTOR_ENGINE = None
GLOBAL_CONNECTOR_ENGINE = None


def connect_engine() -> Union[MockConnection, Engine]:
    """
    全局数据连接引擎。

    :return: 数据连接引擎
    """
    global GLOBAL_CONNECTOR_ENGINE
    if GLOBAL_CONNECTOR_ENGINE is None:
        GLOBAL_CONNECTOR_ENGINE = create_engine(
            config.get_config('db_engine.engine'), **config.get_config('db_engine.engine_option')
        )
    return GLOBAL_CONNECTOR_ENGINE


def async_connect_engine() -> AsyncEngine:
    """
    异步数据连接引擎。

    :return: 异步数据连接引擎
    """
    global ASYNC_CONNECTOR_ENGINE
    if ASYNC_CONNECTOR_ENGINE is None:
        ASYNC_CONNECTOR_ENGINE = create_async_engine(
            config.get_config('db_engine.async_engine'), **config.get_config('db_engine.engine_option')
        )
    return ASYNC_CONNECTOR_ENGINE