import aiomysql
from contextlib import asynccontextmanager
from typing import  Dict,Optional, AsyncGenerator
from foundation.observability.logger.loggering import server_logger
from foundation.utils.common import handler_err
from foundation.infrastructure.config import config_handler

# 异步数据库连接池
class AsyncMySQLPool:
    _instance = None
    
    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super().__new__(cls)
        return cls._instance
    
    def __init__(self):
        if not hasattr(self, '_pool'):
            self._pool = None
            self._initialized = False
    
    async def initialize(self):
        """初始化连接池"""
        try:
            
            self._pool = await aiomysql.create_pool(
                host=config_handler.get("mysql", "MYSQL_HOST" , "localhost"),
                port=int(config_handler.get("mysql", "MYSQL_PORT" , "3306")),
                user=config_handler.get("mysql", "MYSQL_USER"),
                password=config_handler.get("mysql", "MYSQL_PASSWORD"),
                db=config_handler.get("mysql", "MYSQL_DB"),
                minsize=int(config_handler.get("mysql", "MYSQL_MIN_SIZE" , "1")),
                maxsize=int(config_handler.get("mysql", "MYSQL_MAX_SIZE" , "2")),
                autocommit=config_handler.get("mysql", "MYSQL_AUTO_COMMIT")
            )
            self._initialized = True
            server_logger.info("异步MySQL连接池初始化成功")
        except Exception as e:
            server_logger.error(f"连接池初始化失败: {e}")
            raise
    
    async def close(self):
        """关闭连接池"""
        if self._pool:
            self._pool.close()
            await self._pool.wait_closed()
            server_logger.info("异步MySQL连接池已关闭")
    
    @asynccontextmanager
    async def get_connection(self) -> AsyncGenerator[aiomysql.Connection, None]:
        """获取数据库连接的上下文管理器"""
        if not self._initialized:
            # 如果没有初始化，使用默认配置初始化
            await self.initialize()
        
        async with self._pool.acquire() as conn:
            try:
                yield conn
            except Exception as e:
                server_logger.error(f"数据库连接操作失败: {e}")
                raise
    
    @asynccontextmanager
    async def get_cursor(self, connection: Optional[aiomysql.Connection] = None) -> AsyncGenerator[aiomysql.Cursor, None]:
        """获取游标的上下文管理器"""
        if connection:
            # 使用提供的连接
            async with connection.cursor(aiomysql.DictCursor) as cursor:
                try:
                    yield cursor
                except Exception as e:
                    server_logger.error(f"游标操作失败: {e}")
                    raise
        else:
            # 创建新连接
            async with self.get_connection() as conn:
                async with conn.cursor(aiomysql.DictCursor) as cursor:
                    try:
                        yield cursor
                    except Exception as e:
                        server_logger.error(f"游标操作失败: {e}")
                        raise


# 全局数据库连接池实例
#async_db_pool = AsyncMySQLPool()