# shared/database/database.py
import sys
import os
from pathlib import Path

from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy import text
from sqlalchemy.orm import sessionmaker
from shared.config.settings import settings
import asyncio
from contextlib import asynccontextmanager
from shared.utils.logger import get_logger

logger = get_logger(__name__)

class DatabaseManager:
    """数据库管理器"""
    
    def __init__(self):
        self.engine = None
        self.async_session = None
        self.is_connected = False
    
    async def connect(self):
        """连接数据库"""
        if not settings.DATABASE_URL:
            logger.warning("未配置数据库连接，跳过数据库初始化")
            self.is_connected = False
            return
            
        try:
            # 创建异步引擎
            self.engine = create_async_engine(
                settings.DATABASE_URL,
                echo=settings.DEBUG,
                pool_size=20,
                max_overflow=30,
                pool_recycle=3600
            )
            
            # 创建异步会话工厂
            self.async_session = async_sessionmaker(
                self.engine,
                class_=AsyncSession,
                expire_on_commit=False
            )
            
            # 测试连接
            async with self.engine.begin() as conn:
                await conn.execute(text("SELECT 1"))
            
            self.is_connected = True
            logger.info("数据库连接成功")
            
        except Exception as e:
            logger.error(f"数据库连接失败: {e}")
            self.is_connected = False
            raise
    
    async def disconnect(self):
        """断开数据库连接"""
        if self.engine:
            await self.engine.dispose()
            self.is_connected = False
            logger.info("数据库连接已断开")
    
    @asynccontextmanager
    async def session(self):
        """获取数据库会话的异步上下文管理器"""
        if not self.is_connected:
            await self.connect()
        
        session = self.async_session()
        try:
            yield session
        finally:
            await session.close()
    
    async def get_session(self) -> AsyncSession:
        """获取数据库会话"""
        if not self.is_connected:
            await self.connect()
        
        return self.async_session()
    
    async def create_tables(self):
        """创建数据库表"""
        from shared.models.database import Base
        
        try:
            async with self.engine.begin() as conn:
                await conn.run_sync(Base.metadata.create_all)
            logger.info("数据库表创建成功")
        except Exception as e:
            logger.error(f"数据库表创建失败: {e}")
            raise

# 全局数据库管理器实例
db_manager = DatabaseManager()

# 数据库依赖注入
async def get_db_session():
    """获取数据库会话的依赖函数"""
    session = await db_manager.get_session()
    try:
        yield session
    finally:
        await session.close()