from sqlalchemy import create_engine, select, update, insert, delete, and_, or_, text
from sqlalchemy.orm import Session, sessionmaker
from sqlalchemy.exc import SQLAlchemyError
from loguru import logger
from typing import List, Dict, Optional, Any
import json

from config.database import DATABASE_CONFIG, SQLALCHEMY_CONFIG
from models.orm_models import Base, StrategyPosition, StrategyOrder, StrategyKX

class DatabaseManager:
    """数据库管理器"""
    
    _instance = None
    
    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._initialized = False
        return cls._instance
    
    def __init__(self):
        if not self._initialized:
            self._engine = None
            self._session_factory = None
            self._initialized = True
            self._init_engine()
    
    def _init_engine(self):
        """初始化数据库引擎"""
        try:
            # 构建数据库URL
            db_url = (
                f"mysql+pymysql://{DATABASE_CONFIG['user']}:{DATABASE_CONFIG['password']}"
                f"@{DATABASE_CONFIG['host']}:{DATABASE_CONFIG['port']}"
                f"/{DATABASE_CONFIG['database']}?charset={DATABASE_CONFIG['charset']}"
            )
            
            # 创建引擎
            self._engine = create_engine(
                db_url,
                echo=SQLALCHEMY_CONFIG['echo'],
                echo_pool=SQLALCHEMY_CONFIG['echo_pool'],
                pool_size=DATABASE_CONFIG['pool_size'],
                max_overflow=DATABASE_CONFIG['max_overflow'],
                pool_recycle=DATABASE_CONFIG['pool_recycle'],
                pool_pre_ping=SQLALCHEMY_CONFIG['pool_pre_ping']
            )
            
            # 创建会话工厂
            self._session_factory = sessionmaker(
                bind=self._engine,
                expire_on_commit=False
            )
            
            # 创建表（如果不存在）
            Base.metadata.create_all(self._engine)
            
            logger.info("SQLAlchemy数据库引擎初始化成功")
            
        except Exception as e:
            logger.error(f"数据库引擎初始化失败: {e}")
            raise
    
    def get_session(self) -> Session:
        """获取数据库会话"""
        if self._session_factory is None:
            self._init_engine()
        return self._session_factory()
    
    def close(self):
        """关闭数据库连接"""
        if self._engine:
            self._engine.dispose()
            logger.info("数据库连接已关闭")