"""
数据库事务管理工具
提供统一的事务处理和异常处理机制
"""

from contextlib import contextmanager
from flask import current_app
from app import db
import traceback


class TransactionError(Exception):
    """事务错误基类"""
    pass


class TransactionRollbackError(TransactionError):
    """事务回滚错误"""
    pass


@contextmanager
def transaction(auto_commit=True, auto_rollback=True):
    """
    事务上下文管理器

    Args:
        auto_commit: 是否在成功时自动提交
        auto_rollback: 是否在失败时自动回滚

    Usage:
        with transaction() as session:
            # 执行数据库操作
            pass
    """
    try:
        yield db.session
        if auto_commit:
            db.session.commit()
    except Exception as e:
        if auto_rollback:
            db.session.rollback()

        # 记录错误日志
        error_msg = f"事务执行失败: {str(e)}"
        current_app.logger.error(f"{error_msg}\n{traceback.format_exc()}")

        # 抛出事务错误
        raise TransactionRollbackError(error_msg) from e


def safe_commit():
    """
    安全提交事务

    Returns:
        tuple: (success: bool, error: str or None)
    """
    try:
        db.session.commit()
        return True, None
    except Exception as e:
        db.session.rollback()
        error_msg = f"事务提交失败: {str(e)}"
        current_app.logger.error(f"{error_msg}\n{traceback.format_exc()}")
        return False, error_msg


def safe_rollback():
    """
    安全回滚事务

    Returns:
        bool: 是否回滚成功
    """
    try:
        db.session.rollback()
        return True
    except Exception as e:
        current_app.logger.error(f"事务回滚失败: {str(e)}\n{traceback.format_exc()}")
        return False


def execute_in_transaction(func):
    """
    装饰器：在事务中执行函数

    Args:
        func: 要执行的函数

    Returns:
        函数执行结果或TransactionError

    Usage:
        @execute_in_transaction
        def create_license():
            # 创建卡密逻辑
            pass
    """
    def wrapper(*args, **kwargs):
        try:
            result = func(*args, **kwargs)
            db.session.commit()
            return result
        except Exception as e:
            db.session.rollback()
            error_msg = f"事务执行失败: {str(e)}"
            current_app.logger.error(f"{error_msg}\n{traceback.format_exc()}")
            raise TransactionError(error_msg) from e
    return wrapper