#!/usr/bin/env python3
"""
重试机制模块
提供重试装饰器和工具函数
"""
import time
import logging
from functools import wraps
from typing import Callable, Optional, Type, Tuple, Any

from src.logging_config import get_logger

logger = get_logger(__name__)


def retry(
    max_attempts: int = 3,
    delay: float = 1.0,
    backoff_factor: float = 2.0,
    exceptions: Optional[Tuple[Type[Exception], ...]] = None,
    on_retry: Optional[Callable[[int, Exception], None]] = None
) -> Callable:
    """
    重试装饰器
    
    参数:
        max_attempts: 最大重试次数
        delay: 初始延迟时间（秒）
        backoff_factor: 退避因子，每次重试延迟时间乘以该因子
        exceptions: 要捕获的异常类型，None表示捕获所有异常
        on_retry: 重试时的回调函数，参数为 (attempt, exception)
    
    使用示例:
        @retry(max_attempts=3, delay=2.0, backoff_factor=2.0)
        def fetch_data():
            # 可能失败的代码
            pass
        
        @retry(max_attempts=5, exceptions=(ConnectionError, TimeoutError))
        def network_request():
            # 网络请求代码
            pass
    """
    def decorator(func: Callable) -> Callable:
        @wraps(func)
        def wrapper(*args, **kwargs) -> Any:
            last_exception = None
            
            for attempt in range(max_attempts):
                try:
                    return func(*args, **kwargs)
                except Exception as e:
                    # 检查是否需要捕获此异常
                    if exceptions and not isinstance(e, exceptions):
                        raise
                    
                    last_exception = e
                    
                    # 如果是最后一次尝试，不再重试
                    if attempt == max_attempts - 1:
                        logger.error(
                            f"{func.__name__} 在 {max_attempts} 次尝试后仍然失败: {e}"
                        )
                        raise
                    
                    # 计算延迟时间
                    current_delay = delay * (backoff_factor ** attempt)
                    
                    logger.warning(
                        f"{func.__name__} 第 {attempt + 1} 次尝试失败: {e}, "
                        f"{current_delay:.2f}秒后重试..."
                    )
                    
                    # 调用重试回调
                    if on_retry:
                        try:
                            on_retry(attempt + 1, e)
                        except Exception as callback_error:
                            logger.error(f"重试回调执行失败: {callback_error}")
                    
                    # 等待
                    time.sleep(current_delay)
            
            # 理论上不会到达这里，但为了类型检查
            if last_exception:
                raise last_exception
        
        return wrapper
    return decorator


def retry_with_exponential_backoff(
    max_attempts: int = 3,
    initial_delay: float = 1.0,
    max_delay: float = 60.0
) -> Callable:
    """
    使用指数退避的重试装饰器
    
    参数:
        max_attempts: 最大重试次数
        initial_delay: 初始延迟时间（秒）
        max_delay: 最大延迟时间（秒）
    
    使用示例:
        @retry_with_exponential_backoff(max_attempts=5, initial_delay=2.0)
        def api_call():
            # API调用代码
            pass
    """
    def decorator(func: Callable) -> Callable:
        @wraps(func)
        def wrapper(*args, **kwargs) -> Any:
            last_exception = None
            
            for attempt in range(max_attempts):
                try:
                    return func(*args, **kwargs)
                except Exception as e:
                    last_exception = e
                    
                    if attempt == max_attempts - 1:
                        logger.error(
                            f"{func.__name__} 在 {max_attempts} 次尝试后仍然失败: {e}"
                        )
                        raise
                    
                    # 计算延迟时间（指数退避，但不超过最大延迟）
                    current_delay = min(initial_delay * (2 ** attempt), max_delay)
                    
                    logger.warning(
                        f"{func.__name__} 第 {attempt + 1} 次尝试失败: {e}, "
                        f"{current_delay:.2f}秒后重试..."
                    )
                    
                    time.sleep(current_delay)
            
            if last_exception:
                raise last_exception
        
        return wrapper
    return decorator


def retry_on_exception(
    exception_type: Type[Exception],
    max_attempts: int = 3,
    delay: float = 1.0
) -> Callable:
    """
    只在特定异常时重试的装饰器
    
    参数:
        exception_type: 要捕获的异常类型
        max_attempts: 最大重试次数
        delay: 延迟时间（秒）
    
    使用示例:
        @retry_on_exception(ConnectionError, max_attempts=5, delay=2.0)
        def fetch_data():
            # 可能抛出 ConnectionError 的代码
            pass
    """
    def decorator(func: Callable) -> Callable:
        @wraps(func)
        def wrapper(*args, **kwargs) -> Any:
            last_exception = None
            
            for attempt in range(max_attempts):
                try:
                    return func(*args, **kwargs)
                except exception_type as e:
                    last_exception = e
                    
                    if attempt == max_attempts - 1:
                        logger.error(
                            f"{func.__name__} 在 {max_attempts} 次尝试后仍然失败: {e}"
                        )
                        raise
                    
                    logger.warning(
                        f"{func.__name__} 第 {attempt + 1} 次尝试失败: {e}, "
                        f"{delay:.2f}秒后重试..."
                    )
                    
                    time.sleep(delay)
            
            if last_exception:
                raise last_exception
        
        return wrapper
    return decorator


class RetryContext:
    """重试上下文管理器"""
    
    def __init__(
        self,
        operation_name: str,
        max_attempts: int = 3,
        delay: float = 1.0,
        backoff_factor: float = 2.0,
        exceptions: Optional[Tuple[Type[Exception], ...]] = None
    ):
        """
        初始化重试上下文
        
        参数:
            operation_name: 操作名称
            max_attempts: 最大重试次数
            delay: 初始延迟时间（秒）
            backoff_factor: 退避因子
            exceptions: 要捕获的异常类型
        """
        self.operation_name = operation_name
        self.max_attempts = max_attempts
        self.delay = delay
        self.backoff_factor = backoff_factor
        self.exceptions = exceptions
        self.attempt = 0
    
    def __enter__(self):
        self.attempt = 0
        return self
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is None:
            return False
        
        # 检查是否需要捕获此异常
        if self.exceptions and not isinstance(exc_val, self.exceptions):
            return False
        
        self.attempt += 1
        
        # 如果超过最大尝试次数，不再重试
        if self.attempt >= self.max_attempts:
            logger.error(
                f"{self.operation_name} 在 {self.max_attempts} 次尝试后仍然失败: {exc_val}"
            )
            return False
        
        # 计算延迟时间
        current_delay = self.delay * (self.backoff_factor ** (self.attempt - 1))
        
        logger.warning(
            f"{self.operation_name} 第 {self.attempt} 次尝试失败: {exc_val}, "
            f"{current_delay:.2f}秒后重试..."
        )
        
        # 等待
        time.sleep(current_delay)
        
        # 抑制异常，继续重试
        return True


def async_retry(
    max_attempts: int = 3,
    delay: float = 1.0,
    backoff_factor: float = 2.0
) -> Callable:
    """
    异步重试装饰器（用于异步函数）
    
    参数:
        max_attempts: 最大重试次数
        delay: 初始延迟时间（秒）
        backoff_factor: 退避因子
    
    使用示例:
        @async_retry(max_attempts=3, delay=2.0)
        async def async_fetch_data():
            # 异步代码
            pass
    """
    import asyncio
    
    def decorator(func: Callable) -> Callable:
        @wraps(func)
        async def wrapper(*args, **kwargs) -> Any:
            last_exception = None
            
            for attempt in range(max_attempts):
                try:
                    return await func(*args, **kwargs)
                except Exception as e:
                    last_exception = e
                    
                    if attempt == max_attempts - 1:
                        logger.error(
                            f"{func.__name__} 在 {max_attempts} 次尝试后仍然失败: {e}"
                        )
                        raise
                    
                    # 计算延迟时间
                    current_delay = delay * (backoff_factor ** attempt)
                    
                    logger.warning(
                        f"{func.__name__} 第 {attempt + 1} 次尝试失败: {e}, "
                        f"{current_delay:.2f}秒后重试..."
                    )
                    
                    # 异步等待
                    await asyncio.sleep(current_delay)
            
            if last_exception:
                raise last_exception
        
        return wrapper
    return decorator


if __name__ == '__main__':
    # 测试代码
    
    # 测试重试装饰器
    call_count = 0
    
    @retry(max_attempts=3, delay=0.1)
    def test_retry():
        global call_count
        call_count += 1
        print(f"调用次数: {call_count}")
        if call_count < 3:
            raise ValueError("测试异常")
        return "成功"
    
    result = test_retry()
    print(f"测试结果: {result}")
    
    # 测试重试上下文管理器
    context_call_count = 0
    
    def test_context_operation():
        global context_call_count
        context_call_count += 1
        print(f"上下文调用次数: {context_call_count}")
        if context_call_count < 3:
            raise ValueError("测试异常")
        return "成功"
    
    with RetryContext("测试操作", max_attempts=3, delay=0.1):
        result = test_context_operation()
        print(f"上下文测试结果: {result}")
    
    # 测试特定异常重试
    @retry_on_exception(ValueError, max_attempts=3, delay=0.1)
    def test_specific_exception():
        raise ValueError("测试异常")
    
    try:
        test_specific_exception()
    except ValueError as e:
        print(f"特定异常测试: {e}")