"""
缓存服务
提供数据缓存功能（使用内存缓存）
"""
import time
from typing import Optional, Any, Dict
from app.utils.logger import logger


class CacheService:
    """内存缓存服务类"""

    def __init__(self):
        """初始化内存缓存"""
        self._cache: Dict[str, tuple[Any, float]] = {}  # key: (value, expire_time)
        logger.info("内存缓存初始化成功")

    def get(self, key: str) -> Optional[Any]:
        """
        获取缓存数据

        Args:
            key: 缓存键

        Returns:
            缓存的数据，不存在或过期返回None
        """
        try:
            if key in self._cache:
                value, expire_time = self._cache[key]
                # 检查是否过期
                if time.time() < expire_time:
                    return value
                else:
                    # 删除过期数据
                    del self._cache[key]
            return None
        except Exception as e:
            logger.error(f"获取缓存失败: {e}")
            return None

    def set(self, key: str, value: Any, ttl: int = 3600) -> bool:
        """
        设置缓存数据

        Args:
            key: 缓存键
            value: 要缓存的数据
            ttl: 过期时间（秒）

        Returns:
            是否成功
        """
        try:
            expire_time = time.time() + ttl
            self._cache[key] = (value, expire_time)
            return True
        except Exception as e:
            logger.error(f"设置缓存失败: {e}")
            return False

    def delete(self, key: str) -> bool:
        """
        删除缓存

        Args:
            key: 缓存键

        Returns:
            是否成功
        """
        try:
            if key in self._cache:
                del self._cache[key]
            return True
        except Exception as e:
            logger.error(f"删除缓存失败: {e}")
            return False

    def exists(self, key: str) -> bool:
        """
        检查缓存是否存在

        Args:
            key: 缓存键

        Returns:
            是否存在
        """
        try:
            if key in self._cache:
                _, expire_time = self._cache[key]
                if time.time() < expire_time:
                    return True
                else:
                    del self._cache[key]
            return False
        except Exception as e:
            logger.error(f"检查缓存失败: {e}")
            return False

    def clear_pattern(self, pattern: str) -> int:
        """
        清除匹配模式的所有缓存

        Args:
            pattern: 键模式（如 "stock:*"）

        Returns:
            删除的键数量
        """
        try:
            # 简单的模式匹配（支持*通配符）
            pattern = pattern.replace('*', '')
            keys_to_delete = [k for k in self._cache.keys() if pattern in k]

            for key in keys_to_delete:
                del self._cache[key]

            return len(keys_to_delete)
        except Exception as e:
            logger.error(f"清除缓存失败: {e}")
            return 0

    def clear_expired(self):
        """清除所有过期的缓存"""
        try:
            current_time = time.time()
            expired_keys = [
                key for key, (_, expire_time) in self._cache.items()
                if current_time >= expire_time
            ]

            for key in expired_keys:
                del self._cache[key]

            if expired_keys:
                logger.info(f"清除了{len(expired_keys)}个过期缓存")
        except Exception as e:
            logger.error(f"清除过期缓存失败: {e}")


# 创建全局实例
cache_service = CacheService()