"""限流控制"""
import time
import logging
from collections import deque
from typing import Dict
from config import MESSAGE_RATE_LIMIT

logger = logging.getLogger(__name__)


class RateLimiter:
    """令牌桶限流器"""
    
    def __init__(self, max_requests: int = MESSAGE_RATE_LIMIT, window: int = 60):
        """初始化限流器
        
        Args:
            max_requests: 时间窗口内最大请求数
            window: 时间窗口（秒）
        """
        self.max_requests = max_requests
        self.window = window
        # 使用deque存储时间戳
        self.requests: deque = deque()
        logger.info(f"限流器已启用: {max_requests}条/{window}秒")
    
    def is_allowed(self) -> bool:
        """检查是否允许请求
        
        Returns:
            是否允许
        """
        current_time = time.time()
        
        # 清理过期的请求记录
        while self.requests and self.requests[0] < current_time - self.window:
            self.requests.popleft()
        
        # 检查是否超过限制
        if len(self.requests) < self.max_requests:
            self.requests.append(current_time)
            return True
        else:
            logger.warning(f"触发限流: 已达到 {self.max_requests}条/{self.window}秒")
            return False
    
    def get_remaining(self) -> int:
        """获取剩余可用次数"""
        current_time = time.time()
        
        # 清理过期的请求记录
        while self.requests and self.requests[0] < current_time - self.window:
            self.requests.popleft()
        
        return max(0, self.max_requests - len(self.requests))
    
    def get_reset_time(self) -> float:
        """获取重置时间（秒）"""
        if not self.requests:
            return 0
        
        oldest_request = self.requests[0]
        reset_time = oldest_request + self.window - time.time()
        return max(0, reset_time)


# 全局限流器实例（单例）
_rate_limiter: RateLimiter = RateLimiter()


def get_rate_limiter() -> RateLimiter:
    """获取全局限流器实例"""
    return _rate_limiter