# rate_limiter.py
import time
from datetime import datetime, timedelta
from typing import Optional
import logging

logger = logging.getLogger(__name__)

class RateLimiter:
    """A rate limiter that enforces a maximum number of requests per time period."""
    
    def __init__(self, max_requests: int, time_window: int):
        """
        Initialize the rate limiter.
        
        Args:
            max_requests: Maximum number of requests allowed in the time window
            time_window: Time window in seconds
        """
        self.max_requests = max_requests
        self.time_window = time_window
        self.requests = []
        self.last_cleanup = datetime.now()
        
    def _cleanup_old_requests(self) -> None:
        """Remove requests older than the time window."""
        now = datetime.now()
        if (now - self.last_cleanup).total_seconds() > self.time_window:
            cutoff = now - timedelta(seconds=self.time_window)
            self.requests = [req for req in self.requests if req > cutoff]
            self.last_cleanup = now
            
    def wait_if_needed(self) -> Optional[float]:
        """
        Wait if necessary to respect the rate limit.
        
        Returns:
            Optional[float]: The number of seconds waited, or None if no wait was needed
        """
        self._cleanup_old_requests()
        
        if len(self.requests) >= self.max_requests:
            oldest_request = self.requests[0]
            wait_time = (datetime.now() - oldest_request).total_seconds()
            if wait_time < self.time_window:
                sleep_time = self.time_window - wait_time
                logger.info(f"Rate limit reached. Waiting {sleep_time:.2f} seconds...")
                time.sleep(sleep_time)
                return sleep_time
                
        self.requests.append(datetime.now())
        return None
        
    def reset(self) -> None:
        """Reset the rate limiter's request history."""
        self.requests = []
        self.last_cleanup = datetime.now()