"""Token-bucket rate limiter for HTTP requests."""
import time
import random
import threading
import logging

logger = logging.getLogger(__name__)


class HTTPRateLimiter:
    """Token-bucket rate limiter with jitter for polite crawling."""

    def __init__(self, rate: float = 1.0, jitter: float = 0.5):
        """
        Args:
            rate: Maximum requests per second
            jitter: Random jitter range in seconds (±jitter/2)
        """
        self.rate = rate
        self.jitter = jitter
        self.min_interval = 1.0 / rate if rate > 0 else 0
        self._last_request = 0.0
        self._lock = threading.Lock()

    def wait(self):
        """Block until the next request is allowed."""
        with self._lock:
            now = time.monotonic()
            elapsed = now - self._last_request
            wait_time = self.min_interval - elapsed

            if self.jitter > 0:
                wait_time += random.uniform(-self.jitter / 2, self.jitter / 2)

            if wait_time > 0:
                logger.debug("Rate limiting: waiting %.2fs", wait_time)
                time.sleep(wait_time)

            self._last_request = time.monotonic()

    def update_rate(self, rate: float):
        """Update the rate limit (e.g., from profile config)."""
        with self._lock:
            self.rate = rate
            self.min_interval = 1.0 / rate if rate > 0 else 0