"""Rate limiting: per agent or per tool; reject or queue if exceeded.

Optional; not wired to Executor or Orchestrator by default. Wire by calling
allow(key) before tool invocation or message routing and checking the result.
"""

import time
from collections import defaultdict

from fusionagi._logger import logger


class RateLimiter:
    """Simple in-memory rate limiter: max N calls per window_seconds per key."""

    def __init__(self, max_calls: int = 60, window_seconds: float = 60.0) -> None:
        self._max_calls = max_calls
        self._window = window_seconds
        self._calls: dict[str, list[float]] = defaultdict(list)

    def allow(self, key: str) -> tuple[bool, str]:
        """Record a call for key; return (True, "") or (False, reason)."""
        now = time.monotonic()
        cutoff = now - self._window
        self._calls[key] = [t for t in self._calls[key] if t > cutoff]
        if len(self._calls[key]) >= self._max_calls:
            reason = f"Rate limit exceeded for {key}"
            logger.info("Rate limiter rejected", extra={"key": key, "reason": reason})
            return False, reason
        self._calls[key].append(now)
        return True, ""

    def reset(self, key: str | None = None) -> None:
        """Reset counts for key or all."""
        if key is None:
            self._calls.clear()
        else:
            self._calls.pop(key, None)