from __future__ import annotations

import time


class LoopRateLimiter:
    """循环速率限制：检测持续回显循环并抑制对话。

    当同一会话在短时间内反复收到相同内容的消息时，
    判定为回显循环，对 conversation 进行抑制。
    """

    def __init__(self, max_loops: int = 5, window_s: float = 30.0, cooldown_s: float = 60.0):
        self._max_loops = max_loops
        self._window_s = window_s
        self._cooldown_s = cooldown_s
        self._counters: dict[str, list[float]] = {}
        self._suppressed: dict[str, float] = {}

    def check(self, conversation_key: str, content: str) -> bool:
        """返回 True 表示应该抑制此消息。"""

        if conversation_key in self._suppressed:
            suppressed_at = self._suppressed[conversation_key]
            if time.monotonic() - suppressed_at < self._cooldown_s:
                return True
            del self._suppressed[conversation_key]

        now = time.monotonic()
        if conversation_key not in self._counters:
            self._counters[conversation_key] = []
        timestamps = self._counters[conversation_key]

        timestamps.append(now)
        timestamps[:] = [t for t in timestamps if now - t <= self._window_s]

        if len(timestamps) >= self._max_loops:
            self._suppressed[conversation_key] = now
            self._counters.pop(conversation_key, None)
            return True

        return False

    def is_suppressed(self, conversation_key: str) -> bool:
        if conversation_key in self._suppressed:
            if time.monotonic() - self._suppressed[conversation_key] < self._cooldown_s:
                return True
            del self._suppressed[conversation_key]
        return False

    def reset(self, conversation_key: str) -> None:
        self._counters.pop(conversation_key, None)
        self._suppressed.pop(conversation_key, None)