from __future__ import annotations

import time
from collections import OrderedDict

_MsgId = str


class MessageDedup:
    def __init__(self, max_size: int = 500, ttl: int = 300):
        self._max_size = max_size
        self._ttl = ttl
        self._seen: OrderedDict[_MsgId, float] = OrderedDict()

    def is_duplicate(self, msg_id: _MsgId) -> bool:
        self._evict_expired()
        if msg_id in self._seen:
            self._seen.move_to_end(msg_id)
            return True
        return False

    def mark_seen(self, msg_id: _MsgId) -> None:
        self._evict_expired()
        self._seen[msg_id] = time.monotonic()
        self._seen.move_to_end(msg_id)
        while len(self._seen) > self._max_size:
            self._seen.popitem(last=False)

    def check_and_mark(self, msg_id: _MsgId) -> bool:
        if self.is_duplicate(msg_id):
            return True
        self.mark_seen(msg_id)
        return False

    def _evict_expired(self) -> None:
        now = time.monotonic()
        expired = [k for k, ts in self._seen.items() if now - ts > self._ttl]
        for k in expired:
            del self._seen[k]

    def clear(self) -> None:
        self._seen.clear()

    def __len__(self) -> int:
        self._evict_expired()
        return len(self._seen)


dedup = MessageDedup()