import hashlib
import time
from collections import OrderedDict


class InboundDedupeStore:
    def __init__(self, max_entries: int = 2048, ttl_seconds: int = 300):
        self._store: OrderedDict[str, float] = OrderedDict()
        self.max_entries = max_entries
        self.ttl_seconds = ttl_seconds

    @staticmethod
    def _hash(guid: str, account_id: str) -> str:
        return hashlib.sha256(f"{account_id}:{guid}".encode()).hexdigest()

    def is_duplicate(self, guid: str, account_id: str) -> bool:
        key = self._hash(guid, account_id)
        now = time.time()
        self._evict_expired(now)
        if key in self._store:
            return True
        self._store[key] = now
        while len(self._store) > self.max_entries:
            self._store.popitem(last=False)
        return False

    def _evict_expired(self, now: float):
        deadline = now - self.ttl_seconds
        while self._store:
            _key, ts = next(iter(self._store.items()))
            if ts < deadline:
                self._store.popitem(last=False)
            else:
                break

    def clear(self):
        self._store.clear()

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