"""Trimmer implementations for Kademlia buckets.

Ported from net.i2p.kademlia.{RejectTrimmer, RandomTrimmer, RandomIfOldTrimmer}.
"""

import random
import time as _time

from i2p_kademlia.kbucket import KBucket, KBucketTrimmer


def _now_ms() -> int:
    return int(_time.time() * 1000)


class RejectTrimmer(KBucketTrimmer):
    """Always reject new entries when bucket is full. Flood-resistant."""

    def trim(self, bucket: KBucket, to_add: bytes) -> bool:
        return False


class RandomTrimmer(KBucketTrimmer):
    """Remove a random entry to make room. Not flood-resistant."""

    def __init__(self, max_size: int) -> None:
        self._max = max_size

    def trim(self, bucket: KBucket, to_add: bytes) -> bool:
        entries = list(bucket.get_entries())
        if len(entries) >= self._max and entries:
            victim = random.choice(entries)
            bucket.remove(victim)
        return True


class RandomIfOldTrimmer(RandomTrimmer):
    """Remove random entry only if bucket hasn't been updated recently (5 min)."""

    _STALE_THRESHOLD = 5 * 60 * 1000  # 5 minutes

    def trim(self, bucket: KBucket, to_add: bytes) -> bool:
        if bucket.last_changed > _now_ms() - self._STALE_THRESHOLD:
            return False  # Bucket is fresh, reject
        return super().trim(bucket, to_add)