/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
 * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
 * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.apache.tuweni.gossip;

import org.apache.tuweni.plumtree.Peer;
import org.apache.tuweni.plumtree.PeerPruning;

import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;

/**
 * Function counting the number of times a peer showed.
 */
final class CountingPeerPruningFunction implements PeerPruning {

  private final int numberOfOccurrences;
  private final Map<Peer, Integer> countingOccurrences = Collections.synchronizedMap(new WeakHashMap<>());

  public CountingPeerPruningFunction(int numberOfOccurrences) {
    this.numberOfOccurrences = numberOfOccurrences;
  }

  @Override
  public boolean prunePeer(Peer peer) {
    Integer currentValue = countingOccurrences.putIfAbsent(peer, 1);
    if (currentValue != null) {
      if (currentValue + 1 >= numberOfOccurrences) {
        countingOccurrences.remove(peer);
        return true;
      }
      countingOccurrences.put(peer, currentValue + 1);
    }

    return false;
  }
}
