/*
    * 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.maven.shared.jar.identification.exposers;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.List;
  import java.util.Locale;
  import java.util.jar.JarEntry;
  
  import org.apache.commons.collections4.Bag;
  import org.apache.commons.collections4.bag.HashBag;
  import org.apache.maven.shared.jar.JarAnalyzer;
  import org.apache.maven.shared.jar.identification.JarIdentification;
  import org.apache.maven.shared.jar.identification.JarIdentificationExposer;
  
  /**
   * Exposer that examines a a JAR and uses the most recent timestamp as a potential version.
   */
  @Singleton
  @Named("timestamp")
  public class TimestampExposer implements JarIdentificationExposer {
      @Override
      public void expose(JarIdentification identification, JarAnalyzer jarAnalyzer) {
          List<JarEntry> entries = jarAnalyzer.getEntries();
          SimpleDateFormat tsformat = new SimpleDateFormat("yyyyMMdd", Locale.US); // $NON-NLS-1$
          Bag<String> timestamps = new HashBag<>();
          for (JarEntry entry : entries) {
              long time = entry.getTime();
              String timestamp = tsformat.format(new Date(time));
              timestamps.add(timestamp);
          }
  
          String ts = "";
          int tsmax = 0;
          for (String timestamp : timestamps) {
              int count = timestamps.getCount(timestamp);
              if (count > tsmax) {
                  ts = timestamp;
                  tsmax = count;
              }
          }
  
          if (ts != null && !ts.isEmpty()) {
              identification.addVersion(ts);
          }
      }
  }