/*
    * 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.plugin;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.inject.Named;
  import javax.inject.Singleton;
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.project.ExtensionDescriptor;
  import org.apache.maven.project.MavenProject;
  import org.codehaus.plexus.classworlds.realm.ClassRealm;
  import org.codehaus.plexus.classworlds.realm.NoSuchRealmException;
  import org.codehaus.plexus.personality.plexus.lifecycle.phase.Disposable;
  
  /**
   * Default extension realm cache implementation. Assumes cached data does not change.
   */
  @Named
  @Singleton
  public class DefaultExtensionRealmCache implements ExtensionRealmCache, Disposable {
      /**
       * CacheKey
       */
      protected static class CacheKey implements Key {
  
          private final List<File> files;
  
          private final List<Long> timestamps;
  
          private final List<Long> sizes;
  
          private final List<String> ids;
  
          private final int hashCode;
  
          public CacheKey(List<Artifact> extensionArtifacts) {
              this.files = new ArrayList<>(extensionArtifacts.size());
              this.timestamps = new ArrayList<>(extensionArtifacts.size());
              this.sizes = new ArrayList<>(extensionArtifacts.size());
              this.ids = new ArrayList<>(extensionArtifacts.size());
  
              for (Artifact artifact : extensionArtifacts) {
                  File file = artifact.getFile();
                  files.add(file);
                  timestamps.add((file != null) ? Long.valueOf(file.lastModified()) : Long.valueOf(0));
                  sizes.add((file != null) ? Long.valueOf(file.length()) : Long.valueOf(0));
                  ids.add(artifact.getVersion());
              }
  
              this.hashCode =
                      31 * files.hashCode() + 31 * ids.hashCode() + 31 * timestamps.hashCode() + 31 * sizes.hashCode();
          }
  
          @Override
          public int hashCode() {
              return hashCode;
          }
  
          @Override
          public boolean equals(Object o) {
              if (o == this) {
                  return true;
              }
  
              if (!(o instanceof CacheKey)) {
                  return false;
              }
  
              CacheKey other = (CacheKey) o;
  
              return ids.equals(other.ids)
                      && files.equals(other.files)
                      && timestamps.equals(other.timestamps)
                      && sizes.equals(other.sizes);
          }
  
          @Override
          public String toString() {
             return files.toString();
         }
     }
 
     protected final Map<Key, CacheRecord> cache = new ConcurrentHashMap<>();
 
     @Override
     public Key createKey(List<Artifact> extensionArtifacts) {
         return new CacheKey(extensionArtifacts);
     }
 
     public CacheRecord get(Key key) {
         return cache.get(key);
     }
 
     public CacheRecord put(
             Key key, ClassRealm extensionRealm, ExtensionDescriptor extensionDescriptor, List<Artifact> artifacts) {
         Objects.requireNonNull(extensionRealm, "extensionRealm cannot be null");
 
         if (cache.containsKey(key)) {
             throw new IllegalStateException("Duplicate extension realm for extension " + key);
         }
 
         CacheRecord record = new CacheRecord(extensionRealm, extensionDescriptor, artifacts);
 
         cache.put(key, record);
 
         return record;
     }
 
     public void flush() {
         for (CacheRecord record : cache.values()) {
             ClassRealm realm = record.getRealm();
             try {
                 realm.getWorld().disposeRealm(realm.getId());
             } catch (NoSuchRealmException e) {
                 // ignore
             }
         }
         cache.clear();
     }
 
     public void register(MavenProject project, Key key, CacheRecord record) {
         // default cache does not track extension usage
     }
 
     public void dispose() {
         flush();
     }
 }