/*
    * 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.resolver.internal.ant;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.apache.maven.model.Model;
  import org.apache.maven.resolver.internal.ant.types.Pom;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.artifact.DefaultArtifact;
  import org.eclipse.aether.repository.WorkspaceReader;
  import org.eclipse.aether.repository.WorkspaceRepository;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  
  /**
   * Workspace reader caching available POMs and artifacts for ant builds.
   * <p>
   * &lt;pom&gt; elements are cached if they are defined by the 'file'-attribute, as they reference a backing pom.xml file that
   * can be used for resolution with Aether. &lt;artifact&gt; elements are cached if they directly define a 'pom'-attribute
   * or child. The POM may be file-based or in-memory.
   */
  public class ProjectWorkspaceReader implements WorkspaceReader {
  
      private static volatile ProjectWorkspaceReader instance;
  
      private static final Object LOCK = new Object();
  
      private Map<String, Artifact> artifacts = new ConcurrentHashMap<>();
  
      public void addPom(Pom pom) {
          if (pom.getFile() != null) {
              Model model = pom.getModel(pom);
              Artifact aetherArtifact =
                      new DefaultArtifact(model.getGroupId(), model.getArtifactId(), null, "pom", model.getVersion());
              aetherArtifact = aetherArtifact.setFile(pom.getFile());
              String coords = coords(aetherArtifact);
              artifacts.put(coords, aetherArtifact);
          }
      }
  
      public void addArtifact(org.apache.maven.resolver.internal.ant.types.Artifact artifact) {
          if (artifact.getPom() != null) {
              Pom pom = artifact.getPom();
              Artifact aetherArtifact;
              if (pom.getFile() != null) {
                  Model model = pom.getModel(pom);
                  aetherArtifact = new DefaultArtifact(
                          model.getGroupId(),
                          model.getArtifactId(),
                          artifact.getClassifier(),
                          artifact.getType(),
                          model.getVersion());
              } else {
                  aetherArtifact = new DefaultArtifact(
                          pom.getGroupId(),
                          pom.getArtifactId(),
                          artifact.getClassifier(),
                          artifact.getType(),
                          pom.getVersion());
              }
              aetherArtifact = aetherArtifact.setFile(artifact.getFile());
  
              String coords = coords(aetherArtifact);
              artifacts.put(coords, aetherArtifact);
          }
      }
  
      private String coords(Artifact artifact) {
          return ArtifactIdUtils.toId(artifact);
      }
  
      public WorkspaceRepository getRepository() {
          return new WorkspaceRepository("ant");
      }
  
      public File findArtifact(Artifact artifact) {
          artifact = artifacts.get(coords(artifact));
          return (artifact != null) ? artifact.getFile() : null;
      }
 
     public List<String> findVersions(Artifact artifact) {
         List<String> versions = new ArrayList<>();
         for (Artifact art : artifacts.values()) {
             if (ArtifactIdUtils.equalsVersionlessId(artifact, art)) {
                 versions.add(art.getVersion());
             }
         }
         return versions;
     }
 
     ProjectWorkspaceReader() {}
 
     public static ProjectWorkspaceReader getInstance() {
         if (instance == null) {
             synchronized (LOCK) {
                 if (instance == null) {
                     instance = new ProjectWorkspaceReader();
                 }
             }
         }
         return instance;
     }
 
     static void dropInstance() {
         instance = null;
     }
 }