/*
    * 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.plugins.shade.resource;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.jar.Attributes;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  import java.util.jar.JarOutputStream;
  import java.util.jar.Manifest;
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  
  /**
   * A resource processor that allows the arbitrary addition of attributes to
   * the first MANIFEST.MF that is found in the set of JARs being processed, or
   * to a newly created manifest for the shaded JAR.
   *
   * @author Jason van Zyl
   * @since 1.2
   */
  public class ManifestResourceTransformer extends AbstractCompatibilityTransformer {
      private final List<String> defaultAttributes =
              Arrays.asList("Export-Package", "Import-Package", "Provide-Capability", "Require-Capability");
  
      // Configuration
      private String mainClass;
  
      private Map<String, Object> manifestEntries;
  
      private List<String> additionalAttributes;
  
      // Fields
      private boolean manifestDiscovered;
  
      private Manifest manifest;
  
      private long time = Long.MIN_VALUE;
  
      private String shade;
  
      public void setMainClass(String mainClass) {
          this.mainClass = mainClass;
      }
  
      public void setManifestEntries(Map<String, Object> manifestEntries) {
          this.manifestEntries = manifestEntries;
      }
  
      public void setAdditionalAttributes(List<String> additionalAttributes) {
          this.additionalAttributes = additionalAttributes;
      }
  
      @Override
      public boolean canTransformResource(String resource) {
          return JarFile.MANIFEST_NAME.equalsIgnoreCase(resource);
      }
  
      @Override
      public void processResource(String resource, InputStream is, List<Relocator> relocators, long time)
              throws IOException {
          // We just want to take the first manifest we come across as that's our project's manifest. This is the behavior
          // now which is situational at best. Right now there is no context passed in with the processing so we cannot
          // tell what artifact is being processed.
          if (!manifestDiscovered) {
              manifest = new Manifest(is);
  
              if (relocators != null && !relocators.isEmpty()) {
                  final Attributes attributes = manifest.getMainAttributes();
  
                  for (final String attribute : defaultAttributes) {
                      final String attributeValue = attributes.getValue(attribute);
                      if (attributeValue != null) {
                          String newValue = relocate(attributeValue, relocators);
                          attributes.putValue(attribute, newValue);
                      }
                  }
  
                  if (additionalAttributes != null) {
                     for (final String attribute : additionalAttributes) {
                         final String attributeValue = attributes.getValue(attribute);
                         if (attributeValue != null) {
                             String newValue = relocate(attributeValue, relocators);
                             attributes.putValue(attribute, newValue);
                         }
                     }
                 }
             }
 
             manifestDiscovered = true;
 
             if (time > this.time) {
                 this.time = time;
             }
         }
     }
 
     @Override
     public boolean hasTransformedResource() {
         return true;
     }
 
     @Override
     public void modifyOutputStream(JarOutputStream jos) throws IOException {
         // If we didn't find a manifest, then let's create one.
         if (manifest == null) {
             manifest = new Manifest();
         }
 
         Attributes attributes = manifest.getMainAttributes();
 
         if (mainClass != null) {
             attributes.put(Attributes.Name.MAIN_CLASS, mainClass);
         }
 
         if (manifestEntries != null) {
             for (Map.Entry<String, Object> entry : manifestEntries.entrySet()) {
                 if (entry.getValue() == null) {
                     attributes.remove(new Attributes.Name(entry.getKey()));
                 } else {
                     attributes.put(new Attributes.Name(entry.getKey()), entry.getValue());
                 }
             }
         }
 
         JarEntry jarEntry = new JarEntry(JarFile.MANIFEST_NAME);
         jarEntry.setTime(time);
         jos.putNextEntry(jarEntry);
         manifest.write(jos);
     }
 
     private String relocate(String originalValue, List<Relocator> relocators) {
         String newValue = originalValue;
         for (Relocator relocator : relocators) {
             String value;
             do {
                 value = newValue;
                 newValue = relocator.relocateClass(value);
             } while (!value.equals(newValue));
         }
         return newValue;
     }
 
     /**
      * The shades to apply this transformer to or no shades if no filter is applied.
      *
      * @param shade {@code null}, {@code jar}, {@code test-jar}, {@code sources-jar} or {@code test-sources-jar}.
      */
     public void setForShade(String shade) {
         this.shade = shade;
     }
 
     public boolean isForShade(String shade) {
         return isUsedForDefaultShading() || this.shade.equalsIgnoreCase(shade);
     }
 
     public boolean isUsedForDefaultShading() {
         return this.shade == null || this.shade.isEmpty();
     }
 }