package org.apache.maven.plugins.enforcer;
   
   /*
    * 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.
   */
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.factory.ArtifactFactory;
  import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
  import org.apache.maven.artifact.repository.ArtifactRepository;
  import org.apache.maven.artifact.resolver.ArtifactCollector;
  import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
  import org.apache.maven.enforcer.rule.api.EnforcerRule;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
  import org.apache.maven.plugin.logging.Log;
  import org.apache.maven.plugins.enforcer.utils.DependencyVersionMap;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.shared.dependency.tree.DependencyNode;
  import org.apache.maven.shared.dependency.tree.DependencyTreeBuilder;
  import org.apache.maven.shared.dependency.tree.DependencyTreeBuilderException;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
  import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
  import org.codehaus.plexus.i18n.I18N;
  
  /**
   * @author <a href="mailto:rex@e-hoffman.org">Rex Hoffman</a>
   */
  public class DependencyConvergence
      implements EnforcerRule
  {
  
      private static Log log;
  
      private static I18N i18n;
      
      private boolean uniqueVersions; 
  
      public void setUniqueVersions( boolean uniqueVersions )
      {
          this.uniqueVersions = uniqueVersions;
      }
      
      /**
       * Uses the {@link EnforcerRuleHelper} to populate the values of the
       * {@link DependencyTreeBuilder#buildDependencyTree(MavenProject, ArtifactRepository, ArtifactFactory, ArtifactMetadataSource, ArtifactFilter, ArtifactCollector)}
       * factory method. <br/>
       * This method simply exists to hide all the ugly lookup that the {@link EnforcerRuleHelper} has to do.
       * 
       * @param helper
       * @return a Dependency Node which is the root of the project's dependency tree
       * @throws EnforcerRuleException
       */
      private DependencyNode getNode( EnforcerRuleHelper helper )
          throws EnforcerRuleException
      {
          try
          {
              MavenProject project = (MavenProject) helper.evaluate( "${project}" );
              DependencyTreeBuilder dependencyTreeBuilder =
                  (DependencyTreeBuilder) helper.getComponent( DependencyTreeBuilder.class );
              ArtifactRepository repository = (ArtifactRepository) helper.evaluate( "${localRepository}" );
              ArtifactFactory factory = (ArtifactFactory) helper.getComponent( ArtifactFactory.class );
              ArtifactMetadataSource metadataSource =
                  (ArtifactMetadataSource) helper.getComponent( ArtifactMetadataSource.class );
              ArtifactCollector collector = (ArtifactCollector) helper.getComponent( ArtifactCollector.class );
              ArtifactFilter filter = null; // we need to evaluate all scopes
              DependencyNode node =
                  dependencyTreeBuilder.buildDependencyTree( project, repository, factory, metadataSource, filter,
                                                             collector );
              return node;
          }
          catch ( ExpressionEvaluationException e )
          {
              throw new EnforcerRuleException( "Unable to lookup an expression " + e.getLocalizedMessage(), e );
          }
          catch ( ComponentLookupException e )
          {
              throw new EnforcerRuleException( "Unable to lookup a component " + e.getLocalizedMessage(), e );
          }
          catch ( DependencyTreeBuilderException e )
         {
             throw new EnforcerRuleException( "Could not build dependency tree " + e.getLocalizedMessage(), e );
         }
     }
 
     public void execute( EnforcerRuleHelper helper )
         throws EnforcerRuleException
     {
         if ( log == null )
         {
             log = helper.getLog();
         }
         try
         {
             if ( i18n == null )
             {
                 i18n = (I18N) helper.getComponent( I18N.class );
             }
             DependencyNode node = getNode( helper );
             DependencyVersionMap visitor = new DependencyVersionMap( log );
             visitor.setUniqueVersions( uniqueVersions );
             node.accept( visitor );
             List<CharSequence> errorMsgs = new ArrayList<CharSequence>();
             errorMsgs.addAll( getConvergenceErrorMsgs( visitor.getConflictedVersionNumbers() ) );
             for ( CharSequence errorMsg : errorMsgs )
             {
                 log.warn( errorMsg );
             }
             if ( errorMsgs.size() > 0 )
             {
                 throw new EnforcerRuleException( "Failed while enforcing releasability the error(s) are " + errorMsgs );
             }
         }
         catch ( ComponentLookupException e )
         {
             throw new EnforcerRuleException( "Unable to lookup a component " + e.getLocalizedMessage(), e );
         }
         catch ( Exception e )
         {
             throw new EnforcerRuleException( e.getLocalizedMessage(), e );
         }
     }
 
     private String getFullArtifactName( Artifact artifact )
     {
         return artifact.getGroupId() + ":" + artifact.getArtifactId() + ":" + artifact.getVersion();
     }
 
     private StringBuilder buildTreeString( DependencyNode node )
     {
         List<String> loc = new ArrayList<String>();
         DependencyNode currentNode = node;
         while ( currentNode != null )
         {
             loc.add( getFullArtifactName( currentNode.getArtifact() ) );
             currentNode = currentNode.getParent();
         }
         Collections.reverse( loc );
         StringBuilder builder = new StringBuilder();
         for ( int i = 0; i < loc.size(); i++ )
         {
             for ( int j = 0; j < i; j++ )
             {
                 builder.append( "  " );
             }
             builder.append( "+-" + loc.get( i ) );
             builder.append( "\n" );
         }
         return builder;
     }
 
     private List<String> getConvergenceErrorMsgs( List<List<DependencyNode>> errors )
     {
         List<String> errorMsgs = new ArrayList<String>();
         for ( List<DependencyNode> nodeList : errors )
         {
             errorMsgs.add( buildConvergenceErrorMsg( nodeList ) );
         }
         return errorMsgs;
     }
 
     private String buildConvergenceErrorMsg( List<DependencyNode> nodeList )
     {
         StringBuilder builder = new StringBuilder();
         builder.append( "\nDependency convergence error for " + getFullArtifactName( nodeList.get( 0 ).getArtifact() )
             + " paths to dependency are:\n" );
         if ( nodeList.size() > 0 )
         {
             builder.append( buildTreeString( nodeList.get( 0 ) ) );
         }
         for ( DependencyNode node : nodeList.subList( 1, nodeList.size() ) )
         {
             builder.append( "and\n" );
             builder.append( buildTreeString( node ) );
         }
         return builder.toString();
     }
 
     /**
      * If your rule is cacheable, you must return a unique id when parameters or conditions change that would cause the
      * result to be different. Multiple cached results are stored based on their id. The easiest way to do this is to
      * return a hash computed from the values of your parameters. If your rule is not cacheable, then the result here is
      * not important, you may return anything.
      */
     public String getCacheId()
     {
         return "";
     }
 
     /**
      * This tells the system if the results are cacheable at all. Keep in mind that during forked builds and other
      * things, a given rule may be executed more than once for the same project. This means that even things that change
      * from project to project may still be cacheable in certain instances.
      */
     public boolean isCacheable()
     {
         return false;
     }
 
     /**
      * If the rule is cacheable and the same id is found in the cache, the stored results are passed to this method to
      * allow double checking of the results. Most of the time this can be done by generating unique ids, but sometimes
      * the results of objects returned by the helper need to be queried. You may for example, store certain objects in
      * your rule and then query them later.
      */
     public boolean isResultValid( EnforcerRule arg0 )
     {
         return false;
     }
 }