/*

  * 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.eclipse.writers;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.util.Arrays;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.Set;

 import java.util.jar.Attributes;

 import java.util.jar.Manifest;

 import org.apache.maven.artifact.repository.ArtifactRepository;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.apache.maven.plugin.eclipse.EclipseSourceDir;

 import org.apache.maven.plugin.eclipse.Messages;

 import org.apache.maven.plugin.eclipse.writers.wtp.AbstractWtpResourceWriter;

 import org.apache.maven.plugin.ide.IdeDependency;

 import org.apache.maven.project.MavenProject;

 import org.codehaus.plexus.util.IOUtil;

 /**

  * Common behaviours for creating or adapting the manifest files for eclipse environments.

  * 

  * @author <a href="mailto:nir@cfc.at">Richard van Nieuwenhoven </a>

  */

 public abstract class AbstractEclipseManifestWriter

     extends AbstractEclipseWriter

 {

     protected static final String MANIFEST_MF_FILENAME = "MANIFEST.MF";

     protected static final String META_INF_DIRECTORY = "META-INF";

     public AbstractEclipseManifestWriter()

     {

         super();

     }

     /**

      * Aphabeticaly sort the classpath. Do this by splitting it up, sort the entries and gleue them together again.

      * 

      * @param newValue classpath to sort

      * @return the sorted classpath

      */

     protected String orderClasspath( String newValue )

     {

         if ( newValue == null )

         {

             return null;

         }

         String[] entries = newValue.split( " " );

         Arrays.sort( entries );

         StringBuffer buffer = new StringBuffer( newValue.length() );

         for ( int index = 0; index < entries.length; index++ )

         {

             buffer.append( entries[index] );

             buffer.append( ' ' );

         }

         return buffer.toString();

     }

     /**

      * Read and parse the existing manifest file.

      * 

      * @param manifestFile file

      * @return the read manifest

      * @throws IOException if the file could not be read

      */

     protected Manifest readExistingManifest( File manifestFile )

         throws IOException

     {

         if ( !manifestFile.exists() )

         {

             return null;

         }

         Manifest existingManifest = new Manifest();

         FileInputStream inputStream = new FileInputStream( manifestFile );

         try

         {

             existingManifest.read( inputStream );

         }

         finally

         {

             IOUtil.close( inputStream );

         }

         return existingManifest;

     }

     /**

      * Add one dependency to the blank separated classpath stringbuffer. When the project is available in the reactor

      * (current build) then the project is used else the jar representing the artifact. System dependencies will only be

      * included if they are in this project.

      * 

      * @param classpath existing classpath to append

      * @param dependency dependency to append as jar or as project

      */

     protected void addDependencyToClassPath( StringBuffer classpath, IdeDependency dependency )

     {

         if ( !dependency.isTestDependency() && !dependency.isProvided()

             && !dependency.isSystemScopedOutsideProject( this.config.getProject() ) )

         {

             // blank is the separator in manifest classpath's

             if ( classpath.length() != 0 )

             {

                 classpath.append( ' ' );

             }

             // if the dependency is a workspace project add the project and not

             // the jar

             if ( !dependency.isReferencedProject() )

             {

                 classpath.append( dependency.getFile().getName() );

             }

             else

             {

                 classpath.append( dependency.getEclipseProjectName() + ".jar" );

             }

         }

     }

     /**

      * Check if the two manifests are equal. Manifest.equal can not be used because of the special case the Classpath

      * entr, witch must be comaired sorted so that a different oder in the classpath does not result in "not equal".

      * This not not realy correct but in this case it is more important to reduce the number of version-controll files.

      * 

      * @param manifest the new manifest

      * @param existingManifest to compaire the new one with

      * @return are the manifests equal

      */

     protected boolean areManifestsEqual( Manifest manifest, Manifest existingManifest )

     {

         if ( existingManifest == null )

         {

             log.info( "@@@ FALSE - Manifest are not equal because existingManifest is null" );

             return false;

         }

         Set keys = new HashSet();

         Attributes existingMap = existingManifest.getMainAttributes();

         Attributes newMap = manifest.getMainAttributes();

         keys.addAll( existingMap.keySet() );

         keys.addAll( newMap.keySet() );

         Iterator iterator = keys.iterator();

         while ( iterator.hasNext() )

         {

             Attributes.Name key = (Attributes.Name) iterator.next();

             String newValue = (String) newMap.get( key );

             String existingValue = (String) existingMap.get( key );

             // special case classpath... they are equal when there entries

             // are equal

             if ( Attributes.Name.CLASS_PATH.equals( key ) )

             {

                 newValue = orderClasspath( newValue );

                 existingValue = orderClasspath( existingValue );

             }

             if ( ( newValue == null || !newValue.equals( existingValue ) )

                 && ( existingValue == null || !existingValue.equals( newValue ) ) )

             {

                 log.info( "@@@ FALSE - Manifest are not equal because key = " + key + " has existing value = "

                     + existingValue + " and new value = " + newValue + " are different" );

                 return false;

             }

         }

         log.info( "@@@ TRUE - Manifests are equal" );

         return true;

     }

     /**

      * Convert all dependencies in a blank seperated list of jars and projects representing the classpath.

      * 

      * @return the blank separeted classpath string

      */

     protected String constructManifestClasspath()

     {

         StringBuffer stringBuffer = new StringBuffer();

         IdeDependency[] deps = this.config.getDepsOrdered();

         for ( int index = 0; index < deps.length; index++ )

         {

             addDependencyToClassPath( stringBuffer, deps[index] );

         }

         return stringBuffer.toString();

     }

     /**

      * Create a manifest contaigning the required classpath.

      * 

      * @return the newly created manifest

      */

     protected Manifest createNewManifest()

     {

         Manifest manifest = new Manifest();

         manifest.getMainAttributes().put( Attributes.Name.MANIFEST_VERSION, "1.0" );

         manifest.getMainAttributes().put( Attributes.Name.CLASS_PATH, constructManifestClasspath() );

         return manifest;

     }

     /**

      * Verify is the manifest sould be overwritten this sould take in account that the manifest should only be written

      * if the contents of the classpath was changed not the order. The classpath sorting oder should be ignored.

      * 

      * @param manifest the newly created classpath

      * @param manifestFile the file where the manifest

      * @return if the new manifest file must be written

      * @throws MojoExecutionException

      */

     protected boolean shouldNewManifestFileBeWritten( Manifest manifest, File manifestFile )

         throws MojoExecutionException

     {

         try

         {

             Manifest existingManifest = readExistingManifest( manifestFile );

             if ( areManifestsEqual( manifest, existingManifest ) )

             {

                 this.log.info( Messages.getString( "EclipsePlugin.unchangedmanifest", manifestFile.getAbsolutePath() ) );

                 return false;

             }

         }

         catch ( Exception e )

         {

             throw new MojoExecutionException( Messages.getString( "EclipseCleanMojo.nofilefound",

                                                                   manifestFile.getAbsolutePath() ), e );

         }

         return true;

     }

     /**

      * Search the project for the existing META-INF directory where the manifest should be located.

      * 

      * @return the absolute path to the META-INF directory

      * @throws MojoExecutionException

      */

     protected abstract String getMetaInfBaseDirectory( MavenProject project )

         throws MojoExecutionException;

     /**

      * If the existing manifest file located in <code>getMetaInfBaseDirectory()</code> already has a correct

      * MANIFEST_VERSION and CLASS_PATH value then do nothing.

      * <p>

      * Otherwise generate a <b>NEW</b> (i.e the old one is overwritten) which only contains values for MANIFEST_VERSION

      * and CLASS_PATH, all other previous entries are not kept.

      * 

      * @see AbstractWtpResourceWriter#write(EclipseSourceDir[], ArtifactRepository, File)

      * @param sourceDirs all eclipse source directorys

      * @param localRepository the local reposetory

      * @param buildOutputDirectory build output directory (target)

      * @throws MojoExecutionException when writing the config files was not possible

      */

     public void write()

         throws MojoExecutionException

     {

         String metaInfBaseDirectory = getMetaInfBaseDirectory( this.config.getProject() );

         if ( metaInfBaseDirectory == null )

         {

             // TODO: if this really is an error, shouldn't we stop the build??

             throw new MojoExecutionException(

                                               Messages.getString(

                                                                   "EclipseCleanMojo.nofilefound",

                                                                   new Object[] { EclipseManifestWriter.META_INF_DIRECTORY } ) );

         }

         File manifestFile =

             new File( metaInfBaseDirectory + File.separatorChar + EclipseManifestWriter.META_INF_DIRECTORY

                 + File.separatorChar + EclipseManifestWriter.MANIFEST_MF_FILENAME );

         Manifest manifest = createNewManifest();

         if ( shouldNewManifestFileBeWritten( manifest, manifestFile ) )

         {

             log.info( "Writing manifest..." );

             manifestFile.getParentFile().mkdirs();

             try

             {

                 FileOutputStream stream = new FileOutputStream( manifestFile );

                 manifest.write( stream );

                 stream.close();

             }

             catch ( Exception e )

             {

                 this.log.error( Messages.getString( "EclipsePlugin.cantwritetofile",

                                                     new Object[] { manifestFile.getAbsolutePath() } ) );

             }

         }

     }

 }