package org.apache.maven.wrapper;
   
   /*
    * 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.io.File;
  import java.math.BigInteger;
  import java.net.URI;
  import java.security.MessageDigest;
  
  /**
   * @author Hans Dockter
   */
  public class PathAssembler
  {
      public static final String MAVEN_USER_HOME_STRING = "MAVEN_USER_HOME";
  
      public static final String PROJECT_STRING = "PROJECT";
  
      private File mavenUserHome;
  
      public PathAssembler()
      {
      }
  
      public PathAssembler( File mavenUserHome )
      {
          this.mavenUserHome = mavenUserHome;
      }
  
      /**
       * Determines the local locations for the distribution to use given the supplied configuration.
       *
       * @param configuration a wrapper configuration
       * @return the local distribution
       */
      public LocalDistribution getDistribution( WrapperConfiguration configuration )
      {
          String baseName = getDistName( configuration.getDistribution() );
          String distName = removeExtension( baseName );
          String rootDirName = rootDirName( distName, configuration );
          File distDir = new File( getBaseDir( configuration.getDistributionBase() ),
                                   configuration.getDistributionPath() + "/" + rootDirName );
          File distZip = new File( getBaseDir( configuration.getZipBase() ),
                                   configuration.getZipPath() + "/" + rootDirName + "/" + baseName );
          return new LocalDistribution( distDir, distZip );
      }
  
      private String rootDirName( String distName, WrapperConfiguration configuration )
      {
          String urlHash = getMd5Hash( configuration.getDistribution().toString() );
          return String.format( "%s/%s", distName, urlHash );
      }
  
      private String getMd5Hash( String string )
      {
          try
          {
              MessageDigest messageDigest = MessageDigest.getInstance( "MD5" );
              byte[] bytes = string.getBytes();
              messageDigest.update( bytes );
              return new BigInteger( 1, messageDigest.digest() ).toString( 32 );
          }
          catch ( Exception e )
          {
              throw new RuntimeException( "Could not hash input string.", e );
          }
      }
  
      private String removeExtension( String name )
      {
          int p = name.lastIndexOf( "." );
          if ( p < 0 )
          {
              return name;
          }
          return name.substring( 0, p );
      }
  
      private String getDistName( URI distUrl )
      {
          String path = distUrl.getPath();
          int p = path.lastIndexOf( "/" );
         if ( p < 0 )
         {
             return path;
         }
         return path.substring( p + 1 );
     }
 
     private File getBaseDir( String base )
     {
         if ( base.equals( MAVEN_USER_HOME_STRING ) )
         {
             return mavenUserHome;
         }
         else if ( base.equals( PROJECT_STRING ) )
         {
             return new File( System.getProperty( "user.dir" ) );
         }
         else
         {
             throw new RuntimeException( "Base: " + base + " is unknown" );
         }
     }
 
     /**
      * Local distribution
      */
     public class LocalDistribution
     {
         private final File distZip;
 
         private final File distDir;
 
         public LocalDistribution( File distDir, File distZip )
         {
             this.distDir = distDir;
             this.distZip = distZip;
         }
 
         /**
          * Returns the location to install the distribution into.
          * @return the location to install the distribution into
          */
         public File getDistributionDir()
         {
             return distDir;
         }
 
         /**
          * Returns the location to install the distribution ZIP file to.
          * @return the location to install the distribution ZIP file to
          */
         public File getZipFile()
         {
             return distZip;
         }
     }
 }