package org.apache.maven.plugins.gpg;
   
   /*
    * 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.IOException;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.codehaus.plexus.util.Os;
  import org.codehaus.plexus.util.StringUtils;
  import org.codehaus.plexus.util.cli.CommandLineException;
  import org.codehaus.plexus.util.cli.CommandLineUtils;
  import org.codehaus.plexus.util.cli.Commandline;
  import org.codehaus.plexus.util.cli.StreamConsumer;
  
  /**
   * Parse the output of <code>gpg --version</code> and exposes these as dedicated objects.
   * 
   * Supported:
   * <ul>
   *   <li>gpg version, i.e. gpg (GnuPG) 2.2.15</li>
   * </ul>
   * Unsupported:
   * <ul>
   *   <li>libgcrypt version</li>
   *   <li>Home</li>
   *   <li>Supported algorithms (Pubkey, Cipher, Hash, Compression)</li>
   * </ul>
   * 
   * @author Robert Scholte
   * @since 3.0.0
   */
  public class GpgVersionParser
  {
      private final GpgVersionConsumer consumer;
  
      private GpgVersionParser( GpgVersionConsumer consumer )
      {
          this.consumer = consumer;
  
      }
  
      public static GpgVersionParser parse( String executable )
      {
          Commandline cmd = new Commandline();
  
          if ( StringUtils.isNotEmpty( executable ) )
          {
              cmd.setExecutable( executable );
          }
          else
          {
              cmd.setExecutable( "gpg" + ( Os.isFamily( Os.FAMILY_WINDOWS ) ? ".exe" : "" ) );
          }
  
  
          cmd.createArg().setValue( "--version" );
  
          GpgVersionConsumer out = new GpgVersionConsumer();
  
          try
          {
             CommandLineUtils.executeCommandLine( cmd, null, out, null );
          }
          catch ( CommandLineException e )
          {
              // TODO probably a dedicated exception
          }
  
          return new GpgVersionParser( out );
      }
  
      public GpgVersion getGpgVersion()
      {
          return consumer.getGpgVersion();
  
      }
  
      /**
       * Consumes the output of {@code gpg --version}
       *
       * @author Robert Scholte
      * @since 3.0.0
      */
     static class GpgVersionConsumer
         implements StreamConsumer
     {
         private final Pattern gpgVersionPattern = Pattern.compile( "gpg \\([^)]+\\) .+" );
 
         private GpgVersion gpgVersion;
 
         @Override
         public void consumeLine( String line )
             throws IOException
         {
             Matcher m = gpgVersionPattern.matcher( line );
             if ( m.matches() )
             {
                 gpgVersion = GpgVersion.parse( m.group() );
             }
         }
         
         public GpgVersion getGpgVersion()
         {
             return gpgVersion;
         }
     }
 
 }