/*
    * 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.gpg;
  
  import java.io.IOException;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.maven.plugin.MojoExecutionException;
  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) throws MojoExecutionException {
          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) {
              throw new MojoExecutionException("failed to execute gpg", e);
          }
  
          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;
         }
     }
 }