/*
    * 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.ByteArrayInputStream;
  import java.io.File;
  import java.io.InputStream;
  
  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.DefaultConsumer;
  
  /**
   * A signer implementation that uses the GnuPG command line executable.
   */
  public class GpgSigner extends AbstractGpgSigner {
      private String executable;
  
      public GpgSigner(String executable) {
          this.executable = executable;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      protected void generateSignatureForFile(File file, File signature) throws MojoExecutionException {
          // ----------------------------------------------------------------------------
          // Set up the command line
          // ----------------------------------------------------------------------------
  
          Commandline cmd = new Commandline();
  
          if (StringUtils.isNotEmpty(executable)) {
              cmd.setExecutable(executable);
          } else {
              cmd.setExecutable("gpg" + (Os.isFamily(Os.FAMILY_WINDOWS) ? ".exe" : ""));
          }
  
          GpgVersionParser versionParser = GpgVersionParser.parse(executable);
  
          GpgVersion gpgVersion = versionParser.getGpgVersion();
          if (gpgVersion == null) {
              throw new MojoExecutionException("Could not determine gpg version");
          }
  
          getLog().debug(gpgVersion.toString());
  
          if (args != null) {
              for (String arg : args) {
                  cmd.createArg().setValue(arg);
              }
          }
  
          if (homeDir != null) {
              cmd.createArg().setValue("--homedir");
              cmd.createArg().setFile(homeDir);
          }
  
          if (gpgVersion.isBefore(GpgVersion.parse("2.1"))) {
              if (useAgent) {
                  cmd.createArg().setValue("--use-agent");
              } else {
                  cmd.createArg().setValue("--no-use-agent");
              }
          }
  
          InputStream in = null;
          if (null != passphrase) {
              if (gpgVersion.isAtLeast(GpgVersion.parse("2.0"))) {
                  // required for option --passphrase-fd since GPG 2.0
                  cmd.createArg().setValue("--batch");
              }
  
              if (gpgVersion.isAtLeast(GpgVersion.parse("2.1"))) {
                  // required for option --passphrase-fd since GPG 2.1
                  cmd.createArg().setValue("--pinentry-mode");
                  cmd.createArg().setValue("loopback");
              }
 
             // make --passphrase-fd effective in gpg2
             cmd.createArg().setValue("--passphrase-fd");
             cmd.createArg().setValue("0");
 
             // Prepare the input stream which will be used to pass the passphrase to the executable
             in = new ByteArrayInputStream(passphrase.getBytes());
         }
 
         if (null != keyname) {
             cmd.createArg().setValue("--local-user");
 
             cmd.createArg().setValue(keyname);
         }
 
         cmd.createArg().setValue("--armor");
 
         cmd.createArg().setValue("--detach-sign");
 
         if (getLog().isDebugEnabled()) {
             // instruct GPG to write status information to stdout
             cmd.createArg().setValue("--status-fd");
             cmd.createArg().setValue("1");
         }
 
         if (!isInteractive) {
             cmd.createArg().setValue("--batch");
             cmd.createArg().setValue("--no-tty");
 
             if (null == passphrase && gpgVersion.isAtLeast(GpgVersion.parse("2.1"))) {
                 // prevent GPG from spawning input prompts in Maven non-interactive mode
                 cmd.createArg().setValue("--pinentry-mode");
                 cmd.createArg().setValue("error");
             }
         }
 
         if (!defaultKeyring) {
             cmd.createArg().setValue("--no-default-keyring");
         }
 
         if (StringUtils.isNotEmpty(secretKeyring)) {
             if (gpgVersion.isBefore(GpgVersion.parse("2.1"))) {
                 cmd.createArg().setValue("--secret-keyring");
                 cmd.createArg().setValue(secretKeyring);
             } else {
                 getLog().warn("'secretKeyring' is an obsolete option and ignored. All secret keys "
                         + "are stored in the ‘private-keys-v1.d’ directory below the GnuPG home directory.");
             }
         }
 
         if (StringUtils.isNotEmpty(publicKeyring)) {
             cmd.createArg().setValue("--keyring");
             cmd.createArg().setValue(publicKeyring);
         }
 
         if ("once".equalsIgnoreCase(lockMode)) {
             cmd.createArg().setValue("--lock-once");
         } else if ("multiple".equalsIgnoreCase(lockMode)) {
             cmd.createArg().setValue("--lock-multiple");
         } else if ("never".equalsIgnoreCase(lockMode)) {
             cmd.createArg().setValue("--lock-never");
         }
 
         cmd.createArg().setValue("--output");
         cmd.createArg().setFile(signature);
 
         cmd.createArg().setFile(file);
 
         // ----------------------------------------------------------------------------
         // Execute the command line
         // ----------------------------------------------------------------------------
 
         try {
             int exitCode = CommandLineUtils.executeCommandLine(cmd, in, new DefaultConsumer(), new DefaultConsumer());
 
             if (exitCode != 0) {
                 throw new MojoExecutionException("Exit code: " + exitCode);
             }
         } catch (CommandLineException e) {
             throw new MojoExecutionException("Unable to execute gpg command", e);
         }
     }
 }