/*
    * Copyright 2012 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.maven.bugzilla;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.reflect.Field;
  import java.util.List;
  import java.util.Properties;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang.reflect.FieldUtils;
  import org.apache.maven.artifact.factory.ArtifactFactory;
  import org.apache.maven.artifact.repository.ArtifactRepository;
  import org.apache.maven.execution.MavenSession;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.apache.maven.plugin.PluginManager;
  import org.apache.maven.plugin.logging.Log;
  import org.apache.maven.plugins.help.DescribeMojo;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.project.MavenProjectBuilder;
  import org.apache.maven.settings.Settings;
  
  /**
   * Displays help on the bugzilla maven plugin.
   *
   * @goal help
   * @requiresProject false
   * @description Displays help on the bugzilla maven plugin.
   * @aggregator
   * @threadSafe
   * @since 1.0
   */
  public final class HelpMojo extends AbstractMojo // NOPMD
  { // NOPMD
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    // ... Mojo infrastructure ..................................................
  
    /**
     * Maven Artifact Factory component.
     *
     * @component
     */
    private ArtifactFactory artifactFactory;
  
    /**
     * The Plugin manager instance used to resolve Plugin descriptors.
     *
     * @component role="org.apache.maven.plugin.PluginManager"
     */
    private PluginManager pluginManager;
  
    /**
     * The project builder instance used to retrieve the super-project instance in
     * the event there is no current MavenProject instance. Some MavenProject
     * instance has to be present to use in the plugin manager APIs.
     *
     * @component role="org.apache.maven.project.MavenProjectBuilder"
     */
    private MavenProjectBuilder projectBuilder;
  
    /**
     * The current project, if there is one. This is listed as optional, since the
     * help plugin should be able to function on its own. If this parameter is
     * empty at execution time, this Mojo will instead use the super-project.
     *
     * @parameter expression="${project}"
     * @readonly
     * @since 1.0
     */
    private MavenProject project;
  
    /**
     * The current user system settings for use in Maven. This is used for plugin
     * manager API calls.
     *
     * @parameter expression="${settings}"
     * @required
     * @readonly
    * @since 1.0
    */
   private Settings settings;
 
   /**
    * The current build session instance. This is used for plugin manager API
    * calls.
    *
    * @parameter expression="${session}"
    * @required
    * @readonly
    * @since 1.0
    */
   private MavenSession session;
 
   /**
    * The local repository ArtifactRepository instance. This is used for plugin
    * manager API calls.
    *
    * @parameter expression="${localRepository}"
    * @required
    * @readonly
    * @since 1.0
    */
   private ArtifactRepository localRepository;
 
   /**
    * Remote repositories used for the project.
    *
    * @parameter expression="${project.remoteArtifactRepositories}"
    * @required
    * @readonly
    * @since 1.0
    */
   private List<?> remoteRepositories;
 
   // ... parameter ............................................................
 
   /**
    * The name of the goal help is requested for. If not given, a list of all
    * goals is returned.
    *
    * @parameter expression="${goal}"
    * @since 1.0
    */
   private String goal;
 
   /**
    * This flag specifies that a detailed (verbose) list of goal (Mojo)
    * information should be given.
    * <p>
    * If information on a goal is requested, the detail value is set to
    * <code>true</code> automatically.
    * </p>
    *
    * @parameter expression="${detail}" default-value="false" alias="full"
    * @since 1.0
    */
   private boolean detail;
 
   /**
    * This flag specifies that a medium list of goal (Mojo) information should be
    * given.
    *
    * @parameter expression="${medium}" default-value="true"
    * @since 1.0
    */
   private boolean medium;
 
   /**
    * This flag specifies that a minimal list of goal (Mojo) information should
    * be given.
    *
    * @parameter expression="${minimal}" default-value="false"
    * @since 1.0
    */
   private boolean minimal;
 
   // ... plugin details .......................................................
 
   /**
    * The plugin identifier containing group, artifact id plus version.
    */
   private String pluginId;
 
   /**
    * The version of this plugin.
    */
   private String version;
 
   /**
    * The sort identifier of the plugin. The name in front of the first dash of
    * the artifact identifier.
    */
   private String pluginShortId;
 
   // ****************************** Initializer *******************************
 
   // ****************************** Constructors ******************************
 
   /**
    * Logger implementation to catch output messages of the describe mojo.
    */
   private final class LogCatcher implements Log
   { // NOPMD
     // ******************************** Fields ********************************
 
     // --- constants ----------------------------------------------------------
 
     // --- members ------------------------------------------------------------
 
     /**
      * The logger to delegate configuration calls.
      */
     private final Log delegate;
 
     // ***************************** Initializer ******************************
 
     // ***************************** Constructors *****************************
 
     private LogCatcher(final Log delegate)
     {
       this.delegate = delegate;
     }
 
     // ***************************** Inner Classes ****************************
 
     // ******************************** Methods *******************************
 
     // --- init ---------------------------------------------------------------
 
     // --- get&set ------------------------------------------------------------
 
     // --- business -----------------------------------------------------------
 
     // --- object basics ------------------------------------------------------
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#isDebugEnabled()
      */
     @Override
     public boolean isDebugEnabled()
     {
       return delegate.isDebugEnabled();
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#debug(java.lang.CharSequence)
      */
     @Override
     public void debug(final CharSequence content)
     {
       delegate.debug(content);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#debug(java.lang.CharSequence,
      *      java.lang.Throwable)
      */
     @Override
     public void debug(final CharSequence content, final Throwable error)
     {
       delegate.debug(content, error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#debug(java.lang.Throwable)
      */
     @Override
     public void debug(final Throwable error)
     {
       delegate.debug(error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#isInfoEnabled()
      */
     @Override
     public boolean isInfoEnabled()
     {
       return delegate.isInfoEnabled();
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#info(java.lang.CharSequence)
      */
     @Override
     public void info(final CharSequence content)
     {
       final String string = content.toString();
 
       if (string.startsWith(pluginId))
       {
         final String strippedContent = stripAllGoals(string);
 
         final String fullContent =
             strippedContent + ".\nFor detailed information on a goal, run"
                 + " 'mvn bugzilla:help -Dgoal=GOAL'.";
         delegate.info(fullContent);
       }
       else if (string.startsWith("Mojo: '" + pluginShortId))
       {
         final String strippedContent = stripSingleGoal(string);
         delegate.info(strippedContent);
       }
       else
       {
         delegate.info(content);
       }
     }
 
     private String stripAllGoals(final String string)
     {
       final String tag = "Goal Prefix: " + pluginShortId;
       final int startIndex = string.indexOf(tag) + tag.length();
       final String fragment = string.substring(startIndex).trim();
       final String replaced = replaceHelpIds(fragment);
       return replaced;
     }
 
     private String replaceHelpIds(final String fragment)
     {
       final String replaced =
           fragment.replaceAll("help:describe", pluginShortId + ":help")
               .replace(" [...]", "");
       return replaced;
     }
 
     private String stripSingleGoal(final String string)
     {
       final String replaced = replaceHelpIds(string);
       return replaced;
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#info(java.lang.CharSequence,
      *      java.lang.Throwable)
      */
     @Override
     public void info(final CharSequence content, final Throwable error)
     {
       delegate.info(content, error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#info(java.lang.Throwable)
      */
     @Override
     public void info(final Throwable error)
     {
       delegate.info(error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#isWarnEnabled()
      */
     @Override
     public boolean isWarnEnabled()
     {
       return delegate.isWarnEnabled();
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#warn(java.lang.CharSequence)
      */
     @Override
     public void warn(final CharSequence content)
     {
       delegate.warn(content);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#warn(java.lang.CharSequence,
      *      java.lang.Throwable)
      */
     @Override
     public void warn(final CharSequence content, final Throwable error)
     {
       delegate.warn(content, error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#warn(java.lang.Throwable)
      */
     @Override
     public void warn(final Throwable error)
     {
       delegate.warn(error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#isErrorEnabled()
      */
     @Override
     public boolean isErrorEnabled()
     {
       return delegate.isErrorEnabled();
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#error(java.lang.CharSequence)
      */
     @Override
     public void error(final CharSequence content)
     {
       delegate.error(content);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#error(java.lang.CharSequence,
      *      java.lang.Throwable)
      */
     @Override
     public void error(final CharSequence content, final Throwable error)
     {
       delegate.error(content, error);
     }
 
     /**
      * {@inheritDoc}
      *
      * @see org.apache.maven.plugin.logging.Log#error(java.lang.Throwable)
      */
     @Override
     public void error(final Throwable error)
     {
       delegate.error(error);
     }
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   // --- business -------------------------------------------------------------
 
   /**
    * {@inheritDoc}
    *
    * @see org.apache.maven.plugin.Mojo#execute()
    */
   @Override
   public void execute() throws MojoExecutionException, MojoFailureException
   {
     initPluginInfo();
 
     if (goal != null)
     {
       this.detail = true;
     }
 
     final DescribeMojo describeMojo = createHelpMojo();
 
     try
     {
       describeMojo.execute();
 
       if (!this.detail)
       {
         provideBestPracticesInformation();
       }
     }
     catch (final MojoExecutionException e)
     {
       throw new MojoExecutionException(createErrorMessage(), e);
     }
     catch (final MojoFailureException e)
     {
       throw new MojoExecutionException(createErrorMessage(), e);
     }
   }
 
   private DescribeMojo createHelpMojo() throws MojoFailureException
   {
     final DescribeMojo describeMojo = new DescribeMojo()
     {
       @Override
       public Log getLog()
       {
         return new LogCatcher(super.getLog());
       }
     };
 
     setHelpMojoValues(describeMojo);
 
     return describeMojo;
   }
 
   private void setHelpMojoValues(final DescribeMojo describeMojo)
     throws MojoFailureException
   {
     setValue(describeMojo, "artifactFactory", artifactFactory);
     setValue(describeMojo, "pluginManager", pluginManager);
     setValue(describeMojo, "projectBuilder", projectBuilder);
 
     setValue(describeMojo, "project", project);
     setValue(describeMojo, "settings", settings);
     setValue(describeMojo, "session", session);
 
     setValue(describeMojo, "localRepository", localRepository);
     setValue(describeMojo, "remoteRepositories", remoteRepositories);
 
     setValue(describeMojo, "plugin", pluginId);
     setValue(describeMojo, "goal", goal);
 
     setValue(describeMojo, "detail", detail);
     setValue(describeMojo, "medium", medium);
     setValue(describeMojo, "minimal", minimal);
   }
 
   private void provideBestPracticesInformation()
   {
     final String server = "https://www.smartics.eu";
     final String product = server + "/plugins/bugzilla-maven-plugin";
     getLog()
         .info(
             "== Best Practices ==\n"
                 + " > Project Setup: mvn bugzilla:init\n"
                 + "   See "
                 + product
                 + '/'
                 + version
                 + "/best-practices.html#Project_Set_Up\n"
                 + "\n"
                 + " > After a Release: mvn bugzilla:sync -DreleasedVersion=VERSION\n"
                 + "   See " + product + '/' + version
                 + "/best-practices.html#Release\n" + "\n"
                 + "For more and detailed information please visit:\n" + "   "
                 + product + '/' + version + "/index.html");
   }
 
   private void initPluginInfo() throws MojoExecutionException
   {
     final Properties properties = new Properties();
     final InputStream inStream =
         getClass().getResourceAsStream("/META-INF/build.properties");
     try
     {
       properties.load(inStream);
 
       final String groupId = properties.getProperty("build.groupId");
       final String artifactId = properties.getProperty("build.artifactId");
       this.version = properties.getProperty("build.version");
 
       this.pluginId = groupId + ':' + artifactId + ':' + version;
 
       final int endIndexShortId = artifactId.indexOf('-');
       this.pluginShortId = artifactId.substring(0, endIndexShortId);
     }
     catch (final IOException e)
     {
       throw new MojoExecutionException("Cannot determine plugin properties.", e);
     }
     finally
     {
       IOUtils.closeQuietly(inStream);
     }
   }
 
   private String createErrorMessage()
   {
     return "Cannot provide help information"
            + (goal != null ? " on " + goal : "") + '.';
   }
 
   private static void setValue(final Object object, final String fieldName,
       final Object value) throws MojoFailureException
   {
     final Class<?> type = object.getClass();
 
     try
     {
       final Field field = FieldUtils.getField(type, fieldName, true);
       field.setAccessible(true);
       field.set(object, value);
     }
     catch (final Exception e)
     {
       throw new MojoFailureException("Cannot change describe mojo's field '"
                                      + fieldName + "'.", e);
     }
   }
 
   // --- object basics --------------------------------------------------------
 
 }