/*
    * Copyright 2011-2013 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.tagcloud.maven;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ServiceLoader;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.apache.maven.project.MavenProject;
  import org.codehaus.plexus.util.DirectoryScanner;
  
  import de.smartics.maven.util.LoggingUtils;
  import de.smartics.tagcloud.TagCloud;
  import de.smartics.tagcloud.TagCloudFactory;
  import de.smartics.tagcloud.collector.TokenizerTagCollector;
  
  /**
   * Base implementation for tag cloud mojos.
   *
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public abstract class AbstractTagCloudMojo extends AbstractMojo
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The Maven project.
     *
     * @parameter expression="${project}"
     * @required
     * @readonly
     * @since 1.0
     */
    protected MavenProject project;
  
    /**
     * The base directory to scan files.
     *
     * @parameter expression="${project.build.sourceDirectory}
     * @since 1.0
     */
    protected String basedir;
  
    /**
     * The filter for files to include to be passed to the tag collection.
     *
     * @parameter
     * @since 1.0
     */
    protected String[] includes;
  
    /**
     * The filter for files to exclude to be passed to the tag collection..
     *
     * @parameter
     * @since 1.0
     */
    protected String[] excludes;
  
    /**
     * A simple flag to skip the generation of the XML file. If set on the command
     * line use <code>-Dtagcloud.skip</code>.
     *
     * @parameter expression="${tagcloud.skip}" default-value="false"
     * @since 1.0
     */
    protected boolean skip;
  
    /**
     * Specifies the log level used for this plugin.
     * <p>
     * Allowed values are <code>SEVERE</code>, <code>WARNING</code>,
     * <code>INFO</code> and <code>FINEST</code>.
     * </p>
     *
     * @parameter expression="${tagcloud.logLevel}"
    * @since 1.0
    */
   protected String logLevel;
 
   /**
    * Specifies the encoding to be used to read the source files.
    *
    * @parameter expression="${project.build.sourceEncoding}"
    * @since 1.0
    */
   protected String encoding;
 
   /**
    * The filter removes Java reserved words from the tag cloud.
    *
    * @parameter default-value="true"
    * @since 1.0
    */
   protected boolean useJavaReservedWordsFilter;
 
   /**
    * The filter removes usual Java words from the tag cloud.
    *
    * @parameter default-value="false"
    * @since 1.0
    */
   protected boolean useUsualWordsFilter;
 
   /**
    * The list of words to be removed from the tag cloud. This allows an
    * individual configuration.
    *
    * @parameter
    * @since 1.0
    */
   protected String[] wordsToFilter;
 
   // ****************************** Initializer *******************************
 
   // ****************************** Constructors ******************************
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   // --- business -------------------------------------------------------------
 
   /**
    * {@inheritDoc}
    */
   @Override
   public void execute() throws MojoExecutionException, MojoFailureException
   {
     if (!skip)
     {
       if (canBuild())
       {
         runExecution();
       }
       else
       {
         getLog()
             .debug(
                 "Skipping tag cloud since no test classes are provided by this project.");
       }
     }
     else
     {
       getLog().info("Skipping tag cloud XML generation since skip=true.");
     }
   }
 
   private void runExecution() throws MojoExecutionException
   {
     init();
 
     try
     {
       final TagCloud tagCloud = createTagCloud();
       runWith(tagCloud);
     }
     catch (final IOException e)
     {
       throw new MojoExecutionException("Cannot generate tag cloud XML file.", e);
     }
   }
 
   /**
    * Subclasses will get the generated cloud passed by overriding this method.
    *
    * @param tagCloud the generated tag cloud.
    * @throws MojoExecutionException on any problem encountered.
    */
   protected abstract void runWith(TagCloud tagCloud)
     throws MojoExecutionException;
 
   private TagCloud createTagCloud() throws MojoExecutionException, IOException
   {
     final String[] sourceFileNames = calcSourceFiles();
 
     final TagCloudFactory factory = createFactoryInstance();
     final TagCloud tagCloud = factory.createJavaCloud();
     final TokenizerTagCollector tagCollector =
         new TokenizerTagCollector(encoding, tagCloud);
     for (final String sourceFileName : sourceFileNames)
     {
       final File sourceFile = new File(basedir, sourceFileName);
       final InputStream input = FileUtils.openInputStream(sourceFile);
       tagCollector.collect(input);
     }
     return tagCloud;
   }
 
   protected TagCloudFactory createFactoryInstance()
     throws MojoExecutionException
   {
     final ServiceLoader<TagCloudFactory> loader =
         ServiceLoader.load(TagCloudFactory.class);
     for (TagCloudFactory factory : loader)
     {
       factory.setUseJavaReservedWordsFilter(useJavaReservedWordsFilter);
       factory.setUseUsualWordsFilter(useUsualWordsFilter);
       factory.setWordsToFilter(wordsToFilter);
       return factory;
     }
     throw new MojoExecutionException(
         "No TagCloudFactory implementation registered.");
   }
 
   private String[] calcSourceFiles()
   {
     final DirectoryScanner scanner = new DirectoryScanner();
     if (includes != null)
     {
       scanner.setIncludes(includes);
     }
     else
     {
       scanner.setIncludes(new String[]
       { "**/*.java" });
     }
     scanner.setExcludes(excludes);
     scanner.setBasedir(basedir);
     scanner.scan();
     final String[] sourceFiles = scanner.getIncludedFiles();
     return sourceFiles;
   }
 
   private boolean canBuild()
   {
     final String packaging = project.getPackaging();
     return !("pom".equals(packaging) || !new File(project.getBuild()
         .getSourceDirectory()).exists());
   }
 
   private void init() throws MojoExecutionException
   {
     LoggingUtils.configureLogger(getLog(), logLevel);
   }
 
   // --- object basics --------------------------------------------------------
 
 }