/*
    * 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.clean;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.FileSystems;
  import java.nio.file.Path;
  
  import org.apache.maven.execution.MavenSession;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.apache.maven.plugins.annotations.Parameter;
  
  /**
   * Goal which cleans the build.
   * <p>
   * This attempts to clean a project's working directory of the files that were generated at build-time. By default, it
   * discovers and deletes the directories configured in <code>project.build.directory</code>,
   * <code>project.build.outputDirectory</code>, <code>project.build.testOutputDirectory</code>, and
   * <code>project.reporting.outputDirectory</code>.
   * </p>
   * <p>
   * Files outside the default may also be included in the deletion by configuring the <code>filesets</code> tag.
   * </p>
   *
   * @author <a href="mailto:evenisse@maven.org">Emmanuel Venisse</a>
   * @see org.apache.maven.plugins.clean.Fileset
   * @since 2.0
   */
  @Mojo(name = "clean", threadSafe = true)
  public class CleanMojo extends AbstractMojo {
  
      public static final String FAST_MODE_BACKGROUND = "background";
  
      public static final String FAST_MODE_AT_END = "at-end";
  
      public static final String FAST_MODE_DEFER = "defer";
  
      /**
       * This is where build results go.
       */
      @Parameter(defaultValue = "${project.build.directory}", readonly = true, required = true)
      private File directory;
  
      /**
       * This is where compiled classes go.
       */
      @Parameter(defaultValue = "${project.build.outputDirectory}", readonly = true, required = true)
      private File outputDirectory;
  
      /**
       * This is where compiled test classes go.
       */
      @Parameter(defaultValue = "${project.build.testOutputDirectory}", readonly = true, required = true)
      private File testOutputDirectory;
  
      /**
       * This is where the site plugin generates its pages.
       *
       * @since 2.1.1
       */
      @Parameter(defaultValue = "${project.build.outputDirectory}", readonly = true, required = true)
      private File reportDirectory;
  
      /**
       * Sets whether the plugin runs in verbose mode. As of plugin version 2.3, the default value is derived from Maven's
       * global debug flag (compare command line switch <code>-X</code>). <br/>
       * Starting with <b>3.0.0</b> the property has been renamed from <code>clean.verbose</code> to
       * <code>maven.clean.verbose</code>.
       *
       * @since 2.1
       */
      @Parameter(property = "maven.clean.verbose")
      private Boolean verbose;
  
      /**
       * The list of file sets to delete, in addition to the default directories. For example:
       *
       * <pre>
       * &lt;filesets&gt;
       *   &lt;fileset&gt;
      *     &lt;directory&gt;src/main/generated&lt;/directory&gt;
      *     &lt;followSymlinks&gt;false&lt;/followSymlinks&gt;
      *     &lt;useDefaultExcludes&gt;true&lt;/useDefaultExcludes&gt;
      *     &lt;includes&gt;
      *       &lt;include&gt;*.java&lt;/include&gt;
      *     &lt;/includes&gt;
      *     &lt;excludes&gt;
      *       &lt;exclude&gt;Template*&lt;/exclude&gt;
      *     &lt;/excludes&gt;
      *   &lt;/fileset&gt;
      * &lt;/filesets&gt;
      * </pre>
      *
      * @since 2.1
      */
     @Parameter
     private Fileset[] filesets;
 
     /**
      * Sets whether the plugin should follow symbolic links while deleting files from the default output directories of
      * the project. Not following symlinks requires more IO operations and heap memory, regardless whether symlinks are
      * actually present. So projects with a huge output directory that knowingly does not contain symlinks can improve
      * performance by setting this parameter to <code>true</code>. <br/>
      * Starting with <code>3.0.0</code> the property has been renamed from <code>clean.followSymLinks</code> to
      * <code>maven.clean.followSymLinks</code>.
      *
      * @since 2.1
      */
     @Parameter(property = "maven.clean.followSymLinks", defaultValue = "false")
     private boolean followSymLinks;
 
     /**
      * Disables the plugin execution. <br/>
      * Starting with <code>3.0.0</code> the property has been renamed from <code>clean.skip</code> to
      * <code>maven.clean.skip</code>.
      *
      * @since 2.2
      */
     @Parameter(property = "maven.clean.skip", defaultValue = "false")
     private boolean skip;
 
     /**
      * Indicates whether the build will continue even if there are clean errors.
      *
      * @since 2.2
      */
     @Parameter(property = "maven.clean.failOnError", defaultValue = "true")
     private boolean failOnError;
 
     /**
      * Indicates whether the plugin should undertake additional attempts (after a short delay) to delete a file if the
      * first attempt failed. This is meant to help deleting files that are temporarily locked by third-party tools like
      * virus scanners or search indexing.
      *
      * @since 2.4.2
      */
     @Parameter(property = "maven.clean.retryOnError", defaultValue = "true")
     private boolean retryOnError;
 
     /**
      * Disables the deletion of the default output directories configured for a project. If set to <code>true</code>,
      * only the files/directories selected via the parameter {@link #filesets} will be deleted. <br/>
      * Starting with <b>3.0.0</b> the property has been renamed from <code>clean.excludeDefaultDirectories</code> to
      * <code>maven.clean.excludeDefaultDirectories</code>.
      *
      * @since 2.3
      */
     @Parameter(property = "maven.clean.excludeDefaultDirectories", defaultValue = "false")
     private boolean excludeDefaultDirectories;
 
     /**
      * Enables fast clean if possible. If set to <code>true</code>, when the plugin is executed, a directory to
      * be deleted will be atomically moved inside the <code>maven.clean.fastDir</code> directory and a thread will
      * be launched to delete the needed files in the background.  When the build is completed, maven will wait
      * until all the files have been deleted.  If any problem occurs during the atomic move of the directories,
      * the plugin will default to the traditional deletion mechanism.
      *
      * @since 3.2
      */
     @Parameter(property = "maven.clean.fast", defaultValue = "false")
     private boolean fast;
 
     /**
      * When fast clean is specified, the <code>fastDir</code> property will be used as the location where directories
      * to be deleted will be moved prior to background deletion.  If not specified, the
      * <code>${maven.multiModuleProjectDirectory}/target/.clean</code> directory will be used.  If the
      * <code>${build.directory}</code> has been modified, you'll have to adjust this property explicitly.
      * In order for fast clean to work correctly, this directory and the various directories that will be deleted
      * should usually reside on the same volume.  The exact conditions are system-dependent though, but if an atomic
      * move is not supported, the standard deletion mechanism will be used.
      *
      * @see #fast
      * @since 3.2
      */
     @Parameter(property = "maven.clean.fastDir")
     private File fastDir;
 
     /**
      * Mode to use when using fast clean.  Values are: <code>background</code> to start deletion immediately and
      * waiting for all files to be deleted when the session ends, <code>at-end</code> to indicate that the actual
      * deletion should be performed synchronously when the session ends, or <code>defer</code> to specify that
      * the actual file deletion should be started in the background when the session ends.  This should only be used
      * when maven is embedded in a long-running process.
      *
      * @see #fast
      * @since 3.2
      */
     @Parameter(property = "maven.clean.fastMode", defaultValue = FAST_MODE_BACKGROUND)
     private String fastMode;
 
     @Parameter(defaultValue = "${session}", readonly = true)
     private MavenSession session;
 
     /**
      * Deletes file-sets in the following project build directory order: (source) directory, output directory, test
      * directory, report directory, and then the additional file-sets.
      *
      * @throws MojoExecutionException When a directory failed to get deleted.
      * @see org.apache.maven.plugin.Mojo#execute()
      */
     public void execute() throws MojoExecutionException {
         if (skip) {
             getLog().info("Clean is skipped.");
             return;
         }
 
         String multiModuleProjectDirectory =
                 session != null ? session.getSystemProperties().getProperty("maven.multiModuleProjectDirectory") : null;
         Path fastDir;
         if (fast && this.fastDir != null) {
             fastDir = toNullablePath(this.fastDir);
         } else if (fast && multiModuleProjectDirectory != null) {
             fastDir = FileSystems.getDefault()
                     .getPath(multiModuleProjectDirectory)
                     .resolve("target")
                     .resolve(".clean");
         } else {
             fastDir = null;
             if (fast) {
                 getLog().warn("Fast clean requires maven 3.3.1 or newer, "
                         + "or an explicit directory to be specified with the 'fastDir' configuration of "
                         + "this plugin, or the 'maven.clean.fastDir' user property to be set.");
             }
         }
         if (fast
                 && !FAST_MODE_BACKGROUND.equals(fastMode)
                 && !FAST_MODE_AT_END.equals(fastMode)
                 && !FAST_MODE_DEFER.equals(fastMode)) {
             throw new IllegalArgumentException("Illegal value '" + fastMode + "' for fastMode. Allowed values are '"
                     + FAST_MODE_BACKGROUND + "', '" + FAST_MODE_AT_END + "' and '" + FAST_MODE_DEFER + "'.");
         }
 
         Cleaner cleaner = new Cleaner(session, getLog(), isVerbose(), fastDir, fastMode);
 
         try {
             for (Path directoryItem : getDirectories()) {
                 if (directoryItem != null) {
                     cleaner.delete(directoryItem, null, followSymLinks, failOnError, retryOnError);
                 }
             }
 
             if (filesets != null) {
                 for (Fileset fileset : filesets) {
                     if (fileset.getDirectory() == null) {
                         throw new MojoExecutionException("Missing base directory for " + fileset);
                     }
                     final String[] includes = fileset.getIncludes();
                     final String[] excludes = fileset.getExcludes();
                     final boolean useDefaultExcludes = fileset.isUseDefaultExcludes();
                     final GlobSelector selector;
                     if ((includes != null && includes.length != 0)
                             || (excludes != null && excludes.length != 0)
                             || useDefaultExcludes) {
                         selector = new GlobSelector(includes, excludes, useDefaultExcludes);
                     } else {
                         selector = null;
                     }
                     cleaner.delete(
                             fileset.getDirectory().toPath(),
                             selector,
                             fileset.isFollowSymlinks(),
                             failOnError,
                             retryOnError);
                 }
             }
         } catch (IOException e) {
             throw new MojoExecutionException("Failed to clean project: " + e.getMessage(), e);
         }
     }
 
     /**
      * Indicates whether verbose output is enabled.
      *
      * @return <code>true</code> if verbose output is enabled, <code>false</code> otherwise.
      */
     private boolean isVerbose() {
         return (verbose != null) ? verbose : getLog().isDebugEnabled();
     }
 
     /**
      * Gets the directories to clean (if any). The returned array may contain null entries.
      *
      * @return The directories to clean or an empty array if none, never <code>null</code>.
      */
     private Path[] getDirectories() {
         Path[] directories;
         if (excludeDefaultDirectories) {
             directories = new Path[0];
         } else {
             directories = new Path[] {
                 toNullablePath(directory),
                 toNullablePath(outputDirectory),
                 toNullablePath(testOutputDirectory),
                 toNullablePath(reportDirectory)
             };
         }
         return directories;
     }
 
     private static Path toNullablePath(File file) {
         return file != null ? file.toPath() : null;
     }
 }