/*
    * 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.dependency.fromDependencies;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.Writer;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.util.ArrayList;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Objects;
  import java.util.Set;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugins.annotations.Component;
  import org.apache.maven.plugins.annotations.LifecyclePhase;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.apache.maven.plugins.annotations.Parameter;
  import org.apache.maven.plugins.annotations.ResolutionScope;
  import org.apache.maven.plugins.dependency.utils.DependencyUtil;
  import org.apache.maven.project.MavenProjectHelper;
  import org.apache.maven.project.ProjectBuildingRequest;
  import org.apache.maven.shared.artifact.filter.collection.ArtifactsFilter;
  import org.apache.maven.shared.transfer.repository.RepositoryManager;
  
  /**
   * This goal outputs a classpath string of dependencies from the local repository to a file or log.
   *
   * @author ankostis
   * @since 2.0-alpha-2
   */
  // CHECKSTYLE_OFF: LineLength
  @Mojo(
          name = "build-classpath",
          requiresDependencyResolution = ResolutionScope.TEST,
          defaultPhase = LifecyclePhase.GENERATE_SOURCES,
          threadSafe = true)
  // CHECKSTYLE_ON: LineLength
  public class BuildClasspathMojo extends AbstractDependencyFilterMojo implements Comparator<Artifact> {
  
      @Parameter(property = "outputEncoding", defaultValue = "${project.reporting.outputEncoding}")
      private String outputEncoding;
  
      /**
       * Strip artifact version during copy (only works if prefix is set)
       */
      @Parameter(property = "mdep.stripVersion", defaultValue = "false")
      private boolean stripVersion = false;
  
      /**
       * Strip artifact classifier during copy (only works if prefix is set)
       */
      @Parameter(property = "mdep.stripClassifier", defaultValue = "false")
      private boolean stripClassifier = false;
  
      /**
       * The prefix to prepend on each dependent artifact. If undefined, the paths refer to the actual files store in the
       * local repository (the stripVersion parameter does nothing then).
       */
      @Parameter(property = "mdep.prefix")
      private String prefix;
  
      /**
       * If defined, the name of a property to which the classpath string will be written.
       */
      @Parameter(property = "mdep.outputProperty")
      private String outputProperty;
  
      /**
       * The file to write the classpath string. If undefined, it just prints the classpath as [INFO].
       */
      @Parameter(property = "mdep.outputFile")
      private File outputFile;
  
     /**
      * If 'true', it skips the up-to-date-check, and always regenerates the classpath file.
      */
     @Parameter(property = "mdep.regenerateFile", defaultValue = "false")
     private boolean regenerateFile;
 
     /**
      * Override the char used between the paths. This field is initialized to contain the first character of the value
      * of the system property file.separator. On UNIX systems the value of this field is '/'; on Microsoft Windows
      * systems it is '\'. The default is File.separator
      *
      * @since 2.0
      */
     @Parameter(property = "mdep.fileSeparator", defaultValue = "")
     private String fileSeparator;
 
     /**
      * Override the char used between path folders. The system-dependent path-separator character. This field is
      * initialized to contain the first character of the value of the system property path.separator. This character is
      * used to separate filenames in a sequence of files given as a path list. On UNIX systems, this character is ':';
      * on Microsoft Windows systems it is ';'.
      *
      * @since 2.0
      */
     @Parameter(property = "mdep.pathSeparator", defaultValue = "")
     private String pathSeparator;
 
     /**
      * Replace the absolute path to the local repo with this property. This field is ignored it prefix is declared. The
      * value will be forced to "${M2_REPO}" if no value is provided AND the attach flag is true.
      *
      * @since 2.0
      */
     @Parameter(property = "mdep.localRepoProperty", defaultValue = "")
     private String localRepoProperty;
 
     /**
      * Attach the classpath file to the main artifact so it can be installed and deployed.
      *
      * @since 2.0
      */
     @Parameter(defaultValue = "false")
     private boolean attach;
 
     /**
      * Write out the classpath in a format compatible with filtering (classpath=xxxxx)
      *
      * @since 2.0
      */
     @Parameter(property = "mdep.outputFilterFile", defaultValue = "false")
     private boolean outputFilterFile;
 
     /**
      * Either append the artifact's baseVersion or uniqueVersion to the filename. Will only be used if
      * {@link #isStripVersion()} is {@code false}.
      *
      * @since 2.6
      */
     @Parameter(property = "mdep.useBaseVersion", defaultValue = "true")
     private boolean useBaseVersion = true;
 
     /**
      * Maven ProjectHelper
      */
     @Component
     private MavenProjectHelper projectHelper;
 
     @Component
     private RepositoryManager repositoryManager;
 
     /**
      * Main entry into mojo. Gets the list of dependencies and iterates to create a classpath.
      *
      * @throws MojoExecutionException with a message if an error occurs.
      * @see #getResolvedDependencies(boolean)
      */
     @Override
     protected void doExecute() throws MojoExecutionException {
         // initialize the separators.
         boolean isFileSepSet = fileSeparator != null && !fileSeparator.isEmpty();
         boolean isPathSepSet = pathSeparator != null && !pathSeparator.isEmpty();
 
         // don't allow them to have absolute paths when they attach.
         if (attach && (localRepoProperty == null || localRepoProperty.isEmpty())) {
             localRepoProperty = "${M2_REPO}";
         }
 
         Set<Artifact> artifacts = getResolvedDependencies(true);
 
         if (artifacts == null || artifacts.isEmpty()) {
             getLog().info("No dependencies found.");
         }
 
         List<Artifact> artList = new ArrayList<>(artifacts);
 
         StringBuilder sb = new StringBuilder();
         Iterator<Artifact> i = artList.iterator();
 
         if (i.hasNext()) {
             appendArtifactPath(i.next(), sb);
 
             while (i.hasNext()) {
                 sb.append(isPathSepSet ? this.pathSeparator : File.pathSeparator);
                 appendArtifactPath(i.next(), sb);
             }
         }
 
         String cpString = sb.toString();
 
         // if file separator is set, I need to replace the default one from all
         // the file paths that were pulled from the artifacts
         if (isFileSepSet) {
             // Escape file separators to be used as literal strings
             final String pattern = Pattern.quote(File.separator);
             final String replacement = Matcher.quoteReplacement(fileSeparator);
             cpString = cpString.replaceAll(pattern, replacement);
         }
 
         // make the string valid for filtering
         if (outputFilterFile) {
             cpString = "classpath=" + cpString;
         }
 
         if (outputProperty != null) {
             getProject().getProperties().setProperty(outputProperty, cpString);
             if (getLog().isDebugEnabled()) {
                 getLog().debug(outputProperty + " = " + cpString);
             }
         }
 
         if (outputFile == null) {
             getLog().info("Dependencies classpath:" + System.lineSeparator() + cpString);
         } else {
             if (regenerateFile || !isUpToDate(cpString)) {
                 storeClasspathFile(cpString, outputFile);
             } else {
                 this.getLog().info("Skipped writing classpath file '" + outputFile + "'.  No changes found.");
             }
         }
         if (attach) {
             attachFile(cpString);
         }
     }
 
     /**
      * @param cpString The classpath.
      * @throws MojoExecutionException in case of an error.
      */
     protected void attachFile(String cpString) throws MojoExecutionException {
         File attachedFile = new File(getProject().getBuild().getDirectory(), "classpath");
         storeClasspathFile(cpString, attachedFile);
 
         projectHelper.attachArtifact(getProject(), attachedFile, "classpath");
     }
 
     /**
      * Appends the artifact path into the specified StringBuilder.
      *
      * @param art {@link Artifact}
      * @param sb {@link StringBuilder}
      */
     protected void appendArtifactPath(Artifact art, StringBuilder sb) {
         if (prefix == null) {
             String file = art.getFile().getPath();
             // substitute the property for the local repo path to make the classpath file portable.
             if (localRepoProperty != null && !localRepoProperty.isEmpty()) {
                 ProjectBuildingRequest projectBuildingRequest = session.getProjectBuildingRequest();
                 File localBasedir = repositoryManager.getLocalRepositoryBasedir(projectBuildingRequest);
 
                 file = file.replace(localBasedir.getAbsolutePath(), localRepoProperty);
             }
             sb.append(file);
         } else {
             // TODO: add param for prepending groupId and version.
             sb.append(prefix);
             sb.append(File.separator);
             sb.append(DependencyUtil.getFormattedFileName(
                     art, this.stripVersion, this.prependGroupId, this.useBaseVersion, this.stripClassifier));
         }
     }
 
     /**
      * Checks that new classpath differs from that found inside the old classpathFile.
      *
      * @return true if the specified classpath equals the one found inside the file, false otherwise (including when
      *         file does not exist but new classpath does).
      */
     private boolean isUpToDate(String cpString) {
         try {
             String oldCp = readClasspathFile();
             return Objects.equals(cpString, oldCp);
         } catch (IOException ex) {
             this.getLog()
                     .warn("Error while reading old classpath file '" + outputFile + "' for up-to-date check: " + ex);
 
             return false;
         }
     }
 
     /**
      * Stores the specified string into that file.
      *
      * @param cpString the string to write into the file
      */
     private void storeClasspathFile(String cpString, File out) throws MojoExecutionException {
         // make sure the parent path exists.
         out.getParentFile().mkdirs();
 
         String encoding = Objects.toString(outputEncoding, StandardCharsets.UTF_8.name());
         try (Writer w = Files.newBufferedWriter(out.toPath(), Charset.forName(encoding))) {
             w.write(cpString);
             getLog().info("Wrote classpath file '" + out + "'.");
         } catch (IOException ex) {
             throw new MojoExecutionException("Error while writing to classpath file '" + out, ex);
         }
     }
 
     /**
      * Reads the file specified by the mojo param 'outputFile' into a string. Assumes the field
      * 'outputFile' is not null.
      *
      * @return the string contained in the classpathFile, if it exists, or null otherwise
      * @throws IOException in case of an error
      */
     protected String readClasspathFile() throws IOException {
         if (outputFile == null) {
             throw new IllegalArgumentException(
                     "The outputFile parameter " + "cannot be null if the file is intended to be read.");
         }
 
         if (!outputFile.isFile()) {
             return null;
         }
 
         String encoding = Objects.toString(outputEncoding, StandardCharsets.UTF_8.name());
 
         try (Stream<String> lines = Files.lines(outputFile.toPath(), Charset.forName(encoding))) {
             return lines.collect(Collectors.joining());
         }
     }
 
     /**
      * Compares artifacts lexicographically, using pattern [group_id][artifact_id][version].
      *
      * @param art1 first object
      * @param art2 second object
      * @return the value <code>0</code> if the argument string is equal to this string; a value less than <code>0</code>
      *         if this string is lexicographically less than the string argument; and a value greater than
      *         <code>0</code> if this string is lexicographically greater than the string argument.
      */
     @Override
     public int compare(Artifact art1, Artifact art2) {
         if (art1 == art2) {
             return 0;
         } else if (art1 == null) {
             return -1;
         } else if (art2 == null) {
             return +1;
         }
 
         String s1 = art1.getGroupId() + art1.getArtifactId() + art1.getVersion();
         String s2 = art2.getGroupId() + art2.getArtifactId() + art2.getVersion();
 
         return s1.compareTo(s2);
     }
 
     @Override
     protected ArtifactsFilter getMarkedArtifactFilter() {
         return null;
     }
 
     /**
      * @param outputFile the outputFile to set
      */
     public void setOutputFile(File outputFile) {
         this.outputFile = outputFile;
     }
 
     /**
      * @param theOutputProperty the outputProperty to set
      */
     public void setOutputProperty(String theOutputProperty) {
         this.outputProperty = theOutputProperty;
     }
 
     /**
      * @param theFileSeparator the fileSeparator to set
      */
     public void setFileSeparator(String theFileSeparator) {
         this.fileSeparator = theFileSeparator;
     }
 
     /**
      * @param thePathSeparator the pathSeparator to set
      */
     public void setPathSeparator(String thePathSeparator) {
         this.pathSeparator = thePathSeparator;
     }
 
     /**
      * @param thePrefix the prefix to set
      */
     public void setPrefix(String thePrefix) {
         this.prefix = thePrefix;
     }
 
     /**
      * @param theRegenerateFile the regenerateFile to set
      */
     public void setRegenerateFile(boolean theRegenerateFile) {
         this.regenerateFile = theRegenerateFile;
     }
 
     /**
      * @return the stripVersion
      */
     public boolean isStripVersion() {
         return this.stripVersion;
     }
 
     /**
      * @param theStripVersion the stripVersion to set
      */
     public void setStripVersion(boolean theStripVersion) {
         this.stripVersion = theStripVersion;
     }
 
     /**
      * @param localRepoProperty {@link #localRepoProperty}
      */
     public void setLocalRepoProperty(String localRepoProperty) {
         this.localRepoProperty = localRepoProperty;
     }
 }