/*
    * 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.shared.dependency.analyzer;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.io.File;
  import java.io.IOException;
  import java.net.URL;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Set;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.project.MavenProject;
  
  /**
   * <p>DefaultProjectDependencyAnalyzer class.</p>
   *
   * @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>
   */
  @Named
  @Singleton
  public class DefaultProjectDependencyAnalyzer implements ProjectDependencyAnalyzer {
      /**
       * ClassAnalyzer
       */
      @Inject
      private ClassAnalyzer classAnalyzer;
  
      /**
       * DependencyAnalyzer
       */
      @Inject
      private DependencyAnalyzer dependencyAnalyzer;
  
      /** {@inheritDoc} */
      public ProjectDependencyAnalysis analyze(MavenProject project) throws ProjectDependencyAnalyzerException {
          try {
              Map<Artifact, Set<String>> artifactClassMap = buildArtifactClassMap(project);
  
              Set<String> mainDependencyClasses = buildMainDependencyClasses(project);
              Set<String> testDependencyClasses = buildTestDependencyClasses(project);
  
              Set<String> dependencyClasses = new HashSet<>();
              dependencyClasses.addAll(mainDependencyClasses);
              dependencyClasses.addAll(testDependencyClasses);
  
              Set<String> testOnlyDependencyClasses =
                      buildTestOnlyDependencyClasses(mainDependencyClasses, testDependencyClasses);
  
              Map<Artifact, Set<String>> usedArtifacts = buildUsedArtifacts(artifactClassMap, dependencyClasses);
              Set<Artifact> mainUsedArtifacts =
                      buildUsedArtifacts(artifactClassMap, mainDependencyClasses).keySet();
  
              Set<Artifact> testArtifacts = buildUsedArtifacts(artifactClassMap, testOnlyDependencyClasses)
                      .keySet();
              Set<Artifact> testOnlyArtifacts = removeAll(testArtifacts, mainUsedArtifacts);
  
              Set<Artifact> declaredArtifacts = buildDeclaredArtifacts(project);
              Set<Artifact> usedDeclaredArtifacts = new LinkedHashSet<>(declaredArtifacts);
              usedDeclaredArtifacts.retainAll(usedArtifacts.keySet());
  
              Map<Artifact, Set<String>> usedUndeclaredArtifactsWithClasses = new LinkedHashMap<>(usedArtifacts);
              Set<Artifact> usedUndeclaredArtifacts =
                      removeAll(usedUndeclaredArtifactsWithClasses.keySet(), declaredArtifacts);
              usedUndeclaredArtifactsWithClasses.keySet().retainAll(usedUndeclaredArtifacts);
  
              Set<Artifact> unusedDeclaredArtifacts = new LinkedHashSet<>(declaredArtifacts);
              unusedDeclaredArtifacts = removeAll(unusedDeclaredArtifacts, usedArtifacts.keySet());
  
              Set<Artifact> testArtifactsWithNonTestScope = getTestArtifactsWithNonTestScope(testOnlyArtifacts);
  
              return new ProjectDependencyAnalysis(
                     usedDeclaredArtifacts, usedUndeclaredArtifactsWithClasses,
                     unusedDeclaredArtifacts, testArtifactsWithNonTestScope);
         } catch (IOException exception) {
             throw new ProjectDependencyAnalyzerException("Cannot analyze dependencies", exception);
         }
     }
 
     /**
      * This method defines a new way to remove the artifacts by using the conflict id. We don't care about the version
      * here because there can be only 1 for a given artifact anyway.
      *
      * @param start  initial set
      * @param remove set to exclude
      * @return set with remove excluded
      */
     private static Set<Artifact> removeAll(Set<Artifact> start, Set<Artifact> remove) {
         Set<Artifact> results = new LinkedHashSet<>(start.size());
 
         for (Artifact artifact : start) {
             boolean found = false;
 
             for (Artifact artifact2 : remove) {
                 if (artifact.getDependencyConflictId().equals(artifact2.getDependencyConflictId())) {
                     found = true;
                     break;
                 }
             }
 
             if (!found) {
                 results.add(artifact);
             }
         }
 
         return results;
     }
 
     private static Set<Artifact> getTestArtifactsWithNonTestScope(Set<Artifact> testOnlyArtifacts) {
         Set<Artifact> nonTestScopeArtifacts = new LinkedHashSet<>();
 
         for (Artifact artifact : testOnlyArtifacts) {
             if (artifact.getScope().equals("compile")) {
                 nonTestScopeArtifacts.add(artifact);
             }
         }
 
         return nonTestScopeArtifacts;
     }
 
     private Map<Artifact, Set<String>> buildArtifactClassMap(MavenProject project) throws IOException {
         Map<Artifact, Set<String>> artifactClassMap = new LinkedHashMap<>();
 
         Set<Artifact> dependencyArtifacts = project.getArtifacts();
 
         for (Artifact artifact : dependencyArtifacts) {
             File file = artifact.getFile();
 
             if (file != null && file.getName().endsWith(".jar")) {
                 // optimized solution for the jar case
 
                 try (JarFile jarFile = new JarFile(file)) {
                     Enumeration<JarEntry> jarEntries = jarFile.entries();
 
                     Set<String> classes = new HashSet<>();
 
                     while (jarEntries.hasMoreElements()) {
                         String entry = jarEntries.nextElement().getName();
                         if (entry.endsWith(".class")) {
                             String className = entry.replace('/', '.');
                             className = className.substring(0, className.length() - ".class".length());
                             classes.add(className);
                         }
                     }
 
                     artifactClassMap.put(artifact, classes);
                 }
             } else if (file != null && file.isDirectory()) {
                 URL url = file.toURI().toURL();
                 Set<String> classes = classAnalyzer.analyze(url);
 
                 artifactClassMap.put(artifact, classes);
             }
         }
 
         return artifactClassMap;
     }
 
     private static Set<String> buildTestOnlyDependencyClasses(
             Set<String> mainDependencyClasses, Set<String> testDependencyClasses) {
         Set<String> testOnlyDependencyClasses = new HashSet<>(testDependencyClasses);
         testOnlyDependencyClasses.removeAll(mainDependencyClasses);
         return testOnlyDependencyClasses;
     }
 
     private Set<String> buildMainDependencyClasses(MavenProject project) throws IOException {
         String outputDirectory = project.getBuild().getOutputDirectory();
         return buildDependencyClasses(outputDirectory);
     }
 
     private Set<String> buildTestDependencyClasses(MavenProject project) throws IOException {
         String testOutputDirectory = project.getBuild().getTestOutputDirectory();
         return buildDependencyClasses(testOutputDirectory);
     }
 
     private Set<String> buildDependencyClasses(String path) throws IOException {
         URL url = new File(path).toURI().toURL();
 
         return dependencyAnalyzer.analyze(url);
     }
 
     private static Set<Artifact> buildDeclaredArtifacts(MavenProject project) {
         Set<Artifact> declaredArtifacts = project.getDependencyArtifacts();
 
         if (declaredArtifacts == null) {
             declaredArtifacts = Collections.emptySet();
         }
 
         return declaredArtifacts;
     }
 
     private static Map<Artifact, Set<String>> buildUsedArtifacts(
             Map<Artifact, Set<String>> artifactClassMap, Set<String> dependencyClasses) {
         Map<Artifact, Set<String>> usedArtifacts = new HashMap<>();
 
         for (String className : dependencyClasses) {
             Artifact artifact = findArtifactForClassName(artifactClassMap, className);
 
             if (artifact != null) {
                 Set<String> classesFromArtifact = usedArtifacts.get(artifact);
                 if (classesFromArtifact == null) {
                     classesFromArtifact = new HashSet<String>();
                     usedArtifacts.put(artifact, classesFromArtifact);
                 }
                 classesFromArtifact.add(className);
             }
         }
 
         return usedArtifacts;
     }
 
     private static Artifact findArtifactForClassName(Map<Artifact, Set<String>> artifactClassMap, String className) {
         for (Map.Entry<Artifact, Set<String>> entry : artifactClassMap.entrySet()) {
             if (entry.getValue().contains(className)) {
                 return entry.getKey();
             }
         }
 
         return null;
     }
 }