/*
    * 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 org.basepom.mojo.duplicatefinder.artifact;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  import static com.google.common.base.Preconditions.checkState;
  import static java.lang.String.format;
  import static org.basepom.mojo.duplicatefinder.artifact.ArtifactHelper.getOutputDirectory;
  import static org.basepom.mojo.duplicatefinder.artifact.ArtifactHelper.getTestOutputDirectory;
  import static org.basepom.mojo.duplicatefinder.artifact.ArtifactHelper.isTestArtifact;
  
  import org.basepom.mojo.duplicatefinder.ClasspathElement;
  import org.basepom.mojo.duplicatefinder.ClasspathElement.ClasspathArtifact;
  import org.basepom.mojo.duplicatefinder.ClasspathElement.ClasspathLocalFolder;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.base.MoreObjects;
  import com.google.common.collect.ImmutableMap;
  import com.google.common.collect.ImmutableMultimap;
  import com.google.common.collect.ImmutableSet;
  import com.google.common.collect.ImmutableSortedSet;
  import com.google.common.collect.Multimap;
  import com.google.common.collect.MultimapBuilder;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.DefaultArtifact;
  import org.apache.maven.artifact.DependencyResolutionRequiredException;
  import org.apache.maven.artifact.versioning.VersionRange;
  import org.apache.maven.project.MavenProject;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Resolves artifact references from the project into local and repository files and folders.
   * <p>
   * Only manages the dependencies because the main project can have multiple (two) folders for the project. This is not supported by this resolver.
   */
  @SuppressFBWarnings("NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE")
  public class ArtifactFileResolver {
  
      private static final Logger LOG = LoggerFactory.getLogger(ArtifactFileResolver.class);
  
      // A BiMultimap would come in really handy here...
      private final Multimap<File, Artifact> localFileArtifactCache;
      private final Map<Artifact, File> localArtifactFileCache;
  
      private final Map<Artifact, File> repoArtifactCache;
  
      // the artifact cache can not be a bimap, because for system artifacts, it is possible that multiple
      // maven coordinates point to the same file.
      private final Multimap<File, Artifact> repoFileCache = MultimapBuilder
              .hashKeys()
              .hashSetValues()
              .build();
      private final boolean preferLocal;
  
      public ArtifactFileResolver(final MavenProject project,
              final boolean preferLocal) throws DependencyResolutionRequiredException, IOException {
          checkNotNull(project, "project is null");
          this.preferLocal = preferLocal;
  
          // This needs to be a multimap, because it is possible by jiggling with classifiers that a local project
          // (with local folders) does map to multiple artifacts and therefore the file <-> artifact relation is not
          // 1:1 but 1:n. As found in https://github.com/basepom/duplicate-finder-maven-plugin/issues/10
          ImmutableMultimap.Builder<File, Artifact> localFileArtifactCacheBuilder = ImmutableMultimap.builder();
  
          // This can not be an immutable map builder, because the map is used for looking up while it is built up.
          this.repoArtifactCache = new HashMap<>(project.getArtifacts().size());
  
          for (final Artifact artifact : project.getArtifacts()) {
              final File repoPath = artifact.getFile().getCanonicalFile();
              final Artifact canonicalizedArtifact = ArtifactFileResolver.canonicalizeArtifact(artifact);
  
              checkState(repoPath.exists(), "Repository Path '%s' does not exist.", repoPath);
              final File oldFile = repoArtifactCache.put(canonicalizedArtifact, repoPath);
              checkState(oldFile == null || oldFile.equals(repoPath), "Already encountered a file for %s: %s", canonicalizedArtifact, oldFile);
              repoFileCache.put(repoPath, canonicalizedArtifact);
          }
  
         for (final MavenProject referencedProject : project.getProjectReferences().values()) {
             // referenced projects only have GAV coordinates but no scope.
             final Set<Artifact> repoArtifacts = findRepoArtifacts(referencedProject, repoArtifactCache);
 
             // This can happen if another sub-project in the reactor is e.g. used as a compiler plugin dependency.
             // In that case, the dependency will show up as a referenced project but not in the artifacts list from the project.
             // Fix up straight from the referenced project.
             if (repoArtifacts.isEmpty()) {
                 LOG.debug(
                         format("Found project reference to %s but no repo reference, probably used in a plugin dependency.", referencedProject.getArtifact()));
             }
 
             for (final Artifact artifact : repoArtifacts) {
 
                 final File outputDir = isTestArtifact(artifact) ? getTestOutputDirectory(referencedProject) : getOutputDirectory(referencedProject);
 
                 if (outputDir.exists()) {
                     localFileArtifactCacheBuilder.put(outputDir, artifact);
                 }
             }
         }
 
         this.localFileArtifactCache = localFileArtifactCacheBuilder.build();
 
         // Flip the File -> Artifact multimap. This also acts as a sanity check because no artifact
         // must be present more than one and the Map.Builder will choke if a key is around more than
         // once.
         ImmutableMap.Builder<Artifact, File> localArtifactFileCacheBuilder = ImmutableMap.builder();
         for (Map.Entry<File, Artifact> entry : localFileArtifactCache.entries()) {
             localArtifactFileCacheBuilder.put(entry.getValue(), entry.getKey());
         }
 
         this.localArtifactFileCache = localArtifactFileCacheBuilder.build();
     }
 
     public ImmutableMultimap<File, Artifact> resolveArtifactsForScopes(final Set<String> scopes) {
         checkNotNull(scopes, "scopes is null");
 
         final ImmutableMultimap.Builder<File, Artifact> inScopeBuilder = ImmutableMultimap.builder();
         for (final Artifact artifact : listArtifacts()) {
             if (artifact.getArtifactHandler().isAddedToClasspath()) {
                 if (scopes.isEmpty() || scopes.contains(artifact.getScope())) {
                     final File file = resolveFileForArtifact(artifact);
                     checkState(file != null, "No file for artifact '%s' found!", artifact);
                     inScopeBuilder.put(file, artifact);
                 }
             }
         }
 
         return inScopeBuilder.build();
     }
 
     public ImmutableSortedSet<ClasspathElement> getClasspathElementsForElements(final Collection<File> elements) {
         final ImmutableSortedSet.Builder<ClasspathElement> builder = ImmutableSortedSet.naturalOrder();
 
         for (final File element : elements) {
             resolveClasspathElementsForFile(element, builder);
         }
         return builder.build();
     }
 
     private void resolveClasspathElementsForFile(final File file, ImmutableSet.Builder<ClasspathElement> builder) {
         checkNotNull(file, "file is null");
 
         if (preferLocal && localFileArtifactCache.containsKey(file)) {
             for (Artifact artifact : localFileArtifactCache.get(file)) {
                 builder.add(new ClasspathArtifact(artifact));
             }
             return;
         }
 
         if (repoFileCache.containsKey(file)) {
             for (Artifact artifact : repoFileCache.get(file)) {
                 builder.add(new ClasspathArtifact(artifact));
             }
             return;
         }
 
         if (localFileArtifactCache.containsKey(file)) {
             for (Artifact artifact : localFileArtifactCache.get(file)) {
                 builder.add(new ClasspathArtifact(artifact));
             }
             return;
         }
 
         builder.add(new ClasspathLocalFolder(file));
     }
 
     private File resolveFileForArtifact(final Artifact artifact) {
         checkNotNull(artifact, "artifact is null");
 
         if (preferLocal && localArtifactFileCache.containsKey(artifact)) {
             return localArtifactFileCache.get(artifact);
         }
 
         if (repoArtifactCache.containsKey(artifact)) {
             return repoArtifactCache.get(artifact);
         }
 
         return localArtifactFileCache.get(artifact);
     }
 
     @VisibleForTesting
     static DefaultArtifact canonicalizeArtifact(final Artifact artifact) {
         final VersionRange versionRange =
                 artifact.getVersionRange() == null ? VersionRange.createFromVersion(artifact.getVersion()) : artifact.getVersionRange();
         String type = MoreObjects.firstNonNull(artifact.getType(), "jar");
         String classifier = artifact.getClassifier();
 
         if ("test-jar".equals(type) && (classifier == null || "tests".equals(classifier))) {
             type = "jar";
             classifier = "tests";
         }
 
         return new DefaultArtifact(artifact.getGroupId(),
                 artifact.getArtifactId(),
                 versionRange,
                 artifact.getScope(),
                 type,
                 classifier,
                 artifact.getArtifactHandler(),
                 artifact.isOptional());
     }
 
     private Set<Artifact> listArtifacts() {
         return ImmutableSet.<Artifact>builder().addAll(localArtifactFileCache.keySet()).addAll(repoArtifactCache.keySet()).build();
     }
 
     private static Set<Artifact> findRepoArtifacts(final MavenProject project, final Map<Artifact, File> repoArtifactCache) {
         final ImmutableSet.Builder<Artifact> builder = ImmutableSet.builder();
 
         for (final Artifact artifact : repoArtifactCache.keySet()) {
             if (Objects.equals(project.getArtifact().getGroupId(), artifact.getGroupId())
                     && Objects.equals(project.getArtifact().getArtifactId(), artifact.getArtifactId())
                     && Objects.equals(project.getArtifact().getBaseVersion(), artifact.getBaseVersion())) {
                 builder.add(artifact);
             }
         }
         return builder.build();
     }
 }