/*
    * 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.internal.aether;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.UncheckedIOException;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.Objects;
  
  import org.apache.maven.model.InputLocation;
  import org.apache.maven.model.Plugin;
  import org.eclipse.aether.AbstractRepositoryListener;
  import org.eclipse.aether.RepositoryEvent;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.RequestTrace;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.collection.CollectStepData;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.resolution.ArtifactDescriptorRequest;
  import org.eclipse.aether.resolution.ArtifactRequest;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A class building reverse tree using {@link CollectStepData} trace data provided in {@link RepositoryEvent}
   * events fired during collection.
   *
   * @since 3.9.0
   */
  class ReverseTreeRepositoryListener extends AbstractRepositoryListener {
      @Override
      public void artifactResolved(RepositoryEvent event) {
          requireNonNull(event, "event cannot be null");
  
          if (!isLocalRepositoryArtifactOrMissing(event.getSession(), event.getArtifact())) {
              return;
          }
  
          RequestTrace trace = event.getTrace();
  
          CollectStepData collectStepTrace = null;
          ArtifactRequest artifactRequest = null;
          ArtifactDescriptorRequest artifactDescriptorRequest = null;
          Plugin plugin = null;
  
          while (trace != null) {
              Object data = trace.getData();
              if (data instanceof CollectStepData) {
                  collectStepTrace = (CollectStepData) data;
              } else if (data instanceof ArtifactDescriptorRequest) {
                  artifactDescriptorRequest = (ArtifactDescriptorRequest) data;
              } else if (data instanceof ArtifactRequest) {
                  artifactRequest = (ArtifactRequest) data;
              } else if (data instanceof Plugin) {
                  plugin = (Plugin) data;
              }
              trace = trace.getParent();
          }
  
          Path trackingDir;
          boolean missing = event.getFile() == null;
          if (missing) {
              // missing artifact - let's track the path anyway
              File dir = event.getSession().getLocalRepository().getBasedir();
              dir = new File(
                      dir, event.getSession().getLocalRepositoryManager().getPathForLocalArtifact(event.getArtifact()));
              trackingDir = dir.getParentFile().toPath().resolve(".tracking");
          } else {
              trackingDir = event.getFile().getParentFile().toPath().resolve(".tracking");
          }
  
          String baseName;
          String ext = missing ? ".miss" : ".dep";
          Path trackingFile = null;
 
         String indent = "";
         ArrayList<String> trackingData = new ArrayList<>();
 
         if (collectStepTrace == null && plugin != null) {
             ext = ".plugin";
             baseName = plugin.getGroupId() + "_" + plugin.getArtifactId() + "_" + plugin.getVersion();
             trackingFile = trackingDir.resolve(baseName + ext);
             if (Files.exists(trackingFile)) {
                 return;
             }
 
             if (event.getArtifact() != null) {
                 trackingData.add(indent + event.getArtifact());
                 indent += "  ";
             }
             trackingData.add(indent + plugin.getGroupId() + ":" + plugin.getArtifactId() + ":" + plugin.getVersion());
             indent += "  ";
 
             InputLocation location = plugin.getLocation("");
             if (location != null && location.getSource() != null) {
                 trackingData.add(indent + location.getSource().getModelId() + " (implicit)");
                 indent += "  ";
             }
         } else if (collectStepTrace != null) {
             if (collectStepTrace.getPath().get(0).getArtifact() == null) {
                 return;
             }
             baseName = ArtifactIdUtils.toId(collectStepTrace.getPath().get(0).getArtifact())
                     .replace(":", "_");
             trackingFile = trackingDir.resolve(baseName + ext);
             if (Files.exists(trackingFile)) {
                 return;
             }
 
             Artifact resolvedArtifact = event.getArtifact();
             Artifact nodeArtifact = collectStepTrace.getNode().getArtifact();
 
             if (isInScope(resolvedArtifact, nodeArtifact) || "pom".equals(resolvedArtifact.getExtension())) {
                 Dependency node = collectStepTrace.getNode();
                 trackingData.add(resolvedArtifact.toString());
                 indent += "  ";
                 trackingData.add(indent + node + " (" + collectStepTrace.getContext() + ")");
                 ListIterator<DependencyNode> iter = collectStepTrace
                         .getPath()
                         .listIterator(collectStepTrace.getPath().size());
                 while (iter.hasPrevious()) {
                     DependencyNode curr = iter.previous();
                     indent += "  ";
                     trackingData.add(indent + curr + " (" + collectStepTrace.getContext() + ")");
                 }
             }
         }
 
         if (trackingFile == null) {
             return;
         }
         try {
             Files.createDirectories(trackingDir);
 
             trackingData.add("");
             if (!missing) {
                 if (event.getRepository() != null) {
                     trackingData.add("Repository: " + event.getRepository());
                 }
             } else {
                 List<RemoteRepository> repositories = new ArrayList<>();
                 if (artifactRequest != null && artifactRequest.getRepositories() != null) {
                     repositories.addAll(artifactRequest.getRepositories());
                 } else if (artifactDescriptorRequest != null && artifactDescriptorRequest.getRepositories() != null) {
                     repositories.addAll(artifactDescriptorRequest.getRepositories());
                 }
                 if (!repositories.isEmpty()) {
                     trackingData.add("Configured repositories:");
                     for (RemoteRepository r : repositories) {
                         trackingData.add(" - " + r.getId() + " : " + r.getUrl());
                     }
                 } else {
                     trackingData.add("No repositories configured");
                 }
             }
 
             Files.write(trackingFile, trackingData, StandardCharsets.UTF_8);
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
     }
 
     /**
      * Returns {@code true} if passed in artifact is originating from local repository. In other words, we want
      * to process and store tracking information ONLY into local repository, not to any other place. This method
      * filters out currently built artifacts, as events are fired for them as well, but their resolved artifact
      * file would point to checked out source-tree, not the local repository.
      * <p>
      * Visible for testing.
      */
     static boolean isLocalRepositoryArtifactOrMissing(RepositorySystemSession session, Artifact artifact) {
         return artifact.getFile() == null
                 || artifact.getFile()
                         .getPath()
                         .startsWith(session.getLocalRepository().getBasedir().getPath());
     }
 
     /**
      * Unravels trace tree (going upwards from current node), looking for {@link CollectStepData} trace data.
      * This method may return {@code null} if no collect step data found in passed trace data or it's parents.
      * <p>
      * Visible for testing.
      */
     static CollectStepData lookupCollectStepData(RequestTrace trace) {
         CollectStepData collectStepTrace = null;
         while (trace != null) {
             if (trace.getData() instanceof CollectStepData) {
                 collectStepTrace = (CollectStepData) trace.getData();
                 break;
             }
             trace = trace.getParent();
         }
         return collectStepTrace;
     }
 
     /**
      * The event "artifact resolved" if fired WHENEVER an artifact is resolved, BUT it happens also when an artifact
      * descriptor (model, the POM) is being built, and parent (and parent of parent...) is being asked for. Hence, this
      * method "filters" out in WHICH artifact are we interested in, but it intentionally neglects extension as
      * ArtifactDescriptorReader modifies extension to "pom" during collect. So all we have to rely on is GAV only.
      */
     static boolean isInScope(Artifact artifact, Artifact nodeArtifact) {
         return Objects.equals(artifact.getGroupId(), nodeArtifact.getGroupId())
                 && Objects.equals(artifact.getArtifactId(), nodeArtifact.getArtifactId())
                 && Objects.equals(artifact.getVersion(), nodeArtifact.getVersion());
     }
 }