/*
    * 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.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.ListIterator;
  import java.util.Objects;
  
  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 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 (!isLocalRepositoryArtifact(event.getSession(), event.getArtifact())) {
              return;
          }
  
          CollectStepData collectStepTrace = lookupCollectStepData(event.getTrace());
          if (collectStepTrace == null) {
              return;
          }
  
          Artifact resolvedArtifact = event.getArtifact();
          Artifact nodeArtifact = collectStepTrace.getNode().getArtifact();
  
          if (isInScope(resolvedArtifact, nodeArtifact)) {
              Dependency node = collectStepTrace.getNode();
              ArrayList<String> trackingData = new ArrayList<>();
              trackingData.add(node + " (" + collectStepTrace.getContext() + ")");
              String indent = "";
              ListIterator<DependencyNode> iter = collectStepTrace
                      .getPath()
                      .listIterator(collectStepTrace.getPath().size());
              while (iter.hasPrevious()) {
                  DependencyNode curr = iter.previous();
                  indent += "  ";
                  trackingData.add(indent + curr + " (" + collectStepTrace.getContext() + ")");
              }
              try {
                  Path trackingDir =
                          resolvedArtifact.getFile().getParentFile().toPath().resolve(".tracking");
                  Files.createDirectories(trackingDir);
                  Path trackingFile = trackingDir.resolve(collectStepTrace
                          .getPath()
                          .get(0)
                          .getArtifact()
                          .toString()
                          .replace(":", "_"));
                  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 isLocalRepositoryArtifact(RepositorySystemSession session, Artifact artifact) {
         return 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());
     }
 }