/*
    * 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.resolver.examples.util;
  
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.graph.DependencyVisitor;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  import org.eclipse.aether.util.graph.manager.DependencyManagerUtils;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver;
  
  /**
   * A dependency visitor that dumps the graph to the console.
   */
  public class ConsoleDependencyGraphDumper implements DependencyVisitor {
  
      private final PrintStream out;
  
      private final List<ChildInfo> childInfos = new ArrayList<>();
  
      public ConsoleDependencyGraphDumper() {
          this(null);
      }
  
      public ConsoleDependencyGraphDumper(PrintStream out) {
          this.out = (out != null) ? out : System.out;
      }
  
      public boolean visitEnter(DependencyNode node) {
          out.println(formatIndentation() + formatNode(node));
          childInfos.add(new ChildInfo(node.getChildren().size()));
          return true;
      }
  
      private String formatIndentation() {
          StringBuilder buffer = new StringBuilder(128);
          for (Iterator<ChildInfo> it = childInfos.iterator(); it.hasNext(); ) {
              buffer.append(it.next().formatIndentation(!it.hasNext()));
          }
          return buffer.toString();
      }
  
      private String formatNode(DependencyNode node) {
          StringBuilder buffer = new StringBuilder(128);
          Artifact a = node.getArtifact();
          Dependency d = node.getDependency();
          buffer.append(a);
          if (d != null && d.getScope().length() > 0) {
              buffer.append(" [").append(d.getScope());
              if (d.isOptional()) {
                  buffer.append(", optional");
              }
              buffer.append("]");
          }
          String premanaged = DependencyManagerUtils.getPremanagedVersion(node);
          if (premanaged != null && !premanaged.equals(a.getBaseVersion())) {
              buffer.append(" (version managed from ").append(premanaged).append(")");
          }
  
          premanaged = DependencyManagerUtils.getPremanagedScope(node);
          if (premanaged != null && !premanaged.equals(d.getScope())) {
              buffer.append(" (scope managed from ").append(premanaged).append(")");
          }
          DependencyNode winner = (DependencyNode) node.getData().get(ConflictResolver.NODE_DATA_WINNER);
          if (winner != null && !ArtifactIdUtils.equalsId(a, winner.getArtifact())) {
              Artifact w = winner.getArtifact();
              buffer.append(" (conflicts with ");
              if (ArtifactIdUtils.toVersionlessId(a).equals(ArtifactIdUtils.toVersionlessId(w))) {
                  buffer.append(w.getVersion());
              } else {
                  buffer.append(w);
              }
              buffer.append(")");
          }
          return buffer.toString();
      }
  
     public boolean visitLeave(DependencyNode node) {
         if (!childInfos.isEmpty()) {
             childInfos.remove(childInfos.size() - 1);
         }
         if (!childInfos.isEmpty()) {
             childInfos.get(childInfos.size() - 1).index++;
         }
         return true;
     }
 
     private static class ChildInfo {
 
         final int count;
 
         int index;
 
         ChildInfo(int count) {
             this.count = count;
         }
 
         public String formatIndentation(boolean end) {
             boolean last = index + 1 >= count;
             if (end) {
                 return last ? "\\- " : "+- ";
             }
             return last ? "   " : "|  ";
         }
     }
 }