/*
    * 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.eclipse.aether.util.graph.visitor;
  
  import java.util.ArrayDeque;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Deque;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.function.Consumer;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  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.graph.Exclusion;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  import org.eclipse.aether.util.graph.manager.DependencyManagerUtils;
  import org.eclipse.aether.util.graph.transformer.ConflictResolver;
  import org.eclipse.aether.version.VersionConstraint;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A dependency visitor that dumps the graph to any {@link Consumer}{@code <String>}. Meant for diagnostic and testing, as
   * it may output the graph to standard output, error or even some logging interface.
   *
   * @since 1.9.8
   */
  public class DependencyGraphDumper implements DependencyVisitor {
      /**
       * Decorator of "effective dependency": shows effective scope and optionality.
       */
      public static Function<DependencyNode, String> effectiveDependency() {
          return dependencyNode -> {
              Dependency d = dependencyNode.getDependency();
              if (d != null) {
                  if (!d.getScope().isEmpty()) {
                      String result = d.getScope();
                      if (d.isOptional()) {
                          result += ", optional";
                      }
                      return "[" + result + "]";
                  }
              }
              return null;
          };
      }
      /**
       * Decorator of "managed version": explains on nodes what was managed.
       */
      public static Function<DependencyNode, String> premanagedVersion() {
          return dependencyNode -> {
              if (dependencyNode.getArtifact() != null) {
                  String premanagedVersion = DependencyManagerUtils.getPremanagedVersion(dependencyNode);
                  if (premanagedVersion != null
                          && !premanagedVersion.equals(
                                  dependencyNode.getArtifact().getBaseVersion())) {
                      return "(version managed from " + premanagedVersion + ")";
                  }
              }
              return null;
          };
      }
      /**
       * Decorator of "managed scope": explains on nodes what was managed.
       */
      public static Function<DependencyNode, String> premanagedScope() {
          return dependencyNode -> {
              Dependency d = dependencyNode.getDependency();
              if (d != null) {
                  String premanagedScope = DependencyManagerUtils.getPremanagedScope(dependencyNode);
                  if (premanagedScope != null && !premanagedScope.equals(d.getScope())) {
                      return "(scope managed from " + premanagedScope + ")";
                  }
              }
             return null;
         };
     }
     /**
      * Decorator of "managed optionality": explains on nodes what was managed.
      */
     public static Function<DependencyNode, String> premanagedOptional() {
         return dependencyNode -> {
             Dependency d = dependencyNode.getDependency();
             if (d != null) {
                 Boolean premanagedOptional = DependencyManagerUtils.getPremanagedOptional(dependencyNode);
                 if (premanagedOptional != null && !premanagedOptional.equals(d.getOptional())) {
                     return "(optionality managed from " + premanagedOptional + ")";
                 }
             }
             return null;
         };
     }
     /**
      * Decorator of "managed exclusions": explains on nodes what was managed.
      */
     public static Function<DependencyNode, String> premanagedExclusions() {
         return dependencyNode -> {
             Dependency d = dependencyNode.getDependency();
             if (d != null) {
                 Collection<Exclusion> premanagedExclusions =
                         DependencyManagerUtils.getPremanagedExclusions(dependencyNode);
                 if (premanagedExclusions != null && !equals(premanagedExclusions, d.getExclusions())) {
                     return "(exclusions managed from " + premanagedExclusions + ")";
                 }
             }
             return null;
         };
     }
     /**
      * Decorator of "managed properties": explains on nodes what was managed.
      */
     public static Function<DependencyNode, String> premanagedProperties() {
         return dependencyNode -> {
             if (dependencyNode.getArtifact() != null) {
                 Map<String, String> premanagedProperties =
                         DependencyManagerUtils.getPremanagedProperties(dependencyNode);
                 if (premanagedProperties != null
                         && !equals(
                                 premanagedProperties,
                                 dependencyNode.getArtifact().getProperties())) {
                     return "(properties managed from " + premanagedProperties + ")";
                 }
             }
             return null;
         };
     }
     /**
      * Decorator of "range member": explains on nodes what range it participates in.
      */
     public static Function<DependencyNode, String> rangeMember() {
         return dependencyNode -> {
             VersionConstraint constraint = dependencyNode.getVersionConstraint();
             if (constraint != null && constraint.getRange() != null) {
                 return "(range '" + constraint.getRange() + "')";
             }
             return null;
         };
     }
     /**
      * Decorator of "winner node": explains on losers why lost.
      */
     public static Function<DependencyNode, String> winnerNode() {
         return dependencyNode -> {
             if (dependencyNode.getArtifact() != null) {
                 DependencyNode winner =
                         (DependencyNode) dependencyNode.getData().get(ConflictResolver.NODE_DATA_WINNER);
                 if (winner != null) {
                     if (ArtifactIdUtils.equalsId(dependencyNode.getArtifact(), winner.getArtifact())) {
                         return "(nearer exists)";
                     } else {
                         Artifact w = winner.getArtifact();
                         String result = "conflicts with ";
                         if (ArtifactIdUtils.toVersionlessId(dependencyNode.getArtifact())
                                 .equals(ArtifactIdUtils.toVersionlessId(w))) {
                             result += w.getVersion();
                         } else {
                             result += w;
                         }
                         return "(" + result + ")";
                     }
                 }
             }
             return null;
         };
     }
     /**
      * Decorator of "artifact properties": prints out asked properties, if present.
      */
     public static Function<DependencyNode, String> artifactProperties(Collection<String> properties) {
         requireNonNull(properties, "properties");
         return dependencyNode -> {
             if (!properties.isEmpty() && dependencyNode.getDependency() != null) {
                 String props = properties.stream()
                         .map(p -> p + "="
                                 + dependencyNode.getDependency().getArtifact().getProperty(p, "n/a"))
                         .collect(Collectors.joining(","));
                 if (!props.isEmpty()) {
                     return "(" + props + ")";
                 }
             }
             return null;
         };
     }
 
     /**
      * The standard "default" decorators.
      *
      * @since 2.0.0
      */
     private static final List<Function<DependencyNode, String>> DEFAULT_DECORATORS =
             Collections.unmodifiableList(Arrays.asList(
                     effectiveDependency(),
                     premanagedVersion(),
                     premanagedScope(),
                     premanagedOptional(),
                     premanagedExclusions(),
                     premanagedProperties(),
                     rangeMember(),
                     winnerNode()));
 
     /**
      * Extends {@link #DEFAULT_DECORATORS} decorators with passed in ones.
      *
      * @since 2.0.0
      */
     public static List<Function<DependencyNode, String>> defaultsWith(
             Collection<Function<DependencyNode, String>> extras) {
         requireNonNull(extras, "extras");
         ArrayList<Function<DependencyNode, String>> result = new ArrayList<>(DEFAULT_DECORATORS);
         result.addAll(extras);
         return result;
     }
 
     private final Consumer<String> consumer;
 
     private final List<Function<DependencyNode, String>> decorators;
 
     private final Deque<DependencyNode> nodes = new ArrayDeque<>();
 
     /**
      * Creates instance with given consumer.
      *
      * @param consumer The string consumer, must not be {@code null}.
      */
     public DependencyGraphDumper(Consumer<String> consumer) {
         this(consumer, DEFAULT_DECORATORS);
     }
 
     /**
      * Creates instance with given consumer and decorators.
      *
      * @param consumer The string consumer, must not be {@code null}.
      * @param decorators The decorators to apply, must not be {@code null}.
      * @since 2.0.0
      */
     public DependencyGraphDumper(Consumer<String> consumer, Collection<Function<DependencyNode, String>> decorators) {
         this.consumer = requireNonNull(consumer);
         this.decorators = new ArrayList<>(decorators);
     }
 
     @Override
     public boolean visitEnter(DependencyNode node) {
         nodes.push(node);
         consumer.accept(formatLine(nodes));
         return true;
     }
 
     @Override
     public boolean visitLeave(DependencyNode node) {
         if (!nodes.isEmpty()) {
             nodes.pop();
         }
         return true;
     }
 
     protected String formatLine(Deque<DependencyNode> nodes) {
         return formatIndentation(nodes) + formatNode(nodes);
     }
 
     protected String formatIndentation(Deque<DependencyNode> nodes) {
         StringBuilder buffer = new StringBuilder(128);
         Iterator<DependencyNode> iter = nodes.descendingIterator();
         DependencyNode parent = iter.hasNext() ? iter.next() : null;
         DependencyNode child = iter.hasNext() ? iter.next() : null;
         while (parent != null && child != null) {
             boolean lastChild = parent.getChildren().get(parent.getChildren().size() - 1) == child;
             boolean end = child == nodes.peekFirst();
             String indent;
             if (end) {
                 indent = lastChild ? "\\- " : "+- ";
             } else {
                 indent = lastChild ? "   " : "|  ";
             }
             buffer.append(indent);
             parent = child;
             child = iter.hasNext() ? iter.next() : null;
         }
         return buffer.toString();
     }
 
     protected String formatNode(Deque<DependencyNode> nodes) {
         DependencyNode node = requireNonNull(nodes.peek(), "bug: should not happen");
         StringBuilder buffer = new StringBuilder(128);
         Artifact a = node.getArtifact();
         buffer.append(a);
         for (Function<DependencyNode, String> decorator : decorators) {
             String decoration = decorator.apply(node);
             if (decoration != null) {
                 buffer.append(" ").append(decoration);
             }
         }
         return buffer.toString();
     }
 
     private static boolean equals(Collection<Exclusion> c1, Collection<Exclusion> c2) {
         return c1 != null && c2 != null && c1.size() == c2.size() && c1.containsAll(c2);
     }
 
     private static boolean equals(Map<String, String> m1, Map<String, String> m2) {
         return m1 != null
                 && m2 != null
                 && m1.size() == m2.size()
                 && m1.entrySet().stream().allMatch(entry -> Objects.equals(m2.get(entry.getKey()), entry.getValue()));
     }
 }