/*
    * 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.graph;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.version.Version;
  import org.eclipse.aether.version.VersionConstraint;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A node within a dependency graph.
   */
  public final class DefaultDependencyNode implements DependencyNode {
  
      private List<DependencyNode> children;
  
      private Dependency dependency;
  
      private Artifact artifact;
  
      private List<? extends Artifact> relocations;
  
      private Collection<? extends Artifact> aliases;
  
      private VersionConstraint versionConstraint;
  
      private Version version;
  
      private byte managedBits;
  
      private List<RemoteRepository> repositories;
  
      private String context;
  
      private Map<Object, Object> data;
  
      /**
       * Creates a new node with the specified dependency.
       *
       * @param dependency The dependency associated with this node, may be {@code null} for a root node.
       */
      public DefaultDependencyNode(Dependency dependency) {
          this.dependency = dependency;
          artifact = (dependency != null) ? dependency.getArtifact() : null;
          children = new ArrayList<>(0);
          aliases = Collections.emptyList();
          relocations = Collections.emptyList();
          repositories = Collections.emptyList();
          context = "";
          data = Collections.emptyMap();
      }
  
      /**
       * Creates a new root node with the specified artifact as its label. Note that the new node has no dependency, i.e.
       * {@link #getDependency()} will return {@code null}. Put differently, the specified artifact will not be subject to
       * dependency collection/resolution.
       *
       * @param artifact The artifact to use as label for this node, may be {@code null}.
       */
      public DefaultDependencyNode(Artifact artifact) {
          this.artifact = artifact;
          children = new ArrayList<>(0);
          aliases = Collections.emptyList();
          relocations = Collections.emptyList();
          repositories = Collections.emptyList();
          context = "";
          data = Collections.emptyMap();
      }
  
      /**
       * Creates a mostly shallow clone of the specified node. The new node has its own copy of any custom data and
       * initially no children.
       *
       * @param node The node to copy, must not be {@code null}.
      */
     public DefaultDependencyNode(DependencyNode node) {
         dependency = node.getDependency();
         artifact = node.getArtifact();
         children = new ArrayList<>(0);
         setAliases(node.getAliases());
         setRequestContext(node.getRequestContext());
         setManagedBits(node.getManagedBits());
         setRelocations(node.getRelocations());
         setRepositories(node.getRepositories());
         setVersion(node.getVersion());
         setVersionConstraint(node.getVersionConstraint());
         Map<?, ?> data = node.getData();
         setData(data.isEmpty() ? null : new HashMap<>(data));
     }
 
     public List<DependencyNode> getChildren() {
         return children;
     }
 
     public void setChildren(List<DependencyNode> children) {
         if (children == null) {
             this.children = new ArrayList<>(0);
         } else {
             this.children = children;
         }
     }
 
     public Dependency getDependency() {
         return dependency;
     }
 
     public Artifact getArtifact() {
         return artifact;
     }
 
     public void setArtifact(Artifact artifact) {
         if (dependency == null) {
             throw new IllegalStateException("node does not have a dependency");
         }
         dependency = dependency.setArtifact(artifact);
         this.artifact = dependency.getArtifact();
     }
 
     public List<? extends Artifact> getRelocations() {
         return relocations;
     }
 
     /**
      * Sets the sequence of relocations that was followed to resolve this dependency's artifact.
      *
      * @param relocations The sequence of relocations, may be {@code null}.
      */
     public void setRelocations(List<? extends Artifact> relocations) {
         if (relocations == null || relocations.isEmpty()) {
             this.relocations = Collections.emptyList();
         } else {
             this.relocations = relocations;
         }
     }
 
     public Collection<? extends Artifact> getAliases() {
         return aliases;
     }
 
     /**
      * Sets the known aliases for this dependency's artifact.
      *
      * @param aliases The known aliases, may be {@code null}.
      */
     public void setAliases(Collection<? extends Artifact> aliases) {
         if (aliases == null || aliases.isEmpty()) {
             this.aliases = Collections.emptyList();
         } else {
             this.aliases = aliases;
         }
     }
 
     public VersionConstraint getVersionConstraint() {
         return versionConstraint;
     }
 
     /**
      * Sets the version constraint that was parsed from the dependency's version declaration.
      *
      * @param versionConstraint The version constraint for this node, may be {@code null}.
      */
     public void setVersionConstraint(VersionConstraint versionConstraint) {
         this.versionConstraint = versionConstraint;
     }
 
     public Version getVersion() {
         return version;
     }
 
     /**
      * Sets the version that was selected for the dependency's target artifact.
      *
      * @param version The parsed version, may be {@code null}.
      */
     public void setVersion(Version version) {
         this.version = version;
     }
 
     public void setScope(String scope) {
         if (dependency == null) {
             throw new IllegalStateException("node does not have a dependency");
         }
         dependency = dependency.setScope(scope);
     }
 
     public void setOptional(Boolean optional) {
         if (dependency == null) {
             throw new IllegalStateException("node does not have a dependency");
         }
         dependency = dependency.setOptional(optional);
     }
 
     public int getManagedBits() {
         return managedBits;
     }
 
     /**
      * Sets a bit field indicating which attributes of this node were subject to dependency management.
      *
      * @param managedBits The bit field indicating the managed attributes or {@code 0} if dependency management wasn't
      *            applied.
      */
     public void setManagedBits(int managedBits) {
         this.managedBits = (byte) (managedBits & 0x1F);
     }
 
     public List<RemoteRepository> getRepositories() {
         return repositories;
     }
 
     /**
      * Sets the remote repositories from which this node's artifact shall be resolved.
      *
      * @param repositories The remote repositories to use for artifact resolution, may be {@code null}.
      */
     public void setRepositories(List<RemoteRepository> repositories) {
         if (repositories == null || repositories.isEmpty()) {
             this.repositories = Collections.emptyList();
         } else {
             this.repositories = repositories;
         }
     }
 
     public String getRequestContext() {
         return context;
     }
 
     public void setRequestContext(String context) {
         this.context = (context != null) ? context : "";
     }
 
     public Map<Object, Object> getData() {
         return data;
     }
 
     public void setData(Map<Object, Object> data) {
         if (data == null) {
             this.data = Collections.emptyMap();
         } else {
             this.data = data;
         }
     }
 
     public void setData(Object key, Object value) {
         requireNonNull(key, "key cannot be null");
 
         if (value == null) {
             if (!data.isEmpty()) {
                 data.remove(key);
 
                 if (data.isEmpty()) {
                     data = Collections.emptyMap();
                 }
             }
         } else {
             if (data.isEmpty()) {
                 data = new HashMap<>(1, 2); // nodes can be numerous so let's be space conservative
             }
             data.put(key, value);
         }
     }
 
     public boolean accept(DependencyVisitor visitor) {
         if (visitor.visitEnter(this)) {
             for (DependencyNode child : children) {
                 if (!child.accept(visitor)) {
                     break;
                 }
             }
         }
 
         return visitor.visitLeave(this);
     }
 
     @Override
     public String toString() {
         Dependency dep = getDependency();
         if (dep == null) {
             return String.valueOf(getArtifact());
         }
         return dep.toString();
     }
 }