package org.eclipse.aether.internal.impl.collect;
   
   /*
    * 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.
   */
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.graph.DependencyCycle;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  
  /**
   * @see DefaultDependencyCollector
   */
  final class DefaultDependencyCycle
      implements DependencyCycle
  {
  
      private final List<Dependency> dependencies;
  
      private final int cycleEntry;
  
      DefaultDependencyCycle( NodeStack nodes, int cycleEntry, Dependency dependency )
      {
          // skip root node unless it actually has a dependency or is considered the cycle entry (due to its label)
          int offset = ( cycleEntry > 0 && nodes.get( 0 ).getDependency() == null ) ? 1 : 0;
          Dependency[] dependencies = new Dependency[nodes.size() - offset + 1];
          for ( int i = 0, n = dependencies.length - 1; i < n; i++ )
          {
              DependencyNode node = nodes.get( i + offset );
              dependencies[i] = node.getDependency();
              // when cycle starts at root artifact as opposed to root dependency, synthesize a dependency
              if ( dependencies[i] == null )
              {
                  dependencies[i] = new Dependency( node.getArtifact(), null );
              }
          }
          dependencies[dependencies.length - 1] = dependency;
          this.dependencies = Collections.unmodifiableList( Arrays.asList( dependencies ) );
          this.cycleEntry = cycleEntry;
      }
  
      public List<Dependency> getPrecedingDependencies()
      {
          return dependencies.subList( 0, cycleEntry );
      }
  
      public List<Dependency> getCyclicDependencies()
      {
          return dependencies.subList( cycleEntry, dependencies.size() );
      }
  
      @Override
      public String toString()
      {
          StringBuilder buffer = new StringBuilder( 256 );
          for ( int i = 0, n = dependencies.size(); i < n; i++ )
          {
              if ( i > 0 )
              {
                  buffer.append( " -> " );
              }
              buffer.append( ArtifactIdUtils.toVersionlessId( dependencies.get( i ).getArtifact() ) );
          }
          return buffer.toString();
      }
  
  }