package org.eclipse.aether.internal.test.util;
   
   /*
    * 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.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.StringReader;
  import java.net.URL;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.artifact.DefaultArtifact;
  import org.eclipse.aether.graph.DefaultDependencyNode;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.graph.DependencyNode;
  import org.eclipse.aether.version.InvalidVersionSpecificationException;
  import org.eclipse.aether.version.VersionScheme;
  
  /**
   * Creates a dependency graph from a text description. <h2>Definition</h2> Each (non-empty) line in the input defines
   * one node of the resulting graph:
   * 
   * <pre>
   * line      ::= (indent? ("(null)" | node | reference))? comment?
   * comment   ::= "#" rest-of-line
   * indent    ::= "|  "*  ("+" | "\\") "- "
   * reference ::= "^" id
   * node      ::= coords (range)? space (scope("&lt;" premanagedScope)?)? space "optional"? space
   *                  ("relocations=" coords ("," coords)*)? ("(" id ")")?
   * coords    ::= groupId ":" artifactId (":" extension (":" classifier)?)? ":" version
   * </pre>
   * 
   * The special token {@code (null)} may be used to indicate an "empty" root node with no dependency.
   * <p>
   * If {@code indent} is empty, the line defines the root node. Only one root node may be defined. The level is
   * calculated by the distance from the beginning of the line. One level is three characters of indentation.
   * <p>
   * The {@code ^id} syntax allows to reuse a previously built node to share common sub graphs among different parent
   * nodes.
   * <h2>Example</h2>
   * 
   * <pre>
   * gid:aid:ver
   * +- gid:aid2:ver scope
   * |  \- gid:aid3:ver        (id1)    # assign id for reference below
   * +- gid:aid4:ext:ver scope
   * \- ^id1                            # reuse previous node
   * </pre>
   * 
   * <h2>Multiple definitions in one resource</h2>
   * <p>
   * By using {@link #parseMultiResource(String)}, definitions divided by a line beginning with "---" can be read from the
   * same resource. The rest of the line is ignored.
   * <h2>Substitutions</h2>
   * <p>
   * You may define substitutions (see {@link #setSubstitutions(String...)},
   * {@link #DependencyGraphParser(String, Collection)}). Every '%s' in the definition will be substituted by the next
   * String in the defined substitutions.
   * <h3>Example</h3>
   * 
   * <pre>
   * parser.setSubstitutions( &quot;foo&quot;, &quot;bar&quot; );
   * String def = &quot;gid:%s:ext:ver\n&quot; + &quot;+- gid:%s:ext:ver&quot;;
   * </pre>
   * 
   * The first node will have "foo" as its artifact id, the second node (child to the first) will have "bar" as its
   * artifact id.
   */
  public class DependencyGraphParser
  {
  
      private final VersionScheme versionScheme;
 
     private final String prefix;
 
     private Collection<String> substitutions;
 
     /**
      * Create a parser with the given prefix and the given substitution strings.
      * 
      * @see DependencyGraphParser#parseResource(String)
      */
     public DependencyGraphParser( String prefix, Collection<String> substitutions )
     {
         this.prefix = prefix;
         this.substitutions = substitutions;
         versionScheme = new TestVersionScheme();
     }
 
     /**
      * Create a parser with the given prefix.
      * 
      * @see DependencyGraphParser#parseResource(String)
      */
     public DependencyGraphParser( String prefix )
     {
         this( prefix, Collections.<String>emptyList() );
     }
 
     /**
      * Create a parser with an empty prefix.
      */
     public DependencyGraphParser()
     {
         this( "" );
     }
 
     /**
      * Parse the given graph definition.
      */
     public DependencyNode parseLiteral( String dependencyGraph )
         throws IOException
     {
         BufferedReader reader = new BufferedReader( new StringReader( dependencyGraph ) );
         DependencyNode node = parse( reader );
         reader.close();
         return node;
     }
 
     /**
      * Parse the graph definition read from the given classpath resource. If a prefix is set, this method will load the
      * resource from 'prefix + resource'.
      */
     public DependencyNode parseResource( String resource )
         throws IOException
     {
         URL res = this.getClass().getClassLoader().getResource( prefix + resource );
         if ( res == null )
         {
             throw new IOException( "Could not find classpath resource " + prefix + resource );
         }
         return parse( res );
     }
 
     /**
      * Parse multiple graphs in one resource, divided by "---".
      */
     public List<DependencyNode> parseMultiResource( String resource )
         throws IOException
     {
         URL res = this.getClass().getClassLoader().getResource( prefix + resource );
         if ( res == null )
         {
             throw new IOException( "Could not find classpath resource " + prefix + resource );
         }
 
         BufferedReader reader = new BufferedReader( new InputStreamReader( res.openStream(), StandardCharsets.UTF_8 ) );
 
         List<DependencyNode> ret = new ArrayList<>();
         DependencyNode root = null;
         while ( ( root = parse( reader ) ) != null )
         {
             ret.add( root );
         }
         return ret;
     }
 
     /**
      * Parse the graph definition read from the given URL.
      */
     public DependencyNode parse( URL resource )
         throws IOException
     {
         BufferedReader reader = null;
         try
         {
             reader = new BufferedReader( new InputStreamReader( resource.openStream(), StandardCharsets.UTF_8 ) );
             return parse( reader );
         }
         finally
         {
             try
             {
                 if ( reader != null )
                 {
                     reader.close();
                     reader = null;
                 }
             }
             catch ( final IOException e )
             {
                 // Suppressed due to an exception already thrown in the try block.
             }
         }
     }
 
     private DependencyNode parse( BufferedReader in )
         throws IOException
     {
         Iterator<String> substitutionIterator = ( substitutions != null ) ? substitutions.iterator() : null;
 
         String line = null;
 
         DependencyNode root = null;
         DependencyNode node = null;
         int prevLevel = 0;
 
         Map<String, DependencyNode> nodes = new HashMap<>();
         LinkedList<DependencyNode> stack = new LinkedList<>();
         boolean isRootNode = true;
 
         while ( ( line = in.readLine() ) != null )
         {
             line = cutComment( line );
 
             if ( isEmpty( line ) )
             {
                 // skip empty line
                 continue;
             }
 
             if ( isEOFMarker( line ) )
             {
                 // stop parsing
                 break;
             }
 
             while ( line.contains( "%s" ) )
             {
                 if ( !substitutionIterator.hasNext() )
                 {
                     throw new IllegalStateException( "not enough substitutions to fill placeholders" );
                 }
                 line = line.replaceFirst( "%s", substitutionIterator.next() );
             }
 
             LineContext ctx = createContext( line );
             if ( prevLevel < ctx.getLevel() )
             {
                 // previous node is new parent
                 stack.add( node );
             }
 
             // get to real parent
             while ( prevLevel > ctx.getLevel() )
             {
                 stack.removeLast();
                 prevLevel -= 1;
             }
 
             prevLevel = ctx.getLevel();
 
             if ( ctx.getDefinition() != null && ctx.getDefinition().reference != null )
             {
                 String reference = ctx.getDefinition().reference;
                 DependencyNode child = nodes.get( reference );
                 if ( child == null )
                 {
                     throw new IllegalStateException( "undefined reference " + reference );
                 }
                 node.getChildren().add( child );
             }
             else
             {
 
                 node = build( isRootNode ? null : stack.getLast(), ctx, isRootNode );
 
                 if ( isRootNode )
                 {
                     root = node;
                     isRootNode = false;
                 }
 
                 if ( ctx.getDefinition() != null && ctx.getDefinition().id != null )
                 {
                     nodes.put( ctx.getDefinition().id, node );
                 }
             }
         }
 
         return root;
     }
 
     private boolean isEOFMarker( String line )
     {
         return line.startsWith( "---" );
     }
 
     private static boolean isEmpty( String line )
     {
         return line == null || line.length() == 0;
     }
 
     private static String cutComment( String line )
     {
         int idx = line.indexOf( '#' );
 
         if ( idx != -1 )
         {
             line = line.substring( 0, idx );
         }
 
         return line;
     }
 
     private DependencyNode build( DependencyNode parent, LineContext ctx, boolean isRoot )
     {
         NodeDefinition def = ctx.getDefinition();
         if ( !isRoot && parent == null )
         {
             throw new IllegalStateException( "dangling node: " + def );
         }
         else if ( ctx.getLevel() == 0 && parent != null )
         {
             throw new IllegalStateException( "inconsistent leveling (parent for level 0?): " + def );
         }
 
         DefaultDependencyNode node;
         if ( def != null )
         {
             DefaultArtifact artifact = new DefaultArtifact( def.coords, def.properties );
             Dependency dependency = new Dependency( artifact, def.scope, def.optional );
             node = new DefaultDependencyNode( dependency );
             int managedBits = 0;
             if ( def.premanagedScope != null )
             {
                 managedBits |= DependencyNode.MANAGED_SCOPE;
                 node.setData( "premanaged.scope", def.premanagedScope );
             }
             if ( def.premanagedVersion != null )
             {
                 managedBits |= DependencyNode.MANAGED_VERSION;
                 node.setData( "premanaged.version", def.premanagedVersion );
             }
             node.setManagedBits( managedBits );
             if ( def.relocations != null )
             {
                 List<Artifact> relocations = new ArrayList<>();
                 for ( String relocation : def.relocations )
                 {
                     relocations.add( new DefaultArtifact( relocation ) );
                 }
                 node.setRelocations( relocations );
             }
             try
             {
                 node.setVersion( versionScheme.parseVersion( artifact.getVersion() ) );
                 node.setVersionConstraint( versionScheme.parseVersionConstraint( def.range != null ? def.range
                                 : artifact.getVersion() ) );
             }
             catch ( InvalidVersionSpecificationException e )
             {
                 throw new IllegalArgumentException( "bad version: " + e.getMessage(), e );
             }
         }
         else
         {
             node = new DefaultDependencyNode( (Dependency) null );
         }
 
         if ( parent != null )
         {
             parent.getChildren().add( node );
         }
 
         return node;
     }
 
     public String dump( DependencyNode root )
     {
         StringBuilder ret = new StringBuilder();
 
         List<NodeEntry> entries = new ArrayList<>();
 
         addNode( root, 0, entries );
 
         for ( NodeEntry nodeEntry : entries )
         {
             char[] level = new char[( nodeEntry.getLevel() * 3 )];
             Arrays.fill( level, ' ' );
 
             if ( level.length != 0 )
             {
                 level[level.length - 3] = '+';
                 level[level.length - 2] = '-';
             }
 
             String definition = nodeEntry.getDefinition();
 
             ret.append( level ).append( definition ).append( "\n" );
         }
 
         return ret.toString();
 
     }
 
     private void addNode( DependencyNode root, int level, List<NodeEntry> entries )
     {
 
         NodeEntry entry = new NodeEntry();
         Dependency dependency = root.getDependency();
         StringBuilder defBuilder = new StringBuilder();
         if ( dependency == null )
         {
             defBuilder.append( "(null)" );
         }
         else
         {
             Artifact artifact = dependency.getArtifact();
 
             defBuilder.append( artifact.getGroupId() ).append( ":" ).append( artifact.getArtifactId() ).append( ":" )
                     .append( artifact.getExtension() ).append( ":" ).append( artifact.getVersion() );
             if ( dependency.getScope() != null && ( !"".equals( dependency.getScope() ) ) )
             {
                 defBuilder.append( ":" ).append( dependency.getScope() );
             }
 
             Map<String, String> properties = artifact.getProperties();
             if ( !( properties == null || properties.isEmpty() ) )
             {
                 for ( Map.Entry<String, String> prop : properties.entrySet() )
                 {
                     defBuilder.append( ";" ).append( prop.getKey() ).append( "=" ).append( prop.getValue() );
                 }
             }
         }
 
         entry.setDefinition( defBuilder.toString() );
         entry.setLevel( level++ );
 
         entries.add( entry );
 
         for ( DependencyNode node : root.getChildren() )
         {
             addNode( node, level, entries );
         }
 
     }
 
     class NodeEntry
     {
         int level;
 
         String definition;
 
         Map<String, String> properties;
 
         public int getLevel()
         {
             return level;
         }
 
         public void setLevel( int level )
         {
             this.level = level;
         }
 
         public String getDefinition()
         {
             return definition;
         }
 
         public void setDefinition( String definition )
         {
             this.definition = definition;
         }
 
         public Map<String, String> getProperties()
         {
             return properties;
         }
 
         public void setProperties( Map<String, String> properties )
         {
             this.properties = properties;
         }
     }
 
     private static LineContext createContext( String line )
     {
         LineContext ctx = new LineContext();
         String definition;
 
         String[] split = line.split( "- " );
         if ( split.length == 1 ) // root
         {
             ctx.setLevel( 0 );
             definition = split[0];
         }
         else
         {
             ctx.setLevel( (int) Math.ceil( (double) split[0].length() / (double) 3 ) );
             definition = split[1];
         }
 
         if ( "(null)".equalsIgnoreCase( definition ) )
         {
             return ctx;
         }
 
         ctx.setDefinition( new NodeDefinition( definition ) );
 
         return ctx;
     }
 
     static class LineContext
     {
         NodeDefinition definition;
 
         int level;
 
         public NodeDefinition getDefinition()
         {
             return definition;
         }
 
         public void setDefinition( NodeDefinition definition )
         {
             this.definition = definition;
         }
 
         public int getLevel()
         {
             return level;
         }
 
         public void setLevel( int level )
         {
             this.level = level;
         }
     }
 
     public Collection<String> getSubstitutions()
     {
         return substitutions;
     }
 
     public void setSubstitutions( Collection<String> substitutions )
     {
         this.substitutions = substitutions;
     }
 
     public void setSubstitutions( String... substitutions )
     {
         setSubstitutions( Arrays.asList( substitutions ) );
     }
 
 }