package org.eclipse.aether.graph;

/*
 * 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.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static java.util.Objects.requireNonNull;

import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.version.Version;
import org.eclipse.aether.version.VersionConstraint;

A node within a dependency graph.
/**
 * 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.
Params:
dependency – The dependency associated with this node, may be null for a root node./**
     * 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. getDependency() will return null. Put differently, the specified artifact will not be subject to dependency collection/resolution. 
Params:
artifact – The artifact to use as label for this node, may be null./**
     * 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.
Params:
node – The node to copy, must not be null./**
     * 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.
Params:
relocations – The sequence of relocations, may be null./**
     * 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.
Params:
aliases – The known aliases, may be null./**
     * 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.
Params:
versionConstraint – The version constraint for this node, may be null./**
     * 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.
Params:
version – The parsed version, may be null./**
     * 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.
Params:
managedBits – The bit field indicating the managed attributes or 0 if dependency management wasn't applied./**
     * 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.
Params:
repositories – The remote repositories to use for artifact resolution, may be null./**
     * 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();
    }

}