package org.apache.maven.model.normalization;

/*
 * 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.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.inject.Named;
import javax.inject.Singleton;

import org.apache.maven.model.Build;
import org.apache.maven.model.Dependency;
import org.apache.maven.model.Model;
import org.apache.maven.model.Plugin;
import org.apache.maven.model.building.ModelBuildingRequest;
import org.apache.maven.model.building.ModelProblemCollector;
import org.apache.maven.model.merge.MavenModelMerger;
import org.codehaus.plexus.util.StringUtils;

/**
 * Handles normalization of a model.
 *
 * @author Benjamin Bentmann
 */
@Named
@Singleton
public class DefaultModelNormalizer
    implements ModelNormalizer
{

    private DuplicateMerger merger = new DuplicateMerger();

    @Override
    public void mergeDuplicates( Model model, ModelBuildingRequest request, ModelProblemCollector problems )
    {
        Build build = model.getBuild();
        if ( build != null )
        {
            List<Plugin> plugins = build.getPlugins();
            Map<Object, Plugin> normalized = new LinkedHashMap<>( plugins.size() * 2 );

            for ( Plugin plugin : plugins )
            {
                Object key = plugin.getKey();
                Plugin first = normalized.get( key );
                if ( first != null )
                {
                    merger.mergePlugin( plugin, first );
                }
                normalized.put( key, plugin );
            }

            if ( plugins.size() != normalized.size() )
            {
                build.setPlugins( new ArrayList<>( normalized.values() ) );
            }
        }

        /*
         * NOTE: This is primarily to keep backward-compat with Maven 2.x which did not validate that dependencies are
         * unique within a single POM. Upon multiple declarations, 2.x just kept the last one but retained the order of
         * the first occurrence. So when we're in lenient/compat mode, we have to deal with such broken POMs and mimic
         * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from
         * aftereffects and bogus error messages.
         */
        List<Dependency> dependencies = model.getDependencies();
        Map<String, Dependency> normalized = new LinkedHashMap<>( dependencies.size() * 2 );

        for ( Dependency dependency : dependencies )
        {
            normalized.put( dependency.getManagementKey(), dependency );
        }

        if ( dependencies.size() != normalized.size() )
        {
            model.setDependencies( new ArrayList<>( normalized.values() ) );
        }
    }

    /**
     * DuplicateMerger
     */
    protected static class DuplicateMerger
        extends MavenModelMerger
    {

        public void mergePlugin( Plugin target, Plugin source )
        {
            super.mergePlugin( target, source, false, Collections.emptyMap() );
        }

    }

    @Override
    public void injectDefaultValues( Model model, ModelBuildingRequest request, ModelProblemCollector problems )
    {
        injectDependencyDefaults( model.getDependencies() );

        Build build = model.getBuild();
        if ( build != null )
        {
            for ( Plugin plugin : build.getPlugins() )
            {
                injectDependencyDefaults( plugin.getDependencies() );
            }
        }
    }

    private void injectDependencyDefaults( List<Dependency> dependencies )
    {
        for ( Dependency dependency : dependencies )
        {
            if ( StringUtils.isEmpty( dependency.getScope() ) )
            {
                // we cannot set this directly in the MDO due to the interactions with dependency management
                dependency.setScope( "compile" );
            }
        }
    }

}
