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

import java.util.HashMap;
import java.util.Map;

import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.collection.CollectRequest;
import org.eclipse.aether.collection.CollectResult;
import org.eclipse.aether.collection.DependencyCollectionException;
import org.eclipse.aether.impl.DependencyCollector;
import org.eclipse.aether.internal.impl.collect.bf.BfDependencyCollector;
import org.eclipse.aether.internal.impl.collect.df.DfDependencyCollector;
import org.eclipse.aether.spi.locator.Service;
import org.eclipse.aether.spi.locator.ServiceLocator;
import org.eclipse.aether.util.ConfigUtils;

import static java.util.Objects.requireNonNull;

/**
 * Default implementation of {@link DependencyCollector} that merely indirect to selected delegate.
 */
@Singleton
@Named
public class DefaultDependencyCollector
        implements DependencyCollector, Service
{
    private static final String CONFIG_PROP_COLLECTOR_IMPL = "aether.collector.impl";

    private static final String DEFAULT_COLLECTOR_IMPL = DfDependencyCollector.NAME;

    private final Map<String, DependencyCollectorDelegate> delegates;

    /**
     * Default ctor for SL.
     *
     * @deprecated SL is to be removed.
     */
    @Deprecated
    public DefaultDependencyCollector()
    {
        this.delegates = new HashMap<>();
    }

    @Inject
    public DefaultDependencyCollector( Map<String, DependencyCollectorDelegate> delegates )
    {
        this.delegates = requireNonNull( delegates );
    }

    @Override
    public void initService( ServiceLocator locator )
    {
        BfDependencyCollector bf = new BfDependencyCollector();
        bf.initService( locator );
        DfDependencyCollector df = new DfDependencyCollector();
        df.initService( locator );
        this.delegates.put( BfDependencyCollector.NAME, bf );
        this.delegates.put( DfDependencyCollector.NAME, df );
    }

    @Override
    public CollectResult collectDependencies( RepositorySystemSession session, CollectRequest request )
            throws DependencyCollectionException
    {
        String delegateName = ConfigUtils.getString( session, DEFAULT_COLLECTOR_IMPL, CONFIG_PROP_COLLECTOR_IMPL );
        DependencyCollectorDelegate delegate = delegates.get( delegateName );
        if ( delegate == null )
        {
            throw new IllegalArgumentException( "Unknown collector impl: '" + delegateName
                    + "', known implementations are " + delegates.keySet() );
        }
        return delegate.collectDependencies( session, request );
    }
}
