package org.apache.maven.repository.internal;

/*
 * 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.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import org.apache.maven.model.Parent;
import org.apache.maven.model.Repository;
import org.apache.maven.model.building.FileModelSource;
import org.apache.maven.model.building.ModelSource;
import org.apache.maven.model.resolution.InvalidRepositoryException;
import org.apache.maven.model.resolution.ModelResolver;
import org.apache.maven.model.resolution.UnresolvableModelException;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.RequestTrace;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.eclipse.aether.impl.ArtifactResolver;
import org.eclipse.aether.impl.RemoteRepositoryManager;
import org.eclipse.aether.impl.VersionRangeResolver;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.resolution.ArtifactRequest;
import org.eclipse.aether.resolution.ArtifactResolutionException;
import org.eclipse.aether.resolution.VersionRangeRequest;
import org.eclipse.aether.resolution.VersionRangeResolutionException;
import org.eclipse.aether.resolution.VersionRangeResult;

/**
 * A model resolver to assist building of dependency POMs. This resolver gives priority to those repositories that have
 * been initially specified and repositories discovered in dependency POMs are recessively merged into the search chain.
 *
 * @author Benjamin Bentmann
 * @see DefaultArtifactDescriptorReader
 */
class DefaultModelResolver
    implements ModelResolver
{

    private final RepositorySystemSession session;

    private final RequestTrace trace;

    private final String context;

    private List<RemoteRepository> repositories;

    private final List<RemoteRepository> externalRepositories;

    private final ArtifactResolver resolver;

    private final VersionRangeResolver versionRangeResolver;

    private final RemoteRepositoryManager remoteRepositoryManager;

    private final Set<String> repositoryIds;

    public DefaultModelResolver( RepositorySystemSession session, RequestTrace trace, String context,
                                 ArtifactResolver resolver, VersionRangeResolver versionRangeResolver,
                                 RemoteRepositoryManager remoteRepositoryManager, List<RemoteRepository> repositories )
    {
        this.session = session;
        this.trace = trace;
        this.context = context;
        this.resolver = resolver;
        this.versionRangeResolver = versionRangeResolver;
        this.remoteRepositoryManager = remoteRepositoryManager;
        this.repositories = repositories;
        List<RemoteRepository> externalRepositories = new ArrayList<RemoteRepository>();
        externalRepositories.addAll( repositories );
        this.externalRepositories = Collections.unmodifiableList( externalRepositories );

        this.repositoryIds = new HashSet<String>();
    }

    private DefaultModelResolver( DefaultModelResolver original )
    {
        this.session = original.session;
        this.trace = original.trace;
        this.context = original.context;
        this.resolver = original.resolver;
        this.versionRangeResolver = original.versionRangeResolver;
        this.remoteRepositoryManager = original.remoteRepositoryManager;
        this.repositories = new ArrayList<RemoteRepository>( original.repositories );
        this.externalRepositories = original.externalRepositories;
        this.repositoryIds = new HashSet<String>( original.repositoryIds );
    }

    @Override
    public void addRepository( Repository repository )
        throws InvalidRepositoryException
    {
        addRepository( repository, false );
    }

    @Override
    public void addRepository( final Repository repository, boolean replace )
        throws InvalidRepositoryException
    {
        if ( session.isIgnoreArtifactDescriptorRepositories() )
        {
            return;
        }

        if ( !repositoryIds.add( repository.getId() ) )
        {
            if ( !replace )
            {
                return;
            }

            removeMatchingRepository( repositories, repository.getId() );
        }

        List<RemoteRepository> newRepositories =
            Collections.singletonList( ArtifactDescriptorUtils.toRemoteRepository( repository ) );

        this.repositories =
            remoteRepositoryManager.aggregateRepositories( session, repositories, newRepositories, true );
    }

    private static void removeMatchingRepository( Iterable<RemoteRepository> repositories, final String id )
    {
        Iterables.removeIf( repositories, new Predicate<RemoteRepository>()
        {
            @Override
            public boolean apply( RemoteRepository remoteRepository )
            {
                return remoteRepository.getId().equals( id );
            }
        } );
    }

    @Override
    public ModelResolver newCopy()
    {
        return new DefaultModelResolver( this );
    }

    @Override
    public ModelSource resolveModel( String groupId, String artifactId, String version )
        throws UnresolvableModelException
    {
        Artifact pomArtifact = new DefaultArtifact( groupId, artifactId, "", "pom", version );

        try
        {
            ArtifactRequest request = new ArtifactRequest( pomArtifact, repositories, context );
            request.setTrace( trace );
            pomArtifact = resolver.resolveArtifact( session, request ).getArtifact();
        }
        catch ( ArtifactResolutionException e )
        {
            throw new UnresolvableModelException( e.getMessage(), groupId, artifactId, version, e );
        }

        File pomFile = pomArtifact.getFile();

        return new FileModelSource( pomFile );
    }

    public ModelSource resolveModel( Parent parent )
        throws UnresolvableModelException
    {
        Artifact artifact = new DefaultArtifact( parent.getGroupId(), parent.getArtifactId(), "", "pom",
                                                 parent.getVersion() );

        VersionRangeRequest versionRangeRequest = new VersionRangeRequest( artifact, repositories, context );
        versionRangeRequest.setTrace( trace );

        try
        {
            VersionRangeResult versionRangeResult =
                versionRangeResolver.resolveVersionRange( session, versionRangeRequest );

            if ( versionRangeResult.getHighestVersion() == null )
            {
                throw new UnresolvableModelException( "No versions matched the requested range '" + parent.getVersion()
                                                          + "'", parent.getGroupId(), parent.getArtifactId(),
                                                      parent.getVersion() );

            }

            if ( versionRangeResult.getVersionConstraint() != null
                     && versionRangeResult.getVersionConstraint().getRange() != null
                     && versionRangeResult.getVersionConstraint().getRange().getUpperBound() == null )
            {
                throw new UnresolvableModelException( "The requested version range '" + parent.getVersion()
                                                          + "' does not specify an upper bound", parent.getGroupId(),
                                                      parent.getArtifactId(), parent.getVersion() );

            }

            parent.setVersion( versionRangeResult.getHighestVersion().toString() );
        }
        catch ( VersionRangeResolutionException e )
        {
            throw new UnresolvableModelException( e.getMessage(), parent.getGroupId(), parent.getArtifactId(),
                                                  parent.getVersion(), e );

        }

        return resolveModel( parent.getGroupId(), parent.getArtifactId(), parent.getVersion() );
    }

}