package org.eclipse.aether.internal.impl;

/*
 * 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.List;
import static java.util.Objects.requireNonNull;
import java.util.Set;

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

import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.impl.RepositoryConnectorProvider;
import org.eclipse.aether.repository.Authentication;
import org.eclipse.aether.repository.Proxy;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.spi.connector.RepositoryConnector;
import org.eclipse.aether.spi.connector.RepositoryConnectorFactory;
import org.eclipse.aether.spi.locator.Service;
import org.eclipse.aether.spi.locator.ServiceLocator;
import org.eclipse.aether.transfer.NoRepositoryConnectorException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 */
@Singleton
@Named
public class DefaultRepositoryConnectorProvider
    implements RepositoryConnectorProvider, Service
{

    private static final Logger LOGGER = LoggerFactory.getLogger( DefaultRepositoryConnectorProvider.class );

    private Collection<RepositoryConnectorFactory> connectorFactories = new ArrayList<>();

    public DefaultRepositoryConnectorProvider()
    {
        // enables default constructor
    }

    @Inject
    DefaultRepositoryConnectorProvider( Set<RepositoryConnectorFactory> connectorFactories )
    {
        setRepositoryConnectorFactories( connectorFactories );
    }

    public void initService( ServiceLocator locator )
    {
        connectorFactories = locator.getServices( RepositoryConnectorFactory.class );
    }

    public DefaultRepositoryConnectorProvider addRepositoryConnectorFactory( RepositoryConnectorFactory factory )
    {
        connectorFactories.add( requireNonNull( factory, "repository connector factory cannot be null" ) );
        return this;
    }

    public DefaultRepositoryConnectorProvider setRepositoryConnectorFactories(
            Collection<RepositoryConnectorFactory> factories )
    {
        if ( factories == null )
        {
            this.connectorFactories = new ArrayList<>();
        }
        else
        {
            this.connectorFactories = factories;
        }
        return this;
    }

    public RepositoryConnector newRepositoryConnector( RepositorySystemSession session, RemoteRepository repository )
        throws NoRepositoryConnectorException
    {
        requireNonNull( repository, "remote repository cannot be null" );

        PrioritizedComponents<RepositoryConnectorFactory> factories = new PrioritizedComponents<>( session );
        for ( RepositoryConnectorFactory factory : this.connectorFactories )
        {
            factories.add( factory, factory.getPriority() );
        }

        List<NoRepositoryConnectorException> errors = new ArrayList<>();
        for ( PrioritizedComponent<RepositoryConnectorFactory> factory : factories.getEnabled() )
        {
            try
            {
                RepositoryConnector connector = factory.getComponent().newInstance( session, repository );

                if ( LOGGER.isDebugEnabled() )
                {
                    StringBuilder buffer = new StringBuilder( 256 );
                    buffer.append( "Using connector " ).append( connector.getClass().getSimpleName() );
                    Utils.appendClassLoader( buffer, connector );
                    buffer.append( " with priority " ).append( factory.getPriority() );
                    buffer.append( " for " ).append( repository.getUrl() );

                    Authentication auth = repository.getAuthentication();
                    if ( auth != null )
                    {
                        buffer.append( " with " ).append( auth );
                    }

                    Proxy proxy = repository.getProxy();
                    if ( proxy != null )
                    {
                        buffer.append( " via " ).append( proxy.getHost() ).append( ':' ).append( proxy.getPort() );

                        auth = proxy.getAuthentication();
                        if ( auth != null )
                        {
                            buffer.append( " with " ).append( auth );
                        }
                    }

                    LOGGER.debug( buffer.toString() );
                }

                return connector;
            }
            catch ( NoRepositoryConnectorException e )
            {
                // continue and try next factory
                errors.add( e );
            }
        }
        if ( LOGGER.isDebugEnabled() && errors.size() > 1 )
        {
            for ( Exception e : errors )
            {
                LOGGER.debug( "Could not obtain connector factory for {}", repository, e );
            }
        }

        StringBuilder buffer = new StringBuilder( 256 );
        if ( factories.isEmpty() )
        {
            buffer.append( "No connector factories available" );
        }
        else
        {
            buffer.append( "Cannot access " ).append( repository.getUrl() );
            buffer.append( " with type " ).append( repository.getContentType() );
            buffer.append( " using the available connector factories: " );
            factories.list( buffer );
        }

        throw new NoRepositoryConnectorException( repository, buffer.toString(), errors.size() == 1 ? errors.get( 0 )
                        : null );
    }

}
