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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Licensed 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.
 */
package org.neo4j.driver;

import java.net.URI;

import org.neo4j.driver.exceptions.ServiceUnavailableException;
import org.neo4j.driver.internal.DriverFactory;
import org.neo4j.driver.internal.SecuritySettings;
import org.neo4j.driver.internal.cluster.RoutingSettings;
import org.neo4j.driver.internal.retry.RetrySettings;
import org.neo4j.driver.internal.security.SecurityPlan;

import static org.neo4j.driver.internal.Scheme.NEO4J_URI_SCHEME;

/**
 * Creates {@link Driver drivers}, optionally letting you {@link #driver(URI, Config)} to configure them.
 * @see Driver
 * @since 1.0
 */
public class GraphDatabase
{
    private static final String LOGGER_NAME = GraphDatabase.class.getSimpleName();

    /**
     * Return a driver for a Neo4j instance with the default configuration settings
     *
     * @param uri the URL to a Neo4j instance
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( String uri )
    {
        return driver( uri, Config.defaultConfig() );
    }

    /**
     * Return a driver for a Neo4j instance with the default configuration settings
     *
     * @param uri the URL to a Neo4j instance
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( URI uri )
    {
        return driver( uri, Config.defaultConfig() );
    }

    /**
     * Return a driver for a Neo4j instance with custom configuration.
     *
     * @param uri the URL to a Neo4j instance
     * @param config user defined configuration
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( URI uri, Config config )
    {
        return driver( uri, AuthTokens.none(), config );
    }

    /**
     * Return a driver for a Neo4j instance with custom configuration.
     *
     * @param uri the URL to a Neo4j instance
     * @param config user defined configuration
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( String uri, Config config )
    {
        return driver( URI.create( uri ), config );
    }

    /**
     * Return a driver for a Neo4j instance with the default configuration settings
     *
     * @param uri the URL to a Neo4j instance
     * @param authToken authentication to use, see {@link AuthTokens}
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( String uri, AuthToken authToken )
    {
        return driver( uri, authToken, Config.defaultConfig() );
    }

    /**
     * Return a driver for a Neo4j instance with the default configuration settings
     *
     * @param uri the URL to a Neo4j instance
     * @param authToken authentication to use, see {@link AuthTokens}
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( URI uri, AuthToken authToken )
    {
        return driver( uri, authToken, Config.defaultConfig() );
    }

    /**
     * Return a driver for a Neo4j instance with custom configuration.
     *
     * @param uri the URL to a Neo4j instance
     * @param authToken authentication to use, see {@link AuthTokens}
     * @param config user defined configuration
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( String uri, AuthToken authToken, Config config )
    {
        return driver( URI.create( uri ), authToken, config );
    }

    /**
     * Return a driver for a Neo4j instance with custom configuration.
     *
     * @param uri       the URL to a Neo4j instance
     * @param authToken authentication to use, see {@link AuthTokens}
     * @param config    user defined configuration
     * @return a new driver to the database instance specified by the URL
     */
    public static Driver driver( URI uri, AuthToken authToken, Config config )
    {
        return driver( uri, authToken, config, new DriverFactory() );
    }

    static Driver driver( URI uri, AuthToken authToken, Config config, DriverFactory driverFactory )
    {
        config = getOrDefault( config );
        RoutingSettings routingSettings = config.routingSettings();
        RetrySettings retrySettings = config.retrySettings();
        SecuritySettings securitySettings = config.securitySettings();
        SecurityPlan securityPlan = securitySettings.createSecurityPlan( uri.getScheme() );
        return driverFactory.newInstance( uri, authToken, routingSettings, retrySettings, config, securityPlan );
    }

    /**
     * Try to create a neo4j driver from the first available address.
     * This is wrapper for the {@link #driver} method that finds the first
     * server to respond positively.
     *
     * @param routingUris an {@link Iterable} of server {@link URI}s for Neo4j instances. All given URIs should
     * have 'neo4j' scheme.
     * @param authToken authentication to use, see {@link AuthTokens}
     * @param config user defined configuration
     * @return a new driver instance
     */
    public static Driver routingDriver( Iterable routingUris, AuthToken authToken, Config config )
    {
        return routingDriver( routingUris, authToken, config, new DriverFactory() );
    }

    static Driver routingDriver( Iterable routingUris, AuthToken authToken, Config config, DriverFactory driverFactory )
    {
        assertRoutingUris( routingUris );
        Logger log = createLogger( config );

        for ( URI uri : routingUris )
        {
            final Driver driver = driver( uri, authToken, config, driverFactory );
            try
            {
                driver.verifyConnectivity();
                return driver;
            }
            catch ( ServiceUnavailableException e )
            {
                log.warn( "Unable to create routing driver for URI: " + uri, e );
                closeDriver( driver, uri, log );
            }
            catch ( Throwable e )
            {
                // for any other errors, we first close the driver and then rethrow the original error out.
                closeDriver( driver, uri, log );
                throw e;
            }
        }

        throw new ServiceUnavailableException( "Failed to discover an available server" );
    }

    private static void closeDriver( Driver driver, URI uri, Logger log )
    {
        try
        {
            driver.close();
        }
        catch ( Throwable closeError )
        {
            log.warn( "Unable to close driver towards URI: " + uri, closeError );
        }
    }

    private static void assertRoutingUris( Iterable uris )
    {
        for ( URI uri : uris )
        {
            if ( !NEO4J_URI_SCHEME.equals( uri.getScheme() ) )
            {
                throw new IllegalArgumentException(
                        "Illegal URI scheme, expected '" + NEO4J_URI_SCHEME + "' in '" + uri + "'" );
            }
        }
    }

    private static Logger createLogger( Config config )
    {
        Logging logging = getOrDefault( config ).logging();
        return logging.getLog( LOGGER_NAME );
    }

    private static Config getOrDefault( Config config )
    {
        return config != null ? config : Config.defaultConfig();
    }
}