/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.engine.jdbc.connections.internal;

import java.beans.BeanInfo;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import org.hibernate.HibernateException;
import org.hibernate.MultiTenancyStrategy;
import org.hibernate.boot.registry.StandardServiceInitiator;
import org.hibernate.boot.registry.selector.spi.StrategySelector;
import org.hibernate.cfg.AvailableSettings;
import org.hibernate.cfg.Environment;
import org.hibernate.engine.jdbc.connections.spi.ConnectionProvider;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.internal.util.beans.BeanInfoHelper;
import org.hibernate.service.spi.ServiceRegistryImplementor;

import org.jboss.logging.Logger;

Instantiates and configures an appropriate ConnectionProvider. 
Author:
Gavin King, Steve Ebersole, Brett Meyer/**
 * Instantiates and configures an appropriate {@link ConnectionProvider}.
 *
 * @author Gavin King
 * @author Steve Ebersole
 * @author Brett Meyer
 */
public class ConnectionProviderInitiator implements StandardServiceInitiator<ConnectionProvider> {
	private static final CoreMessageLogger LOG = Logger.getMessageLogger(
			CoreMessageLogger.class,
			ConnectionProviderInitiator.class.getName()
	);

	
Singleton access
/**
	 * Singleton access
	 */
	public static final ConnectionProviderInitiator INSTANCE = new ConnectionProviderInitiator();

	
The strategy for c3p0 connection pooling
/**
	 * The strategy for c3p0 connection pooling
	 */
	public static final String C3P0_STRATEGY = "c3p0";

	
The strategy for proxool connection pooling
/**
	 * The strategy for proxool connection pooling
	 */
	public static final String PROXOOL_STRATEGY = "proxool";

	
No idea.  Is this even still used?
/**
	 * No idea.  Is this even still used?
	 */
	public static final String INJECTION_DATA = "hibernate.connection_provider.injection_data";

	// mapping from legacy connection provider name to actual
	// connection provider that will be used
	private static final Map<String,String> LEGACY_CONNECTION_PROVIDER_MAPPING;

	static {
		LEGACY_CONNECTION_PROVIDER_MAPPING = new HashMap<String,String>( 5 );

		LEGACY_CONNECTION_PROVIDER_MAPPING.put(
				"org.hibernate.connection.DatasourceConnectionProvider",
				DatasourceConnectionProviderImpl.class.getName()
		);
		LEGACY_CONNECTION_PROVIDER_MAPPING.put(
				"org.hibernate.connection.DriverManagerConnectionProvider",
				DriverManagerConnectionProviderImpl.class.getName()
		);
		LEGACY_CONNECTION_PROVIDER_MAPPING.put(
				"org.hibernate.connection.UserSuppliedConnectionProvider",
				UserSuppliedConnectionProviderImpl.class.getName()
		);
	}

	@Override
	public Class<ConnectionProvider> getServiceInitiated() {
		return ConnectionProvider.class;
	}

	@Override
	public ConnectionProvider initiateService(Map configurationValues, ServiceRegistryImplementor registry) {
		final MultiTenancyStrategy strategy = MultiTenancyStrategy.determineMultiTenancyStrategy(  configurationValues );
		if ( strategy == MultiTenancyStrategy.DATABASE || strategy == MultiTenancyStrategy.SCHEMA ) {
			// nothing to do, but given the separate hierarchies have to handle this here.
			return null;
		}

		final StrategySelector strategySelector = registry.getService( StrategySelector.class );

		ConnectionProvider connectionProvider = null;
		final String providerName = getConfiguredConnectionProviderName( configurationValues );
		if ( providerName != null ) {
			connectionProvider = instantiateExplicitConnectionProvider( providerName, strategySelector );
		}
		else if ( configurationValues.get( Environment.DATASOURCE ) != null ) {
			connectionProvider = new DatasourceConnectionProviderImpl();
		}

		if ( connectionProvider == null ) {
			if ( c3p0ConfigDefined( configurationValues ) ) {
				connectionProvider = instantiateC3p0Provider( strategySelector );
			}
		}

		if ( connectionProvider == null ) {
			if ( proxoolConfigDefined( configurationValues ) ) {
				connectionProvider = instantiateProxoolProvider( strategySelector );
			}
		}

		if ( connectionProvider == null ) {
			if ( configurationValues.get( Environment.URL ) != null ) {
				connectionProvider = new DriverManagerConnectionProviderImpl();
			}
		}

		if ( connectionProvider == null ) {
			LOG.noAppropriateConnectionProvider();
			connectionProvider = new UserSuppliedConnectionProviderImpl();
		}


		final Map injectionData = (Map) configurationValues.get( INJECTION_DATA );
		if ( injectionData != null && injectionData.size() > 0 ) {
			final ConnectionProvider theConnectionProvider = connectionProvider;
			new BeanInfoHelper( connectionProvider.getClass() ).applyToBeanInfo(
					connectionProvider,
					new BeanInfoHelper.BeanInfoDelegate() {
						public void processBeanInfo(BeanInfo beanInfo) throws Exception {
							final PropertyDescriptor[] descriptors = beanInfo.getPropertyDescriptors();
							for ( PropertyDescriptor descriptor : descriptors ) {
								final String propertyName = descriptor.getName();
								if ( injectionData.containsKey( propertyName ) ) {
									final Method method = descriptor.getWriteMethod();
									method.invoke(
											theConnectionProvider,
											injectionData.get( propertyName )
									);
								}
							}
						}
					}
			);
		}

		return connectionProvider;
	}

	private String getConfiguredConnectionProviderName( Map configurationValues ) {
		String providerName = (String) configurationValues.get( Environment.CONNECTION_PROVIDER );
		if ( LEGACY_CONNECTION_PROVIDER_MAPPING.containsKey( providerName ) ) {
			final String actualProviderName = LEGACY_CONNECTION_PROVIDER_MAPPING.get( providerName );
			LOG.providerClassDeprecated( providerName, actualProviderName );
			providerName = actualProviderName;
		}
		return providerName;
	}

	private ConnectionProvider instantiateExplicitConnectionProvider(
			String providerName,
			StrategySelector strategySelector) {
		try {
			LOG.instantiatingExplicitConnectionProvider( providerName );
            // This relies on selectStrategyImplementor trying
            // classLoaderService.classForName( name ).
            // TODO: Maybe we shouldn't rely on that here and do it manually?
			return strategySelector.selectStrategyImplementor( ConnectionProvider.class, providerName ).newInstance();
		}
		catch ( Exception e ) {
			throw new HibernateException( "Could not instantiate connection provider [" + providerName + "]", e );
		}
	}

	private ConnectionProvider instantiateC3p0Provider(StrategySelector strategySelector) {
		try {
			return strategySelector.selectStrategyImplementor( ConnectionProvider.class, C3P0_STRATEGY ).newInstance();
		}
		catch ( Exception e ) {
			LOG.c3p0ProviderClassNotFound( C3P0_STRATEGY );
			return null;
		}
	}

	private static boolean c3p0ConfigDefined(Map configValues) {
		for ( Object key : configValues.keySet() ) {
			if ( String.class.isInstance( key )
					&& ( (String) key ).startsWith( AvailableSettings.C3P0_CONFIG_PREFIX ) ) {
				return true;
			}
		}
		return false;
	}

	private ConnectionProvider instantiateProxoolProvider(StrategySelector strategySelector) {
		try {
			return strategySelector.selectStrategyImplementor( ConnectionProvider.class, PROXOOL_STRATEGY ).newInstance();
		}
		catch ( Exception e ) {
			LOG.proxoolProviderClassNotFound( PROXOOL_STRATEGY );
			return null;
		}
	}

	private static boolean proxoolConfigDefined(Map configValues) {
		for ( Object key : configValues.keySet() ) {
			if ( String.class.isInstance( key )
					&& ( (String) key ).startsWith( AvailableSettings.PROXOOL_CONFIG_PREFIX ) ) {
				return true;
			}
		}
		return false;
	}

	
Build the connection properties capable of being passed to the DriverManager.getConnection forms taking Properties argument. We seek out all keys in the passed map which start with hibernate.connection., using them to create a new Properties instance. The keys in this new Properties have the hibernate.connection. prefix trimmed. 
Params:
properties – The map from which to build the connection specific properties.
Returns:
The connection properties./**
	 * Build the connection properties capable of being passed to the {@link java.sql.DriverManager#getConnection}
	 * forms taking {@link Properties} argument.  We seek out all keys in the passed map which start with
	 * {@code hibernate.connection.}, using them to create a new {@link Properties} instance.  The keys in this
	 * new {@link Properties} have the {@code hibernate.connection.} prefix trimmed.
	 *
	 * @param properties The map from which to build the connection specific properties.
	 *
	 * @return The connection properties.
	 */
	public static Properties getConnectionProperties(Map<?,?> properties) {
		final Properties result = new Properties();
		for ( Map.Entry entry : properties.entrySet() ) {
			if ( ! ( String.class.isInstance( entry.getKey() ) ) || ! String.class.isInstance( entry.getValue() ) ) {
				continue;
			}
			final String key = (String) entry.getKey();
			final String value = (String) entry.getValue();
			if ( key.startsWith( Environment.CONNECTION_PREFIX ) ) {
				if ( SPECIAL_PROPERTIES.contains( key ) ) {
					if ( Environment.USER.equals( key ) ) {
						result.setProperty( "user", value );
					}
				}
				else {
					result.setProperty(
							key.substring( Environment.CONNECTION_PREFIX.length() + 1 ),
							value
					);
				}
			}
			else if ( CONDITIONAL_PROPERTIES.containsKey( key ) ) {
				result.setProperty( CONDITIONAL_PROPERTIES.get( key ), value );
			}
		}
		return result;
	}

	private static final Set<String> SPECIAL_PROPERTIES;

	static {
		SPECIAL_PROPERTIES = new HashSet<String>();
		SPECIAL_PROPERTIES.add( Environment.DATASOURCE );
		SPECIAL_PROPERTIES.add( Environment.URL );
		SPECIAL_PROPERTIES.add( Environment.CONNECTION_PROVIDER );
		SPECIAL_PROPERTIES.add( Environment.POOL_SIZE );
		SPECIAL_PROPERTIES.add( Environment.ISOLATION );
		SPECIAL_PROPERTIES.add( Environment.DRIVER );
		SPECIAL_PROPERTIES.add( Environment.USER );
	}

	// Connection properties (map value) that automatically need set if the
	// Hibernate property (map key) is available. Makes the assumption that
	// both settings use the same value type.
	private static final Map<String, String> CONDITIONAL_PROPERTIES;

	static {
		CONDITIONAL_PROPERTIES = new HashMap<String, String>();
		// Oracle requires that includeSynonyms=true in order for getColumns to work using a table synonym name.
		CONDITIONAL_PROPERTIES.put( Environment.ENABLE_SYNONYMS, "includeSynonyms" );
	}
}