EDIT

// $Id$

/**

 * Copyright (C) 2009 EDIT

 * European Distributed Institute of Taxonomy 

 * http://www.e-taxonomy.eu

 * 

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.cdm.remote.config;

import java.io.File;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Properties;

import javax.naming.NamingException;

import javax.sql.DataSource;

import org.apache.log4j.Logger;

import org.springframework.beans.factory.xml.XmlBeanFactory;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.core.io.FileSystemResource;

import org.springframework.jndi.JndiObjectFactoryBean;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import eu.etaxonomy.cdm.model.common.CdmMetaData;

import eu.etaxonomy.cdm.model.common.CdmMetaData.MetaDataPropertyName;

/**

 * The <code>DataSourceConfigurer</code> can be used as a replacement for a xml configuration in the application context.

 * Enter the following in your application context configuration in order to enable the <code>DataSourceConfigurer</code>:

 *  

<pre>

<!-- enable processing of annotations such as @Autowired and @Configuration -->

<context:annotation-config/>

<bean class="eu.etaxonomy.cdm.remote.config.DataSourceConfigurer" >

</bean>

</pre>

 * The <code>DataSourceConfigurer</code> allows alternative ways to specify a data source:

 * 

 * <ol>

 * <li>Specify the data source bean to use in the Java environment properties: 

 * <code>-Dcdm.datasource={dataSourceName}</code> ({@link #ATTRIBUTE_DATASOURCE_NAME}). 

 * The data source bean with the given name will then be loaded from the <code>cdm.beanDefinitionFile</code> 

 * ({@link #CDM_BEAN_DEFINITION_FILE}), which must be a valid Spring bean definition file.

 * </li>

 * <li> 

 * Use a JDBC data source which is bound into the JNDI context. In this case the JNDI name is specified 

 * via the {@link #ATTRIBUTE_JDBC_JNDI_NAME} as attribute to the ServletContext. 

 * This scenario usually being used by the cdm-server application.

 * </li>

 * </ol>

 * The attributes used in (1) and (2) are in a first step being searched in the ServletContext 

 * if not found search in a second step in the environment variables of the OS, see:{@link #findProperty(String, boolean)}. 

 * 

 * @author a.kohlbecker

 * @date 04.02.2011

 *

 */

@Configuration

public class DataSourceConfigurer extends AbstractWebApplicationConfigurer {

	public static final Logger logger = Logger.getLogger(DataSourceConfigurer.class);

    private static final String ATTRIBUTE_JDBC_JNDI_NAME = "cdm.jdbcJndiName";

    private static final String ATTRIBUTE_HIBERNATE_DIALECT = "hibernate.dialect";

    private static final String CDM_BEAN_DEFINITION_FILE = "cdm.beanDefinitionFile";

    private static final String ATTRIBUTE_DATASOURCE_NAME = "cdm.datasource";

    private static final String DATASOURCE_BEANDEF_DEFAULT = System.getProperty("user.home")+File.separator+".cdmLibrary"+File.separator+"datasources.xml";

	private static String beanDefinitionFile = DATASOURCE_BEANDEF_DEFAULT;

	public void setBeanDefinitionFile(String filename){

		beanDefinitionFile = filename;

	}

	private DataSource dataSource;

	private Properties getHibernateProperties() {

		Properties hibernateProperties = webApplicationContext.getBean("jndiHibernateProperties", Properties.class);

		return hibernateProperties;

	}

	@Bean

	public DataSource dataSource() {

		String beanName = findProperty(ATTRIBUTE_DATASOURCE_NAME, true);

		String jndiName = null;

		if(this.dataSource == null){

			jndiName = findProperty(ATTRIBUTE_JDBC_JNDI_NAME, false);

			if(jndiName != null){

				dataSource = useJndiDataSource(jndiName);

			} else {

				dataSource = loadDataSourceBean(beanName);

			}

		}

		if(dataSource == null){

			return null;

		} 

		// validate correct schema version

		try {

			Connection connection = dataSource.getConnection();

			ResultSet resultSet = connection.createStatement().executeQuery(MetaDataPropertyName.DB_SCHEMA_VERSION.getSqlQuery());

			String version = null;

			if(resultSet.next()){

				version = resultSet.getString(1);

			} else {

				throw new RuntimeException("Unable to retrieve version info from data source " + dataSource.toString());

			}

			connection.close();

			if(!CdmMetaData.isDbSchemaVersionCompatible(version)){

				/*

				 * any exception thrown here would be nested into a spring

				 * BeanException which can not be caught in the servlet

				 * container, so we post the information into the

				 * ServletContext

				 */

				String errorMessage = "Incompatible version [" + (beanName != null ? beanName : jndiName) + "] expected version: " + CdmMetaData.getDbSchemaVersion() + ",  data base version  " + version;

				addErrorMessageToServletContextAttributes(errorMessage);

			}

		} catch (SQLException e) {

			RuntimeException re =   new RuntimeException("Unable to connect or to retrieve version info from data source " + dataSource.toString() , e);

			addErrorMessageToServletContextAttributes(re.getMessage());

			throw re;

		}

		return dataSource; 

	}

	private DataSource useJndiDataSource(String jndiName) {

		logger.info("using jndi datasource '" + jndiName + "'");

		JndiObjectFactoryBean jndiFactory = new JndiObjectFactoryBean();

		/*

		JndiTemplate jndiTemplate = new JndiTemplate();

		jndiFactory.setJndiTemplate(jndiTemplate); no need to use a JndiTemplate 

		if I try using JndiTemplate I get an org.hibernate.AnnotationException: "Unknown Id.generator: system-increment" 

		when running multiple intances via the Bootloader

		*/

		jndiFactory.setResourceRef(true);

		jndiFactory.setJndiName(jndiName);

		try {

			jndiFactory.afterPropertiesSet();

		} catch (IllegalArgumentException e) {

			logger.error(e);

		} catch (NamingException e) {

			logger.error(e);

		}

		Object obj = jndiFactory.getObject();

		return (DataSource)obj;

	}

	private DataSource loadDataSourceBean(String beanName) {

		String beanDefinitionFileFromProperty = findProperty(CDM_BEAN_DEFINITION_FILE, false);

		String path = (beanDefinitionFileFromProperty != null ? beanDefinitionFileFromProperty : beanDefinitionFile);

		logger.info("loading DataSourceBean '" + beanName + "' from: " + path);

		FileSystemResource file = new FileSystemResource(path);

		XmlBeanFactory beanFactory  = new XmlBeanFactory(file);

		DataSource dataSource = beanFactory.getBean(beanName, DataSource.class);

		if(dataSource instanceof ComboPooledDataSource){

			logger.info("DataSourceBean '" + beanName + "' is a ComboPooledDataSource [URL:" + ((ComboPooledDataSource)dataSource).getJdbcUrl()+ "]");

		} else {

			logger.error("DataSourceBean '" + beanName + "' IS NOT a ComboPooledDataSource");

		}

		return dataSource;

	}

	@Bean

	public Properties hibernateProperties(){

		Properties props = getHibernateProperties();

		props.setProperty(ATTRIBUTE_HIBERNATE_DIALECT, inferHibernateDialectName());

		return props;

	}

	public String inferHibernateDialectName() {

		DataSource ds = dataSource();

		String url = "<SEE PRIOR REFLECTION ERROR>";

		Method m = null;

		try {

			m = ds.getClass().getMethod("getUrl");

		} catch (SecurityException e) {

			logger.error(e);

		} catch (NoSuchMethodException e) {

			try {

				m = ds.getClass().getMethod("getJdbcUrl");

			} catch (SecurityException e2) {

				logger.error(e2);

			} catch (NoSuchMethodException e2) {

				logger.error(e2);

			}

		}

		try {

			url = (String)m.invoke(ds);

		} catch (IllegalArgumentException e) {

			logger.error(e);

		} catch (IllegalAccessException e) {

			logger.error(e);

		} catch (InvocationTargetException e) {

			logger.error(e);

		} catch (SecurityException e) {

			logger.error(e);

		} 

		if(url != null && url.contains("mysql")){

			return "org.hibernate.dialect.MySQLDialect";

		}

		logger.error("hibernate dialect mapping for "+url+ " not jet implemented or unavailable");

		return null;

	}

}