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.database.update;

import java.sql.ResultSet;

import org.apache.commons.lang.StringUtils;

import org.apache.log4j.Logger;

import eu.etaxonomy.cdm.common.monitor.DefaultProgressMonitor;

import eu.etaxonomy.cdm.common.monitor.IProgressMonitor;

import eu.etaxonomy.cdm.database.CdmDataSource;

import eu.etaxonomy.cdm.database.ICdmDataSource;

import eu.etaxonomy.cdm.database.update.v36_40.SchemaUpdater_36_40;

import eu.etaxonomy.cdm.database.update.v36_40.TermUpdater_36_40;

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

/**

 * This class launches CDM model updates.

 * Currently it splits the update in model updates and defined term related updates by

 * using a {@link ISchemaUpdater schema updater} and a {@link ITermUpdater}. However, this

 * architecture often results in problems and therefore will be replaced by only 1 schema updater.

 * Term updates will be handled differently or also by using the schema updater.

 * <BR>

 * For each new schema version number there usually exists 1 {@link ISchemaUpdater} which is

 * represents a list of schema update steps. {@link ISchemaUpdater schema updaters} are linked

 * to previous updaters which are called, if relevant, previous to the latest updater.

 * So it is possible to upgrade multiple schema version steps in one call.

 * <BR><BR>

 * As said before each {@link ISchemaUpdater schema updater} creates a list of

 * {@link ISchemaUpdaterStep update steps}.

 * <BR><BR>

 * {@link ISchemaUpdater} support progression monitoring with each update step being one task.

 * <BR><BR>

 * ATTENTION: Some steps in the schema update are not transactional by nature. E.g. adding or removing a column

 * to a table in a SQL database can not be handled in a transaction. Therefore failures in

 * certain steps may not lead to a complete rollback of all steps covered by a {@link ISchemaUpdater}.

 * This may lead to a situation where the database becomes inconsistent.

 * <BR><BR>

 * <u>HOW TO ADD A NEW UPDATER?</u><BR>

 * Adding a new updater currently still needs adjustment at multiple places.

 * <BR>

 * <BR>1.) Increment {@link CdmMetaData} schema version number and term version number.

 * <BR>2.) Create a new class instance of {@link SchemaUpdaterBase} (e.g. by copying an old one).

 * <BR>3.) Update startSchemaVersion and endSchemaVersion in this new class, where startSchemaVersion

 * is the old schema version and endSchemaVersion is the new schema version.

 * <BR>4.) Implement {@link ISchemaUpdater#getPreviousUpdater()} and {@link ISchemaUpdater#getNextUpdater()}

 * in a way that the former returns an instance of the previous schema updater and the later returns null (for now).

 * <BR>5.) Go to the previous schema updater class and adjust {@link ISchemaUpdater#getNextUpdater()}

 * in a way that it returns an instance of the newly created updater.

 * <BR>6.) Repeat steps 2.-5. for {@link ITermUpdater}

 * <BR>7.) Adjust {@link #getCurrentSchemaUpdater()} and {@link #getCurrentTermUpdater()} to return

 * instances of the newly created updaters.

 *

 * @see ISchemaUpdater

 * @see ITermUpdater

 * @see ISchemaUpdaterStep

 * @see ITermUpdaterStep

 *

 * @author a.mueller

 * @date 10.09.2010

 *

 */

public class CdmUpdater {

    private static final Logger logger = Logger.getLogger(CdmUpdater.class);

    public static CdmUpdater NewInstance(){

        return new CdmUpdater();

    }

    private ITermUpdater getCurrentTermUpdater() {

        return TermUpdater_36_40.NewInstance();

    }

    /**

     * Returns the current CDM updater

     * @return

     */

    private ISchemaUpdater getCurrentSchemaUpdater() {

        return SchemaUpdater_36_40.NewInstance();

    }

    /**

     * @param datasource

     * @param monitor may be <code>null</code>

     * @return

     */

    public boolean updateToCurrentVersion(ICdmDataSource datasource, IProgressMonitor monitor){

        boolean result = true;

        if (monitor == null){

            monitor = DefaultProgressMonitor.NewInstance();

        }

        CaseType caseType = CaseType.caseTypeOfDatasource(datasource);

        ISchemaUpdater currentSchemaUpdater = getCurrentSchemaUpdater();

        // TODO do we really always update the terms??

        ITermUpdater currentTermUpdater = getCurrentTermUpdater();

        int steps = currentSchemaUpdater.countSteps(datasource, monitor, caseType);

        steps += currentTermUpdater.countSteps(datasource, monitor, caseType);

        steps++;  //for hibernate_sequences update

        String taskName = "Update to schema version " + currentSchemaUpdater.getTargetVersion() + " and to term version " + currentTermUpdater.getTargetVersion(); //+ currentSchemaUpdater.getVersion();

        monitor.beginTask(taskName, steps);

        try {

            datasource.startTransaction();

            result &= currentSchemaUpdater.invoke(datasource, monitor, caseType);

            if (result == true){

                result &= currentTermUpdater.invoke(datasource, monitor, caseType);

                updateHibernateSequence(datasource, monitor, caseType);

            }

            if (result == false){

                datasource.rollback();

            }else{

                datasource.commitTransaction();

            }

        } catch (Exception e) {

            result = false;

            monitor.warning("Stopped schema updater");

        } finally {

            String message = "Update finished " + (result ? "successfully" : "with ERRORS");

            monitor.subTask(message);

            if (!result){

                monitor.warning(message);

                monitor.setCanceled(true);

            }else{

                monitor.done();

            }

            logger.info(message);

        }

        return result;

    }

    /**

     * Updating terms often inserts new terms, vocabularies and representations.

     * Therefore the counter in hibernate_sequences must be increased.

     * We do this once at the end of term updating.

     * @param caseType

     * @return true if update was successful, false otherwise

     */

    private boolean updateHibernateSequence(ICdmDataSource datasource, IProgressMonitor monitor, CaseType caseType) {

        boolean result = true;

        monitor.subTask("Update hibernate sequences");

        try {

            String sql = "SELECT * FROM hibernate_sequences ";

            ResultSet rs = datasource.executeQuery(sql);

            while (rs.next()){

                String table = rs.getString("sequence_name");

                Integer val = rs.getInt("next_val");

                result &= updateSingleValue(datasource, monitor, table, val, caseType);

            }

        } catch (Exception e) {

            String message = "Exception occurred when trying to update hibernate_sequences table: " + e.getMessage();

            monitor.warning(message, e);

            logger.error(message);

            result = false;

        }finally{

            monitor.worked(1);

        }

        return result;

    }

    /**

     *

     * @param datasource

     * @param monitor

     * @param table

     * @param oldVal

     * @param caseType

     * @return

     */

    private boolean updateSingleValue(ICdmDataSource datasource, IProgressMonitor monitor, String table, Integer oldVal, CaseType caseType){

        if (table.equals("default")){  //found in flora central africa test database

            return true;

        }

        try {

            Integer newVal;

            try {

                String id = table.equalsIgnoreCase("AuditEvent")? "revisionNumber" : "id";

                String sql = " SELECT max(%s) FROM %s ";

                newVal = (Integer)datasource.getSingleValue(String.format(sql, id, caseType.transformTo(table)));

            } catch (Exception e) {

                String message = "Could not retrieve max value for table '%s'. Will not update hibernate_sequence for this table. " +

                        "Usually this will not cause problems, however, if new data has been added to " +

                        "this table by the update script one may encounter 'unique identifier' " +

                        "exceptions when trying to add further data.";

                monitor.warning(String.format(message,table), e);

                //TODO

                return true;

            }

            if (newVal != null){

                //This is how {@link PooledOptimizer#generate(org.hibernate.id.enhanced.AccessCallback)} works

                //it substracts the increment size from the value in hibernate_sequences to get the initial value.

                //Haven't checked why.

                //For the correct increment size see eu.etaxonomy.cdm.model.common.package-info.java

                int incrementSize = 10;

                newVal = newVal + incrementSize;

                if (newVal != null && newVal >= oldVal){

                    String sql = " UPDATE hibernate_sequences " +

                            " SET next_val = %d " +

                            " WHERE sequence_name = '%s' ";

                    datasource.executeUpdate(String.format(sql, newVal + 1 , table) );

                }

            }

            return true;

        } catch (Exception e) {

            String message = "Exception occurred when trying to read or update hibernate_sequences table for value " + table + ": " + e.getMessage();

            monitor.warning(message, e);

            logger.error(message);

            return false;

        }

    }

    /**

     *

     *

     * @param args SERVER DB_NAME1[,DB_NAME2,...] [USER] [PASSWORD] [PORT]

     */

    public static void main(String[] args) {

//        logger.warn("main method not yet fully implemented (only works with mysql!!!)");

//        if(args.length < 2){

//            logger.error("Arguments missing: server database [username [password]]");

//        }

        //TODO better implementation

        CdmUpdater myUpdater = new CdmUpdater();

        System.out.println("CdmUpdater\nArguments: SERVER DB_NAME1[,DB_NAME2,...] [USER] [PASSWORD] [PORT]");

        String server = args[0];

        String database  = args[1];

        String[] databaseNames = StringUtils.split(database, ',');

        String username = args.length > 2 ? args[2] : null;

        String password  = args.length > 3 ? args[3] : null;

        int port  = 3306;

        if( args.length > 4){

            try {

                port = Integer.parseInt(args[4]);

            } catch (Exception e) {

                // ignore

            }

        }

        System.out.println("Number of databases to update: " + databaseNames.length);

        for(String dnName : databaseNames){

            System.out.println(dnName + " UPDATE ...");

            ICdmDataSource dataSource = CdmDataSource.NewMySqlInstance(server, dnName, port, username, password, null);

            boolean success = myUpdater.updateToCurrentVersion(dataSource, null);

            System.out.println(dnName + " DONE " + (success ? "successfully" : "with ERRORS"));

            System.out.println("====================================================================");

        }

    }

}