EDIT

/**

* Copyright (C) 2017 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.SQLException;

import org.apache.log4j.Logger;

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

import eu.etaxonomy.cdm.database.DatabaseTypeEnum;

import eu.etaxonomy.cdm.database.ICdmDataSource;

/**

 * @author a.mueller

 \* @since 15.06.2017

 *

 */

public class IndexRenamer extends SchemaUpdaterStepBase {

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

    private String tableName;

    private String oldIndexName;

    private String newIndexName;

    private String columnName;

    private Integer length;

// ********************** FACTORY ****************************************/

    public static final IndexRenamer NewStringInstance(String tableName, String oldIndexName,

            String newIndexName, String columnName, Integer length){

        return new IndexRenamer(tableName, oldIndexName,

                newIndexName, columnName, length == null ? 255 : length);

    }

    public static final IndexRenamer NewIntegerInstance(String tableName, String oldIndexName,

            String newIndexName, String columnName){

        return new IndexRenamer(tableName, oldIndexName, newIndexName, columnName, null);

    }

    /**

     * @param stepName

     */

    protected IndexRenamer(String tableName, String oldIndexName,

            String newIndexName, String columnName, Integer length) {

        super("Rename index " + oldIndexName + " to " + newIndexName);

        this.tableName = tableName;

        this.oldIndexName = oldIndexName;

        this.newIndexName = newIndexName;

        this.columnName = columnName;

        this.length = length;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public void invoke(ICdmDataSource datasource, IProgressMonitor monitor, CaseType caseType,

            SchemaUpdateResult result) throws SQLException {

        try {

            String[] updateQuery = getCreateQuery(datasource, caseType, tableName, oldIndexName, newIndexName, columnName, length);

            try {

                datasource.executeUpdate(updateQuery[0]);

            } catch (Exception e) {

                if (updateQuery.length > 1){

                    datasource.executeUpdate(updateQuery[1]);

                }else{

                    throw e;

                }

            }

            return;

        } catch (Exception e) {

            String message = "Index ("+tableName +"."+oldIndexName+") could not be renamed "

                    + "to ("+newIndexName+") or drop/add was not possible.\n"

                    + "Please ask your admin to rename manually.";

            logger.warn(message);

            result.addWarning(message, this, "invoke");

            return;

        }

    }

    private String[] getCreateQuery(ICdmDataSource datasource, CaseType caseType, String tableName, String oldIndexName, String newIndexName, String columnName, Integer length) {

        DatabaseTypeEnum type = datasource.getDatabaseType();

//      String indexName = "_UniqueKey";

        String[] updateQueries;

        if (type.equals(DatabaseTypeEnum.MySQL)){

            //https://stackoverflow.com/questions/1463363/how-do-i-rename-an-index-in-mysql

            //in future: https://dev.mysql.com/worklog/task/?id=6555

            String format = "ALTER TABLE @@%s@@ DROP INDEX %s, ADD INDEX %s (%s%s)";

            updateQueries = new String[]{String.format(format, tableName, oldIndexName, newIndexName, columnName, length!= null ? "("+length+")": "")};

        }else if (type.equals(DatabaseTypeEnum.H2) || type.equals(DatabaseTypeEnum.PostgreSQL)){

            //http://www.h2database.com/html/grammar.html#alter_index_rename

            //https://www.postgresql.org/docs/9.4/static/sql-alterindex.html (maybe IF EXISTS does not work prior to 9.x)

            String format = "ALTER INDEX %s %s RENAME TO %s";

            updateQueries = new String[]{String.format(format, " IF EXISTS ", oldIndexName, newIndexName),

                    String.format(format, "", oldIndexName, newIndexName)};

        }else if (type.equals(DatabaseTypeEnum.SqlServer2005)){

            //TODO Untested !!!!

            //https://docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp-rename-transact-sql

            //https://www.mssqltips.com/sqlservertip/2709/script-to-rename-constraints-and-indexes-to-conform-to-a-sql-server-naming-convention/

            //https://stackoverflow.com/questions/40865886/rename-sql-server-index-in-ms-sql-server

            String format = "EXEC sp_rename N'%s.%s', N'%s', N'INDEX'";

            updateQueries = new String[]{String.format(format, tableName, oldIndexName, newIndexName)};

        }else{

            throw new IllegalArgumentException("Datasource type not supported yet: " + type.getName());

        }

//      updateQuery = updateQuery.replace("@indexName", indexName);

        for (int i = 0; i < updateQueries.length ; i++ ){

            updateQueries[i] = caseType.replaceTableNames(updateQueries[i]);

        }

        return updateQueries;

}

}