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 java.sql.SQLException;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

import org.apache.log4j.Logger;

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

import eu.etaxonomy.cdm.database.ICdmDataSource;

/**

 * @author a.mueller

 * @date 16.09.2010

 *

 */

public class SortIndexUpdater extends SchemaUpdaterStepBase<SortIndexUpdater> implements ISchemaUpdaterStep {

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

	private final String tableName;

	private final String sortIndexColumn;

	private final String parentColumn;

	private String idColumn = "id";

	private final boolean includeAudTable;

	private Integer baseValue = 0;

	public static final SortIndexUpdater NewInstance(String stepName, String tableName, String parentColumn, String sortIndexColumn, boolean includeAudTable){

		return new SortIndexUpdater(stepName, tableName, parentColumn, sortIndexColumn, "id", includeAudTable, 0);

	}

	public static final SortIndexUpdater NewInstance(String stepName, String tableName, String parentColumn, String sortIndexColumn, String idColumn, boolean includeAudTable){

		return new SortIndexUpdater(stepName, tableName, parentColumn,sortIndexColumn, idColumn, includeAudTable, 0);

	}

	protected SortIndexUpdater(String stepName, String tableName, String parentColumn, String sortIndexColumn, String idColumn, boolean includeAudTable, Integer baseValue) {

		super(stepName);

		this.tableName = tableName;

		this.parentColumn = parentColumn;

		this.sortIndexColumn = sortIndexColumn;

		this.idColumn = idColumn;

		this.includeAudTable = includeAudTable;

		this.baseValue = baseValue;

	}

	@Override

	public Integer invoke(ICdmDataSource datasource, IProgressMonitor monitor, CaseType caseType) throws SQLException {

		boolean result = true;

		result &= addColumn(caseType.transformTo(tableName), datasource, monitor, caseType);

		if (includeAudTable){

			String aud = "_AUD";

			result &= addColumn(caseType.transformTo(tableName + aud), datasource, monitor, caseType);

		}

		return (result == true )? 0 : null;

	}

	private boolean addColumn(String tableName, ICdmDataSource datasource, IProgressMonitor monitor, CaseType caseType) throws SQLException {

		//Note: caseType not required here

		Map<Integer, Set<Integer>> indexMap = makeIndexMap(tableName, datasource);

		updateIndices(tableName, datasource, indexMap);

		return true;

	}

	/**

	 * @param tableName

	 * @param datasource

	 * @param rs

	 * @param index

	 * @param oldParentId

	 * @return

	 * @throws SQLException

	 */

	private Map<Integer, Set<Integer>> makeIndexMap(String tableName, ICdmDataSource datasource) throws SQLException {

		String resulsetQuery = "SELECT @id as id, @parentColumn " +

				" FROM @tableName " +

				" WHERE @parentColumn IS NOT NULL " +

				" ORDER BY @parentColumn,    @id";

		resulsetQuery = resulsetQuery.replace("@tableName", tableName);

		resulsetQuery = resulsetQuery.replace("@parentColumn", parentColumn);

		resulsetQuery = resulsetQuery.replace("@id", idColumn);

		ResultSet rs = datasource.executeQuery(resulsetQuery);

		Integer index = baseValue;

		int oldParentId = -1;

		//increase index with each row, set to 0 if parent is not the same as the previous one

		Map<Integer, Set<Integer>> indexMap = new HashMap<Integer, Set<Integer>>();

		while (rs.next() ){

			int id = rs.getInt("id");

			Object oParentId = rs.getObject(parentColumn);

			if (oParentId != null){

				int parentId = Integer.valueOf(oParentId.toString());

				if (oldParentId != parentId){

					index = baseValue;

					oldParentId = parentId;

				}else{

					index++;

				}

				putIndex(id, index, indexMap);

			}else{

				logger.warn("This should not happen");

				index = baseValue;

			}

//			System.out.println(oParentId + "," + id+","+ index+";");

		}

		return indexMap;

	}

	private void updateIndices(String tableName, ICdmDataSource datasource, Map<Integer, Set<Integer>> indexMap)

			throws SQLException {

		for (Integer index :  indexMap.keySet()){

			Set<Integer> set = indexMap.get(index);

			String idSetString = makeIdSetString(set);

			String updateQuery = "UPDATE @tableName SET @sortIndexColumn = @index WHERE @id IN (@idList) ";

			updateQuery = updateQuery.replace("@tableName", tableName);

			updateQuery = updateQuery.replace("@sortIndexColumn", sortIndexColumn);

			updateQuery = updateQuery.replace("@index", index.toString());

			updateQuery = updateQuery.replace("@idList", idSetString);

			updateQuery = updateQuery.replace("@id", idColumn);

			datasource.executeUpdate(updateQuery);

		}

	}

	private static String makeIdSetString(Set<Integer> set) {

		StringBuffer result = new StringBuffer(set.size() * 5);

		for (Integer id:set){

			result.append(id + ",");

		}

		return result.substring(0, result.length() - 1);

	}

	/**

	 * Adds the id to the index (each id is attached to an (sort)index)

	 */

	private void putIndex(Integer id, Integer index, Map<Integer, Set<Integer>> indexMap) {

		Set<Integer> set = indexMap.get(index);

		if (set == null){

			set = new HashSet<Integer>();

			indexMap.put(index, set);

		}

		set.add(id);

	}

}