EDIT

/**

* 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.ArrayList;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

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> {

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

	private final String tableName;

	private final String sortIndexColumn;

	private final String parentColumn;

	/**

     * @return the parentColumn

     */

    public String getParentColumn() {

        return parentColumn;

    }

    private String idColumn = "id";

	private String currentSortColumn = "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", "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, idColumn, includeAudTable, 0);

	}

    /**

     * Returns an SortIndexUpdater that updates an existing sortindex which might have missing sortindex numbers in between.

     *

     */

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

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

    }

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

		super(stepName);

		this.tableName = tableName;

		this.parentColumn = parentColumn;

		this.sortIndexColumn = sortIndexColumn;

		this.idColumn = idColumn;

		this.currentSortColumn = currentSortColumn;

		this.includeAudTable = includeAudTable;

		this.baseValue = baseValue;

	}

	@Override

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

		boolean result = true;

		result &= addColumn(tableName, datasource);

		if (includeAudTable){

			String aud = "_AUD";

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

		}

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

	}

	private boolean addColumn( String tableName, ICdmDataSource datasource) throws SQLException {

		//Note: caseType not required here

	    Map<Integer, Set<Integer>> indexMap ;

	    if (tableName == null){

	        tableName = this.tableName;

	    }

	    indexMap = makeIndexMap(tableName, datasource);

	    updateIndices(tableName, datasource, indexMap);

		return true;

	}

	public String createIndexMapQuery(){

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

	                " FROM @tableName " +

	                " WHERE @parentColumn IS NOT NULL " +

	                " ORDER BY @parentColumn, @sorted";

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

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

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

	        resultsetQuery = resultsetQuery.replace("@sorted", currentSortColumn);

	        return resultsetQuery;

	}

	/**

	 * For each (new) sortIndex value the according record ids are computed.

	 * This allows updating all records sortindex by sortindex.

	 * @param tableName

	 * @param datasource

	 * @return

	 * @throws SQLException

	 */

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

	    String resultsetQuery = createIndexMapQuery();

		ResultSet rs = datasource.executeQuery(resultsetQuery);

		List<Integer[]> result = new ArrayList<Integer[]>();

		while (rs.next()){

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

            Object oParentId = rs.getObject(parentColumn);

            if (oParentId != null){

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

                result.add(new Integer[]{id,parentId});

            }

		}

        return makeIndexMap( result);

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

	}

	public Map<Integer, Set<Integer>> makeIndexMap(List<Integer[]> oldIndexMap) throws NumberFormatException, SQLException{

	    int oldParentId = -1;

	    Integer index = baseValue;

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

        for (Integer[] entry: oldIndexMap){

            int id = entry[0];

            Integer oParentId = entry[1];

            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;

	}

	public String createUpdateIndicesQuery(String tableName, Integer index, String idSetString){

	    if (tableName == null){

	        tableName = this.tableName;

	    }

	    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);

        return updateQuery;

	}

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

			throws SQLException {

	    String updateQuery ;

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

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

			String idSetString = makeIdSetString(set);

			updateQuery = createUpdateIndicesQuery(tableName, index, idSetString);

			datasource.executeUpdate(updateQuery);

		}

	}

	public 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)

	 */

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

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

		if (set == null){

			set = new HashSet<>();

			indexMap.put(index, set);

		}

		set.add(id);

	}

	public String getChildrenCountQuery(){

        String countSelect = "SELECT COUNT(child.id) as realCount, parent.countChildren as countChildren, parent.id as parentID FROM @tableName child RIGHT JOIN @tableName parent ON child.parent_id = parent.id GROUP BY parent.id";

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

        return countSelect;

	}

	public String getUpdateChildrenCount(int count, int id){

        String countUpdate =  "UPDATE @tableName SET countChildren = " + count+" WHERE id = " + id;

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

        return countUpdate;

    }

	public void updateChildrenCount(String select, ICdmDataSource datasource) throws SQLException{

	    ResultSet rs;

        rs = datasource.executeQuery(select);

        List<Integer[]> result = new ArrayList<Integer[]>();

        int count ;

        int countChildren;

        int parentId;

        while (rs.next()){

            count = rs.getInt("realCount");

            countChildren = rs.getInt("countChildren");

            parentId = rs.getInt("parentID");

            if (count != countChildren){

                String updateQuery = getUpdateChildrenCount(count, parentId);

                datasource.executeUpdate(updateQuery);

            }

        }

	}

}