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Copyright 2010, Google Inc.
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    * Redistributions of source code must retain the above copyright
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*/

package com.google.refine.model.changes;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;

import com.google.refine.history.Change;
import com.google.refine.model.Cell;
import com.google.refine.model.Column;
import com.google.refine.model.ColumnGroup;
import com.google.refine.model.Project;
import com.google.refine.model.Row;
import com.google.refine.util.Pool;

public class ColumnReorderChange extends ColumnChange {
    final protected List<String>    _columnNames;
    protected List<Column>          _oldColumns;
    protected List<Column>          _newColumns;
    protected List<Column>          _removedColumns;
    protected List<ColumnGroup>     _oldColumnGroups;
    protected CellAtRowCellIndex[]  _oldCells;
    
    public ColumnReorderChange(List<String> columnNames) {
        _columnNames = columnNames;
    }
    
    @Override
    public void apply(Project project) {
        synchronized (project) {
            if (_newColumns == null) {
                _newColumns = new ArrayList<Column>();
                _oldColumns = new ArrayList<Column>(project.columnModel.columns);
                
                for (String n : _columnNames) {
                    Column column = project.columnModel.getColumnByName(n);
                    if (column != null) {
                        _newColumns.add(column);
                    }
                }
                
                _oldColumnGroups = new ArrayList<ColumnGroup>(project.columnModel.columnGroups);
            }
            
            if (_removedColumns == null) {
            	_removedColumns = new ArrayList<Column>();
	            for (String n : project.columnModel.getColumnNames()) {
	            	Column oldColumn = project.columnModel.getColumnByName(n);
	            	if(!_newColumns.contains(oldColumn)) {
	            		_removedColumns.add(oldColumn);
	            	}
	            }
            }

            if (_oldCells == null) {
	            _oldCells = new CellAtRowCellIndex[project.rows.size() * _removedColumns.size()];

	            int count = 0;
	            for (int i = 0; i < project.rows.size(); i++) {
	                for (int j = 0; j < _removedColumns.size(); j++) {
	            		int cellIndex = _removedColumns.get(j).getCellIndex();
	            		Row row = project.rows.get(i);

	            		Cell oldCell = null;
	            		if (cellIndex < row.cells.size()) {
	            			oldCell = row.cells.get(cellIndex);
	            		}
	            		_oldCells[count++] = new CellAtRowCellIndex(i, cellIndex,oldCell);
	            	}
	            }
            }

            //Clear cells on removed columns.
            for (int i = 0; i < project.rows.size(); i++) {
                for (int j = 0; j < _removedColumns.size(); j++) {
            		int cellIndex = _removedColumns.get(j).getCellIndex();
            		Row row = project.rows.get(i);
            		row.setCell(cellIndex, null);
            	}
            }

            project.columnModel.columns.clear();
            project.columnModel.columns.addAll(_newColumns);
            project.columnModel.columnGroups.clear();

            project.update();
        }
    }

    @Override
    public void revert(Project project) {
        synchronized (project) {
            project.columnModel.columns.clear();
            project.columnModel.columns.addAll(_oldColumns);
            
            project.columnModel.columnGroups.clear();
            project.columnModel.columnGroups.addAll(_oldColumnGroups);


            for (int i = 0; i < _oldCells.length; i++) {
                Row row = project.rows.get(_oldCells[i].row);
                row.setCell(_oldCells[i].cellIndex,_oldCells[i].cell);
            }

            project.update();
        }
    }

    @Override
    public void save(Writer writer, Properties options) throws IOException {
        writer.write("columnNameCount="); writer.write(Integer.toString(_columnNames.size())); writer.write('\n');
        for (String n : _columnNames) {
            writer.write(n);
            writer.write('\n');
        }
        writer.write("oldColumnCount="); writer.write(Integer.toString(_oldColumns.size())); writer.write('\n');
        for (Column c : _oldColumns) {
            c.save(writer);
            writer.write('\n');
        }
        writer.write("newColumnCount="); writer.write(Integer.toString(_newColumns.size())); writer.write('\n');
        for (Column c : _newColumns) {
            c.save(writer);
            writer.write('\n');
        }
        writer.write("removedColumnCount="); writer.write(Integer.toString(_removedColumns.size())); writer.write('\n');
        for (Column c : _removedColumns) {
            c.save(writer);
            writer.write('\n');
        }
        writer.write("oldCellCount="); writer.write(Integer.toString(_oldCells.length)); writer.write('\n');
        for (CellAtRowCellIndex c : _oldCells) {
            c.save(writer, options);
            writer.write('\n');
        }

        writeOldColumnGroups(writer, options, _oldColumnGroups);
        writer.write("/ec/\n"); // end of change marker
    }
    
    static public Change load(LineNumberReader reader, Pool pool) throws Exception {
        List<String> columnNames = new ArrayList<String>();
        List<Column> oldColumns = new ArrayList<Column>();
        List<Column> newColumns = new ArrayList<Column>();
        List<Column> removedColumns = new ArrayList<Column>();
        CellAtRowCellIndex[] oldCells = new CellAtRowCellIndex[0];
        List<ColumnGroup> oldColumnGroups = null;
        
        String line;
        while ((line = reader.readLine()) != null && !"/ec/".equals(line)) {
            int equal = line.indexOf('=');
            CharSequence field = line.subSequence(0, equal);
            
            if ("columnNameCount".equals(field)) {
                int count = Integer.parseInt(line.substring(equal + 1));
                for (int i = 0; i < count; i++) {
                    line = reader.readLine();
                    if (line != null) {
                        columnNames.add(line);
                    }
                }
            } else if ("oldColumnCount".equals(field)) {
                int count = Integer.parseInt(line.substring(equal + 1));
                for (int i = 0; i < count; i++) {
                    line = reader.readLine();
                    if (line != null) {
                        oldColumns.add(Column.load(line));
                    }
                }
            } else if ("newColumnCount".equals(field)) {
                int count = Integer.parseInt(line.substring(equal + 1));
                for (int i = 0; i < count; i++) {
                    line = reader.readLine();
                    if (line != null) {
                        newColumns.add(Column.load(line));
                    }
                }
            } else if ("removedColumnCount".equals(field)) {
                int count = Integer.parseInt(line.substring(equal + 1));
                for (int i = 0; i < count; i++) {
                    line = reader.readLine();
                    if (line != null) {
                    	removedColumns.add(Column.load(line));
                    }
                }
            } else if ("oldCellCount".equals(field)) {
                int oldCellCount = Integer.parseInt(line.substring(equal + 1));

                oldCells = new CellAtRowCellIndex[oldCellCount];
                for (int i = 0; i < oldCellCount; i++) {
                    line = reader.readLine();
                    if (line != null) {
                        oldCells[i] = CellAtRowCellIndex.load(line, pool);
                    }
                }
            } else if ("oldColumnGroupCount".equals(field)) {
                int oldColumnGroupCount = Integer.parseInt(line.substring(equal + 1));
                
                oldColumnGroups = readOldColumnGroups(reader, oldColumnGroupCount);
            }
        }
        
        ColumnReorderChange change = new ColumnReorderChange(columnNames);
        change._oldColumns = oldColumns;
        change._newColumns = newColumns;
        change._removedColumns = removedColumns;
        change._oldCells = oldCells;
        change._oldColumnGroups = oldColumnGroups != null ?
                oldColumnGroups : new LinkedList<ColumnGroup>();
        
        return change;
    }
}
