/*******************************************************************************
 * Copyright (c) 2012 Original authors and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Original authors and others - initial API and implementation
 ******************************************************************************/
package org.simantics.browsing.ui.nattable.override;

import org.eclipse.nebula.widgets.nattable.copy.command.CopyDataToClipboardCommand;
import org.eclipse.nebula.widgets.nattable.layer.cell.ILayerCell;
import org.eclipse.nebula.widgets.nattable.serializing.ISerializer;
import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Display;

/**
 * CopyDataToClipboardSerializer implementation that limits the amount of data that is copied.
 * Copying too much data will result in OutOfMemoryError.
 * 
 * @see org.eclipse.nebula.widgets.nattable.copy.serializing.CopyDataToClipboardSerializer
 * 
 * @author MLMARKO
 *
 */
public class CopyDataToClipboardSerializer implements ISerializer {
	
	public static final int COPY_THRESHOLD = 500000; // threshold for preventing OOM.

    private final ILayerCell[][] copiedCells;
    private final CopyDataToClipboardCommand command;

    public CopyDataToClipboardSerializer(ILayerCell[][] copiedCells,
            CopyDataToClipboardCommand command) {
        this.copiedCells = copiedCells;
        this.command = command;
    }

    @Override
    public void serialize() {
        final String cellDelimeter = this.command.getCellDelimeter();
        final String rowDelimeter = this.command.getRowDelimeter();

        final TextTransfer textTransfer = TextTransfer.getInstance();
        final StringBuilder textData = new StringBuilder();
        int count = 0;
        for (ILayerCell[] cells : copiedCells) {
        	count+= cells.length;
        }
        if (count <= COPY_THRESHOLD) {
	        int currentRow = 0;
	        for (ILayerCell[] cells : this.copiedCells) {
	            int currentCell = 0;
	            for (ILayerCell cell : cells) {
	                final String delimeter = ++currentCell < cells.length ? cellDelimeter
	                        : ""; //$NON-NLS-1$
	                if (cell != null) {
	                    textData.append(getTextForCell(cell) + delimeter);
	                } else {
	                    textData.append(delimeter);
	                }
	            }
	            if (++currentRow < this.copiedCells.length) {
	                textData.append(rowDelimeter);
	            }
	        }
        } else {
        	textData.append("Too many cells copied (" + count + ")");
        }
        if (textData.length() > 0) {
            final Clipboard clipboard = new Clipboard(Display.getDefault());
            try {
                clipboard.setContents(new Object[] { textData.toString() },
                        new Transfer[] { textTransfer });
            } finally {
                clipboard.dispose();
            }
        }
    }

    protected String getTextForCell(ILayerCell cell) {
        return String.valueOf(cell.getDataValue());
    }

    final protected CopyDataToClipboardCommand getCommand() {
        return this.command;
    }
}