/*=========================================================================

  Program:   FusionViewer
  Module:    $RCSfile: FileAndTextTransferHandler.java,v $
  Language:  Java
  Date:      $Date: 2007/02/02 19:27:57 $
  Version:   $Revision: 1.2 $
  
  Copyright (c) Insightful Corporation.  All rights reserved.
  See Copyright.txt for details.
  
  This software is distributed WITHOUT ANY WARRANTY; without even
  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

package org.fusionviewer.ui;

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;

import javax.swing.JComponent;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.TransferHandler;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.text.Position;

/**\class FileAndTextTransferHandler
 *\brief TransferHandler for drag and drop of file paths into a JTextField.
 * 
 * Based on the drag and drop example program in the Java Tutorial.
 * http://java.sun.com/docs/books/tutorial/uiswing/misc/dnd.html
 * 
 * Usage:
 * FileAndTextTransferHandler transferHandler = new FileAndTextTransferHandler();
 * JTextField field = new JTextField();
 * field.setDragEnabled(true);
 * field.setTransferHandler(transferHandler);
 */
public class FileAndTextTransferHandler extends TransferHandler {
	private JTextField source;
	private boolean shouldRemove;

	// Start and end position in the source text.
	// We need this information when performing a MOVE
	// in order to remove the dragged text from the source.
	Position p0 = null, p1 = null;

	public FileAndTextTransferHandler() {
	}

	public boolean importData(JComponent c, Transferable t) {
		JTextField tc;

		if (!canImport(c, t.getTransferDataFlavors())) {
			return false;
		}

		try {
			tc = (JTextField) c;
			
			if (hasFileFlavor(t.getTransferDataFlavors())) {
				List files = (List) t.getTransferData(DataFlavor.javaFileListFlavor);
				Iterator fileIterator = files.iterator();
				if (fileIterator.hasNext()) {
					File file = (File) fileIterator.next();
					
					tc.setText(file.getAbsolutePath());
				}
			} else if (hasStringFlavor(t.getTransferDataFlavors())) {
				if (tc.equals(source)
						&& (tc.getCaretPosition() >= p0.getOffset())
						&& (tc.getCaretPosition() <= p1.getOffset())) {
					shouldRemove = false;
					return true;
				}
				String str = (String) t.getTransferData(DataFlavor.stringFlavor);
				tc.replaceSelection(str);
				return true;
			}
		} catch (UnsupportedFlavorException ufe) {
			JOptionPane.showMessageDialog(c,
					"Error transferring data\n\n" + ufe.getMessage(),
					"Error", JOptionPane.ERROR_MESSAGE);
		} catch (IOException ieo) {
			JOptionPane.showMessageDialog(c,
					"Error transferring data\n\n" + ieo.getMessage(),
					"Error", JOptionPane.ERROR_MESSAGE);
		}
		
		return false;
	}

	protected Transferable createTransferable(JComponent c) {
		source = (JTextField) c;
		int start = source.getSelectionStart();
		int end = source.getSelectionEnd();
		Document doc = source.getDocument();
		if (start == end)
			return null;
		
		try {
			p0 = doc.createPosition(start);
			p1 = doc.createPosition(end);
		} catch (BadLocationException e) {
			JOptionPane.showMessageDialog(c,
					"Error transferring data\n\n" + e.getMessage(),
					"Error", JOptionPane.ERROR_MESSAGE);
		}
		shouldRemove = true;
		
		return new StringSelection(source.getSelectedText());
	}

	public int getSourceActions(JComponent c) {
		return COPY_OR_MOVE;
	}

	// Remove the old text if the action is a MOVE.
	// However, we do not allow dropping on top of the selected text,
	// so in that case do nothing.
	protected void exportDone(JComponent c, Transferable data, int action) {
		if (shouldRemove && (action == MOVE)) {
			if ((p0 != null) && (p1 != null)
					&& (p0.getOffset() != p1.getOffset())) {
				try {
					JTextComponent tc = (JTextComponent) c;
					tc.getDocument().remove(p0.getOffset(),
							p1.getOffset() - p0.getOffset());
				} catch (BadLocationException e) {
					JOptionPane.showMessageDialog(c,
							"Error transferring data\n\n" + e.getMessage(),
							"Error", JOptionPane.ERROR_MESSAGE);
				}
			}
		}
		source = null;
	}

	public boolean canImport(JComponent c, DataFlavor[] flavors) {
		if (hasFileFlavor(flavors))
			return true;
		
		if (hasStringFlavor(flavors))
			return true;
		
		return false;
	}

	private boolean hasFileFlavor(DataFlavor[] flavors) {
		for (int i = 0; i < flavors.length; i++) {
			if (DataFlavor.javaFileListFlavor.equals(flavors[i]))
				return true;
		}
		return false;
	}

	private boolean hasStringFlavor(DataFlavor[] flavors) {
		for (int i = 0; i < flavors.length; i++) {
			if (DataFlavor.stringFlavor.equals(flavors[i]))
				return true;
		}
		return false;
	}
}