/*******************************************************************************
 * Copyright (c) 2006 Sybase, Inc. 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:
 *     Sybase, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.pagedesigner.dnd.internal;

import org.eclipse.gef.commands.Command;
import org.eclipse.gef.dnd.TemplateTransfer;
import org.eclipse.jst.pagedesigner.commands.PaletteDropInsertCommand;
import org.eclipse.jst.pagedesigner.editors.pagedesigner.PageDesignerResources;
import org.eclipse.jst.pagedesigner.editors.palette.IDropSourceData;
import org.eclipse.jst.pagedesigner.editors.palette.ITagDropSourceData;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.graphics.Point;
import org.eclipse.ui.texteditor.ITextEditorDropTargetListener;
import org.eclipse.wst.sse.ui.StructuredTextEditor;
import org.eclipse.wst.sse.ui.internal.ExtendedEditorDropTargetAdapter;

/**
 * @author mengbo
 */
public class DesignerSourceDropTargetListener extends
		ExtendedEditorDropTargetAdapter implements
		ITextEditorDropTargetListener {
	private int _location;

	private StructuredTextEditor _textEditor;

	/**
	 * @param textEditor
	 */
	public DesignerSourceDropTargetListener(StructuredTextEditor textEditor) {
		super(false);
		_textEditor = textEditor;
		setTextViewer(_textEditor.getTextViewer());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.texteditor.ITextEditorDropTargetListener#getTransfers()
	 */
	public Transfer[] getTransfers() {
		return new Transfer[] { TemplateTransfer.getInstance(),
				TextTransfer.getInstance() };
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DropTargetListener#dragOperationChanged(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void dragOperationChanged(DropTargetEvent event) {
		super.dragOperationChanged(event);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DropTargetListener#dragOver(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void dragOver(DropTargetEvent event) {
		StyledText text = null;
		if (_textEditor.getTextViewer() != null) {
			text = _textEditor.getTextViewer().getTextWidget();
			if (TemplateTransfer.getInstance().isSupportedType(
					event.currentDataType)) {
				if (_textEditor.getTextViewer() != null) {
						Point p = new Point(event.x, event.y);
						SourceViewerDragDropHelper.getInstance().updateCaret(
								_textEditor, p);
						_location = text.getCaretOffset();
						if (TemplateTransfer.getInstance().isSupportedType(
								event.currentDataType)) {
							_location = SourceViewerDragDropHelper.getInstance()
									.getValidLocation(_textEditor, _location);
						}
						SourceViewerDragDropHelper.getInstance().showCaret(
								_textEditor, _location);
				    }
		
			} else if (TextTransfer.getInstance().isSupportedType(
					event.currentDataType)) {
				super.dragOver(event);
				_location = text.getCaretOffset();
			}
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DropTargetListener#drop(org.eclipse.swt.dnd.DropTargetEvent)
	 */
	public void drop(DropTargetEvent event) {
		StyledText text = null;
		if (_textEditor.getTextViewer() != null) {
			text = _textEditor.getTextViewer().getTextWidget();
		}
		text.setCaretOffset(_location);
		Command command = getCommand(event);
		if (command == null) {
			return;
		}
		command.execute();
	}

	private Command getCommand(DropTargetEvent event) {
		if (TextTransfer.getInstance().isSupportedType(event.currentDataType)) {
			Object data = event.data;
			if (data instanceof String) {
				SourceViewLocalDropCommand command = new SourceViewLocalDropCommand(
						_textEditor, data, _location);
				return command;
			}
		} else if (TemplateTransfer.getInstance().isSupportedType(
				event.currentDataType)) {
			Object data = event.data;
			PaletteDropInsertCommand command = null;
			if (data instanceof IDropSourceData) {
			    final IDropSourceData dropSourceData = (IDropSourceData) data;
			    if (!(hasIllegalCharacters(dropSourceData))) {
					// "Create new item"
					command = new PaletteDropInsertCommand(
							PageDesignerResources
									.getInstance()
									.getString(
											"DesignerSourceDropTargetListener.InserCommandLabel"), _textEditor, dropSourceData, _location); //$NON-NLS-1$
			    }
			}
			return command;
		}
		return null;
	}

	private boolean hasIllegalCharacters(final IDropSourceData data) {
		//temporary fix for adopter product where palette item has illegal characters in identifier
		//has effect of disabling drop into source view
		if (data instanceof ITagDropSourceData) {
			final ITagDropSourceData tag = (ITagDropSourceData)data;
			return tag.getTagName().indexOf("##") > 0; //$NON-NLS-1$
		}
		return false;
	}
}