/*******************************************************************************
 * Copyright (c) 2004-2008 Istvan Rath and Daniel Varro
 * 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:
 *    Istvan Rath - initial API and implementation
 *******************************************************************************/

 package org.eclipse.viatra2.treeeditor.commands;

import org.eclipse.viatra2.errors.VPMCoreException;
import org.eclipse.viatra2.treeeditor.ViatraTreeEditor;

import java.util.Vector;

public class ViatraEditorCommandStack {

	/**
	 * Internal marker class used for marking save points on the Command Stack.
	 * @author Istvan Rath
	 *
	 */
	private class SaveMark extends ViatraEditorCommand {

		@Override
		public void execute() throws VPMCoreException {	}

		@Override
		public void undo() throws VPMCoreException { }
		
	}
	
	private Vector<ViatraEditorCommand> iCommands;
	
	private ViatraTreeEditor iVTE;
		
	
	/**
	 * Points to the last command which has been executed.
	 */
	private int iCurrentIndex = 0;
	
	public ViatraEditorCommandStack(ViatraTreeEditor vte) {
		iCommands = new Vector<ViatraEditorCommand>();
		iCommands.add(new SaveMark()); // add initial savemark
		iVTE = vte;
	}
	
	public void execute(ViatraEditorCommand cmd) {
		
		try {
			cmd.execute();
			for (int i=iCurrentIndex+1; i<iCommands.size(); i++)
				iCommands.remove(i);
			iCommands.add(cmd);
			iCurrentIndex++;
		}
		catch (VPMCoreException e) {
			iVTE.getFramework().getLogger().fatal(e.toString());
			iVTE.getFramework().getTopmodel().getTransactionManager().abortTransaction();
		}
		// iVTE.setDirty();
		// debugmsg();
	}
	
	public void undo() {
		try {
			iCommands.get(iCurrentIndex).undo();
			iCurrentIndex--;
		} catch (VPMCoreException e) {
			iVTE.getFramework().getLogger().fatal(e.toString());
		}
		iVTE.updateActions();
		// debugmsg();
	}
	
	public void redo() {
		try {
			iCommands.get(iCurrentIndex+1).execute();
			iCurrentIndex++;
		} catch (VPMCoreException e) {
			iVTE.getFramework().getLogger().fatal(e.toString());
		}
		iVTE.updateActions();
		// debugmsg();
	}
	
	private void debugmsg() {
		iVTE.getFramework().getLogger().debug("[VECommandStack] currindex is "+iCurrentIndex+", element at currindex is "+iCommands.get(iCurrentIndex).toString());
	}
	
	public boolean isUndoable() {
		return isDirty();
	}
	
	public boolean isRedoable() {
		return iCurrentIndex<iCommands.size()-1;
	}
	
	public void markSave() {
		this.execute(new SaveMark());
	}
	
	public boolean isDirty() {
		return !(iCommands.get(iCurrentIndex) instanceof SaveMark);
	}
	

}