/*******************************************************************************
 * Copyright (c) 2007, 2012 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.browsing.ui.swt.widgets.impl;

import java.util.List;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.widgets.Table;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.management.ISessionContext;
import org.simantics.utils.ReflectionUtils;
import org.simantics.utils.datastructures.Pair;
import org.simantics.utils.ui.ISelectionUtils;

abstract public class TableSelectionListenerImpl<T, T2> implements SelectionListener, Widget {

	private ISessionContext context;
	private Object lastInput = null;
	
    final private Class<?> clazz;
	
	public TableSelectionListenerImpl() {
        clazz = ReflectionUtils.getSingleParameterType(getClass());
	}
	
	@Override
	public void widgetDefaultSelected(SelectionEvent e) {
		widgetSelected(e);
	}
	
	@Override
	public void widgetSelected(SelectionEvent e) {

		Table table = (Table)e.getSource();
		@SuppressWarnings("unchecked")
		List<Pair<String, Object>> items = (List<Pair<String, Object>>)table.getData();
		Pair<String, Object> pair = (Pair<String, Object>)items.get(table.getSelectionIndex());
		final Object selection = pair.second;
		final Object input = lastInput;
		
		try {
			context.getSession().syncRequest(new WriteRequest() {

				@SuppressWarnings("unchecked")
				@Override
				public void perform(WriteGraph graph) throws DatabaseException {

					T single = (T) ISelectionUtils.filterSingleSelection((ISelection)input, clazz);
					applySelection(graph, single, (T2)selection);
					
				}
				
			});
		} catch (DatabaseException e1) {
			e1.printStackTrace();
		}
		
	}

	@Override
	public void setInput(ISessionContext context, Object parameter) {
		this.context = context;
		lastInput = parameter;
	}
	
	abstract public void applySelection(WriteGraph graph, T input, T2 selection) throws DatabaseException;
	
}