/*******************************************************************************
 * Copyright (c) 2008, 2012 Obeo.
 * 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:
 *     Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.emf.eef.runtime.ui.widgets.settings;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.eclipse.emf.common.notify.AdapterFactory;
import org.eclipse.emf.common.util.BasicEList;
import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider;
import org.eclipse.jface.viewers.Viewer;

/**
 * @author <a href="mailto:goulwen.lefur@obeo.fr">Goulwen Le Fur</a>
 */
public class AdvancedEEFEditorContentProvider extends AdapterFactoryContentProvider {

	private List<Object> choiceOfValues;

	private boolean eefInput = false;

	/**
	 * @param adapterFactory
	 */
	public AdvancedEEFEditorContentProvider(AdapterFactory adapterFactory) {
		super(adapterFactory);
		choiceOfValues = new ArrayList<Object>();
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer,
	 *      java.lang.Object, java.lang.Object)
	 */
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
		super.inputChanged(viewer, oldInput, newInput);
		if (newInput instanceof EEFEditorSettings) {
			choiceOfValues.clear();
			computeChoiceOfValues(newInput);
			eefInput = true;
		} else {
			eefInput = false;
		}
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider#getElements(java.lang.Object)
	 */
	public Object[] getElements(Object object) {
		if (object instanceof EEFEditorSettings) {
			EList<Resource> resources = new BasicEList<Resource>(((EEFEditorSettings)object).getSource()
					.eResource().getResourceSet().getResources());
			resources.retainAll(this.choiceOfValues);
			return resources.toArray();
		}
		return super.getElements(object);
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider#getChildren(java.lang.Object)
	 */
	public Object[] getChildren(Object object) {
		if (eefInput) {
			Object[] children = super.getChildren(object);
			List<Object> result = new ArrayList<Object>();
			for (Object child : children) {
				if (choiceOfValues.contains(child))
					result.add(child);
			}
			return result.toArray();
		} else {
			return super.getChildren(object);
		}
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.emf.edit.ui.provider.AdapterFactoryContentProvider#hasChildren(java.lang.Object)
	 */
	public boolean hasChildren(Object object) {
		if (eefInput) {
			return getChildren(object).length > 0;
		} else {
			return super.hasChildren(object);
		}
	}

	/**
	 * Compute the choice of values for the given input.
	 * 
	 * @param input
	 *            the input to process
	 */
	private void computeChoiceOfValues(Object input) {
		Object choiceOfValues2 = ((EEFEditorSettings)input).choiceOfValues(adapterFactory);
		if (choiceOfValues2 instanceof Collection<?>) {
			for (Object next : ((Collection<?>)choiceOfValues2)) {
				while (next != null) {
					if (next instanceof Resource) {
						choiceOfValues.add(next);
						next = null;
					} else if (next instanceof EObject) {
						choiceOfValues.add(next);
						EObject eContainer = ((EObject)next).eContainer();
						if (eContainer == null) {
							next = ((EObject)next).eResource();
						} else {
							next = eContainer;
						}
					} else if ("".equals(next)) {
						choiceOfValues.add(next);
						next = null;
					}
				}
			}
		}
	}

}