/*******************************************************************************
 * Copyright (c) 2013 Red Hat, Inc.
 * 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:
 *    Red Hat - initial API and implementation
 *******************************************************************************/
package org.eclipse.linuxtools.internal.rpm.ui.editor;

import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.QualifiedName;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.linuxtools.internal.rpm.ui.editor.actions.Messages;
import org.eclipse.linuxtools.rpm.core.IRPMConstants;
import org.eclipse.linuxtools.rpm.core.RPMProject;
import org.eclipse.linuxtools.rpm.core.RPMProjectLayout;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IFileEditorInput;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchSite;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.part.EditorPart;

/**
 * Utility class for RPM UI Editor Handler related things.
 *
 */
public class RPMHandlerUtils {

	/**
	 * Utility classes should not have a public or default constructor.
	 */
	private RPMHandlerUtils() {}

	/**
	 * Extract the IResource that was selected when the event was fired.
	 * @param event The fired execution event.
	 * @return The resource that was selected.
	 */
	public static IResource getResource(ExecutionEvent event) {
		IWorkbenchPart part = HandlerUtil.getActivePart(event);
		if (part == null) {
			return null;
		}
		if (part instanceof EditorPart) {
			IEditorInput input = ((EditorPart) part).getEditorInput();
			if (input instanceof IFileEditorInput) {
				return ((IFileEditorInput) input).getFile();
			}
			return null;
		}
		IWorkbenchSite site = part.getSite();
		if (site == null) {
			return null;
		}
		ISelectionProvider provider = site.getSelectionProvider();
		if (provider == null) {
			return null;
		}
		ISelection selection = provider.getSelection();
		if (selection instanceof IStructuredSelection) {
			Object element = ((IStructuredSelection) selection)
					.getFirstElement();
			if (element instanceof IResource) {
				return (IResource) element;
			} else if (element instanceof IAdaptable) {
				IAdaptable adaptable = (IAdaptable) element;
				return (IResource) adaptable.getAdapter(IResource.class);
			} else {
				return null;
			}
		}
		return null;
	}

	/**
	 * Get an RPMProject for the resource creating a new instance to an RPMProject.
	 * @param resource The resource to check its parent project.
	 * @return The RPMProject of the resource passed in.
	 */
	public static RPMProject getRPMProject(IResource resource) {
		RPMProject rc = null;

		try {
			IProject parentProject = resource.getProject();

			// determine if project selected is an RPMProject
			if (parentProject.hasNature(IRPMConstants.RPM_NATURE_ID)) {
				if (parentProject.getPersistentProperty(new QualifiedName(IRPMConstants.RPM_CORE_ID, IRPMConstants.SPECS_FOLDER)) != null){
					rc = new RPMProject(parentProject, RPMProjectLayout.RPMBUILD);
				} else {
					rc = new RPMProject(parentProject, RPMProjectLayout.FLAT);
				}
			} else {
				rc = new RPMProject(parentProject, RPMProjectLayout.FLAT);
			}
		} catch (CoreException e) {
			SpecfileLog.logError(Messages.RPMHandlerUtils_cannotCreateRPMProject, e);
		}
		return rc;
	}
}
