/*
 * Copyright (c) 2004 - 2012 Eike Stepper (Berlin, Germany) 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:
 *    Eike Stepper - initial API and implementation
 */
package org.eclipse.emf.cdo.releng.manifests;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IFileEditorInput;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.handlers.HandlerUtil;

/**
 * @author Eike Stepper
 */
public abstract class AbstractProjectHandler extends AbstractHandler
{
  public AbstractProjectHandler()
  {
  }

  public final Object execute(ExecutionEvent event) throws ExecutionException
  {
    IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
    IWorkbenchPage page = window.getActivePage();
    if (page == null)
    {
      return null;
    }

    IProject project = getProject(page);
    if (project != null)
    {
      execute(page, project);
    }

    return null;
  }

  private IProject getProject(IWorkbenchPage page)
  {
    IResource resource = null;
    ISelection selection = page.getSelection();
    if (selection instanceof IStructuredSelection)
    {
      IStructuredSelection ssel = (IStructuredSelection)selection;
      if (ssel.size() == 1)
      {
        Object element = ssel.getFirstElement();
        if (element instanceof IResource)
        {
          resource = (IResource)element;
        }

        if (resource == null && element instanceof IAdaptable)
        {
          resource = (IResource)((IAdaptable)element).getAdapter(IResource.class);
        }

        if (resource == null)
        {
          resource = (IResource)Platform.getAdapterManager().getAdapter(element, IResource.class);
        }
      }
    }

    if (resource == null)
    {
      IEditorPart editor = page.getActiveEditor();
      if (editor != null)
      {
        IEditorInput input = editor.getEditorInput();
        if (input instanceof IFileEditorInput)
        {
          resource = ((IFileEditorInput)input).getFile();
        }
      }
    }

    if (resource == null)
    {
      return null;
    }

    return resource.getProject();
  }

  protected abstract void execute(IWorkbenchPage page, IProject project);
}