/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.debug.internal.ui.sourcelookup.browsers;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.debug.core.sourcelookup.ISourceContainer;
import org.eclipse.debug.internal.ui.DebugUIPlugin;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.swt.custom.BusyIndicator;

/**
 * ArchiveFilter
 */
public class ArchiveFilter extends ViewerFilter {

	/**
	 * Collection of archives and containers to display
	 */
	private Set<IResource> fArchives;

	/**
	 * Collection of already existing archives
	 */
	private List<ISourceContainer> fExisting;

	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ViewerFilter#select(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
	 */
	@Override
	public boolean select(Viewer viewer, Object parentElement, Object element) {
		return fArchives.contains(element) && !fExisting.contains(element);
	}

	/**
	 * Constructs a new filter to display archives and their containers,
	 * excluding the resources in the given list.
	 *
	 * @param objects resources to exclude
	 */
	public ArchiveFilter(List<ISourceContainer> objects) {
		fExisting = objects;
		init();
	}

	/**
	 * Search for all archives in the workspace.
	 */
	private void init() {
		BusyIndicator.showWhile(DebugUIPlugin.getStandardDisplay(), () -> {
			fArchives = new HashSet<>();
			traverse(ResourcesPlugin.getWorkspace().getRoot(), fArchives);
		});
	}

	/**
	 * Traverse the given container, adding archives to the given set.
	 * Returns whether any files were added
	 * @param container the container to check
	 * @param set the set to add any found archives to
	 * @return <code>true</code> if any archives have been added false otherwise
	 */
	private boolean traverse(IContainer container, Set<IResource> set) {
		boolean added = false;
		try {
			IResource[] resources = container.members();
			for (int i = 0; i < resources.length; i++) {
				IResource resource = resources[i];
				if (resource instanceof IFile) {
					IFile file = (IFile)resource;
					String ext = file.getFileExtension();
					if (ext != null && (ext.equalsIgnoreCase("jar") || ext.equalsIgnoreCase("zip"))) { //$NON-NLS-1$ //$NON-NLS-2$
						set.add(file);
						added = true;
					}
				} else if (resource instanceof IContainer) {
					if (traverse((IContainer)resource, set)) {
						set.add(resource);
						added = true;
					}
				}
			}
		} catch (CoreException e) {
		}
		return added;
	}
}