/*******************************************************************************
 * Copyright (c) 2004, 2014 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.osgi.internal.loader.sources;

import java.net.URL;
import java.util.*;
import org.eclipse.osgi.internal.loader.BundleLoader;
import org.eclipse.osgi.util.ManifestElement;

public class FilteredSourcePackage extends SingleSourcePackage {
	private static final char ALL = '*';
	private final String[] includes;
	private final String[] excludes;

	public FilteredSourcePackage(String name, BundleLoader supplier, String includes, String excludes) {
		super(name, supplier);
		this.includes = includes != null ? ManifestElement.getArrayFromList(includes) : null;
		this.excludes = excludes != null ? ManifestElement.getArrayFromList(excludes) : null;
	}

	@Override
	public URL getResource(String name) {
		if (isFiltered(name, getId()))
			return null;
		return super.getResource(name);
	}

	@Override
	public Enumeration<URL> getResources(String name) {
		if (isFiltered(name, getId()))
			return null;
		return super.getResources(name);
	}

	@Override
	public Class<?> loadClass(String name) throws ClassNotFoundException {
		if (isFiltered(name, getId()))
			return null;
		return super.loadClass(name);
	}

	private boolean isFiltered(String name, String pkgName) {
		String lastName = getName(name, pkgName);
		return !isIncluded(lastName) || isExcluded(lastName);
	}

	private String getName(String name, String pkgName) {
		if (!BundleLoader.DEFAULT_PACKAGE.equals(pkgName) && pkgName.length() + 1 <= name.length())
			return name.substring(pkgName.length() + 1);
		return name;
	}

	private boolean isIncluded(String name) {
		if (includes == null)
			return true;
		return isInList(name, includes);
	}

	private boolean isExcluded(String name) {
		if (excludes == null)
			return false;
		return isInList(name, excludes);
	}

	private boolean isInList(String name, String[] list) {
		for (String s : list) {
			int len = s.length();
			if (len == 0)
				continue;
			if (s.charAt(0) == ALL && len == 1) {
				return true; // handles "*" wild card
			}
			if (s.charAt(len - 1) == ALL) {
				if (name.startsWith(s.substring(0, len - 1))) {
					return true;
				}
			}
			if (name.equals(s)) {
				return true;
			}
		}
		return false;
	}

	@Override
	public Collection<String> listResources(String path, String filePattern) {
		Collection<String> result = super.listResources(path, filePattern);
		for (Iterator<String> resources = result.iterator(); resources.hasNext();) {
			String resource = resources.next();
			int lastSlash = resource.lastIndexOf('/');
			String fileName = lastSlash >= 0 ? resource.substring(lastSlash + 1) : resource;
			if (!isIncluded(fileName) || isExcluded(fileName))
				resources.remove();
		}
		return result;
	}

}