/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.tuscany.sca.node;

import java.io.IOException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import org.oasisopen.sca.ServiceRuntimeException;

/**
 * ContributionLocationHelper
 *
 * @version $Rev$ $Date$
 */
public class ContributionLocationHelper {

    /**
     * Returns the location of the SCA contribution containing the given class.
     *
     * @param anchorClass
     * @return
     */
    public static String getContributionLocation(final Class<?> anchorClass) {
        URL url = AccessController.doPrivileged(new PrivilegedAction<URL>() {
            public URL run() {
                return anchorClass.getProtectionDomain().getCodeSource().getLocation();
            }
        });
        String uri = url.toString();
        return uri;
    }

    /**
     * Find the contribution location by seraching a resource on the classpath
     * @param resourceName
     * @return
     */
    public static String getContributionLocation(String resourceName) {
        return getContributionLocation(null, resourceName);
    }

    /**
     * Find the contribution locations by seraching a resource on the classpath
     * @param resourceName
     * @return
     */
    public static List<String> getContributionLocations(String resourceName) {
        return getContributionLocations(null, resourceName);

    }

    /**
     * Find the contribution location by seraching a resource using the given classloader
     * @param classLoader
     * @param resourceName
     * @return
     */
    public static String getContributionLocation(ClassLoader classLoader, String resourceName) {
        if (classLoader == null) {
            classLoader = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
                public ClassLoader run() {
                    return Thread.currentThread().getContextClassLoader();
                }
            });
        }
        URL resourceURL = getResource(classLoader, resourceName);
        if (resourceURL == null) {
            return null;
        }
        return getRootLocation(resourceURL, resourceName);
    }

    /**
     * Find the contribution locations by seraching a resource using the given classloader
     * @param classLoader The classloader that is used to call getResources()
     * @param resourceName The name of the resource
     * @return A list of locations that contain the resource
     */
    public static List<String> getContributionLocations(ClassLoader classLoader, String resourceName) {
        if (classLoader == null) {
            classLoader = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
                public ClassLoader run() {
                    return Thread.currentThread().getContextClassLoader();
                }
            });
        }
        Enumeration<URL> resourceURLs = getResources(classLoader, resourceName);
        List<String> locations = new ArrayList<String>();
        while (resourceURLs != null && resourceURLs.hasMoreElements()) {
            locations.add(getRootLocation(resourceURLs.nextElement(), resourceName));
        }
        return locations;
    }

    private static String getRootLocation(URL resourceURL, String resourceName) {
        String location = null;
        // "jar:file://....../something.jar!/a/b/c/app.composite"
        String url = resourceURL.toExternalForm();
        String protocol = resourceURL.getProtocol();
        if ("file".equals(protocol)) {
            // directory contribution
            if (url.endsWith(resourceName)) {
                location = url.substring(0, url.lastIndexOf(resourceName));
            }
        } else if ("jar".equals(protocol) || "wsjar".equals(protocol) || "zip".equals(protocol)) {
            // jar contribution
            location = url.substring(protocol.length() + 1, url.lastIndexOf("!/"));
        } else if (url.endsWith(resourceName)) {
            location = url.substring(0, url.lastIndexOf(resourceName));
        } else {
            throw new IllegalArgumentException("The root of the resource cannot be determined: " + resourceURL
                + ","
                + resourceName);
        }
        return location;
    }

    private static URL getResource(final ClassLoader classLoader, final String compositeURI) {
        return AccessController.doPrivileged(new PrivilegedAction<URL>() {
            public URL run() {
                return classLoader.getResource(compositeURI);
            }
        });
    }

    private static Enumeration<URL> getResources(final ClassLoader classLoader, final String compositeURI) {
        return AccessController.doPrivileged(new PrivilegedAction<Enumeration<URL>>() {
            public Enumeration<URL> run() {
                try {
                    return classLoader.getResources(compositeURI);
                } catch (IOException e) {
                    throw new ServiceRuntimeException(e);
                }
            }
        });
    }

}