/**
 * Licensed 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 com.sun.facelets.util;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

/**
 * @author Jacob Hookom
 * @author Roland Huss
 * @author Ales Justin (ales.justin@jboss.org)
 * @version $Id: Classpath.java,v 1.11 2009/02/02 23:04:45 rlubke Exp $
 */
public final class Classpath {

   private static boolean isVFSPresent;

   static {
      try {
         Classpath.class.getClassLoader().loadClass("org.jboss.virtual.VFS");
         isVFSPresent = true;
      } catch (Throwable ignored) {
      }
   }

	/**
	 * 
	 */
	public Classpath() {
		super();
	}

	public static URL[] search(String prefix, String suffix) throws IOException {
        return search(Thread.currentThread().getContextClassLoader(), prefix, suffix);
	}

	public static URL[] search(ClassLoader cl, String prefix, String suffix) throws IOException {
      return isVFSPresent ? VFSClasspath.search(cl, prefix, suffix) : doSearch(cl, prefix, suffix);
   }

	private static URL[] doSearch(ClassLoader cl, String prefix, String suffix) throws IOException {
		Enumeration[] e = new Enumeration[] {
				cl.getResources(prefix),
				cl.getResources(prefix + "MANIFEST.MF")
			};
		Set all = new LinkedHashSet();
		URL url;
		URLConnection conn;
		JarFile jarFile;
		for (int i = 0, s = e.length; i < s; ++i) {
			while (e[i].hasMoreElements()) {
				url = (URL) e[i].nextElement();
				conn = url.openConnection();
				conn.setUseCaches(false);
				conn.setDefaultUseCaches(false);
				if (conn instanceof JarURLConnection) {
					jarFile = ((JarURLConnection) conn).getJarFile();
				} else {
					jarFile = getAlternativeJarFile(url);
				}
				if (jarFile != null) {
					searchJar(cl, all, jarFile, prefix, suffix);
				} else {
					boolean searchDone = searchDir(all, new File(URLDecoder.decode(url.getFile(), "UTF-8")), suffix);
					if (!searchDone)
					{
						searchFromURL(all, prefix, suffix, url);
					}
				}
			}
		}
		URL[] urlArray = (URL[]) all.toArray(new URL[all.size()]);
		return urlArray;
	}

    private static boolean searchDir(Set result, File file, String suffix) 
            throws IOException {
		if (file.exists() && file.isDirectory()) {
			File[] fc = file.listFiles();
			String path;
			URL src;
			for (int i = 0; i < fc.length; i++) {
				path = fc[i].getAbsolutePath();
				if (fc[i].isDirectory()) {
					searchDir(result, fc[i], suffix);
				} else if (path.endsWith(suffix)) {
					// result.add(new URL("file:/" + path));
					result.add(fc[i].toURL());
				}
			}
			return true;
		}
		return false;
	}

    /**
	 * Search from URL. Fall back on prefix tokens if not able to read from
	 * original url param.
	 * 
	 * @param result the result urls
	 * @param prefix the current prefix
	 * @param suffix the suffix to match
	 * @param url the current url to start search
	 * @throws IOException for any error
	 */
	private static void searchFromURL(Set result, String prefix, String suffix,
			URL url) throws IOException {
		boolean done = false;
		InputStream is = getInputStream(url);
		if (is != null) {
			try {
				ZipInputStream zis;
				if (is instanceof ZipInputStream)
					zis = (ZipInputStream) is;
				else
					zis = new ZipInputStream(is);
				try {
					ZipEntry entry = zis.getNextEntry();
					// initial entry should not be null
					// if we assume this is some inner jar
					done = (entry != null);
					while (entry != null) {
						String entryName = entry.getName();
						if (entryName.endsWith(suffix)) {
							String urlString = url.toExternalForm();
							result.add(new URL(urlString + entryName));
						}
						entry = zis.getNextEntry();
					}
				} finally {
					zis.close();
				}
			} catch (Exception ignore) {
			}
		}
		if (done == false && prefix.length() > 0) {
			// we add '/' at the end since join adds it as well
			String urlString = url.toExternalForm() + "/";
			String[] split = prefix.split("/");
			prefix = join(split, true);
			String end = join(split, false);
			int p = urlString.lastIndexOf(end);
			url = new URL(urlString.substring(0, p));
			searchFromURL(result, prefix, suffix, url);
		}
	}

	/**
	 * Join tokens, exlude last if param equals true.
	 * 
	 * @param tokens
	 *            the tokens
	 * @param excludeLast
	 *            do we exclude last token
	 * @return joined tokens
	 */
	private static String join(String[] tokens, boolean excludeLast) {
		StringBuffer join = new StringBuffer();
		for (int i = 0; i < tokens.length - (excludeLast ? 1 : 0); i++)
			join.append(tokens[i]).append("/");
		return join.toString();
	}

	/**
	 * Open input stream from url. Ignore any errors.
	 * 
	 * @param url
	 *            the url to open
	 * @return input stream or null if not possible
	 */
	private static InputStream getInputStream(URL url) {
		try {
			return url.openStream();
		} catch (Throwable t) {
			return null;
		}
	}

    /**
	 * For URLs to JARs that do not use JarURLConnection - allowed by the
	 * servlet spec - attempt to produce a JarFile object all the same. Known
	 * servlet engines that function like this include Weblogic and OC4J. This
	 * is not a full solution, since an unpacked WAR or EAR will not have JAR
	 * "files" as such.
	 */
	private static JarFile getAlternativeJarFile(URL url) throws IOException {
		String urlFile = url.getFile();
		// Trim off any suffix - which is prefixed by "!/" on Weblogic
		int separatorIndex = urlFile.indexOf("!/");

		// OK, didn't find that. Try the less safe "!", used on OC4J
		if (separatorIndex == -1) {
			separatorIndex = urlFile.indexOf('!');
		}

		if (separatorIndex != -1) {
			String jarFileUrl = urlFile.substring(0, separatorIndex);
			// And trim off any "file:" prefix.
			if (jarFileUrl.startsWith("file:")) {
				jarFileUrl = jarFileUrl.substring("file:".length());
                                jarFileUrl = URLDecoder.decode(jarFileUrl, "UTF-8");
			}
			return new JarFile(jarFileUrl);
		}
		return null;
	}

    private static void searchJar(ClassLoader cl, Set result, JarFile file,
            String prefix, String suffix) throws IOException {
		Enumeration e = file.entries();
		JarEntry entry;
		String name;
		while (e.hasMoreElements()) {
			try {
				entry = (JarEntry) e.nextElement();
			} catch (Throwable t) {
				continue;
			}
			name = entry.getName();
			if (name.startsWith(prefix) && name.endsWith(suffix)) {
				Enumeration e2 = cl.getResources(name);
				while (e2.hasMoreElements()) {
					result.add(e2.nextElement());
				}
			}
		}
	}

}