/* 
 * Copyright (C) 2015 Shashank Tulsyan <shashaank at neembuu.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package neembuu.uploader.utils;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

/**
 * Util methods for Class.
 * <a href="http://www.dzone.com/snippets/get-all-classes-within-package">Source</a>
 * @author Davide
 */
public class ClassUtils {
    
    /**
     * Test the methods.
     * @param args 
     * @throws java.lang.ClassNotFoundException 
     * @throws java.io.IOException 
     */
    public static void main(String args[]) throws ClassNotFoundException, IOException{
        Class[] classes = getClasses("neembuu.uploader.uploaders");
        for (Class class1 : classes) {
            NULogger.getLogger().info(class1.getName());
        }
    }

    /**
     * Scans all classes accessible from the context class loader which belong
     * to the given package and subpackages.
     *
     * @param packageName The base package
     * @return The classes
     * @throws ClassNotFoundException
     * @throws IOException
     */
    public static Class[] getClasses(String packageName)
            throws ClassNotFoundException, IOException {
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        assert classLoader != null;
        String path = packageName.replace('.', '/');
        Enumeration<URL> resources = classLoader.getResources(path);
        List<File> dirs = new ArrayList<File>();
        while (resources.hasMoreElements()) {
            URL resource = resources.nextElement();
            dirs.add(new File(resource.getFile()));
        }
        ArrayList<Class> classes = new ArrayList<Class>();
        for (File directory : dirs) {
            classes.addAll(findClasses(directory, packageName));
        }
        return classes.toArray(new Class[classes.size()]);
    }

    /**
     * Recursive method used to find all classes in a given directory and
     * subdirs.
     *
     * @param directory The base directory
     * @param packageName The package name for classes found inside the base
     * directory
     * @return The classes
     * @throws ClassNotFoundException
     */
    private static List<Class> findClasses(File directory, String packageName) throws ClassNotFoundException {
        List<Class> classes = new ArrayList<Class>();
        if (!directory.exists()) {
            return classes;
        }
        File[] files = directory.listFiles();
        for (File file : files) {
            if (file.isDirectory()) {
                //assert !file.getName().contains(".");
                //classes.addAll(findClasses(file, packageName + "." + file.getName()));
            } else if (file.getName().endsWith(".class")) {
                classes.add(Class.forName(packageName + '.' + file.getName().substring(0, file.getName().length() - 6)));
            }
        }
        return classes;
    }

}