/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * 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, version 2 of the License.

 *

 * 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. Look for COPYING file in the top folder.

 * If not, see http://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.vm4brwsr;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

import java.io.Writer;

import java.net.URI;

import java.net.URISyntaxException;

import java.net.URL;

import java.util.Enumeration;

import java.util.jar.JarEntry;

import java.util.jar.JarFile;

/** Generator of JavaScript from bytecode of classes on classpath of the VM

 * with a Main method.

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

final class Main {

    private Main() {}

    public static void main(String... args) throws IOException, URISyntaxException {

        final String obfuscate = "--obfuscatelevel";

        final String extension = "--createextension";

        if (args.length < 2) {

            System.err.println("Bck2Brwsr Translator from Java(tm) to JavaScript, (c) Jaroslav Tulach 2012");

            System.err.print("Usage: java -cp ... -jar ... [");

            System.err.print(obfuscate);

            System.err.print(" [");

            boolean first = true;

            for (ObfuscationLevel l : ObfuscationLevel.values()) {

                if (!first) {

                    System.err.print('|');

                }

                System.err.print(l.name());

                first = false;

            }

            System.err.print("]] [");

            System.err.print(extension);

            System.err.println("] <file_to_generate_js_code_to> java/lang/Class org/your/App ...");

            System.exit(9);

        }

        final ClassLoader mainClassLoader = Main.class.getClassLoader();

        ObfuscationLevel obfLevel = ObfuscationLevel.NONE;

        boolean createExtension = false;

        StringArray classes = new StringArray();

        String generateTo = null;

        for (int i = 0; i < args.length; i++) {

            if (obfuscate.equals(args[i])) { // NOI18N

                i++;

                try {

                    obfLevel = ObfuscationLevel.valueOf(args[i]);

                } catch (Exception e) {

                    System.err.print(obfuscate);

                    System.err.print(" parameter needs to be followed by one of ");

                    boolean first = true;

                    for (ObfuscationLevel l : ObfuscationLevel.values()) {

                        if (!first) {

                            System.err.print(", ");

                        }

                        System.err.print(l.name());

                        first = false;

                    }

                    System.err.println();

                    System.exit(1);

                }

                continue;

            }

            if (extension.equals(args[i])) { // NOI18N

                createExtension = true;

                continue;

            }

            if (generateTo == null) {

                generateTo = args[i];

            } else {

                collectClasses(classes, mainClassLoader, args[i]);

            }

        }

        File gt = new File(generateTo);

        if (Boolean.getBoolean("skip.if.exists") && gt.isFile()) {

            System.err.println("Skipping as " + gt + " exists.");

            System.exit(0);

        }

        try (Writer w = new BufferedWriter(new FileWriter(gt))) {

            Bck2Brwsr c = Bck2Brwsr.newCompiler().

                obfuscation(obfLevel).

                addRootClasses(classes.toArray()).

                resources(new LdrRsrcs(Main.class.getClassLoader(), true));

            if (createExtension) {

                c = c.library();

            }

            c.generate(w);

        }

    }

    private static void collectClasses(

            final StringArray dest,

            final ClassLoader cl, final String relativePath)

                throws IOException, URISyntaxException {

        final Enumeration<URL> urls = cl.getResources(relativePath);

        if (!urls.hasMoreElements()) {

            dest.add(relativePath);

            return;

        }

        do {

            final URL url = urls.nextElement();

            switch (url.getProtocol()) {

                case "file":

                    collectClasses(dest, relativePath,

                                   new File(new URI(url.toString())));

                    continue;

                case "jar":

                    final String fullPath = url.getPath();

                    final int sepIndex = fullPath.indexOf('!');

                    final String jarFilePath =

                            (sepIndex != -1) ? fullPath.substring(0, sepIndex)

                                             : fullPath;

                    final URI jarUri = new URI(jarFilePath);

                    if (jarUri.getScheme().equals("file")) {

                        try (JarFile jarFile = new JarFile(new File(jarUri))) {

                            collectClasses(dest, relativePath, jarFile);

                            continue;

                        }

                    }

                    break;

            }

            dest.add(relativePath);

        } while (urls.hasMoreElements());

    }

    private static void collectClasses(final StringArray dest,

                                       final String relativePath,

                                       final File file) {

        if (file.isDirectory()) {

            final File[] subFiles = file.listFiles();

            for (final File subFile: subFiles) {

                collectClasses(dest,

                               extendPath(relativePath, subFile.getName()),

                               subFile);

            }

            return;

        }

        final String filePath = file.getPath();

        if (filePath.endsWith(".class")) {

            validateAndAddClass(dest, relativePath);

        }

    }

    private static void collectClasses(final StringArray dest,

                                       final String relativePath,

                                       final JarFile jarFile) {

        if (relativePath.endsWith(".class")) {

            if (jarFile.getJarEntry(relativePath) != null) {

                validateAndAddClass(dest, relativePath);

            }

            return;

        }

        final String expectedPrefix =

                relativePath.endsWith("/") ? relativePath

                                           : relativePath + '/';

        final Enumeration<JarEntry> entries = jarFile.entries();

        while (entries.hasMoreElements()) {

            final JarEntry entry = entries.nextElement();

            if (!entry.isDirectory()) {

                final String entryName = entry.getName();

                if (entryName.startsWith(expectedPrefix)

                        && entryName.endsWith(".class")) {

                    validateAndAddClass(dest, entryName);

                }

            }

        }

    }

    private static String extendPath(final String relativePath,

                                     final String fileName) {

        return relativePath.endsWith("/") ? relativePath + fileName

                                          : relativePath + '/' + fileName;

    }

    private static void validateAndAddClass(final StringArray dest,

                                            final String relativePath) {

        final String className =

                relativePath.substring(0, relativePath.length() - 6);

        if (!className.endsWith("package-info")) {

            dest.add(className);

        }

    }

}