/**

  * 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.bck2brwsr.launcher;

 import java.io.File;

 import java.io.FileReader;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.Reader;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.jar.JarFile;

 import java.util.logging.Level;

 import org.apidesign.vm4brwsr.Bck2Brwsr;

 /**

  * Lightweight server to launch Bck2Brwsr applications and tests.

  * Supports execution in native browser as well as Java's internal 

  * execution engine.

  */

 final class Bck2BrwsrLauncher extends BaseHTTPLauncher {

     public Bck2BrwsrLauncher(String cmd) {

         super(cmd);

     }

     @Override

     String harnessResource() {

         return "org/apidesign/bck2brwsr/launcher/harness.xhtml";

     }

     @Override

     String compileJar(JarFile jar) throws IOException {

         return CompileCP.compileJAR(jar);

     }

     @Override String compileFromClassPath(URL f, Res loader) throws IOException {

         return CompileCP.compileFromClassPath(f, loader);

     }

     @Override

     void generateBck2BrwsrJS(StringBuilder sb, final Res loader) throws IOException {

         String b2b = System.getProperty("bck2brwsr.js");

         if (b2b != null) {

             LOG.log(Level.INFO, "Serving bck2brwsr.js from {0}", b2b);

             URL bu;

             try {

                 bu = new URL(b2b);

             } catch (MalformedURLException ex) {

                 File f = new File(b2b);

                 if (f.exists()) {

                     bu = f.toURI().toURL();

                 } else {

                     throw ex;

                 }

             }

             try (Reader r = new InputStreamReader(bu.openStream())) {

                 char[] arr = new char[4096];

                 for (;;) {

                    int len = r.read(arr);

                    if (len == -1) {

                        break;

                    }

                    sb.append(arr, 0, len);

                 }

             }

         } else {

             LOG.log(Level.INFO, "Generating bck2brwsr.js from scratch", b2b);

             CompileCP.compileVM(sb, loader);

         }

         sb.append(

               "(function WrapperVM(global) {\n"

             + "  var cache = {};\n"

             + "  function ldCls(res, skip) {\n"

             + "    var c = cache[res];\n"

             + "    if (c) {\n"

             + "      if (c[skip]) return c[skip];\n"

             + "      if (c[skip] === null) return null;\n"

             + "    } else {\n"

             + "      cache[res] = c = new Array();\n"

             + "    }\n"

             + "    var request = new XMLHttpRequest();\n"

             + "    request.open('GET', '/classes/' + res + '?skip=' + skip, false);\n"

             + "    request.send();\n"

             + "    if (request.status !== 200) {\n"

             + "      c[skip] = null;\n"

             + "      return null;\n"

             + "    }\n"

             + "    var arr = eval(request.responseText);\n"

             + "    c[skip] = arr;\n"

             + "    return arr;\n"

             + "  }\n"

             + "  var prevvm = global.bck2brwsr;\n"

             + "  global.bck2brwsr = function() {\n"

             + "    var args = Array.prototype.slice.apply(arguments);\n"

             + "    args.unshift(ldCls);\n"

             + "    return prevvm.apply(null, args);\n"

             + "  };\n"

             + "  global.bck2brwsr.registerExtension = prevvm.registerExtension;\n"

             + "})(this);\n"

         );

         LOG.log(Level.INFO, "Serving bck2brwsr.js", b2b);

     }

 }