/**

 * 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.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

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

        class R implements Bck2Brwsr.Resources {

            @Override

            public InputStream get(String resource) throws IOException {

                return loader.get(resource, 0);

            }

        }

        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);

            Bck2Brwsr.generate(sb, new R());

        }

        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"

            + "})(this);\n"

        );

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

    }

}