/**

  * 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.awt.Desktop;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InterruptedIOException;

 import java.io.OutputStream;

 import java.io.Writer;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Enumeration;

 import java.util.LinkedHashSet;

 import java.util.List;

 import java.util.Set;

 import java.util.concurrent.CountDownLatch;

 import java.util.concurrent.TimeUnit;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.script.Invocable;

 import javax.script.ScriptEngine;

 import javax.script.ScriptEngineManager;

 import javax.script.ScriptException;

 import static org.apidesign.bck2brwsr.launcher.Bck2BrwsrLauncher.copyStream;

 import org.apidesign.vm4brwsr.Bck2Brwsr;

 import org.glassfish.grizzly.PortRange;

 import org.glassfish.grizzly.http.server.HttpHandler;

 import org.glassfish.grizzly.http.server.HttpServer;

 import org.glassfish.grizzly.http.server.NetworkListener;

 import org.glassfish.grizzly.http.server.Request;

 import org.glassfish.grizzly.http.server.Response;

 import org.glassfish.grizzly.http.server.ServerConfiguration;

 /**

  * Lightweight server to launch Bck2Brwsr applications in real browser.

  */

 public class Bck2BrwsrLauncher {

     private Set<ClassLoader> loaders = new LinkedHashSet<>();

     private List<MethodInvocation> methods = new ArrayList<>();

     private long timeOut;

     private String sen;

     public MethodInvocation addMethod(Class<?> clazz, String method) {

         loaders.add(clazz.getClassLoader());

         MethodInvocation c = new MethodInvocation(clazz.getName(), method);

         methods.add(c);

         return c;

     }

     public void setTimeout(long ms) {

         timeOut = ms;

     }

     public void setScriptEngineName(String sen) {

         this.sen = sen;

     }

     public static void main( String[] args ) throws Exception {

         Bck2BrwsrLauncher l = new Bck2BrwsrLauncher();

         final MethodInvocation[] cases = { 

             l.addMethod(Console.class, "welcome"),

             l.addMethod(Console.class, "multiply"),

         };

         l.execute();

         for (MethodInvocation c : cases) {

             System.err.println(c.className + "." + c.methodName + " = " + c.result);

         }

     }

     public void execute() throws IOException {

         try {

             if (sen != null) {

                 executeRhino();

             } else {

                 executeInBrowser();

             }

         } catch (InterruptedException ex) {

             final InterruptedIOException iio = new InterruptedIOException(ex.getMessage());

             iio.initCause(ex);

             throw iio;

         } catch (Exception ex) {

             if (ex instanceof IOException) {

                 throw (IOException)ex;

             }

             if (ex instanceof RuntimeException) {

                 throw (RuntimeException)ex;

             }

             throw new IOException(ex);

         }

     }

     private void executeRhino() throws IOException, ScriptException, NoSuchMethodException {

         StringBuilder sb = new StringBuilder();

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

         ScriptEngineManager sem = new ScriptEngineManager();

         ScriptEngine mach = sem.getEngineByExtension(sen);

         sb.append(

               "\nvar vm = bck2brwsr(org.apidesign.bck2brwsr.vmtest.VMTest.read);"

             + "\nfunction initVM() { return vm; };"

             + "\n");

         Object res = mach.eval(sb.toString());

         if (!(mach instanceof Invocable)) {

             throw new IOException("It is invocable object: " + res);

         }

         Invocable code = (Invocable) mach;

         Object vm = code.invokeFunction("initVM");

         Object console = code.invokeMethod(vm, "loadClass", Console.class.getName());

         final MethodInvocation[] cases = this.methods.toArray(new MethodInvocation[0]);

         for (MethodInvocation mi : cases) {

             mi.result = code.invokeMethod(console, 

                 "invoke__Ljava_lang_String_2Ljava_lang_String_2Ljava_lang_String_2", 

                 mi.className, mi.methodName

             ).toString();

         }

     }

     private void executeInBrowser() throws InterruptedException, URISyntaxException, IOException {

         final CountDownLatch wait = new CountDownLatch(1);

         final MethodInvocation[] cases = this.methods.toArray(new MethodInvocation[0]);

         HttpServer server = HttpServer.createSimpleServer(".", new PortRange(8080, 65535));

         Res resources = new Res();

         final ServerConfiguration conf = server.getServerConfiguration();

         conf.addHttpHandler(new Page("console.xhtml", 

             "org.apidesign.bck2brwsr.launcher.Console", "welcome", "false"

         ), "/console");

         conf.addHttpHandler(new VM(resources), "/bck2brwsr.js");

         conf.addHttpHandler(new VMInit(), "/vm.js");

         conf.addHttpHandler(new Classes(resources), "/classes/");

         conf.addHttpHandler(new HttpHandler() {

             int cnt;

             @Override

             public void service(Request request, Response response) throws Exception {

                 String id = request.getParameter("request");

                 String value = request.getParameter("result");

                 if (id != null && value != null) {

                     value = value.replace("%20", " ");

                     cases[Integer.parseInt(id)].result = value;

                 }

                 if (cnt >= cases.length) {

                     response.getWriter().write("");

                     wait.countDown();

                     cnt = 0;

                     return;

                 }

                 response.getWriter().write("{"

                     + "className: '" + cases[cnt].className + "', "

                     + "methodName: '" + cases[cnt].methodName + "', "

                     + "request: " + cnt

                     + "}");

                 cnt++;

             }

         }, "/data");

         conf.addHttpHandler(new Page("harness.xhtml"), "/");

         server.start();

         NetworkListener listener = server.getListeners().iterator().next();

         int port = listener.getPort();

         URI uri = new URI("http://localhost:" + port + "/execute");

         try {

             Desktop.getDesktop().browse(uri);

         } catch (UnsupportedOperationException ex) {

             String[] cmd = { 

                 "xdg-open", uri.toString()

             };

             Runtime.getRuntime().exec(cmd).waitFor();

         }

         wait.await(timeOut, TimeUnit.MILLISECONDS);

         server.stop();

     }

     static void copyStream(InputStream is, OutputStream os, String baseURL, String... params) throws IOException {

         for (;;) {

             int ch = is.read();

             if (ch == -1) {

                 break;

             }

             if (ch == '$') {

                 int cnt = is.read() - '0';

                 if (cnt == 'U' - '0') {

                     os.write(baseURL.getBytes());

                 }

                 if (cnt < params.length) {

                     os.write(params[cnt].getBytes());

                 }

             } else {

                 os.write(ch);

             }

         }

     }

     private class Res implements Bck2Brwsr.Resources {

         @Override

         public InputStream get(String resource) throws IOException {

             for (ClassLoader l : loaders) {

                 URL u = null;

                 Enumeration<URL> en = l.getResources(resource);

                 while (en.hasMoreElements()) {

                     u = en.nextElement();

                 }

                 if (u != null) {

                     return u.openStream();

                 }

             }

             throw new IOException("Can't find " + resource);

         }

     }

     private static class Page extends HttpHandler {

         private final String resource;

         private final String[] args;

         public Page(String resource, String... args) {

             this.resource = resource;

             this.args = args;

         }

         @Override

         public void service(Request request, Response response) throws Exception {

             response.setContentType("text/html");

             OutputStream os = response.getOutputStream();

             InputStream is = Bck2BrwsrLauncher.class.getResourceAsStream(resource);

             copyStream(is, os, request.getRequestURL().toString(), args);

         }

     }

     private static class VM extends HttpHandler {

         private final Res loader;

         public VM(Res loader) {

             this.loader = loader;

         }

         @Override

         public void service(Request request, Response response) throws Exception {

             response.setCharacterEncoding("UTF-8");

             response.setContentType("text/javascript");

             Bck2Brwsr.generate(response.getWriter(), loader);

         }

     }

     private static class VMInit extends HttpHandler {

         public VMInit() {

         }

         @Override

         public void service(Request request, Response response) throws Exception {

             response.setCharacterEncoding("UTF-8");

             response.setContentType("text/javascript");

             response.getWriter().append(

                 "function ldCls(res) {\n"

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

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

                 + "  request.send();\n"

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

                 + "  return arr;\n"

                 + "}\n"

                 + "var vm = new bck2brwsr(ldCls);\n");

         }

     }

     private static class Classes extends HttpHandler {

         private final Res loader;

         public Classes(Res loader) {

             this.loader = loader;

         }

         @Override

         public void service(Request request, Response response) throws Exception {

             String res = request.getHttpHandlerPath();

             if (res.startsWith("/")) {

                 res = res.substring(1);

             }

             try (InputStream is = loader.get(res)) {

                 response.setContentType("text/javascript");

                 Writer w = response.getWriter();

                 w.append("[");

                 for (int i = 0;; i++) {

                     int b = is.read();

                     if (b == -1) {

                         break;

                     }

                     if (i > 0) {

                         w.append(", ");

                     }

                     if (i % 20 == 0) {

                         w.write("\n");

                     }

                     if (b > 127) {

                         b = b - 256;

                     }

                     w.append(Integer.toString(b));

                 }

                 w.append("\n]");

             } catch (IOException ex) {

                 response.setError();

                 response.setDetailMessage(ex.getMessage());

             }

         }

     }

     public static final class MethodInvocation {

         final String className;

         final String methodName;

         String result;

         MethodInvocation(String className, String methodName) {

             this.className = className;

             this.methodName = methodName;

         }

         @Override

         public String toString() {

             return result;

         }

     }

 }