/**

  * 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.File;

 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.nio.file.Files;

 import java.util.ArrayList;

 import java.util.Arrays;

 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 and tests.

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

  * execution engine.

  */

 public class Bck2BrwsrLauncher {

     private static final Logger LOG = Logger.getLogger(Bck2BrwsrLauncher.class.getName());

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

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

     private long timeOut;

     private String sen;

     private String showURL;

     private final Res resources = new Res();

     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 void setStartPage(String startpage) {

         if (!startpage.startsWith("/")) {

             startpage = "/" + startpage;

         }

         this.showURL = startpage;

     }

     public void addClassLoader(ClassLoader url) {

         this.loaders.add(url);

     }

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

         Bck2BrwsrLauncher l = new Bck2BrwsrLauncher();

         l.setStartPage("org/apidesign/bck2brwsr/launcher/console.xhtml");

         l.addClassLoader(Bck2BrwsrLauncher.class.getClassLoader());

         l.execute();

         System.in.read();

     }

     public void execute() throws IOException {

         try {

             if (sen != null) {

                 executeRhino();

             } else if (showURL != null) {

                 HttpServer server = initServer();

                 server.getServerConfiguration().addHttpHandler(new Page(resources, null), "/");

                 launchServerAndBrwsr(server, showURL);

             } 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 = new bck2brwsr(org.apidesign.bck2brwsr.launcher.Console.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 HttpServer initServer() {

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

         final ServerConfiguration conf = server.getServerConfiguration();

         conf.addHttpHandler(new Page(resources, 

             "org/apidesign/bck2brwsr/launcher/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/");

         return server;

     }

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

         final CountDownLatch wait = new CountDownLatch(1);

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

         HttpServer server = initServer();

         ServerConfiguration conf = server.getServerConfiguration();

         conf.addHttpHandler(new Page(resources, 

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

         ), "/execute");

         final int[] currentTest = { -1 };

         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) {

                     LOG.log(Level.INFO, "Received result for case {0} = {1}", new Object[]{id, value});

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

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

                 }

                 currentTest[0] = cnt;

                 if (cnt >= cases.length) {

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

                     wait.countDown();

                     cnt = 0;

                     return;

                 }

                 final String cn = cases[cnt].className;

                 final String mn = cases[cnt].methodName;

                 LOG.log(Level.INFO, "Request for {0} case. Sending {1}.{2}", new Object[]{cnt, cn, mn});

                 response.getWriter().write("{"

                     + "className: '" + cn + "', "

                     + "methodName: '" + mn + "', "

                     + "request: " + cnt

                     + "}");

                 cnt++;

             }

         }, "/data");

         Object[] brwsr = launchServerAndBrwsr(server, "/execute");

         for (;;) {

             int prev = currentTest[0];

             if (wait.await(timeOut, TimeUnit.MILLISECONDS)) {

                 break;

             }

             if (prev == currentTest[0]) {

                 LOG.log(

                     Level.WARNING, 

                     "Timeout and no test has been executed meanwhile (at {0}). Giving up.", 

                     currentTest[0]

                 );

                 break;

             }

             LOG.log(Level.INFO, 

                 "Timeout, but tests got from {0} to {1}. Trying again.", 

                 new Object[]{prev, currentTest[0]}

             );

         }

         stopServerAndBrwsr(server, brwsr);

     }

     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 Object[] launchServerAndBrwsr(HttpServer server, final String page) throws IOException, URISyntaxException, InterruptedException {

         server.start();

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

         int port = listener.getPort();

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

         LOG.log(Level.INFO, "Showing {0}", uri);

         try {

             Desktop.getDesktop().browse(uri);

             return null;

         } catch (UnsupportedOperationException ex) {

             File dir = File.createTempFile("chrome", ".dir");

             dir.delete();

             dir.mkdirs();

             String[] cmd = { 

                 "google-chrome", "--user-data-dir=" + dir, "--app=" + uri.toString()

             };

             LOG.log(Level.INFO, "Launching {0}", Arrays.toString(cmd));

             final Process process = Runtime.getRuntime().exec(cmd);

             return new Object[] { process, dir };

         }

     }

     private void stopServerAndBrwsr(HttpServer server, Object[] brwsr) throws IOException, InterruptedException {

         Process process = (Process)brwsr[0];

         server.stop();

         InputStream stdout = process.getInputStream();

         InputStream stderr = process.getErrorStream();

         drain("StdOut", stdout);

         drain("StdErr", stderr);

         process.destroy();

         int res = process.waitFor();

         LOG.log(Level.INFO, "Exit code: {0}", res);

         deleteTree((File)brwsr[1]);

     }

     private static void drain(String name, InputStream is) throws IOException {

         int av = is.available();

         if (av > 0) {

             StringBuilder sb = new StringBuilder();

             sb.append("v== ").append(name).append(" ==v\n");

             while (av-- > 0) {

                 sb.append((char)is.read());

             }

             sb.append("\n^== ").append(name).append(" ==^");

             LOG.log(Level.INFO, sb.toString());

         }

     }

     private void deleteTree(File file) {

         File[] arr = file.listFiles();

         if (arr != null) {

             for (File s : arr) {

                 deleteTree(s);

             }

         }

         file.delete();

     }

     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;

         private final Res res;

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

             this.res = res;

             this.resource = resource;

             this.args = args;

         }

         @Override

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

             String r = resource;

             if (r == null) {

                 r = request.getHttpHandlerPath();

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

                     r = r.substring(1);

                 }

             }

             if (r.endsWith(".html") || r.endsWith(".xhtml")) {

                 response.setContentType("text/html");

             }

             OutputStream os = response.getOutputStream();

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

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

             } catch (IOException ex) {

                 response.setDetailMessage(ex.getLocalizedMessage());

                 response.setError();

                 response.setStatus(404);

             }

         }

     }

     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;

         }

     }

 }