/**

  * 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.Closeable;

 import java.io.File;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InterruptedIOException;

 import java.io.OutputStream;

 import java.io.UnsupportedEncodingException;

 import java.io.Writer;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.net.URL;

 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.BlockingQueue;

 import java.util.concurrent.CountDownLatch;

 import java.util.concurrent.LinkedBlockingQueue;

 import java.util.concurrent.TimeUnit;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import org.apidesign.bck2brwsr.launcher.InvocationContext.Resource;

 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;

 import org.glassfish.grizzly.http.util.HttpStatus;

 /**

  * Lightweight server to launch Bck2Brwsr applications and tests.

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

  * execution engine.

  */

 class Bck2BrwsrLauncher extends Launcher implements Closeable {

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

     private static final InvocationContext END = new InvocationContext(null, null, null);

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

     private final BlockingQueue<InvocationContext> methods = new LinkedBlockingQueue<>();

     private long timeOut;

     private final Res resources = new Res();

     private final String cmd;

     private Object[] brwsr;

     private HttpServer server;

     private CountDownLatch wait;

     public Bck2BrwsrLauncher(String cmd) {

         this.cmd = cmd;

     }

     @Override

     InvocationContext runMethod(InvocationContext c) throws IOException {

         loaders.add(c.clazz.getClassLoader());

         methods.add(c);

         try {

             c.await(timeOut);

         } catch (InterruptedException ex) {

             throw new IOException(ex);

         }

         return c;

     }

     public void setTimeout(long ms) {

         timeOut = ms;

     }

     public void addClassLoader(ClassLoader url) {

         this.loaders.add(url);

     }

     ClassLoader[] loaders() {

         return loaders.toArray(new ClassLoader[loaders.size()]);

     }

     public void showURL(String startpage) throws IOException {

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

             startpage = "/" + startpage;

         }

         HttpServer s = initServer(".", true);

         int last = startpage.lastIndexOf('/');

         String prefix = startpage.substring(0, last);

         String simpleName = startpage.substring(last);

         s.getServerConfiguration().addHttpHandler(new SubTree(resources, prefix), "/");

         try {

             launchServerAndBrwsr(s, simpleName);

         } catch (URISyntaxException | InterruptedException ex) {

             throw new IOException(ex);

         }

     }

     void showDirectory(File dir, String startpage) throws IOException {

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

             startpage = "/" + startpage;

         }

         HttpServer s = initServer(dir.getPath(), false);

         try {

             launchServerAndBrwsr(s, startpage);

         } catch (URISyntaxException | InterruptedException ex) {

             throw new IOException(ex);

         }

     }

     @Override

     public void initialize() throws IOException {

         try {

             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 HttpServer initServer(String path, boolean addClasses) throws IOException {

         HttpServer s = HttpServer.createSimpleServer(path, new PortRange(8080, 65535));

         final ServerConfiguration conf = s.getServerConfiguration();

         if (addClasses) {

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

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

         }

         return s;

     }

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

         wait = new CountDownLatch(1);

         server = initServer(".", true);

         final ServerConfiguration conf = server.getServerConfiguration();

         class DynamicResourceHandler extends HttpHandler {

             private final InvocationContext ic;

             public DynamicResourceHandler(InvocationContext ic) {

                 if (ic == null || ic.resources.isEmpty()) {

                     throw new NullPointerException();

                 }

                 this.ic = ic;

                 for (Resource r : ic.resources) {

                     conf.addHttpHandler(this, r.httpPath);

                 }

             }

             public void close() {

                 conf.removeHttpHandler(this);

             }

             @Override

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

                 for (Resource r : ic.resources) {

                     if (r.httpPath.equals(request.getRequestURI())) {

                         LOG.log(Level.INFO, "Serving HttpResource for {0}", request.getRequestURI());

                         response.setContentType(r.httpType);

                         r.httpContent.reset();

                         String[] params = null;

                         if (r.parameters.length != 0) {

                             params = new String[r.parameters.length];

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

                                 params[i] = request.getParameter(r.parameters[i]);

                             }

                         }

                         copyStream(r.httpContent, response.getOutputStream(), null, params);

                     }

                 }

             }

         }

         conf.addHttpHandler(new Page(resources, 

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

         ), "/execute");

         conf.addHttpHandler(new HttpHandler() {

             int cnt;

             List<InvocationContext> cases = new ArrayList<>();

             DynamicResourceHandler prev;

             @Override

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

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

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

                 if (value != null && value.indexOf((char)0xC5) != -1) {

                     value = toUTF8(value);

                 }

                 InvocationContext mi = null;

                 int caseNmbr = -1;

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

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

                     value = decodeURL(value);

                     int indx = Integer.parseInt(id);

                     cases.get(indx).result(value, null);

                     if (++indx < cases.size()) {

                         mi = cases.get(indx);

                         LOG.log(Level.INFO, "Re-executing case {0}", indx);

                         caseNmbr = indx;

                     }

                 } else {

                     if (!cases.isEmpty()) {

                         LOG.info("Re-executing test cases");

                         mi = cases.get(0);

                         caseNmbr = 0;

                     }

                 }

                 if (prev != null) {

                     prev.close();

                     prev = null;

                 }

                 if (mi == null) {

                     mi = methods.take();

                     caseNmbr = cnt++;

                 }

                 if (mi == END) {

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

                     wait.countDown();

                     cnt = 0;

                     LOG.log(Level.INFO, "End of data reached. Exiting.");

                     return;

                 }

                 if (!mi.resources.isEmpty()) {

                     prev = new DynamicResourceHandler(mi);

                 }

                 cases.add(mi);

                 final String cn = mi.clazz.getName();

                 final String mn = mi.methodName;

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

                 response.getWriter().write("{"

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

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

                     + "request: " + caseNmbr

                 );

                 if (mi.html != null) {

                     response.getWriter().write(", html: '");

                     response.getWriter().write(encodeJSON(mi.html));

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

                 }

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

             }

         }, "/data");

         this.brwsr = launchServerAndBrwsr(server, "/execute");

     }

     private static String encodeJSON(String in) {

         StringBuilder sb = new StringBuilder();

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

             char ch = in.charAt(i);

             if (ch < 32 || ch == '\'' || ch == '"') {

                 sb.append("\\u");

                 String hs = "0000" + Integer.toHexString(ch);

                 hs = hs.substring(hs.length() - 4);

                 sb.append(hs);

             } else {

                 sb.append(ch);

             }

         }

         return sb.toString();

     }

     @Override

     public void shutdown() throws IOException {

         methods.offer(END);

         for (;;) {

             int prev = methods.size();

             try {

                 if (wait != null && wait.await(timeOut, TimeUnit.MILLISECONDS)) {

                     break;

                 }

             } catch (InterruptedException ex) {

                 throw new IOException(ex);

             }

             if (prev == methods.size()) {

                 LOG.log(

                     Level.WARNING, 

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

                     methods.size()

                 );

                 break;

             }

             LOG.log(Level.INFO, 

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

                 new Object[]{prev, methods.size()}

             );

         }

         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 == '$' && params.length > 0) {

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

                 if (baseURL != null && cnt == 'U' - '0') {

                     os.write(baseURL.getBytes("UTF-8"));

                 } else {

                     if (cnt >= 0 && cnt < params.length) {

                         os.write(params[cnt].getBytes("UTF-8"));

                     } else {

                         os.write('$');

                         os.write(cnt + '0');

                     }

                 }

             } 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);

         return showBrwsr(uri);

     }

     private static String toUTF8(String value) throws UnsupportedEncodingException {

         byte[] arr = new byte[value.length()];

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

             arr[i] = (byte)value.charAt(i);

         }

         return new String(arr, "UTF-8");

     }

     private static String decodeURL(String s) {

         for (;;) {

             int pos = s.indexOf('%');

             if (pos == -1) {

                 return s;

             }

             int i = Integer.parseInt(s.substring(pos + 1, pos + 2), 16);

             s = s.substring(0, pos) + (char)i + s.substring(pos + 2);

         }

     }

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

         if (brwsr == null) {

             return;

         }

         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;

         try {

             res = process.waitFor();

         } catch (InterruptedException ex) {

             throw new IOException(ex);

         }

         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) {

         if (file == null) {

             return;

         }

         File[] arr = file.listFiles();

         if (arr != null) {

             for (File s : arr) {

                 deleteTree(s);

             }

         }

         file.delete();

     }

     @Override

     public void close() throws IOException {

         shutdown();

     }

     protected Object[] showBrwsr(URI uri) throws IOException {

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

         if (cmd == null) {

             try {

                 LOG.log(Level.INFO, "Trying Desktop.browse on {0} {2} by {1}", new Object[] {

                     System.getProperty("java.vm.name"),

                     System.getProperty("java.vm.vendor"),

                     System.getProperty("java.vm.version"),

                 });

                 java.awt.Desktop.getDesktop().browse(uri);

                 LOG.log(Level.INFO, "Desktop.browse successfully finished");

                 return null;

             } catch (UnsupportedOperationException ex) {

                 LOG.log(Level.INFO, "Desktop.browse not supported: {0}", ex.getMessage());

                 LOG.log(Level.FINE, null, ex);

             }

         }

         {

             String cmdName = cmd == null ? "xdg-open" : cmd;

             String[] cmdArr = { 

                 cmdName, uri.toString()

             };

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

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

             return new Object[] { process, null };

         }

     }

     void generateBck2BrwsrJS(StringBuilder sb, Bck2Brwsr.Resources loader) throws IOException {

         Bck2Brwsr.generate(sb, loader);

         sb.append(

             "(function WrapperVM(global) {"

             + "  function ldCls(res) {\n"

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

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

             + "    request.send();\n"

             + "    if (request.status !== 200) return null;\n"

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

     }

     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 {

         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.length == 0 ? new String[] { "$0" } : args;

         }

         @Override

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

             String r = computePage(request);

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

                 r = r.substring(1);

             }

             String[] replace = {};

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

                 response.setContentType("text/html");

                 LOG.info("Content type text/html");

                 replace = args;

             }

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

                 response.setContentType("application/xhtml+xml");

                 LOG.info("Content type application/xhtml+xml");

                 replace = args;

             }

             OutputStream os = response.getOutputStream();

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

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

             } catch (IOException ex) {

                 response.setDetailMessage(ex.getLocalizedMessage());

                 response.setError();

                 response.setStatus(404);

             }

         }

         protected String computePage(Request request) {

             String r = resource;

             if (r == null) {

                 r = request.getHttpHandlerPath();

             }

             return r;

         }

     }

     private static class SubTree extends Page {

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

             super(res, resource, args);

         }

         @Override

         protected String computePage(Request request) {

             return resource + request.getHttpHandlerPath();

         }

     }

     private class VM extends HttpHandler {

         @Override

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

             response.setCharacterEncoding("UTF-8");

             response.setContentType("text/javascript");

             StringBuilder sb = new StringBuilder();

             generateBck2BrwsrJS(sb, Bck2BrwsrLauncher.this.resources);

             response.getWriter().write(sb.toString());

         }

     }

     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.setStatus(HttpStatus.NOT_FOUND_404);

                 response.setError();

                 response.setDetailMessage(ex.getMessage());

             }

         }

     }

 }