/**

 * 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;

        }

    }

}