/**

 * 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;

        }

    }

}