/**

  * 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.IOException;

 import java.io.InputStream;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 import java.net.URL;

 import java.util.Enumeration;

 import org.apidesign.bck2brwsr.core.JavaScriptBody;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 public class Console {

     public static String welcome() {

         return "HellofromBck2Brwsr";

     }

     public static String multiply() {

         return String.valueOf(Integer.MAX_VALUE / 2 + Integer.MAX_VALUE);

     }

     @JavaScriptBody(args = {"id", "attr"}, body = 

         "return window.document.getElementById(id)[attr].toString();")

     private static native Object getAttr(String id, String attr);

     @JavaScriptBody(args = {"id", "attr", "value"}, body = 

         "window.document.getElementById(id)[attr] = value;")

     private static native void setAttr(String id, String attr, Object value);

     @JavaScriptBody(args = {}, body = "window.close();")

     private static native void closeWindow();

     private static void log(String newText) {

         String id = "result";

         String attr = "value";

         setAttr(id, attr, getAttr(id, attr) + "\n" + newText);

         setAttr(id, "scrollTop", getAttr(id, "scrollHeight"));

     }

     public static void execute() throws Exception {

         String clazz = (String) getAttr("clazz", "value");

         String method = (String) getAttr("method", "value");

         Object res = invokeMethod(clazz, method);

         setAttr("result", "value", res);

     }

     public static void harness(String url) {

         log("Connecting to " + url);

         try {

             URL u = new URL(url);

             for (;;) {

                 String data = (String) u.getContent(new Class[] { String.class });

                 log("\nGot \"" + data + "\"");

                 if (data.isEmpty()) {

                     log("No data, exiting");

                     closeWindow();

                     break;

                 }

                 Case c = Case.parseData(data);

                 log("Invoking " + c.getClassName() + '.' + c.getMethodName() + " as request: " + c.getRequestId());

                 Object result = invokeMethod(c.getClassName(), c.getMethodName());

                 log("Result: " + result);

                 log("Sending back: " + url + "?request=" + c.getRequestId() + "&result=" + result);

                 u = new URL(url + "?request=" + c.getRequestId() + "&result=" + result);

             }

         } catch (Exception ex) {

             log(ex.getMessage());

         }

     }

     static String invoke(String clazz, String method) throws ClassNotFoundException, InvocationTargetException, IllegalAccessException {

         final Object r = invokeMethod(clazz, method);

         return r == null ? "null" : r.toString().toString();

     }

     /** Helper method that inspects the classpath and loads given resource

      * (usually a class file). Used while running tests in Rhino.

      * 

      * @param name resource name to find

      * @return the array of bytes in the given resource

      * @throws IOException I/O in case something goes wrong

      */

     public static byte[] read(String name) throws IOException {

         URL u = null;

         Enumeration<URL> en = Console.class.getClassLoader().getResources(name);

         while (en.hasMoreElements()) {

             u = en.nextElement();

         }

         if (u == null) {

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

         }

         try (InputStream is = u.openStream()) {

             byte[] arr;

             arr = new byte[is.available()];

             int offset = 0;

             while (offset < arr.length) {

                 int len = is.read(arr, offset, arr.length - offset);

                 if (len == -1) {

                     throw new IOException("Can't read " + name);

                 }

                 offset += len;

             }

             return arr;

         }

     }

     private static Object invokeMethod(String clazz, String method) 

     throws ClassNotFoundException, InvocationTargetException, 

     SecurityException, IllegalAccessException, IllegalArgumentException {

         Method found = null;

         Class<?> c = Class.forName(clazz);

         for (Method m : c.getMethods()) {

             if (m.getName().equals(method)) {

                 found = m;

             }

         }

         Object res;

         if (found != null) {

             res = found.invoke(null);

         } else {

             res = "Can't find method " + method + " in " + clazz;

         }

         return res;

     }

     private static final class Case {

         private final Object data;

         private Case(Object data) {

             this.data = data;

         }

         public static Case parseData(String s) {

             return new Case(toJSON(s));

         }

         public String getMethodName() {

             return value("methodName", data);

         }

         public String getClassName() {

             return value("className", data);

         }

         public String getRequestId() {

             return value("request", data);

         }

         @JavaScriptBody(args = "s", body = "return eval('(' + s + ')');")

         private static native Object toJSON(String s);

         @JavaScriptBody(args = {"p", "d"}, body = "return d[p].toString();")

         private static native String value(String p, Object d);

     }

 }