/**

  * 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.mavenhtml;

 import org.apidesign.bck2brwsr.htmlpage.api.On;

 import static org.apidesign.bck2brwsr.htmlpage.api.OnEvent.*;

 import org.apidesign.bck2brwsr.htmlpage.api.Page;

 /** HTML5 & Java demo showing the power of 

  * <a href="http://wiki.apidesign.org/wiki/AnnotationProcessor">annotation processors</a>

  * as well as other goodies.

  * 

  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  */

 @Page(xhtml="Calculator.xhtml")

 public class App {

     private static double memory;

     private static String operation;

     @On(event = CLICK, id="clear")

     static void clear() {

         memory = 0;

         operation = null;

         Calculator.DISPLAY.setValue("0");

     }

     @On(event = CLICK, id= { "plus", "minus", "mul", "div" })

     static void applyOp(String op) {

         memory = getValue();

         operation = op;

         Calculator.DISPLAY.setValue("0");

     }

     @On(event = CLICK, id="result")

     static void computeTheValue() {

         switch (operation) {

             case "plus": setValue(memory + getValue()); break;

             case "minus": setValue(memory - getValue()); break;

             case "mul": setValue(memory * getValue()); break;

             case "div": setValue(memory / getValue()); break;

             default: throw new IllegalStateException(operation);

         }

     }

     @On(event = CLICK, id={"n0", "n1", "n2", "n3", "n4", "n5", "n6", "n7", "n8", "n9"}) 

     static void addDigit(String digit) {

         digit = digit.substring(1);

         String v = Calculator.DISPLAY.getValue();

         if (getValue() == 0.0) {

             Calculator.DISPLAY.setValue(digit);

         } else {

             Calculator.DISPLAY.setValue(v + digit);

         }

     }

     private static void setValue(double v) {

         StringBuilder sb = new StringBuilder();

         sb.append(v);

         if (sb.toString().endsWith(".0")) {

             final int l = sb.length();

             sb.delete(l - 2, l);

         }

         Calculator.DISPLAY.setValue(sb.toString());

     }

     private static double getValue() {

         try {

             return Double.parseDouble(Calculator.DISPLAY.getValue());

         } catch (NumberFormatException ex) {

             Calculator.DISPLAY.setValue("err");

             return 0.0;

         }

     }

 }