/**

  * 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.demo.calc;

 import java.util.List;

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

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

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

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

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

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

 /** 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", properties = {

     @Property(name = "memory", type = double.class),

     @Property(name = "display", type = double.class),

     @Property(name = "operation", type = String.class),

     @Property(name = "hover", type = boolean.class),

     @Property(name = "history", type = double.class, array = true)

 })

 public class Calc {

     static {

         new Calculator().applyBindings().setOperation("plus");

     }

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

     static void clear(Calculator c) {

         c.setMemory(0);

         c.setOperation(null);

         c.setDisplay(0);

     }

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

     static void applyOp(Calculator c, String id) {

         c.setMemory(c.getDisplay());

         c.setOperation(id);

         c.setDisplay(0);

     }

     @On(event = MOUSE_OVER, id= { "result" })

     static void attemptingIn(Calculator c) {

         c.setHover(true);

     }

     @On(event = MOUSE_OUT, id= { "result" })

     static void attemptingOut(Calculator c) {

         c.setHover(false);

     }

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

     static void computeTheValue(Calculator c) {

         final double newValue = compute(

             c.getOperation(), 

             c.getMemory(), 

             c.getDisplay()

         );

         c.setDisplay(newValue);

         c.getHistory().add(newValue);

         c.setMemory(0);

     }

     @OnFunction

     static void recoverMemory(Calculator c, double data) {

         c.setDisplay(data);

     }

     @OnFunction

     static void removeMemory(Calculator c, double data) {

         c.getHistory().remove(data);

     }

     private static double compute(String op, double memory, double display) {

         switch (op) {

             case "plus": return memory + display;

             case "minus": return memory - display;

             case "mul": return memory * display;

             case "div": return memory / display;

             default: throw new IllegalStateException(op);

         }

     }

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

     static void addDigit(String id, Calculator c) {

         id = id.substring(1);

         double v = c.getDisplay();

         if (v == 0.0) {

             c.setDisplay(Integer.parseInt(id));

         } else {

             String txt = Double.toString(v);

             if (txt.endsWith(".0")) {

                 txt = txt.substring(0, txt.length() - 2);

             }

             txt = txt + id;

             c.setDisplay(Double.parseDouble(txt));

         }

     }

     @ComputedProperty

     public static String displayPreview(

         double display, boolean hover, double memory, String operation

     ) {

         if (!hover) {

             return "Type numbers and perform simple operations! Press '=' to get result.";

         }

         return "Attempt to compute " + memory + " " + operation + " " + display + " = " + compute(operation, memory, display);

     }

     @ComputedProperty

     static boolean emptyHistory(List<?> history) {

         return history.isEmpty();

     }

 }