package org.apidesign.bck2brwsr.mavenhtml;

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

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

 @Page(xhtml="Calculator.xhtml")

 public class App {

     private static final int OP_PLUS = 1;

     private static final int OP_MINUS = 2;

     private static final int OP_MUL = 3;

     private static final int OP_DIV = 4;

     static double memory = 0;

     static int operation = 0;

     @OnClick(id="clear")

     static void clear() {

         setValue(0.0);

     }

     private static void setValue(double v) {

         StringBuilder sb = new StringBuilder();

         sb.append(v);

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

     }

     private static double getValue() {

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

     }

     @OnClick(id="plus")

     static void plus() {

         memory = getValue();

         operation = OP_PLUS;

         setValue(0.0);

     }

     @OnClick(id="minus")

     static void minus() {

         memory = getValue();

         operation = OP_MINUS;

         setValue(0.0);

     }

     @OnClick(id="mul")

     static void mul() {

         memory = getValue();

         operation = OP_MUL;

         setValue(0.0);

     }

     @OnClick(id="result")

     static void computeTheValue() {

         switch (operation) {

             case 0: break;

             case OP_PLUS: setValue(memory + getValue()); break;

             case OP_MINUS: setValue(memory - getValue()); break;

             case OP_MUL: setValue(memory * getValue()); break;

         }

     }

     @OnClick(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 ("0".equals(v) || v == null) {

             Calculator.DISPLAY.setValue(digit);

         } else {

             Calculator.DISPLAY.setValue(v + digit);

         }

     }

 }