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);

        }

    }

}