/**

 * 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;

        }

    }

}