/**

 * 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();

    }

}