/**************************************************
*   Author: Morrison
*   Date:  01 Mar 2022
**************************************************/
import javafx.application.Application;
import javafx.application.Platform;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import java.util.function.DoubleBinaryOperator;
public class RPNCalc extends Application
{
    private TextField display;
    private NumberButton[] numButtons;
    private IStack<Double> theStack;
    public RPNCalc()
    {
        theStack = new AStack<>();//NOte: display is top of stack
        display = new TextField();
        display.setStyle("-fx-font-size:16pt;-fx-font-family:'Comic Sans MS';-fx-text-weight:bold;");
        numButtons = new NumberButton[12];
        for(int k = 0; k < 10; k++)
        {
            numButtons[k] = new NumberButton("" + k);
        }
        numButtons[10] = new NumberButton("E");
        numButtons[11] = new NumberButton(".");
    }

    @Override
    public void init()
    {
    }

    @Override
    public void start(Stage primary)
    {
        BorderPane bp = new BorderPane();
        bp.setCenter(makeNumPad());
        bp.setTop(display);
        bp.setBottom(makeOpPad());
        primary.setScene(new Scene(bp, 800, 500));
        primary.show();
    }
    private HBox makeOpPad()
    {
        HBox box = new HBox();
        OpButton plusButton = new OpButton("+", (x, y) -> x + y);
        OpButton timesButton = new OpButton("*", (x, y) -> x*y);
        box.getChildren().addAll(plusButton, timesButton);
        return box;
    }
    private GridPane makeNumPad()
    {
        GridPane numPad = new GridPane();
        numPad.setVgap(15);
        numPad.setHgap(10);
        numPad.add(numButtons[7], 0, 0);
        numPad.add(numButtons[8], 1, 0);
        numPad.add(numButtons[9], 2, 0);
        numPad.add(numButtons[4], 0, 1);
        numPad.add(numButtons[5], 1, 1);
        numPad.add(numButtons[6], 2, 1);
        numPad.add(numButtons[1], 0, 2);
        numPad.add(numButtons[2], 1, 2);
        numPad.add(numButtons[3], 2, 2);
        numPad.add(numButtons[10], 0, 3);
        numPad.add(numButtons[0], 1, 3);
        numPad.add(numButtons[11], 2, 3);
        Button enterButton = new Button("ENTER");
        enterButton.setOnAction( e ->
        {
            try
            {
                double item = Double.parseDouble(display.getText());
                theStack.push(item);
                System.out.println(theStack);
            }
            catch(NumberFormatException ex)
            {
                //TODO: decide how to handle
                System.err.println("QUACK");
            }
            finally
            {
                display.clear();
            }
        });
        numPad.add(enterButton, 0, 4);//TODO make colpan of 2.
        return numPad;
    }
    @Override
    public void stop()
    {
    }
    /************************Inner Classes***********/
    class NumberButton extends Button
    {
        private final String ch;
        public NumberButton(String ch)
        {
            super(ch);
            this.ch = ch;
            setOnAction( e ->
            {
                //when the button is pushed, 
                //the button's character is appended to the 
                //textfield.
                display.setText(display.getText() + ch);
            });
            setStyle("-fx-font-size:16pt;-fx-font-family:'Comic Sans MS';-fx-text-weight:bold;");
           setPrefSize(75,50);
        }
    }
    class OpButton extends Button
    {
        private String symbol;
        private DoubleBinaryOperator op;
        public OpButton(String symbol, DoubleBinaryOperator op)
        {
            super(symbol);
            this.op = op;
            setOnAction( e -> {
                try
                {
                    double first = theStack.pop();
                     double second = Double.parseDouble(display.getText());
                    //TODO: handle NumberFormatException
                    double result = op.applyAsDouble(first, second);
                    display.setText("" + result);
                }
                catch(EmptyStackException ex)
                {
                    //QUACK!!!
                    //TODO: Is there a better way to handle this?`
                }
            });
        }
    }
}