/**************************************************
*   Author: Morrison
*   Date:  12 Apr 202021
**************************************************/

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.BorderPane;
import javafx.scene.layout.GridPane;
import java.util.function.DoubleBinaryOperator;

public class RPN extends Application
{
    private final TextField display;
    private final TextField stackShow;
    private NumberButton[] digits;
    private NumberButton decimalPoint;
    private NumberButton exponent;
    private Button clearButton;
    Button clearEntryButton;
    Button enterButton;
    IStack<Double> theStack;
    private OpButton plus;
    private OpButton times;
    public RPN()
    {
        display = new TextField();
        stackShow = new TextField();
        digits = new NumberButton[10];
        for(int k = 0; k < 10; k++)
        {
            digits[k] = new NumberButton((char)(0x30 + k));
        }
        decimalPoint = new NumberButton('.');
        clearButton = new Button("C");
        clearEntryButton = new Button("CE");
        enterButton = new Button("ENTER");
        exponent = new NumberButton('E');
        theStack = new AStack<>();
        plus = new OpButton( (x,y) -> x + y   , "+");
        times = new OpButton( (x,y) -> x*y, "*");
    }
    
    @Override
    public void init()
    {
    }

    @Override
    public void start(Stage primary)
    {
        BorderPane bp = new BorderPane();
        GridPane gp = new GridPane();
        gp.add(digits[7], 0, 0);
        gp.add(digits[8], 1, 0);
        gp.add(digits[9], 2, 0);
        gp.add(digits[4], 0, 1);
        gp.add(digits[5], 1, 1);
        gp.add(digits[6], 2, 1);
        gp.add(digits[1], 0, 2);
        gp.add(digits[2], 1, 2);
        gp.add(digits[3], 2, 2);
        gp.add(decimalPoint, 0, 3);
        gp.add(digits[0], 1, 3);
        gp.add(exponent, 2, 3);
        gp.add(plus, 3, 0);
        gp.add(times, 3, 1);
        gp.add(enterButton, 0, 4);
        enterButton.setOnAction( e ->
        {
            //contenst of display go to the stack.
            //TODO: Handle end-user stupidity
            double contents = Double.parseDouble(display.getText());
            //push on stack
            theStack.push(contents);
            stackShow.setText(theStack.toString());
        });
        bp.setTop(display);
        bp.setBottom(stackShow);
        bp.setCenter(gp);
        Scene scene = new Scene(bp, 700, 500);
        primary.setScene(scene);
        primary.show();
    }

    @Override
    public void stop()
    {
    }
  
    /********************** Inner Classes ********************/
    class NumberButton extends Button
    {
        private final char num;
        public NumberButton(char num)
        {
            super("" + num);
            this.num = num;
            setOnAction( e ->
            {
                    display.setText(display.getText() + num);

            });
        }

    }
    class OpButton extends Button
    {
        private DoubleBinaryOperator op;

        public OpButton(DoubleBinaryOperator op, String symbol)
        {
            super(symbol);
            this.op = op;
            setOnAction( e ->
            {
                double second = Double.parseDouble(display.getText());
                double first = theStack.pop();
                double result = op.applyAsDouble(first, second);
                theStack.push(result);
                display.setText("" + result);
                stackShow.setText(theStack.toString());
            });
        }
    }
    class FunctionButton extends Button
    {
    }
}