import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

// the ButtonListener handles each button press
public class ButtonListener implements ActionListener {
    // each button listener stores which button it is listening to
    // it also stores the calculator object so it can tell it when
    // the buttons are pressed
    private ButtonType button;
    private Calculator calc;

    // given the button we are listening for, and the calculator object
    public ButtonListener(ButtonType button, Calculator calculator) {
        this.button = button;
        this.calc = calculator;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // check which button we are listening for
        switch (button) {
            case N0:
            case N1:
            case N2:
            case N3:
            case N4:
            case N5:
            case N6:
            case N7:
            case N8:
            case N9:
                // for any of the digits, find out what digit it is
                // then add it to the calculator
                String stringDigit = button.name().substring(1);
                int digit = Integer.parseInt(stringDigit);
                calc.addDigit(digit);
                break;

                // for the other buttons, call the appropriate calculator method
            case DOT:
                calc.setDot();
                break;
            case PLUS:
                calc.setOperator('+');
                break;
            case MINUS:
                calc.setOperator('-');
                break;
            case TIMES:
                calc.setOperator('*');
                break;
            case DIVIDE:
                calc.setOperator('/');
                break;
            case SQRT:
                calc.sqrt();
                break;
            case EQUALS:
                calc.equals();
                break;
            case CLEAR:
                calc.clear();
                break;
        }
    }
}