import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

public class Main extends JFrame {
    JButton button1, button2, plus, enter;
    JTextField screen;
    ArrayList<History> history;

    public Main(String title) throws HeadlessException {
        super(title);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(1920,1080);
        setLocationRelativeTo(null);
        setVisible(true);
        setLayout(new GridBagLayout());
        setPreferredSize(new Dimension(500,500));

        history = new ArrayList<>();

        GridBagConstraints g = new GridBagConstraints();
        g.fill = GridBagConstraints.HORIZONTAL;
        button1 = new JButton("1");
        button2 = new JButton("2");
        enter = new JButton("E");
        plus = new JButton("+");
        plus.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                history.add(new History(Integer.parseInt(screen.getText()),Operation.PLUS));
                screen.setText("");
            }
        });

        enter.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Operation operation = null;
                int result = 0, valueMem = 0;
                for (History historyItem: history){
                    operation = historyItem.operation;
                    valueMem = historyItem.value;
                    if (operation != null) {
                        result = countByOperation(result, valueMem, historyItem.operation);
                    }
                }
                if(valueMem != 0) {
                    screen.setText(String.valueOf(countByOperation(result, Integer.parseInt(screen.getText()), operation)));
                    history = new ArrayList<>();
                }

            }
        });
        screen = new JTextField();
        fillButton(button1, "1");
        fillButton(button2, "2");


        g.gridx = 0;
        g.gridy = 0;
        g.gridwidth = 1;
        g.gridheight = 1;
        g.fill = GridBagConstraints.BOTH;
        add(button1, g);
        g.gridx = 1;
        add(button2, g);
        g.gridx = 2;
        add(plus, g);
        g.gridx = 3;
        add(enter, g);
        g.gridx = 0;
        g.gridy = 1;
        g.gridwidth = 4;
        add(screen, g);

    }

    private void fillButton(JButton button, String text) {
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                screen.setText(screen.getText() + text);
            }
        });
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new Main("Kalkulačka");
            }
        });

    }

    private int countByOperation(int valueA, int valueB, Operation operation) {
        switch (operation) {
            case PLUS -> {
                return valueA + valueB;
            }
            case MINUS -> {
                return valueA - valueB;
            }
            case MULTIPLE -> {
                return valueA * valueB;
            }
            case DIVISION -> {
                return valueA / valueB;
            }
        }
        return 0;
    }
}