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

public class CalculatorSwing extends JFrame implements ActionListener {

    private int rowNumber = 5;
    private int buttonNumber = 19;
    private int operationNumber = 4;

    JPanel[] row = new JPanel[rowNumber];
    JButton[] button = new JButton[buttonNumber];
    String[] buttonString = {"7", "8", "9", "+",
            "4", "5", "6", "-",
            "1", "2", "3", "*",
            ".", "/", "C", "√",
            "+/-", "=", "0"};

    int[] dimW = {300, 45, 100, 90};
    int[] dimH = {35, 40};
    Dimension displayDimension = new Dimension(dimW[0], dimH[0]);
    Dimension regularDimension = new Dimension(dimW[1], dimH[1]);
    Dimension rColumnDimension = new Dimension(dimW[2], dimH[1]);
    Dimension zeroButDimension = new Dimension(dimW[3], dimH[1]);


    boolean[] function = new boolean[operationNumber];
    double[] temporary = {0,0};
    JTextArea display = new JTextArea(1, 20);
    Font font = new Font("Times new Roman", Font.BOLD, 14);

    CalculatorSwing() {
        super("Kalkulatorek");
        setDesign();
        setSize(300, 240);
        setResizable(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        GridLayout grid = new GridLayout(5, 5);
        setLayout(grid);

        for (int i = 0; i < 4; i++)
            function[i] = false;

        FlowLayout f1 = new FlowLayout(FlowLayout.CENTER);
        FlowLayout f2 = new FlowLayout(FlowLayout.CENTER, 1, 1);

        for (int i = 0; i < 5; i++)
            row[i] = new JPanel();
        row[0].setLayout(f1);
        for (int i = 1; i < 5; i++)
            row[i].setLayout(f2);

        for (int i = 0; i < buttonNumber; i++) {
            button[i] = new JButton();
            button[i].setText(buttonString[i]);
            button[i].setFont(font);
            button[i].addActionListener(this);
        }

        display.setFont(font);
        display.setEditable(false);
        display.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        display.setPreferredSize(displayDimension);

        // ustawienie szerokosci przyciskow aby je dopasowac do okienka
        for (int i = 0; i < 14; i++)
            button[i].setPreferredSize(regularDimension);
        for (int i = 14; i < buttonNumber - 1; i++)
            button[i].setPreferredSize(rColumnDimension);

        button[18].setPreferredSize(zeroButDimension);


        setVisible(true);

        for(int i=0; i<=4; i++) add(row[i]);
        row[0].add(display);

        for (int i = 0; i < 4; i++) {
            row[1].add(button[i]);
        }
        row[1].add(button[14]);

        for (int i = 4; i < 8; i++) {
            row[2].add(button[i]);
        }
        row[2].add(button[15]);

        for (int i = 8; i < 12; i++)
        {
            row[3].add(button[i]);
        }
        row[3].add(button[16]);

        row[4].add(button[18]);

        for (int i = 12; i < 14; i++) {
            row[4].add(button[i]);
        }
        row[4].add(button[17]);


    }

    public void clear() {
        try {
            display.setText("");
            for(int i = 0; i < 4; i++)
                function[i] = false;
            for(int i = 0; i < 2; i++)
                temporary[i] = 0;
        } catch(NullPointerException e) {
        }
    }

    public final void setDesign() {
        try {
            UIManager.setLookAndFeel(
                    "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch(Exception e) {
        }
    }


    public void getSqrt() {
        try {
            double value = Math.sqrt(Double.parseDouble(display.getText()));
            display.setText(Double.toString(value));
        } catch(NumberFormatException e) {
        }
    }

    public void getPosNeg() {
        try {
            double value = Double.parseDouble(display.getText());
            if(value != 0) {
                value = value * (-1);
                display.setText(Double.toString(value));
            }
            else {
            }
        } catch(NumberFormatException e) {
        }
    }

    public void getResult() {
        double result = 0;
        temporary[1] = Double.parseDouble(display.getText());
        String temp0 = Double.toString(temporary[0]);
        String temp1 = Double.toString(temporary[1]);
        try {
            if(temp0.contains("-")) {
                String[] temp00 = temp0.split("-", 2);
                temporary[0] = (Double.parseDouble(temp00[1]) * -1);
            }
            if(temp1.contains("-")) {
                String[] temp11 = temp1.split("-", 2);
                temporary[1] = (Double.parseDouble(temp11[1]) * -1);
            }
        } catch(ArrayIndexOutOfBoundsException e) {
        }
        try {
            if(function[2] == true)
                result = temporary[0] * temporary[1];
            else if(function[3] == true)
                result = temporary[0] / temporary[1];
            else if(function[0] == true)
                result = temporary[0] + temporary[1];
            else if(function[1] == true)
                result = temporary[0] - temporary[1];
            display.setText(Double.toString(result));
            for(int i = 0; i < 4; i++)
                function[i] = false;
        } catch(NumberFormatException e) {
        }
    }

    public void actionPerformed(ActionEvent ae) {
        if(ae.getSource() == button[0])
            display.append("7");
        if(ae.getSource() == button[1])
            display.append("8");
        if(ae.getSource() == button[2])
            display.append("9");
        if(ae.getSource() == button[3]) {
            temporary[0] = Double.parseDouble(display.getText());
            function[0] = true;
            display.setText("");
        }
        if(ae.getSource() == button[4])
            display.append("4");
        if(ae.getSource() == button[5])
            display.append("5");
        if(ae.getSource() == button[6])
            display.append("6");
        if(ae.getSource() == button[7]) {
            temporary[0] = Double.parseDouble(display.getText());
            function[1] = true;
            display.setText("");
        }
        if(ae.getSource() == button[8])
            display.append("1");
        if(ae.getSource() == button[9])
            display.append("2");
        if(ae.getSource() == button[10])
            display.append("3");
        if(ae.getSource() == button[11]) {
            temporary[0] = Double.parseDouble(display.getText());
            function[2] = true;
            display.setText("");
        }
        if(ae.getSource() == button[12])
            display.append(".");
        if(ae.getSource() == button[13]) {
            temporary[0] = Double.parseDouble(display.getText());
            function[3] = true;
            display.setText("");
        }
        if(ae.getSource() == button[14])
            clear();
        if(ae.getSource() == button[15])
            getSqrt();
        if(ae.getSource() == button[16])
            getPosNeg();
        if(ae.getSource() == button[17])
            getResult();
        if(ae.getSource() == button[18])
            display.append("0");
    }

    public static void main(String[] arguments) {
        CalculatorSwing c = new CalculatorSwing();
    }
}