package ui.gui.widgets;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

import javax.swing.*;
import java.awt.*;
import java.util.Collections;

import static com.google.zxing.EncodeHintType.ERROR_CORRECTION;
import static com.google.zxing.qrcode.decoder.ErrorCorrectionLevel.L;

/**
 * A fixed-size panel displaying a QR code.
 */
public class QRPanel extends JPanel {
    private final int size;

    private BitMatrix data;

    /**
     * EFFECTS: Init with the specific rectangular size. Min size = max size = preferred size.
     */
    public QRPanel(int size) {
        super();
        setSize(new Dimension(size, size));
        setMaximumSize(new Dimension(size, size));
        setMinimumSize(new Dimension(size, size));
        setPreferredSize(new Dimension(size, size));
        this.size = size;
    }

    /**
     * EFFECTS: Draw the QR code. Leave white if no data is set.
     * MODIFIES: this
     */
    @Override
    protected void paintComponent(Graphics graphics) {
        super.paintComponent(graphics);
        graphics.setColor(Color.WHITE);
        graphics.fillRect(0, 0, size, size);

        if (data == null) {
            return;
        }

        graphics.setColor(Color.BLACK);
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++) {
                if (data.get(i, j)) {
                    graphics.fillRect(i, j, 1, 1);
                }
            }
        }
    }

    /**
     * EFFECTS: Set data and repaint. Nullable.
     * MODIFIES: this
     */
    public void setData(String data) {
        if (data == null) {
            this.data = null;
            invalidate();
            return;
        }
        try {
            this.data = new QRCodeWriter().encode(data, BarcodeFormat.QR_CODE, size, size,
                    Collections.singletonMap(ERROR_CORRECTION, L));
        } catch (WriterException e) {
            e.printStackTrace();
        }
        invalidate();
    }
}