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import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Base64;

@RestController
@RequestMapping("/api/qr")
public class QRCodeController {

    @GetMapping("/generate")
    public ResponseEntity<String> generateQRCode(@RequestParam String text, @RequestParam int width, @RequestParam int height) {
        try {
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height);

            BufferedImage bufferedImage = MatrixToImageWriter.toBufferedImage(bitMatrix);

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage, "png", byteArrayOutputStream);
            byte[] byteArray = byteArrayOutputStream.toByteArray();

            String base64Image = Base64.getEncoder().encodeToString(byteArray);
            return ResponseEntity.ok(base64Image);
        } catch (WriterException | IOException e) {
            e.printStackTrace();
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Error generating QR Code");
        }
    }

    @PostMapping("/decode")
    public ResponseEntity<byte[]> decodeQRCode(@RequestBody String base64Image) {
        try {
            // Remove prefix if exists
            if (base64Image.contains(",")) {
                base64Image = base64Image.substring(base64Image.indexOf(",") + 1);
            }

            byte[] imageBytes = Base64.getDecoder().decode(base64Image);
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(imageBytes);
            BufferedImage bufferedImage = ImageIO.read(byteArrayInputStream);

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage, "png", byteArrayOutputStream);
            byte[] imageInBytes = byteArrayOutputStream.toByteArray();

            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.IMAGE_PNG);
            headers.setContentLength(imageInBytes.length);

            return new ResponseEntity<>(imageInBytes, headers, HttpStatus.OK);
        } catch (IOException e) {
            e.printStackTrace();
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(null);
        }
    }
}