dc4bc/qr/qr.go

package qr

import (
	"fmt"
	"image"
	"log"
	"time"

	"gocv.io/x/gocv"

	encoder "github.com/skip2/go-qrcode"

	"github.com/makiuchi-d/gozxing"
	"github.com/makiuchi-d/gozxing/qrcode"
)

const (
	timeToScan = time.Second * 5
)

type Processor interface {
	ReadQR() ([]byte, error)
	WriteQR(path string, data []byte) error
}

type CameraProcessor struct{}

func NewCameraProcessor() *CameraProcessor {
	return &CameraProcessor{}
}

func (p *CameraProcessor) ReadQR() ([]byte, error) {
	webcam, err := gocv.OpenVideoCapture(0)
	if err != nil {
		return nil, fmt.Errorf("failed to OpenVideoCapture: %w", err)
	}
	window := gocv.NewWindow("Please, show a qr code")

	defer func() {
		if err := webcam.Close(); err != nil {
			log.Fatalf("failed to close camera: %v", err)
		}
	}()
	defer func() {
		if err := window.Close(); err != nil {
			log.Fatalf("failed to close camera window: %v", err)
		}
	}()

	img := gocv.NewMat()
	defer img.Close()

	for {
		webcam.Read(&img)
		window.IMShow(img)
		window.WaitKey(1)

		imgObject, err := img.ToImage()
		if err != nil {
			return nil, fmt.Errorf("failed to get image object: %w", err)
		}
		data, err := ReadDataFromQR(imgObject)
		if err != nil {
			if _, ok := err.(gozxing.NotFoundException); ok {
				continue
			}
			return nil, err
		}
		return data, nil
	}
}

func (p *CameraProcessor) WriteQR(path string, data []byte) error {
	err := encoder.WriteFile(string(data), encoder.Medium, 512, path)
	if err != nil {
		return fmt.Errorf("failed to encode the data: %w", err)
	}

	return nil
}

func ReadDataFromQR(img image.Image) ([]byte, error) {
	bmp, err := gozxing.NewBinaryBitmapFromImage(img)
	if err != nil {
		return nil, fmt.Errorf("failed to get NewBinaryBitmapFromImage: %w", err)
	}

	qrReader := qrcode.NewQRCodeReader()
	result, err := qrReader.Decode(bmp, nil)
	if err != nil {
		if _, ok := err.(gozxing.NotFoundException); ok {
			return nil, err
		}
		return nil, fmt.Errorf("failed to decode the QR-code contents: %w", err)
	}
	return []byte(result.String()), nil
}

func EncodeQR(data []byte) ([]byte, error) {
	return encoder.Encode(string(data), encoder.Medium, 512)
}