refactor(services): Extract barcode generation

services/barcode.go

@@ -0,0 +1,69 @@
+package services
+
+import (
+	"bytes"
+	"fmt"
+	"image/png"
+	"slices"
+
+	"github.com/boombuler/barcode"
+	"github.com/boombuler/barcode/code128"
+	"github.com/boombuler/barcode/ean"
+	"github.com/boombuler/barcode/qr"
+)
+
+type BarcodeGenerator interface {
+	GenerateBarcode(format string, content string) (bytes.Buffer, error)
+	IsTypeSupported(format string) bool
+}
+
+type DefaultBarcodeGenerator struct {
+}
+
+func (b *DefaultBarcodeGenerator) GenerateBarcode(format string, content string, width int, height int) (bytes.Buffer, error) {
+	if !b.IsTypeSupported(format) {
+		return bytes.Buffer{}, fmt.Errorf("unsupported barcode type: %s", format)
+	}
+
+	var generatedCode barcode.Barcode
+	var err error
+
+	switch format {
+	case "ean13":
+		generatedCode, err = ean.Encode(content)
+		if err != nil {
+			return bytes.Buffer{}, err
+		}
+		break
+	case "code128":
+		generatedCode, err = code128.Encode(content)
+		if err != nil {
+			return bytes.Buffer{}, err
+		}
+		break
+	case "qr":
+		generatedCode, err = qr.Encode(content, qr.M, qr.AlphaNumeric)
+		if err != nil {
+			return bytes.Buffer{}, err
+		}
+		break
+	}
+
+	scaledCode, err := barcode.Scale(generatedCode, width, height)
+	if err != nil {
+		return bytes.Buffer{}, err
+	}
+
+	var buf bytes.Buffer
+	err = png.Encode(&buf, scaledCode)
+	if err != nil {
+		return bytes.Buffer{}, err
+	}
+
+	return buf, nil
+}
+
+func (b *DefaultBarcodeGenerator) IsTypeSupported(format string) bool {
+	supportedTypes := []string{"ean13", "code128", "qr"}
+	return slices.Contains(supportedTypes, format)
+}

services/templater.go

@@ -6,13 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"html/template"
-	"image/png"
 	"strings"
-
-	"github.com/boombuler/barcode"
-	"github.com/boombuler/barcode/code128"
-	"github.com/boombuler/barcode/ean"
-	"github.com/boombuler/barcode/qr"
 )
 
 type Templater interface {
@@ -37,48 +31,19 @@ func idToEan13(id string, prefix string) (string, error) {
 }
 
 func (t *DefaultTemplater) GenerateBarcode(code string, format string, prefix string) (string, error) {
-	var generatedCode barcode.Barcode
+	gen := &DefaultBarcodeGenerator{}
 	var err error
 
-	switch format {
-	case "ean13":
-		encodedEan, err := idToEan13(code, prefix)
+	if format == "ean13" {
+		code, err = idToEan13(code, prefix)
 		if err != nil {
 			return "", err
 		}
-		generatedCode, err = ean.Encode(encodedEan)
-		if err != nil {
-			return "", err
-		}
-		break
-	case "code128":
-		generatedCode, err = code128.Encode(prefix + code)
-		if err != nil {
-			return "", err
-		}
-		break
-	case "qr":
-		generatedCode, err = qr.Encode(prefix+code, qr.M, qr.AlphaNumeric)
-		if err != nil {
-			return "", err
-		}
-		break
-	default:
-		return "", errors.New("unknown barcode format")
 	}
 
-	scaledCode, err := barcode.Scale(generatedCode, 1000, 500)
-	if err != nil {
-		return "", err
-	}
+	buf, err := gen.GenerateBarcode(format, code, 1000, 500)
 
-	var buf bytes.Buffer
-	err = png.Encode(&buf, scaledCode)
-	if err != nil {
-		return "", err
-	}
-
-	return base64.StdEncoding.EncodeToString(buf.Bytes()), nil
+	return base64.StdEncoding.EncodeToString(buf.Bytes()), err
 }
 
 func (t *DefaultTemplater) SelectSponsorImage(id int) (string, error) {