fix: decouple images from app config service (#965)

Co-authored-by: Alessandro (Ale) Segala <43508+ItalyPaleAle@users.noreply.github.com>

backend/internal/utils/file_util.go

@@ -10,6 +10,7 @@ import (
 	"mime/multipart"
 	"os"
 	"path/filepath"
+	"strings"
 	"syscall"
 
 	"github.com/google/uuid"
@@ -24,6 +25,15 @@ func GetFileExtension(filename string) string {
 	return filename
 }
 
+// SplitFileName splits a full file name into name and extension.
+func SplitFileName(fullName string) (name, ext string) {
+	dot := strings.LastIndex(fullName, ".")
+	if dot == -1 || dot == 0 {
+		return fullName, "" // no extension or hidden file like .gitignore
+	}
+	return fullName[:dot], fullName[dot+1:]
+}
+
 func GetImageMimeType(ext string) string {
 	switch ext {
 	case "jpg", "jpeg":

backend/internal/utils/file_util_test.go

@@ -2,8 +2,36 @@ package utils
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
+func TestSplitFileName(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		fullName string
+		wantName string
+		wantExt  string
+	}{
+		{"background.jpg", "background", "jpg"},
+		{"archive.tar.gz", "archive.tar", "gz"},
+		{".gitignore", ".gitignore", ""},
+		{"noext", "noext", ""},
+		{"a.b.c", "a.b", "c"},
+		{".hidden.ext", ".hidden", "ext"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.fullName, func(t *testing.T) {
+			t.Parallel()
+			name, ext := SplitFileName(tc.fullName)
+			assert.Equal(t, tc.wantName, name)
+			assert.Equal(t, tc.wantExt, ext)
+		})
+	}
+}
+
 func TestGetFileExtension(t *testing.T) {
 	tests := []struct {
 		name     string