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

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

backend/internal/service/app_images_service_test.go

@@ -0,0 +1,88 @@
+package service
+
+import (
+	"bytes"
+	"io/fs"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+)
+
+func TestAppImagesService_GetImage(t *testing.T) {
+	tempDir := t.TempDir()
+	originalUploadPath := common.EnvConfig.UploadPath
+	common.EnvConfig.UploadPath = tempDir
+	t.Cleanup(func() {
+		common.EnvConfig.UploadPath = originalUploadPath
+	})
+
+	imagesDir := filepath.Join(tempDir, "application-images")
+	require.NoError(t, os.MkdirAll(imagesDir, 0o755))
+
+	filePath := filepath.Join(imagesDir, "background.webp")
+	require.NoError(t, os.WriteFile(filePath, []byte("data"), fs.FileMode(0o644)))
+
+	service := NewAppImagesService(map[string]string{"background": "webp"})
+
+	path, mimeType, err := service.GetImage("background")
+	require.NoError(t, err)
+	require.Equal(t, filePath, path)
+	require.Equal(t, "image/webp", mimeType)
+}
+
+func TestAppImagesService_UpdateImage(t *testing.T) {
+	tempDir := t.TempDir()
+	originalUploadPath := common.EnvConfig.UploadPath
+	common.EnvConfig.UploadPath = tempDir
+	t.Cleanup(func() {
+		common.EnvConfig.UploadPath = originalUploadPath
+	})
+
+	imagesDir := filepath.Join(tempDir, "application-images")
+	require.NoError(t, os.MkdirAll(imagesDir, 0o755))
+
+	oldPath := filepath.Join(imagesDir, "logoLight.svg")
+	require.NoError(t, os.WriteFile(oldPath, []byte("old"), fs.FileMode(0o644)))
+
+	service := NewAppImagesService(map[string]string{"logoLight": "svg"})
+
+	fileHeader := newFileHeader(t, "logoLight.png", []byte("new"))
+
+	require.NoError(t, service.UpdateImage(fileHeader, "logoLight"))
+
+	_, err := os.Stat(filepath.Join(imagesDir, "logoLight.png"))
+	require.NoError(t, err)
+
+	_, err = os.Stat(oldPath)
+	require.ErrorIs(t, err, os.ErrNotExist)
+}
+
+func newFileHeader(t *testing.T, filename string, content []byte) *multipart.FileHeader {
+	t.Helper()
+
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	part, err := writer.CreateFormFile("file", filename)
+	require.NoError(t, err)
+
+	_, err = part.Write(content)
+	require.NoError(t, err)
+
+	require.NoError(t, writer.Close())
+
+	req := httptest.NewRequest(http.MethodPost, "/", body)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+
+	_, fileHeader, err := req.FormFile("file")
+	require.NoError(t, err)
+
+	return fileHeader
+}