fix: technical debts left by the Sites, Authors and SEO slices, plus backend support for the new Sites and Authors pagination

internal/infrastructure/useCases/ListMedia.go

@@ -82,8 +82,7 @@ func (l *ListMediaUseCase) List(query image.ListQuery) (MediaPage, error) {
 		}
 	}
 
-	offset := (query.Page - 1) * query.Size
-	pageStart := min(offset, len(matching))
+	pageStart := min(min(query.Page-1, len(matching))*query.Size, len(matching))
 	pageEnd := min(pageStart+query.Size, len(matching))
 	names := newUploaderNames(l.userRepository)
 	items := []MediaItem{}
@@ -106,6 +105,14 @@ func (l *ListMediaUseCase) List(query image.ListQuery) (MediaPage, error) {
 	return MediaPage{Items: items, Total: len(matching), Page: query.Page, Size: query.Size, Counts: counts}, nil
 }
 
+func (l *ListMediaUseCase) Get(id uint32) (MediaItem, error) {
+	found, err := l.imageRepository.Get(id)
+	if err != nil {
+		return MediaItem{}, err
+	}
+	return l.Describe(found)
+}
+
 func (l *ListMediaUseCase) Describe(img image.Image) (MediaItem, error) {
 	articleCount, err := l.articleUsageCount(img)
 	if err != nil {