First implementation of fetching collections of book managed by user

internal/query/query.go

@@ -184,6 +184,59 @@ func selectBookItem() string {
 	return "books.id, books.title, authors.name as author, books.short_description as description, books.inventaire_id, user_books.rating, user_books.read, DATE(user_books.start_read_date) as start_read_date, user_books.want_read, " + selectStaticFilesPath()
 }
 
+type CollectionsQueryResult struct {
+	ID        uint
+	Name      string
+	BookId    uint
+	BookTitle string
+	CoverPath string
+}
+
+type collectionId struct {
+	ID uint
+}
+
+func FetchAllCollections(db *gorm.DB, userId uint, limit int, offset int) ([]CollectionsQueryResult, error) {
+	var collections []CollectionsQueryResult
+	var collectionIds []collectionId
+	res := fetchCollections(db, userId).Limit(limit).Offset(offset).Find(&collectionIds)
+	if res.Error != nil {
+		return collections, res.Error
+	}
+	for _, collectionId := range collectionIds {
+		queryResults, err := queryBooksForCollection(db, collectionId.ID)
+		if err != nil {
+			return collections, res.Error
+		}
+		collections = append(collections, queryResults...)
+	}
+	return collections, res.Error
+}
+
+func queryBooksForCollection(db *gorm.DB, collectionId uint) ([]CollectionsQueryResult, error) {
+	var collections []CollectionsQueryResult
+	query := db.Model(&model.Collection{})
+	query = query.Select("collections.id, collections.name, books.id as book_id, books.title as book_title, " + selectStaticFilesPath())
+	query = query.Joins("left join collection_books on (collection_books.collection_id = collections.id)")
+	query = query.Joins("left join books on (books.id = collection_books.book_id)")
+	query = joinStaticFiles(query)
+	query = query.Where("collections.id = ?", collectionId)
+	//only takes first 5 books
+	query = query.Limit(5)
+	res := query.Find(&collections)
+	return collections, res.Error
+}
+
+func FetchAllCollectionsCount(db *gorm.DB, userId uint) (int64, error) {
+	var count int64
+	res := fetchCollections(db, userId).Count(&count)
+	return count, res.Error
+}
+
+func fetchCollections(db *gorm.DB, userId uint) *gorm.DB {
+	return db.Model(&model.Collection{}).Where("collections.user_id = ?", userId)
+}
+
 func selectStaticFilesPath() string {
 	return "(CASE COALESCE(static_files.path, '') WHEN '' THEN '' ELSE concat('" + fileutils.GetWsLinkPrefix() + "', static_files.path) END) as CoverPath"
 }