FEAT: Load Catagories from backend

cms/internal/services/db.go

@@ -29,6 +29,7 @@ type Video struct {
 
 type DBClient interface {
 	CreateVideo(ctx context.Context, v Video) (Video, error)
+	ListCategories(ctx context.Context) ([]string, error)
 }
 
 type DBConcrete struct {
@@ -81,6 +82,30 @@ func (svc DBConcrete) CreateVideo(ctx context.Context, v Video) (Video, error) {
 	return v, nil
 }
 
+func (svc DBConcrete) ListCategories(ctx context.Context) ([]string, error) {
+	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
+	if err != nil {
+		return nil, err
+	}
+	defer sqlDB.Close()
+
+	rows, err := sqlDB.QueryContext(ctx, `SELECT name FROM categories ORDER BY name`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var categories []string
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			return nil, err
+		}
+		categories = append(categories, name)
+	}
+	return categories, rows.Err()
+}
+
 func (svc DBConcrete) Migrate() {
 	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
 	if err != nil {