first

backend/internal/modules/pricing/repository.go

@@ -0,0 +1,86 @@
+package pricing
+
+import (
+	"context"
+	"errors"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5/pgconn"
+	"gorm.io/gorm"
+)
+
+var (
+	ErrNotFound         = errors.New("price tier not found")
+	ErrInvalidReference = errors.New("product or unit does not exist")
+)
+
+type Repository interface {
+	Create(ctx context.Context, t *PriceTier) error
+	FindByID(ctx context.Context, id uuid.UUID) (*PriceTier, error)
+	ListByProduct(ctx context.Context, productID uuid.UUID) ([]*PriceTier, error)
+	Update(ctx context.Context, t *PriceTier) error
+	Delete(ctx context.Context, id uuid.UUID) error
+}
+
+type gormRepository struct {
+	db *gorm.DB
+}
+
+func NewRepository(db *gorm.DB) Repository {
+	return &gormRepository{db: db}
+}
+
+func (r *gormRepository) Create(ctx context.Context, t *PriceTier) error {
+	if err := r.db.WithContext(ctx).Create(t).Error; err != nil {
+		if isForeignKeyViolation(err) {
+			return ErrInvalidReference
+		}
+		return err
+	}
+	return nil
+}
+
+func (r *gormRepository) FindByID(ctx context.Context, id uuid.UUID) (*PriceTier, error) {
+	var t PriceTier
+	err := r.db.WithContext(ctx).Where("id = ?", id).First(&t).Error
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		return nil, ErrNotFound
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &t, nil
+}
+
+func (r *gormRepository) ListByProduct(ctx context.Context, productID uuid.UUID) ([]*PriceTier, error) {
+	var list []*PriceTier
+	err := r.db.WithContext(ctx).Where("product_id = ?", productID).Order("position asc, quantity asc").Find(&list).Error
+	if err != nil {
+		return nil, err
+	}
+	return list, nil
+}
+
+func (r *gormRepository) Update(ctx context.Context, t *PriceTier) error {
+	err := r.db.WithContext(ctx).Save(t).Error
+	if isForeignKeyViolation(err) {
+		return ErrInvalidReference
+	}
+	return err
+}
+
+func (r *gormRepository) Delete(ctx context.Context, id uuid.UUID) error {
+	res := r.db.WithContext(ctx).Delete(&PriceTier{}, "id = ?", id)
+	if res.Error != nil {
+		return res.Error
+	}
+	if res.RowsAffected == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func isForeignKeyViolation(err error) bool {
+	var pgErr *pgconn.PgError
+	return errors.As(err, &pgErr) && pgErr.Code == "23503"
+}