first

backend/internal/modules/pricing/service.go

@@ -0,0 +1,72 @@
+package pricing
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+)
+
+type Service struct {
+	repo Repository
+}
+
+func NewService(repo Repository) *Service {
+	return &Service{repo: repo}
+}
+
+func (s *Service) ListByProduct(ctx context.Context, productID uuid.UUID) ([]*PriceTier, error) {
+	return s.repo.ListByProduct(ctx, productID)
+}
+
+func (s *Service) Get(ctx context.Context, id uuid.UUID) (*PriceTier, error) {
+	return s.repo.FindByID(ctx, id)
+}
+
+func (s *Service) Create(ctx context.Context, productID, unitID uuid.UUID, quantity float64, priceCents int64, position int) (*PriceTier, error) {
+	t := &PriceTier{
+		ID:         uuid.New(),
+		ProductID:  productID,
+		UnitID:     unitID,
+		Quantity:   quantity,
+		PriceCents: priceCents,
+		Position:   position,
+	}
+	if err := s.repo.Create(ctx, t); err != nil {
+		return nil, err
+	}
+	return t, nil
+}
+
+func (s *Service) Update(ctx context.Context, id uuid.UUID, unitID uuid.UUID, quantity float64, priceCents int64, position int) (*PriceTier, error) {
+	t, err := s.repo.FindByID(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+	t.UnitID = unitID
+	t.Quantity = quantity
+	t.PriceCents = priceCents
+	t.Position = position
+	if err := s.repo.Update(ctx, t); err != nil {
+		return nil, err
+	}
+	return t, nil
+}
+
+func (s *Service) Delete(ctx context.Context, id uuid.UUID) error {
+	return s.repo.Delete(ctx, id)
+}
+
+// PriceForQuantity is the centralized pricing calculation used by the
+// orders module: given a chosen tier and how many of that tier package the
+// customer wants, it returns the authoritative total in cents. The
+// frontend never gets to supply a price directly.
+func (s *Service) PriceForQuantity(ctx context.Context, tierID uuid.UUID, multiplier int64) (totalCents int64, tier *PriceTier, err error) {
+	t, err := s.repo.FindByID(ctx, tierID)
+	if err != nil {
+		return 0, nil, err
+	}
+	if multiplier < 1 {
+		multiplier = 1
+	}
+	return t.PriceCents * multiplier, t, nil
+}