Reapply "feat(loyalty): EnakPoint & EnakCoin" (#32)

This reverts commit 4e24f9bbb0.

internal/service/point_payment_service.go

@@ -0,0 +1,55 @@
+package service
+
+import (
+	"context"
+	"errors"
+
+	"github.com/google/uuid"
+
+	"apskel-pos-be/internal/appcontext"
+	"apskel-pos-be/internal/constants"
+	"apskel-pos-be/internal/contract"
+	"apskel-pos-be/internal/processor"
+	"apskel-pos-be/internal/repository"
+)
+
+// PointPaymentService serves what the cashier needs before taking EnakPoint
+// (docs/prd-point-coin.md F9).
+type PointPaymentService interface {
+	Preview(ctx context.Context, apctx *appcontext.ContextInfo, orderID uuid.UUID) *contract.Response
+}
+
+type PointPaymentServiceImpl struct {
+	payments *processor.PointPaymentProcessor
+}
+
+func NewPointPaymentService(payments *processor.PointPaymentProcessor) *PointPaymentServiceImpl {
+	return &PointPaymentServiceImpl{payments: payments}
+}
+
+func (s *PointPaymentServiceImpl) Preview(ctx context.Context, apctx *appcontext.ContextInfo, orderID uuid.UUID) *contract.Response {
+	preview, err := s.payments.Preview(ctx, apctx.OrganizationID, orderID)
+	if err != nil {
+		return PointPaymentErrorResponse(err)
+	}
+	return contract.BuildSuccessResponse(preview)
+}
+
+// PointPaymentErrorResponse answers a refused EnakPoint payment as a bad request, PIN
+// problems with their own codes, and anything else as a server error.
+func PointPaymentErrorResponse(err error) *contract.Response {
+	var pinErr *processor.PinError
+	if errors.As(err, &pinErr) {
+		return PinErrorResponse(err)
+	}
+	code := constants.InternalServerErrorCode
+	switch {
+	case errors.Is(err, repository.ErrPointPaymentOrderNotFound):
+		code = constants.NotFoundErrorCode
+	case errors.Is(err, processor.ErrPointPaymentRejected):
+		code = constants.ValidationErrorCode
+	}
+	return contract.BuildErrorResponse([]*contract.ResponseError{
+		contract.NewResponseError(code, constants.WalletServiceEntity, err.Error()),
+	})
+}