chore: initial commit

internal/svc/payment/payment.go

@@ -0,0 +1,132 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package payment
+
+import (
+	"context"
+
+	"github.com/bufbuild/protovalidate-go"
+	"github.com/rs/zerolog/log"
+	"google.golang.org/protobuf/types/known/emptypb"
+
+	"github.com/hexolan/stocklet/internal/pkg/errors"
+	"github.com/hexolan/stocklet/internal/pkg/messaging"
+	commonpb "github.com/hexolan/stocklet/internal/pkg/protogen/common/v1"
+	eventpb "github.com/hexolan/stocklet/internal/pkg/protogen/events/v1"
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/payment/v1"
+)
+
+// Interface for the service
+type PaymentService struct {
+	pb.UnimplementedPaymentServiceServer
+
+	store StorageController
+	pbVal *protovalidate.Validator
+}
+
+// Interface for database methods
+// Flexibility for implementing seperate controllers for different databases (e.g. Postgres, MongoDB, etc)
+type StorageController interface {
+	GetBalance(ctx context.Context, customerId string) (*pb.CustomerBalance, error)
+	GetTransaction(ctx context.Context, transactionId string) (*pb.Transaction, error)
+
+	CreateBalance(ctx context.Context, customerId string) error
+	CreditBalance(ctx context.Context, customerId string, amount float32) error
+	DebitBalance(ctx context.Context, customerId string, amount float32, orderId *string) (*pb.Transaction, error)
+	CloseBalance(ctx context.Context, customerId string) error
+
+	PaymentForOrder(ctx context.Context, orderId string, customerId string, amount float32) error
+}
+
+// Interface for event consumption
+// Flexibility for seperate controllers for different messaging systems (e.g. Kafka, NATS, etc)
+type ConsumerController interface {
+	messaging.ConsumerController
+
+	Attach(svc pb.PaymentServiceServer)
+}
+
+// Create the payment service
+func NewPaymentService(cfg *ServiceConfig, store StorageController) *PaymentService {
+	// Initialise the protobuf validator
+	pbVal, err := protovalidate.New()
+	if err != nil {
+		log.Panic().Err(err).Msg("failed to initialise protobuf validator")
+	}
+
+	// Initialise the service
+	return &PaymentService{
+		store: store,
+		pbVal: pbVal,
+	}
+}
+
+func (svc PaymentService) ServiceInfo(ctx context.Context, req *commonpb.ServiceInfoRequest) (*commonpb.ServiceInfoResponse, error) {
+	return &commonpb.ServiceInfoResponse{
+		Name:          "payment",
+		Source:        "https://github.com/hexolan/stocklet",
+		SourceLicense: "AGPL-3.0",
+	}, nil
+}
+
+func (svc PaymentService) ViewTransaction(ctx context.Context, req *pb.ViewTransactionRequest) (*pb.ViewTransactionResponse, error) {
+	// Attempt to get the transaction from the db
+	transaction, err := svc.store.GetTransaction(ctx, req.TransactionId)
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.ViewTransactionResponse{Transaction: transaction}, nil
+}
+
+func (svc PaymentService) ViewBalance(ctx context.Context, req *pb.ViewBalanceRequest) (*pb.ViewBalanceResponse, error) {
+	// todo: permission checking
+
+	// Attempt to get the balance from the db
+	balance, err := svc.store.GetBalance(ctx, req.CustomerId)
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.ViewBalanceResponse{Balance: balance}, nil
+}
+
+func (svc PaymentService) ProcessUserCreatedEvent(ctx context.Context, req *eventpb.UserCreatedEvent) (*emptypb.Empty, error) {
+	err := svc.store.CreateBalance(ctx, req.UserId)
+	if err != nil {
+		return nil, errors.WrapServiceError(errors.ErrCodeExtService, "error processing event", err)
+	}
+
+	return &emptypb.Empty{}, nil
+}
+
+func (svc PaymentService) ProcessUserDeletedEvent(ctx context.Context, req *eventpb.UserDeletedEvent) (*emptypb.Empty, error) {
+	err := svc.store.CloseBalance(ctx, req.UserId)
+	if err != nil {
+		return nil, errors.WrapServiceError(errors.ErrCodeExtService, "error processing event", err)
+	}
+
+	return &emptypb.Empty{}, nil
+}
+
+func (svc PaymentService) ProcessShipmentAllocationEvent(ctx context.Context, req *eventpb.ShipmentAllocationEvent) (*emptypb.Empty, error) {
+	err := svc.store.PaymentForOrder(ctx, req.OrderId, req.OrderMetadata.CustomerId, req.OrderMetadata.TotalPrice)
+	if err != nil {
+		return nil, errors.WrapServiceError(errors.ErrCodeExtService, "error processing event", err)
+	}
+
+	return &emptypb.Empty{}, nil
+}