This repository contains two solutions:

• DummyBankApi: A bank simulator
• PaymentGateway: a gateway that allows a merchant to:
  • To process a payment through your payment gateway.
  • To retrieve details of a previously made payment.

• Open the PaymentGateway solution in visual studio as Admin (to be able to write in the sqlite db) and set PaymentGateway.API and starting project.
• Open VS CLI and select PaymentGateway.Infrastructure Project in the dropdown and run this command to create your DB:

  update-database

• Open the DummyBankApi solution in visual studio and run it ( select DummyBankApi and not IISExpress)

• Run the PaymentGatewayApi project ( select PaymentGatewayApi and not IISExpress)

Use the Swagger UI interface to make api calls.

• Just for this POC and to test it locally, the solution supports only two currencoes: EUR and USD and the Bank simulator will return failed response when currency is not EUR.
• I return status code 402 for failed Transaction/payment.
• The Bank Service can be unreachable/unavailable, that's why i create an entry of the transaction in our db in status processing before making the bankService call.

• Use Polly to handle retry policies when contacting the external Bank service.
• Use MediatR to create request/handler or (publish/subscribe) Instead of directly calling the bank service, create a an bankProcessingRequest and handle it elsewhere. That way we can add/change handler without touching our PaymentFacade.
• Add reason code to response to explain why the transaction failed.
• Encrypt the credit card data stored on our DB
• Map the expiryDate field to a two field month and year in our DB
• Test the validation of requests
• Add Api tests/ performance tests.
• Better logging

• Use RabbitMq/ServiceBus to handle interaction between paymentGateway and bank api
• Use Azure KeyVolt to store sensitive information like creditcard details
• Use CosmosDB to store transaction status/id.
• Use azure devops CI/CD and Azure App Service to build/deploy and host the App