http-api/src/Application/Payments/LiqPay/TicketGroups/Commands/ProcessCallback/ProcessCallbackCommandHandler.cs

using MediatR;
using cuqmbr.TravelGuide.Application.Common.Persistence;
using cuqmbr.TravelGuide.Application.Common.Services;
using cuqmbr.TravelGuide.Application.Common.Exceptions;
using System.Text;
using Newtonsoft.Json;
using cuqmbr.TravelGuide.Domain.Enums;
using Microsoft.Extensions.Localization;
using cuqmbr.TravelGuide.Domain.Entities;

namespace cuqmbr.TravelGuide.Application.Payments.LiqPay
    .TicketGroups.Commands.ProcessCallback;

public class ProcessCallbackCommandHandler :
    IRequestHandler<ProcessCallbackCommand>
{
    private readonly UnitOfWork _unitOfWork;

    private readonly LiqPayPaymentService _liqPayPaymentService;

    private readonly IStringLocalizer _localizer;

    private readonly EmailSenderService _emailSender;

    public ProcessCallbackCommandHandler(
        UnitOfWork unitOfWork,
        LiqPayPaymentService liqPayPaymentService,
        IStringLocalizer localizer,
        EmailSenderService emailSender)
    {
        _unitOfWork = unitOfWork;
        _liqPayPaymentService = liqPayPaymentService;
        _localizer = localizer;
        _emailSender = emailSender;
    }

    public async Task Handle(
        ProcessCallbackCommand request,
        CancellationToken cancellationToken)
    {
        // Validate signature.

        var isSignatureValid = _liqPayPaymentService
            .IsValidSignature(request.Data, request.Signature);

        if (!isSignatureValid)
        {
            throw new ForbiddenException();
        }


        // Parse request data.

        var dataBytes = Convert.FromBase64String(request.Data);
        var dataJson = Encoding.UTF8.GetString(dataBytes);

        var data = JsonConvert.DeserializeObject<dynamic>(dataJson);

        string status = data.status;


        var ticketGroupGuid = Guid.Parse((string)data.order_id);
        var ticketGroup = await _unitOfWork.TicketGroupRepository
            .GetOneAsync(e => e.Guid == ticketGroupGuid,
                e => e.Tickets, cancellationToken);

        if (ticketGroup == null ||
            ticketGroup.Status == TicketStatus.Purchased)
        {
            throw new ForbiddenException();
        }


        // Process callback status

        if (status.Equals("error") || status.Equals("failure"))
        {
            await _unitOfWork.TicketGroupRepository
                .DeleteOneAsync(ticketGroup, cancellationToken);
        }
        else if (status.Equals("success"))
        {
            // Update ticket status

            ticketGroup.Status = TicketStatus.Purchased;
            await _unitOfWork.TicketGroupRepository
                .UpdateOneAsync(ticketGroup, cancellationToken);


            // Hydrate ticket group

            var vehicleEnrollmentIds =
                ticketGroup.Tickets.Select(t => t.VehicleEnrollmentId);
            var vehicleEnrollments = (await _unitOfWork.VehicleEnrollmentRepository
                .GetPageAsync(
                    ve => vehicleEnrollmentIds.Contains(ve.Id),
                    ve => ve.Route.RouteAddresses,
                    1, vehicleEnrollmentIds.Count(), cancellationToken))
                .Items;

            var routeAddressIds = vehicleEnrollments
                .SelectMany(ve => ve.Route.RouteAddresses)
                .Select(ra => ra.Id);
            var routeAddressDetails = (await _unitOfWork.RouteAddressDetailRepository
                .GetPageAsync(
                    rad => routeAddressIds.Contains(rad.RouteAddressId),
                    1, routeAddressIds.Count(), cancellationToken))
                .Items;

            var addressIds = vehicleEnrollments
                .SelectMany(ve => ve.Route.RouteAddresses)
                .Select(ra => ra.AddressId);
            var addresses = (await _unitOfWork.AddressRepository
                .GetPageAsync(
                    a => addressIds.Contains(a.Id),
                    a => a.City.Region.Country,
                    1, addressIds.Count(), cancellationToken))
                .Items;

            var vehicleIds = vehicleEnrollments
                .Select(ve => ve.VehicleId);
            var vehicles = (await _unitOfWork.VehicleRepository
                .GetPageAsync(
                    v => vehicleIds.Contains(v.Id),
                    v => v.Company,
                    1, vehicleIds.Count(), cancellationToken))
                .Items;

            foreach (var ve in vehicleEnrollments)
            {
                ve.Vehicle = vehicles.Single(v => v.Id == ve.VehicleId);

                foreach (var ra in ve.Route.RouteAddresses)
                {
                    ra.Address = addresses.Single(a => a.Id == ra.AddressId);
                    ra.Details = routeAddressDetails
                        .Where(rad => rad.RouteAddressId == ra.Id)
                        .ToArray();
                }
            }

            foreach (var t in ticketGroup.Tickets)
            {
                t.VehicleEnrollment = vehicleEnrollments
                    .Single(ve => ve.Id == t.VehicleEnrollmentId);
            }


            // Send email

            if (ticketGroup.PassangerEmail != null)
            {
                var subject =
                    _localizer["PaymentProcessing.Ticket" +
                    ".Email.PaymentCompleted.Subject"];

                var ticketDetails = GetTicketDetails(ticketGroup);

                var body = String.Format(
                    _localizer["PaymentProcessing.Ticket" +
                        ".Email.PaymentCompleted.Body"],
                    ticketDetails);

                await _emailSender.SendAsync(
                    new[] { ticketGroup.PassangerEmail }, subject,
                    body, cancellationToken);
            }
        }


        await _unitOfWork.SaveAsync(cancellationToken);
        _unitOfWork.Dispose();
    }

    private string GetTicketDetails(TicketGroup ticketGroup)
    {
        var sb = new StringBuilder();

        sb.AppendLine("General:");
        sb.AppendLine();
        sb.AppendLine($"Ticket uuid: {ticketGroup.Guid}");
        sb.AppendLine($"Purchase Time: {ticketGroup.PurchaseTime}");
        sb.AppendLine();

        var departureRouteAddressId =
            ticketGroup.Tickets.First().DepartureRouteAddressId;
        var arrivalRouteAddressId =
            ticketGroup.Tickets.Last().ArrivalRouteAddressId;

        var departureTime =
            ticketGroup.Tickets.First()
            .VehicleEnrollment.GetDepartureTime(departureRouteAddressId);
        var arrivalTime =
            ticketGroup.Tickets.Last()
            .VehicleEnrollment.GetArrivalTime(arrivalRouteAddressId);

        var departureAddress =
            ticketGroup.Tickets.First()
            .VehicleEnrollment.Route.RouteAddresses
            .Single(ra => ra.Id == departureRouteAddressId)
            .Address;
        var arrivalAddress =
            ticketGroup.Tickets.Last()
            .VehicleEnrollment.Route.RouteAddresses
            .Single(ra => ra.Id == arrivalRouteAddressId)
            .Address;

        var departureAddressName =
            $"{departureAddress.City.Region.Country.Name}, " +
            $"{departureAddress.City.Region.Name}, " +
            $"{departureAddress.City.Name}, " +
            $"{departureAddress.Name}";
        var arrivalAddressName =
            $"{arrivalAddress.City.Region.Country.Name}, " +
            $"{arrivalAddress.City.Region.Name}, " +
            $"{arrivalAddress.City.Name}, " +
            $"{arrivalAddress.Name}";

        sb.AppendLine($"Departure: {departureAddressName} at {departureTime}.");
        sb.AppendLine($"Arrival: {arrivalAddressName} at {arrivalTime}.");
        sb.AppendLine();
        sb.AppendLine();

        sb.AppendLine($"Passanger details:");
        sb.AppendLine();
        sb.AppendLine($"First Name: {ticketGroup.PassangerFirstName}.");
        sb.AppendLine($"Last Name: {ticketGroup.PassangerLastName}.");
        sb.AppendLine($"Patronymic: {ticketGroup.PassangerPatronymic}.");
        sb.AppendLine($"Sex: {ticketGroup.PassangerSex}.");
        sb.AppendLine($"Birth Date: {ticketGroup.PassangerBirthDate}.");
        sb.AppendLine($"Email: {ticketGroup.PassangerEmail}.");
        sb.AppendLine();
        sb.AppendLine();


        sb.AppendLine("Vehicle enrollments' details:");
        sb.AppendLine();

        foreach (var t in ticketGroup.Tickets)
        {
            departureRouteAddressId = t.DepartureRouteAddressId;
            arrivalRouteAddressId = t.ArrivalRouteAddressId;

            departureTime =
                t.VehicleEnrollment.GetDepartureTime(departureRouteAddressId);
            arrivalTime =
                t.VehicleEnrollment.GetArrivalTime(arrivalRouteAddressId);

            departureAddress =
                t.VehicleEnrollment.Route.RouteAddresses
                .Single(ra => ra.Id == departureRouteAddressId)
                .Address;
            arrivalAddress =
                t.VehicleEnrollment.Route.RouteAddresses
                .Single(ra => ra.Id == arrivalRouteAddressId)
                .Address;

            departureAddressName =
                $"{departureAddress.City.Region.Country.Name}, " +
                $"{departureAddress.City.Region.Name}, " +
                $"{departureAddress.City.Name}, " +
                $"{departureAddress.Name}";
            arrivalAddressName =
                $"{arrivalAddress.City.Region.Country.Name}, " +
                $"{arrivalAddress.City.Region.Name}, " +
                $"{arrivalAddress.City.Name}, " +
                $"{arrivalAddress.Name}";

            var vehicle = t.VehicleEnrollment.Vehicle;
            var company = vehicle.Company;

            sb.AppendLine($"Departure: {departureAddressName} at {departureTime}.");
            sb.AppendLine($"Arrival: {arrivalAddressName} at {arrivalTime}.");

            if (vehicle is Bus)
            {
                sb.AppendLine($"Vehicle: Bus, {((Bus)vehicle).Model}, " +
                    $"{((Bus)vehicle).Number}.");
            }
            else if (vehicle is Aircraft)
            {
                sb.AppendLine($"Vehicle: Aircraft, {((Aircraft)vehicle).Model}, " +
                    $"{((Aircraft)vehicle).Number}.");
            }
            else if (vehicle is Train)
            {
                sb.AppendLine($"Vehicle: Train, {((Train)vehicle).Model}, " +
                    $"{((Train)vehicle).Number}.");
            }
            else
            {
                throw new NotImplementedException();
            }

            sb.AppendLine($"Company: {company.Name}, ({company.ContactEmail}, " +
                $"{company.ContactPhoneNumber}).");

            var cost = t.Currency.Round(
                t.VehicleEnrollment
                    .GetCost(departureRouteAddressId,arrivalRouteAddressId));
            sb.AppendLine($"Cost: {cost} {t.Currency.Name}");
            sb.AppendLine();
        }

        return sb.ToString();
    }
}