TournamentCanceledEventHandler.cs

using ClubService.Application.Api;
using ClubService.Application.Api.Exceptions;
using ClubService.Domain.Event;
using ClubService.Domain.ReadModel;
using ClubService.Domain.Repository;

namespace ClubService.Application.EventHandlers.TournamentEventHandlers;

public class TournamentCanceledEventHandler(
    ITournamentReadModelRepository tournamentReadModelRepository,
    ITennisClubReadModelRepository tennisClubReadModelRepository,
    IMemberReadModelRepository memberReadModelRepository,
    IEmailOutboxRepository emailOutboxRepository,
    ILoggerService<TournamentCanceledEventHandler> loggerService)
    : IEventHandler
{
    public async Task Handle(DomainEnvelope<IDomainEvent> domainEnvelope)
    {
        if (!Supports(domainEnvelope))
        {
            loggerService.LogRejectEvent(domainEnvelope);
            return;
        }

        loggerService.LogHandleEvent(domainEnvelope);

        var tournamentReadModel = await tournamentReadModelRepository.GetTournamentById(domainEnvelope.EntityId);

        if (tournamentReadModel == null)
        {
            loggerService.LogTournamentNotFound(domainEnvelope.EntityId);
            throw new TournamentNotFoundException(domainEnvelope.EntityId);
        }

        var tennisClubReadModel =
            await tennisClubReadModelRepository.GetTennisClubById(tournamentReadModel.TennisClubId);

        if (tennisClubReadModel != null)
        {
            var members = await memberReadModelRepository.GetMembersByTennisClubId(tennisClubReadModel.TennisClubId.Id);
            var mailSubject = $"Tournament {tournamentReadModel.Name} canceled";
            var mailBody = $"""
                            Unfortunately the tournament '{tournamentReadModel.Name}' that would have been taking 
                            place from the {tournamentReadModel.StartDate} to the {tournamentReadModel.EndDate} has 
                            been canceled.
                            """;

            foreach (var member in members)
            {
                var emailMessage = new EmailMessage(Guid.NewGuid(), member.Email, mailSubject, mailBody,
                    DateTime.UtcNow);
                await emailOutboxRepository.Add(emailMessage);
            }
        }
        else
        {
             // We can't throw an exception here because deleting a tennis club triggers 
            // that all associated tournaments are deleted.
            loggerService.LogTennisClubNotFound(tournamentReadModel.TennisClubId);
        }

        await tournamentReadModelRepository.Delete(tournamentReadModel);
        loggerService.LogTournamentCanceled(tournamentReadModel.TournamentId);
    }

    private static bool Supports(DomainEnvelope<IDomainEvent> domainEnvelope)
    {
        return domainEnvelope.EventType.Equals(EventType.TOURNAMENT_CANCELED);
    }
}