register-referentie/services/domain/Big.Application/WithdrawRegistration.cs

using Big.Domain;

namespace Big.Application;

/// <summary>A zorgprofessional's request to withdraw their own registration ("trek aanvraag in").</summary>
public sealed record WithdrawRegistrationCommand(RegistrationId RegistrationId);

/// <summary>
/// The withdrawal use case (S-11): a zorgprofessional pulls a still-open registration back. It
/// advances the aggregate to INGETROKKEN, persists it, then cancels the running registratie process
/// by correlating the withdrawal message to its instance (ADR-0014), so the case leaves the
/// behandelaar's werkbak. Idempotent — a repeated or redelivered withdrawal of an already-withdrawn
/// registration is a no-op (not persisted or cancelled again). Cancelling is best-effort: if the
/// registration never started a process the withdrawal still stands (the process cancel is skipped),
/// mirroring how <see cref="BeoordeelRegistratie"/> completes its task best-effort.
/// </summary>
public sealed class WithdrawRegistration(IRegistrationStore store, IWorkflowClient workflow)
{
    public async Task HandleAsync(WithdrawRegistrationCommand command, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(command);

        var registration = await store.GetAsync(command.RegistrationId, ct)
            ?? throw new InvalidOperationException($"No registration {command.RegistrationId} to withdraw.");

        // A repeated withdrawal is a no-op: don't persist or cancel the already-withdrawn one again.
        if (registration.Status == RegistrationStatus.Ingetrokken)
            return;

        registration.Withdraw();
        await store.SaveAsync(registration, ct);

        // Cancel the running process (if one was started) so its Beoordelen task leaves the werkbak.
        if (registration.ProcessInstanceId is not null)
            await workflow.WithdrawProcessAsync(registration.ProcessInstanceId, ct);
    }
}