using Big.Domain;

namespace Big.Application;

/// <summary>
/// Handles one acquired <c>OpenZaakAanmaken</c> external-worker job (ADR-0009): load the registration
/// the job correlates to, open a zaak for it via the ACL (§8.1), attach the zaak to the aggregate, and
/// return the zaak URL so the caller can complete the Flowable job. Pure application logic over ports —
/// it knows nothing of Flowable; the polling loop that feeds it jobs lives in Infrastructure.
/// </summary>
public sealed class OpenZaakWorker(IRegistrationStore store, IAclClient acl)
{
    /// <summary>
    /// Process the job and return the URL of the (existing or newly opened) zaak. Idempotent: if the
    /// registration already has a zaak — a job redelivered after its completion was lost — it returns
    /// that zaak without opening a second one (§8.6, at-least-once delivery). An unknown registration
    /// is an error: it throws, leaving the job un-completed for Flowable to redeliver.
    /// </summary>
    public async Task<Uri> HandleAsync(OpenZaakJob job, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(job);

        var registration = await store.GetAsync(job.RegistrationId, ct)
            ?? throw new InvalidOperationException(
                $"No registration {job.RegistrationId} for OpenZaakAanmaken job {job.JobId}.");

        // A redelivered job whose zaak was already opened completes without opening a second one.
        if (registration.ZaakUrl is not null)
            return registration.ZaakUrl;

        var zaakUrl = await acl.OpenZaakAsync(registration.Bsn, registration.Id.ToString(), ct);
        registration.AttachZaak(zaakUrl);
        await store.SaveAsync(registration, ct);
        return zaakUrl;
    }
}