using Big.Domain;

namespace Big.Application;

/// <summary>One row of the behandelaar's werkbak: a registration awaiting beoordeling, with the
/// public-facing reference (its id) plus the bsn and status a behandelaar needs to triage it.</summary>
public sealed record WerkbakItem(string RegistrationId, string Bsn, string Status);

/// <summary>
/// The werkbak query (S-12c): the registrations awaiting a behandelaar's beoordeling. It reads the
/// open <c>Beoordelen</c> tasks from the workflow engine (§8.2, via <see cref="IUserTaskClient"/>) —
/// the authoritative set of work items — and enriches each with its aggregate (bsn + status). A task
/// whose registration the domain doesn't know, or whose registration is no longer open for beoordeling
/// (e.g. withdrawn — S-11 — while its task lingers until the workflow cancels it), is skipped.
/// </summary>
public sealed class Werkbak(IUserTaskClient tasks, IRegistrationStore store)
{
    public async Task<IReadOnlyList<WerkbakItem>> GetAsync(CancellationToken ct = default)
    {
        var open = await tasks.GetOpenBeoordelingenAsync(ct);

        var items = new List<WerkbakItem>(open.Count);
        foreach (var task in open)
        {
            var registration = await store.GetAsync(task.RegistrationId, ct);
            if (registration is null || !IsOpenForBeoordeling(registration.Status))
                continue;

            items.Add(new WerkbakItem(
                registration.Id.ToString(), registration.Bsn, registration.Status.ToString()));
        }

        return items;
    }

    // Only registrations still open for a decision belong in the werkbak; a terminal one (decided or
    // withdrawn — S-11) whose Beoordelen task has not yet been cleared must not surface to a behandelaar.
    private static bool IsOpenForBeoordeling(RegistrationStatus status)
        => status is RegistrationStatus.Ingediend or RegistrationStatus.InBehandeling;
}