namespace EventSubscriber.Application;

/// <summary>
/// An inbound NRC (Open Notificaties) notification, as Open Notificaties POSTs it to an
/// abonnement callback. Only the fields the projection needs are modelled; the full ZGW
/// "Notificatie" resource also carries <c>aanmaakdatum</c> and <c>kenmerken</c> which the
/// minimal projection ignores (bsn is deferred — see ADR-0008). For a <c>zaken</c>/<c>zaak</c>/<c>create</c>
/// notification <c>hoofdObject</c> and <c>resourceUrl</c> are both the created zaak's URL.
/// </summary>
public sealed record Notification(
    string Kanaal,
    string Resource,
    string Actie,
    Uri ResourceUrl,
    Uri? HoofdObject = null)
{
    /// <summary>A zaak being created — projected as INGEDIEND.</summary>
    public bool IsZaakCreated =>
        Kanaal == "zaken" && Resource == "zaak" && Actie == "create";

    /// <summary>A status being set on a zaak — the approval, projected as INGESCHREVEN (S-09b). In the
    /// walking skeleton the only status ever set after creation is the approval, and the subscriber may
    /// not read OpenZaak (§8.1), so any status-create is taken as the approval.</summary>
    public bool IsZaakStatusSet =>
        Kanaal == "zaken" && Resource == "status" && Actie == "create";

    /// <summary>The zaak URL this notification concerns — <c>hoofdObject</c> (the zaak) for a status
    /// notification, else the resource URL (which, for a zaak-create, is the zaak).</summary>
    public Uri ZaakUrl => HoofdObject ?? ResourceUrl;

    /// <summary>The zaak UUID used as the projection key — the trailing segment of <see cref="ZaakUrl"/>.</summary>
    public string ZaakId => ZaakUrl.Segments[^1].Trim('/');

    /// <summary>
    /// A deterministic dedup key. Open Notificaties carries no notification id and may
    /// redeliver, so the key is derived from the immutable notification content: two
    /// deliveries of the same zaak-create collapse to one. (NRC may also deliver
    /// out of order; the projector tolerates that — order does not change the outcome.)
    /// </summary>
    public string IdempotencyKey => $"{Kanaal}:{Resource}:{Actie}:{ResourceUrl}";
}