namespace ScadaLink.AuditLog.Central;

/// <summary>
/// Tuning knobs for the central <see cref="SiteAuditReconciliationActor"/> singleton.
/// Defaults mirror the M6 Bundle B brief: pull every 5 minutes per site, 256 rows per
/// batch, declare a site "stalled" after two consecutive pull cycles return non-empty
/// AND <c>MoreAvailable=true</c> (the backlog is not draining).
/// </summary>
/// <remarks>
/// <para>
/// Per the M6 plan the reconciliation actor is the fallback when push telemetry is
/// lost; it is intentionally low-frequency. Lowering
/// <see cref="ReconciliationIntervalSeconds"/> in production trades MS SQL load for
/// fresher self-healing — keep the default unless a deployment can prove the extra
/// load is acceptable.
/// </para>
/// <para>
/// <see cref="StalledAfterNonDrainingCycles"/> = 2 because a single non-draining
/// cycle can happen on a surge (e.g. a backed-up site replays its hot queue); the
/// stalled signal should only fire when the backlog persists across cycles, which is
/// the symptom the central health surface is asking us to detect.
/// </para>
/// </remarks>
public sealed class SiteAuditReconciliationOptions
{
    /// <summary>
    /// Period of the reconciliation tick. Each tick visits every known site once.
    /// </summary>
    public int ReconciliationIntervalSeconds { get; set; } = 300;

    /// <summary>
    /// Test-only override for finer control over the tick cadence than
    /// whole-second resolution allows. When non-null, takes precedence over
    /// <see cref="ReconciliationIntervalSeconds"/>. Not bound from config —
    /// production config exposes <see cref="ReconciliationIntervalSeconds"/>
    /// only.
    /// </summary>
    public TimeSpan? ReconciliationIntervalOverride { get; set; }

    /// <summary>
    /// Resolves the effective tick interval, honouring the test override when
    /// set. Falls back to <see cref="ReconciliationIntervalSeconds"/>.
    /// </summary>
    public TimeSpan ReconciliationInterval =>
        ReconciliationIntervalOverride ?? TimeSpan.FromSeconds(ReconciliationIntervalSeconds);

    /// <summary>
    /// Maximum number of <see cref="ScadaLink.Commons.Entities.Audit.AuditEvent"/>
    /// rows requested in a single <c>PullAuditEvents</c> RPC call.
    /// </summary>
    public int BatchSize { get; set; } = 256;

    /// <summary>
    /// Number of consecutive non-draining cycles (events returned AND
    /// <c>MoreAvailable=true</c>) that must accumulate for a site before the actor
    /// publishes <c>SiteAuditTelemetryStalledChanged(Stalled: true)</c> on the
    /// EventStream.
    /// </summary>
    public int StalledAfterNonDrainingCycles { get; set; } = 2;
}