namespace ScadaLink.AuditLog.Central;

/// <summary>
/// Published on the actor-system EventStream by <see cref="AuditLogPurgeActor"/>
/// after each successful partition switch-out. Downstream consumers (Bundle E
/// central health collector, ops dashboards, audit trails) subscribe so a
/// purge action is observable without the actor needing to know about any
/// specific subscriber.
/// </summary>
/// <param name="MonthBoundary">
/// The pf_AuditLog_Month lower-bound boundary that was switched out — i.e.
/// the first instant of the purged month in UTC.
/// </param>
/// <param name="RowsDeleted">
/// Approximate row count purged from the partition, sampled BEFORE the
/// switch. Exact accounting would require a post-switch scan of the staging
/// table, which the dance drops immediately, so this is the closest
/// observable proxy. Zero is a valid value when the actor's enumerator
/// included a partition the operator subsequently emptied by hand.
/// </param>
/// <param name="DurationMs">
/// Wall-clock time spent inside <c>SwitchOutPartitionAsync</c> for this
/// boundary, in milliseconds. Useful for spotting the rare slow purge
/// without spinning up dedicated telemetry.
/// </param>
public sealed record AuditLogPurgedEvent(
    DateTime MonthBoundary,
    long RowsDeleted,
    long DurationMs);