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 *
 * OPC Foundation MIT License 1.00
 *
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 * obtaining a copy of this software and associated documentation
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using System;

namespace Opc.Ua.Server.Fluent
{
    /// <summary>
    /// Optional knobs for
    /// <c>EventNotifierBuilderExtensions.Publish</c>.
    /// </summary>
    /// <remarks>
    /// <para>
    /// All properties are init-only so the same options instance can safely be
    /// reused across multiple <c>Publish</c> registrations.
    /// </para>
    /// <para>
    /// Default behavior (no options supplied): lazy activation, default-field
    /// population enabled, error policy logs and continues, not registered as
    /// a root notifier.
    /// </para>
    /// </remarks>
    public sealed record EventPublishOptions
    {
        /// <summary>
        /// When <c>true</c>, the source's iterator is pumped immediately at
        /// builder seal time and stays active until the manager disposes —
        /// regardless of whether any client is monitoring the node. Useful
        /// for diagnostic event streams whose backpressure or history-storage
        /// guarantees must be preserved across reconnect storms. Default
        /// <c>false</c> (lazy activation: events are pulled only while
        /// <see cref="NodeState.AreEventsMonitored"/> is true).
        /// </summary>
        public bool AlwaysOn { get; init; }

        /// <summary>
        /// When <c>true</c>, the registry does NOT auto-populate
        /// <c>EventId</c>, <c>EventType</c>, <c>SourceNode</c>,
        /// <c>SourceName</c>, <c>Time</c>, <c>ReceiveTime</c>,
        /// <c>Severity</c>, and <c>Message</c> on each yielded event. Use
        /// this when your iterator emits fully-populated events
        /// (e.g. replayed from a history store). Default <c>false</c>
        /// (matches <c>BaseEventState.Initialize</c>).
        /// </summary>
        public bool SkipDefaultPopulation { get; init; }

        /// <summary>
        /// When <c>true</c>, the notifier node is added to the manager's
        /// root-notifier collection so its events propagate to clients that
        /// subscribe to the <c>Server</c> object. Default <c>false</c>:
        /// only direct subscribers to the notifier (or to an ancestor that
        /// the notifier is reachable from via inverse <c>HasNotifier</c>
        /// references) receive events.
        /// </summary>
        /// <remarks>
        /// Enabling this option overwrites the notifier's
        /// <see cref="NodeState.OnReportEvent"/> with the manager's
        /// root-notifier handler, which is incompatible with attaching an
        /// <c>OnEvent</c> interceptor or with direct per-node event monitored
        /// items on the same notifier; the runtime emits a debug-level log
        /// line documenting the trade-off.
        /// </remarks>
        public bool RegisterAsRootNotifier { get; init; }

        /// <summary>
        /// Maximum time the registry waits for the iterator to honor its
        /// <see cref="System.Threading.CancellationToken"/> when the source
        /// deactivates or the manager disposes. After the timeout, the source
        /// is flagged as leaked: any further events the iterator yields are
        /// silently dropped. Default <c>5 seconds</c>.
        /// </summary>
        public TimeSpan CancellationTimeout { get; init; } = TimeSpan.FromSeconds(5);

        /// <summary>
        /// Optional sink that observes exceptions thrown by the factory
        /// invocation, the iterator <c>MoveNextAsync</c> call, or
        /// <see cref="NodeState.ReportEvent"/>. The registry already logs at
        /// <c>Error</c> level using the manager's logger; this hook is for
        /// callers that want to bubble the exception into their own
        /// telemetry. Default <c>null</c>.
        /// </summary>
        public Action<Exception>? OnError { get; init; }
    }
}