using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;

namespace ZB.MOM.WW.ScadaBridge.HealthMonitoring;

/// <summary>
/// Provides cluster node status information for health reporting.
/// Implemented by the Host project which has access to the Akka.NET actor system.
/// </summary>
public interface IClusterNodeProvider
{
    /// <summary>Returns the current status of all cluster nodes for the provider's role scope.</summary>
    /// <returns>A read-only list of node status records for all known cluster nodes.</returns>
    IReadOnlyList<NodeStatus> GetClusterNodes();

    /// <summary>
    /// True when this node is currently the oldest Up member for the provider's
    /// role scope — the node the ClusterSingletonManager hosts singletons on.
    /// This is the canonical product "active node" check (review 01): the site
    /// event-log purge gate, the central self-report loop, and (via plan 02) the
    /// S&amp;F delivery gate all consume it. It is deliberately NOT the cluster
    /// leader — leadership is address-ordered and diverges from singleton
    /// placement once the original first node restarts and rejoins.
    /// </summary>
    bool SelfIsPrimary { get; }
}