using System;

namespace ZB.MOM.WW.OtOpcUa.Host.Historian
{
    /// <summary>
    ///     Point-in-time state of a single historian cluster node. One entry per configured node is
    ///     surfaced inside <see cref="HistorianHealthSnapshot"/> so the status dashboard can render
    ///     per-node health and operators can see which nodes are in cooldown.
    /// </summary>
    public sealed class HistorianClusterNodeState
    {
        /// <summary>
        ///     Gets or sets the configured node hostname exactly as it appears in
        ///     <c>HistorianConfiguration.ServerNames</c>.
        /// </summary>
        public string Name { get; set; } = "";

        /// <summary>
        ///     Gets or sets a value indicating whether the node is currently eligible for new connection
        ///     attempts. <see langword="false"/> means the node is in its post-failure cooldown window
        ///     and the picker is skipping it.
        /// </summary>
        public bool IsHealthy { get; set; }

        /// <summary>
        ///     Gets or sets the UTC timestamp at which the node's cooldown expires, or
        ///     <see langword="null"/> when the node is not in cooldown.
        /// </summary>
        public DateTime? CooldownUntil { get; set; }

        /// <summary>
        ///     Gets or sets the number of times this node has transitioned from healthy to failed
        ///     since startup. Does not decrement on recovery.
        /// </summary>
        public int FailureCount { get; set; }

        /// <summary>
        ///     Gets or sets the message from the most recent failure, or <see langword="null"/> when
        ///     the node has never failed.
        /// </summary>
        public string? LastError { get; set; }

        /// <summary>
        ///     Gets or sets the UTC timestamp of the most recent failure, or <see langword="null"/>
        ///     when the node has never failed.
        /// </summary>
        public DateTime? LastFailureTime { get; set; }
    }
}