using Akka.Actor;
using Akka.Cluster.Tools.PublishSubscribe;
using Akka.Event;
using Microsoft.AspNetCore.SignalR;
using ZB.MOM.WW.OtOpcUa.Commons.Messages.Alerts;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;

/// <summary>
/// Akka actor that subscribes to the <c>alerts</c> DistributedPubSub topic and forwards each
/// <see cref="AlarmTransitionEvent"/> to every SignalR client connected to <see cref="AlertHub"/>.
/// Mirrors <c>FleetStatusSignalRBridge</c>'s design — one bridge per admin node, hub fan-out is
/// per-node, no cluster-singleton needed.
/// </summary>
public sealed class AlertSignalRBridge : ReceiveActor
{
    public const string TopicName = "alerts";

    private readonly IHubContext<AlertHub> _hub;
    private readonly ILoggingAdapter _log = Context.GetLogger();

    public static Props Props(IHubContext<AlertHub> hub) =>
        Akka.Actor.Props.Create(() => new AlertSignalRBridge(hub));

    public AlertSignalRBridge(IHubContext<AlertHub> hub)
    {
        _hub = hub;
        ReceiveAsync<AlarmTransitionEvent>(ForwardAsync);
        Receive<SubscribeAck>(_ => { /* DPS confirmation */ });
    }

    protected override void PreStart() =>
        DistributedPubSub.Get(Context.System).Mediator.Tell(new Subscribe(TopicName, Self));

    private async Task ForwardAsync(AlarmTransitionEvent msg)
    {
        try
        {
            await _hub.Clients.All.SendAsync(AlertHub.MethodName, msg);
        }
        catch (Exception ex)
        {
            _log.Warning(ex, "AlertSignalRBridge: SignalR push failed for {AlarmId}", msg.AlarmId);
        }
    }
}