namespace ClaudeDo.Worker.Hub;

/// <summary>
/// Counts SignalR clients (the ClaudeDo App) currently connected to <see cref="WorkerHub"/>.
/// A <c>Hub</c> instance is transient per connection, so this lives as a DI singleton and is
/// updated from <see cref="WorkerHub.OnConnectedAsync"/>/<see cref="WorkerHub.OnDisconnectedAsync"/>
/// — the only way an out-of-band caller (external MCP's start_list_handler, which only
/// broadcasts) can tell whether anything is listening before claiming it did something.
/// </summary>
public sealed class ConnectedClientTracker
{
    private int _count;

    public bool AnyConnected => Volatile.Read(ref _count) > 0;

    public void Increment() => Interlocked.Increment(ref _count);

    public void Decrement() => Interlocked.Decrement(ref _count);
}