using Opc.Ua;
using Opc.Ua.Server;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;

namespace ZB.MOM.WW.OtOpcUa.OpcUaServer;

/// <summary>
///     <see cref="StandardServer"/> subclass that wires in the v2 <see cref="OtOpcUaNodeManager"/>.
///     Exposes the live node manager after start so callers (<see cref="OpcUaApplicationHost"/>,
///     the fused Host's DI binding) can wrap it in a <see cref="SdkAddressSpaceSink"/> and hand
///     it to <c>OpcUaPublishActor</c>.
/// </summary>
public sealed class OtOpcUaSdkServer : StandardServer
{
    private OtOpcUaNodeManager? _otOpcUaNodeManager;

    /// <summary>The custom node manager once <c>StartAsync</c> has called
    /// <see cref="CreateMasterNodeManager"/>. Null until the SDK has bootstrapped.</summary>
    public OtOpcUaNodeManager? NodeManager => _otOpcUaNodeManager;

    /// <summary>
    ///     Wire the reverse-path sink for inbound Part 9 alarm method calls onto the created
    ///     <see cref="OtOpcUaNodeManager"/>. The host calls this after start with a non-blocking
    ///     <c>mediator.Tell</c> that publishes each <see cref="AlarmCommand"/> onto the
    ///     <c>alarm-commands</c> DistributedPubSub topic. No-op (returns <c>false</c>) when the node
    ///     manager has not been created yet, so the caller can detect a too-early call.
    /// </summary>
    /// <param name="router">The router invoked by the condition handlers once the <c>AlarmAck</c>
    /// gate passes; may be <c>null</c> to clear it.</param>
    /// <returns><c>true</c> when the router was set on a live node manager; <c>false</c> when no node
    /// manager exists yet.</returns>
    public bool SetAlarmCommandRouter(Action<AlarmCommand>? router)
    {
        if (_otOpcUaNodeManager is null) return false;
        _otOpcUaNodeManager.AlarmCommandRouter = router;
        return true;
    }

    /// <inheritdoc />
    protected override MasterNodeManager CreateMasterNodeManager(
        IServerInternal server, ApplicationConfiguration configuration)
    {
        _otOpcUaNodeManager = new OtOpcUaNodeManager(server, configuration);
        return new MasterNodeManager(server, configuration, dynamicNamespaceUri: null, _otOpcUaNodeManager);
    }
}