using Akka.Actor;
using Akka.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.OtOpcUa.Commons.Interfaces;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
using ZB.MOM.WW.OtOpcUa.OpcUaServer;
using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
using ZB.MOM.WW.OtOpcUa.Runtime.Health;
using ZB.MOM.WW.OtOpcUa.Runtime.Historian;
using ZB.MOM.WW.OtOpcUa.Runtime.OpcUa;
using ZB.MOM.WW.OtOpcUa.Runtime.VirtualTags;

namespace ZB.MOM.WW.OtOpcUa.Runtime;

public static class ServiceCollectionExtensions
{
    public const string DriverRole = "driver";

    public const string DriverHostActorName = "driver-host";
    public const string DbHealthProbeActorName = "db-health";
    public const string HistorianAdapterActorName = "historian-adapter";
    public const string DependencyMuxActorName = "dependency-mux";
    public const string OpcUaPublishActorName = "opcua-publish";

    /// <summary>
    /// Registers shared runtime services. Currently binds <see cref="IAlarmHistorianSink"/>
    /// to <see cref="NullAlarmHistorianSink"/> as the default; production deployments
    /// override this with <c>SqliteStoreAndForwardSink</c> wrapping <c>WonderwareHistorianClient</c>.
    /// Call this BEFORE <c>AddAkka</c>.
    /// </summary>
    /// <param name="services">The service collection to register with.</param>
    public static IServiceCollection AddOtOpcUaRuntime(this IServiceCollection services)
    {
        services.TryAddSingleton<IAlarmHistorianSink>(NullAlarmHistorianSink.Instance);
        services.TryAddSingleton<IDriverFactory>(NullDriverFactory.Instance);
        services.TryAddSingleton<IOpcUaAddressSpaceSink>(NullOpcUaAddressSpaceSink.Instance);
        services.TryAddSingleton<IServiceLevelPublisher>(NullServiceLevelPublisher.Instance);
        services.TryAddSingleton<IDriverHealthPublisher, AkkaDriverHealthPublisher>();
        return services;
    }

    /// <summary>
    /// Spawns the per-node driver-role actors on the host's <see cref="ActorSystem"/>:
    /// <see cref="DriverHostActor"/> (one per node), <see cref="DbHealthProbeActor"/>
    /// (consumed by the health endpoint + redundancy calc), and
    /// <see cref="HistorianAdapterActor"/> wrapping the registered <see cref="IAlarmHistorianSink"/>.
    ///
    /// Mirror of <c>WithOtOpcUaControlPlaneSingletons</c> for the driver role. Both must
    /// be registered on the same <see cref="AkkaConfigurationBuilder"/> as the cluster
    /// bootstrap so the actors share the host's ActorSystem.
    ///
    /// Wire from the fused Host's Program.cs when the node carries the <c>driver</c> role:
    /// <code>
    /// services.AddOtOpcUaRuntime();
    /// services.AddAkka("otopcua", (ab, sp) => { ab.WithOtOpcUaClusterBootstrap(sp); if (hasDriver) ab.WithOtOpcUaRuntimeActors(); });
    /// </code>
    /// </summary>
    /// <param name="builder">The Akka configuration builder.</param>
    public static AkkaConfigurationBuilder WithOtOpcUaRuntimeActors(this AkkaConfigurationBuilder builder)
    {
        // Production cluster HOCON (akka.conf) carries this dispatcher block, but consumers that
        // bootstrap their own HOCON (e.g. ServiceCollectionExtensionsTests) wouldn't pick it up
        // — OpcUaPublishActor.Props pins itself to opcua-synchronized-dispatcher and Akka throws
        // ConfigurationException if it doesn't exist. Prepend a fallback so the runtime extension
        // is self-contained.
        builder.AddHocon(@"
            opcua-synchronized-dispatcher {
                type = ""PinnedDispatcher""
                executor = ""thread-pool-executor""
                throughput = 1
            }
        ", HoconAddMode.Prepend);

        builder.WithActors((system, registry, resolver) =>
        {
            var dbFactory = resolver.GetService<IDbContextFactory<OtOpcUaConfigDbContext>>();
            var roleInfo = resolver.GetService<IClusterRoleInfo>();
            // Fallback to Null* if AddOtOpcUaRuntime wasn't called (e.g., test harnesses).
            var historianSink = resolver.GetService<IAlarmHistorianSink>() ?? NullAlarmHistorianSink.Instance;
            var driverFactory = resolver.GetService<IDriverFactory>() ?? NullDriverFactory.Instance;
            var addressSpaceSink = resolver.GetService<IOpcUaAddressSpaceSink>() ?? NullOpcUaAddressSpaceSink.Instance;
            var serviceLevel = resolver.GetService<IServiceLevelPublisher>() ?? NullServiceLevelPublisher.Instance;
            var loggerFactory = resolver.GetService<ILoggerFactory>() ?? NullLoggerFactory.Instance;
            var healthPublisher = resolver.GetService<IDriverHealthPublisher>() ?? NullDriverHealthPublisher.Instance;

            var dbHealth = system.ActorOf(
                DbHealthProbeActor.Props(dbFactory),
                DbHealthProbeActorName);
            registry.Register<DbHealthProbeActorKey>(dbHealth);

            // Dependency mux must be spawned before DriverHostActor so the host can forward
            // AttributeValuePublished into it from the very first driver spawn.
            var mux = system.ActorOf(DependencyMuxActor.Props(), DependencyMuxActorName);
            registry.Register<DependencyMuxActorKey>(mux);

            // OPC UA publish actor — pinned dispatcher, owns the address-space side of the
            // pipeline. Phase7Applier is constructed here so the actor + applier share the
            // same sink reference (when DeferredAddressSpaceSink swaps later, both see it).
            var applier = new Phase7Applier(addressSpaceSink, loggerFactory.CreateLogger<Phase7Applier>());
            var publishActor = system.ActorOf(
                OpcUaPublishActor.Props(
                    sink: addressSpaceSink,
                    serviceLevel: serviceLevel,
                    localNode: roleInfo.LocalNode,
                    dbFactory: dbFactory,
                    applier: applier),
                OpcUaPublishActorName);
            registry.Register<OpcUaPublishActorKey>(publishActor);

            var driverHost = system.ActorOf(
                DriverHostActor.Props(dbFactory, roleInfo.LocalNode, coordinator: null,
                    driverFactory: driverFactory, localRoles: roleInfo.LocalRoles,
                    dependencyMux: mux,
                    opcUaPublishActor: publishActor,
                    healthPublisher: healthPublisher),
                DriverHostActorName);
            registry.Register<DriverHostActorKey>(driverHost);

            var historian = system.ActorOf(
                HistorianAdapterActor.Props(historianSink),
                HistorianAdapterActorName);
            registry.Register<HistorianAdapterActorKey>(historian);
        });

        return builder;
    }
}

/// <summary>Marker key types used by <c>Akka.Hosting</c> to resolve runtime actors from the registry.</summary>
public sealed class DriverHostActorKey { }
public sealed class DbHealthProbeActorKey { }
public sealed class HistorianAdapterActorKey { }
public sealed class DependencyMuxActorKey { }
public sealed class OpcUaPublishActorKey { }