using Akka.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Shouldly;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Core.Authorization;
using ZB.MOM.WW.OtOpcUa.Host.OpcUa;
using ZB.MOM.WW.OtOpcUa.OpcUaServer;
using ZB.MOM.WW.OtOpcUa.OpcUaServer.Security;
using ZB.MOM.WW.OtOpcUa.Runtime.Redundancy;

namespace ZB.MOM.WW.OtOpcUa.Host.Tests.OpcUa;

/// <summary>
///     Gitea #674 review — pins what the hosted service wires onto the node manager for HistoryUpdate: the Primary gate
///     from <see cref="IHistoryUpdateRoleView"/> (read live on every call), and the future-skew bound + clock from
///     <c>ServerHistorian</c> options. Asserted through <see cref="OtOpcUaServerHostedService.BuildHistoryUpdatePosture"/>
///     (what <c>StartAsync</c> applies) so the SDK need not boot.
/// </summary>
public sealed class OtOpcUaServerHostedServiceHistoryUpdateTests
{
    [Fact]
    public void A_registered_view_wires_a_gate_that_reads_it_live()
    {
        var view = new FlippableView { Serve = false };
        var posture = Service(view).BuildHistoryUpdatePosture();

        posture.PrimaryGate.ShouldNotBeNull();
        posture.PrimaryGate().ShouldBeFalse();
        view.Serve = true;
        posture.PrimaryGate().ShouldBeTrue("the gate must read the view on every call, not capture its value");
    }

    /// <summary>The gate comes from the HistoryUpdate view, NOT the data-plane source — a source saying "Primary" must not
    /// open it while the HistoryUpdate verdict is closed (the boot-window distinction).</summary>
    [Fact]
    public void The_gate_ignores_the_data_plane_primary_source()
    {
        var posture = Service(new FlippableView { Serve = false }, new AlwaysPrimary()).BuildHistoryUpdatePosture();

        posture.PrimaryGate!().ShouldBeFalse();
    }

    /// <summary>No view (an admin-only node: no redundancy manager) ⇒ no gate ⇒ HistoryUpdate allowed.</summary>
    [Fact]
    public void No_view_wires_no_gate()
    {
        Service(view: null).BuildHistoryUpdatePosture().PrimaryGate.ShouldBeNull();
    }

    [Fact]
    public void Skew_and_clock_come_from_options_and_the_host_clock()
    {
        var clock = new FixedClock();
        var config = new ConfigurationBuilder().AddInMemoryCollection(new Dictionary<string, string?>
        {
            ["ServerHistorian:HistoryUpdateMaxFutureSkew"] = "00:07:00",
        }).Build();

        var posture = Service(view: null, config: config, clock: clock).BuildHistoryUpdatePosture();

        posture.MaxFutureSkew.ShouldBe(TimeSpan.FromMinutes(7));
        posture.Clock.ShouldBeSameAs(clock);
    }

    [Fact]
    public void An_absent_section_keeps_the_one_day_default()
    {
        Service(view: null).BuildHistoryUpdatePosture().MaxFutureSkew.ShouldBe(TimeSpan.FromDays(1));
    }

    private static OtOpcUaServerHostedService Service(
        IHistoryUpdateRoleView? view, IDriverPrimaryRoleSource? primary = null, IConfiguration? config = null,
        TimeProvider? clock = null) => new(
        Options.Create(new OpcUaApplicationHostOptions()),
        new DeferredAddressSpaceSink(),
        new DeferredServiceLevelPublisher(),
        NullOpcUaUserAuthenticator.Instance,
        NullHistorianDataSource.Instance,
        EmptyDataPlaneAuthoritySource.Instance,
        config ?? new ConfigurationBuilder().Build(),
        () => throw new NotSupportedException("no ActorSystem is needed for the HistoryUpdate posture"),
        new ActorRegistry(),
        dataPlaneAuthorizer: null,
        Options.Create(new AclOptions()),
        clock ?? TimeProvider.System,
        NullLoggerFactory.Instance,
        primaryRoleSource: primary,
        historyUpdateRoleView: view);

    private sealed class FlippableView : IHistoryUpdateRoleView
    {
        public volatile bool Serve;

        public bool ShouldServeHistoryUpdate => Serve;

        public void PublishHistoryUpdateRole(bool shouldServeHistoryUpdate) => Serve = shouldServeHistoryUpdate;
    }

    private sealed class AlwaysPrimary : IDriverPrimaryRoleSource
    {
        public bool ShouldActAsPrimary => true;

        public void PublishPrimaryRole(bool shouldActAsPrimary)
        {
        }
    }

    private sealed class FixedClock : TimeProvider
    {
        public override DateTimeOffset GetUtcNow() => new(2026, 10, 11, 0, 0, 0, TimeSpan.Zero);
    }
}