using Opc.Ua;
using Opc.Ua.Client;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using static ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests.ServerEventRig;

namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests;

/// <summary>
///     Gitea #587 over the wire — every accepted Part 9 method call (Acknowledge, Confirm, AddComment,
///     OneShotShelve, TimedShelve, Unshelve, Enable, Disable) on a native or scripted condition reaches a
///     folder event item and a Server-object (<c>i=2253</c>) item as <b>exactly one</b> condition event
///     carrying the new state.
/// </summary>
/// <remarks>
///     <para>
///         Before #587 a client Acknowledge produced no condition event at all: the SDK's own report is gated
///         on <c>AutoReportStateChanges</c> (never set here), and the engine's re-projection found the node
///         already acknowledged and suppressed its own. The code comments claiming "the SDK auto-fires its own
///         event" were wrong — and a fix that only enabled the SDK's report would still double-report a shelve
///         (the SDK reports before any shelving state is applied, then the re-projection reports the change).
///     </para>
///     <para>
///         Each case runs the engine's (or, for a native alarm, the driver's) answer to the routed command as
///         a re-projection from a pool thread, so "exactly one" covers the duplicate the re-projection could
///         add, not only the method path. The count is read after a later <b>sentinel</b> transition arrives on
///         the same item, so a late duplicate would already be in the queue ahead of it.
///     </para>
/// </remarks>
public sealed class ConditionMethodEventTests
{
    private const NodePermissions All =
        NodePermissions.Browse | NodePermissions.Read | NodePermissions.Subscribe | NodePermissions.AlarmRead
        | NodePermissions.AlarmAcknowledge | NodePermissions.AlarmConfirm | NodePermissions.AlarmShelve
        | NodePermissions.MethodCall;

    /// <summary>
    ///     One accepted method call ⇒ one condition event, to the folder item and to the Server-object item,
    ///     with the new state — while a session holding no grant receives none of it through the Server object.
    /// </summary>
    [Theory]
    [InlineData("Acknowledge", false, true)]
    [InlineData("Confirm", false, true)]
    [InlineData("AddComment", false, true)]
    [InlineData("OneShotShelve", false, true)]
    [InlineData("TimedShelve", false, true)]
    [InlineData("Unshelve", false, true)]
    [InlineData("Disable", false, true)]
    [InlineData("Enable", false, true)]
    [InlineData("Acknowledge", true, true)]
    [InlineData("Confirm", true, true)]
    [InlineData("AddComment", true, true)]
    [InlineData("OneShotShelve", true, true)]
    [InlineData("TimedShelve", true, true)]
    [InlineData("Unshelve", true, true)]
    // Flag off: the server-wide AlarmAck role admits the call; delivery is ungated.
    [InlineData("Acknowledge", false, false)]
    [InlineData("Acknowledge", true, false)]
    [InlineData("OneShotShelve", true, false)]
    public async Task An_accepted_method_call_reports_exactly_one_condition_event(string method, bool native, bool aclOn)
    {
        var ct = TestContext.Current.CancellationToken;
        var rig = await StartAsync($"CondMethod{method}{native}{aclOn}", encrypted: false, ct);
        try
        {
            rig.Enforce(aclOn, [Key()], ClusterGrant(KeyPrincipal, "acl-key", All));
            rig.MaterialiseNative();
            rig.MaterialiseScripted();

            var current = PreState(method, native);
            WireSimulatedOwners(rig, native, () => current, s => current = s);

            using var session = await rig.ConnectAsync(anonymous: false, ct);
            var events = new RecordedEvents();
            var subscription = await RecordedEvents.SubscribeAsync(session, events, ct);
            var folderItem = RecordedEvents.AddEventItem(subscription, UnsNodeId(session, EqA));
            var serverItem = RecordedEvents.AddEventItem(subscription, ObjectIds.Server);
            await subscription.ApplyChangesAsync(ct);
            folderItem.Status.Error.ShouldBeNull();

            using var ungranted = await rig.ConnectAsync(anonymous: true, ct);
            var ungrantedEvents = new RecordedEvents();
            var ungrantedSubscription = await RecordedEvents.SubscribeAsync(ungranted, ungrantedEvents, ct);
            var ungrantedItem = RecordedEvents.AddEventItem(ungrantedSubscription, ObjectIds.Server);
            await ungrantedSubscription.ApplyChangesAsync(ct);

            var condition = ConditionNodeId(session, native);

            // Every transition the test drives also moves the simulated owner's state, so its re-projections
            // carry the node's current message.
            void ProjectAs(string message)
            {
                current = current with { Message = message };
                rig.Project(native, current);
            }

            // A native condition's Confirmed and Shelving are reached only through the methods.
            ProjectAs("setup");
            await RecordedEvents.WaitUntilAsync(() => events.Has(folderItem, "setup"));
            if (native && method == "Confirm")
                await CallAsync(session, condition, "Acknowledge", events.LatestEventId(folderItem, "setup"), ct);
            if (native && method == "Unshelve")
                await CallAsync(session, condition, "OneShotShelve", events.LatestEventId(folderItem, "setup"), ct);
            await rig.DrainProjectionsAsync();

            ProjectAs("base");
            await RecordedEvents.WaitUntilAsync(() => events.Has(folderItem, "base") && events.Has(serverItem, "base"));

            await CallAsync(session, condition, method, events.LatestEventId(folderItem, "base"), ct);
            await rig.DrainProjectionsAsync();

            ProjectAs("sentinel");
            await RecordedEvents.WaitUntilAsync(() =>
                events.Has(folderItem, "sentinel") && events.Has(serverItem, "sentinel")
                && (aclOn || ungrantedEvents.Has(ungrantedItem, "sentinel")));

            foreach (var item in new[] { folderItem, serverItem })
            {
                var baseEvents = events.ConditionEvents(item, "base");
                baseEvents.Count.ShouldBe(2, $"the base transition plus exactly one {method} event ({item.StartNodeId})");
                AssertNewState(method, baseEvents[1]);
            }

            if (aclOn)
            {
                ungrantedEvents.Of(ungrantedItem).ShouldBeEmpty(
                    "a session with no grant receives no condition event through the Server object");
            }
            else
            {
                ungrantedEvents.ConditionEvents(ungrantedItem, "base").Count.ShouldBe(2, "flag off: ungated, still once");
            }

            await ungrantedSubscription.DeleteAsync(true, ct);
            await subscription.DeleteAsync(true, ct);
        }
        finally { await rig.DisposeAsync(); }
    }

    /// <summary>
    ///     A refused call reports nothing: Disable on a native condition is <c>BadNotSupported</c>, so no
    ///     transition happened and no condition event may claim one.
    /// </summary>
    [Fact]
    public async Task A_refused_method_call_reports_no_condition_event()
    {
        var ct = TestContext.Current.CancellationToken;
        var rig = await StartAsync("CondMethodRefused", encrypted: false, ct);
        try
        {
            rig.Enforce(true, [Key()], ClusterGrant(KeyPrincipal, "acl-key", All));
            rig.MaterialiseNative();
            var current = PreState("Disable", native: true);

            using var session = await rig.ConnectAsync(anonymous: false, ct);
            var events = new RecordedEvents();
            var subscription = await RecordedEvents.SubscribeAsync(session, events, ct);
            var folderItem = RecordedEvents.AddEventItem(subscription, UnsNodeId(session, EqA));
            var serverItem = RecordedEvents.AddEventItem(subscription, ObjectIds.Server);
            await subscription.ApplyChangesAsync(ct);

            rig.Project(native: true, current = current with { Message = "base" });
            await RecordedEvents.WaitUntilAsync(() => events.Has(serverItem, "base"));

            var refused = await Should.ThrowAsync<ServiceResultException>(
                CallAsync(session, ConditionNodeId(session, native: true), "Disable", null, ct));
            refused.StatusCode.ShouldBe(StatusCodes.BadNotSupported);

            rig.Project(native: true, current with { Message = "sentinel" });
            await RecordedEvents.WaitUntilAsync(() => events.Has(folderItem, "sentinel") && events.Has(serverItem, "sentinel"));
            events.ConditionEvents(folderItem, "base").Count.ShouldBe(1);
            events.ConditionEvents(serverItem, "base").Count.ShouldBe(1);

            await subscription.DeleteAsync(true, ct);
        }
        finally { await rig.DisposeAsync(); }
    }

    /// <summary>
    ///     Materialising N conditions while a Server-object item is live costs N monitored-bookkeeping visits,
    ///     not N²/2 — and every one of them still ends up marked monitored (#586 review, performance note).
    /// </summary>
    [Fact]
    public async Task Materialising_conditions_under_a_live_server_object_item_visits_each_once()
    {
        const int n = 40;
        var ct = TestContext.Current.CancellationToken;
        var rig = await StartAsync("CondMonitoredCost", encrypted: false, ct);
        try
        {
            rig.EnsureEquipment();
            using var session = await rig.ConnectAsync(anonymous: true, ct);
            var events = new RecordedEvents();
            var subscription = await RecordedEvents.SubscribeAsync(session, events, ct);
            RecordedEvents.AddEventItem(subscription, ObjectIds.Server);
            await subscription.ApplyChangesAsync(ct);

            var before = rig.Nm.AllEventsMonitoringConditionVisits;
            for (var i = 0; i < n; i++)
                rig.Sink.MaterialiseAlarmCondition($"bulk-{i}", EqA, $"bulk {i}", "AlarmCondition", 500, AddressSpaceRealm.Uns);

            (rig.Nm.AllEventsMonitoringConditionVisits - before).ShouldBe(n);
            for (var i = 0; i < n; i++)
                rig.Nm.ConditionEventsMonitored($"bulk-{i}", AddressSpaceRealm.Uns).ShouldBeTrue();

            await subscription.DeleteAsync(true, ct);
            for (var i = 0; i < n; i++)
                rig.Nm.ConditionEventsMonitored($"bulk-{i}", AddressSpaceRealm.Uns).ShouldBeFalse(
                    "the last item's delete still gives every unit back through the full reconcile");
        }
        finally { await rig.DisposeAsync(); }
    }

    // ───────────────────────────── helpers ─────────────────────────────

    /// <summary>The condition state a case starts from — one in which its method is accepted.</summary>
    private static AlarmConditionSnapshot PreState(string method, bool native)
    {
        var s = new AlarmConditionSnapshot(
            Active: true, Acknowledged: false, Confirmed: native, Enabled: true,
            Shelving: AlarmShelvingKind.Unshelved, Severity: 700, Message: "pre");
        if (native) return s; // the driver projection's constants: Confirmed, Unshelved

        return method switch
        {
            "Confirm" => s with { Acknowledged = true, Confirmed = false },
            "Unshelve" => s with { Shelving = AlarmShelvingKind.OneShot },
            "Enable" => s with { Enabled = false },
            _ => s,
        };
    }

    /// <summary>
    ///     Stands in for the scripted engine and the native driver: each routed command comes back as a
    ///     re-projection of the state it produces, from a pool thread.
    /// </summary>
    private static void WireSimulatedOwners(
        ServerEventRig rig, bool native, Func<AlarmConditionSnapshot> current, Action<AlarmConditionSnapshot> set)
    {
        rig.Nm.NativeAlarmAckRouter = _ =>
        {
            // NativeAlarmProjector's answer to the driver's ack echo: Acked, with its Confirmed/Unshelved constants.
            var next = current() with { Acknowledged = true, Confirmed = true, Shelving = AlarmShelvingKind.Unshelved };
            set(next);
            rig.ProjectLater(native: true, next);
        };
        rig.Nm.AlarmCommandRouter = cmd =>
        {
            if (native || cmd.AlarmId != ScriptedAlarmId) return; // the engine owns only scripted alarms
            var s = current();
            var next = cmd.Operation switch
            {
                "Acknowledge" => s with { Acknowledged = true },
                "Confirm" => s with { Confirmed = true },
                "OneShotShelve" => s with { Shelving = AlarmShelvingKind.OneShot },
                "TimedShelve" => s with { Shelving = AlarmShelvingKind.Timed },
                "Unshelve" => s with { Shelving = AlarmShelvingKind.Unshelved },
                "Enable" => s with { Enabled = true },
                "Disable" => s with { Enabled = false },
                _ => s, // AddComment: no field of the snapshot changes
            };
            set(next);
            rig.ProjectLater(native: false, next);
        };
    }

    private static void AssertNewState(string method, VariantCollection e)
    {
        switch (method)
        {
            case "Acknowledge": e[RecordedEvents.AckedField].Value.ShouldBe(true); break;
            case "Confirm": e[RecordedEvents.ConfirmedField].Value.ShouldBe(true); break;
            case "AddComment": (e[RecordedEvents.CommentField].Value as LocalizedText)?.Text.ShouldBe("note"); break;
            case "OneShotShelve": e[RecordedEvents.ShelvingField].Value.ShouldBe(ObjectIds.ShelvedStateMachineType_OneShotShelved); break;
            case "TimedShelve": e[RecordedEvents.ShelvingField].Value.ShouldBe(ObjectIds.ShelvedStateMachineType_TimedShelved); break;
            case "Unshelve": e[RecordedEvents.ShelvingField].Value.ShouldBe(ObjectIds.ShelvedStateMachineType_Unshelved); break;
            case "Disable": e[RecordedEvents.EnabledField].Value.ShouldBe(false); break;
            case "Enable": e[RecordedEvents.EnabledField].Value.ShouldBe(true); break;
            default: throw new ArgumentOutOfRangeException(nameof(method), method, null);
        }
    }

    /// <summary>
    ///     Calls one Part 9 method on the condition by its type's method id (the SDK resolves it against the
    ///     condition's method declarations — the shelve methods included); throws on a bad result.
    /// </summary>
    private static async Task CallAsync(ISession session, NodeId condition, string method, byte[]? eventId, CancellationToken ct)
    {
        var (methodId, args) = method switch
        {
            "Acknowledge" => (MethodIds.AcknowledgeableConditionType_Acknowledge, new object[] { eventId!, new LocalizedText("ack") }),
            "Confirm" => (MethodIds.AcknowledgeableConditionType_Confirm, [eventId!, new LocalizedText("confirm")]),
            "AddComment" => (MethodIds.ConditionType_AddComment, [eventId!, new LocalizedText("note")]),
            "Enable" => (MethodIds.ConditionType_Enable, []),
            "Disable" => (MethodIds.ConditionType_Disable, []),
            "OneShotShelve" => (MethodIds.AlarmConditionType_ShelvingState_OneShotShelve, []),
            "TimedShelve" => (MethodIds.AlarmConditionType_ShelvingState_TimedShelve, [60_000.0]),
            "Unshelve" => (MethodIds.AlarmConditionType_ShelvingState_Unshelve, []),
            _ => throw new ArgumentOutOfRangeException(nameof(method), method, null),
        };
        await session.CallAsync(condition, methodId, ct, args);
    }
}