using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Opc.Ua;
using Opc.Ua.Server;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.Core.Authorization;
using ZB.MOM.WW.OtOpcUa.OpcUaServer.Security;

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

/// <summary>
///     Review 01 L2, the half the wire tests (<c>StaleMonitoredNodeWireTests</c>) cannot reach: an item the
///     ACL revalidation pass has STOOD DOWN is on no SDK fan-out list, so the tombstone a removal runs must find
///     it through the revalidation map. Otherwise it keeps a component-cache reference to the dead node — and
///     the cache hands that node to the next item created on the NodeId.
/// </summary>
public sealed class NodeManagerStaleMonitoredNodeTests : IDisposable
{
    private const string Cluster = "SITE-A";
    private const string Principal = "svc";
    private static CancellationToken Ct => TestContext.Current.CancellationToken;

    private readonly string _pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-stale-{Guid.NewGuid():N}");

    /// <summary>A surgical remove tells a stood-down item and drops it from the revalidation map.</summary>
    [Fact]
    public async Task A_surgical_remove_tells_and_forgets_a_stood_down_item()
    {
        var (host, server) = await BootAsync();
        try
        {
            var nm = server.NodeManager!;
            var (item, nodeId) = await StandDownAsync(nm, "Plant/Modbus/dev1/Speed");

            nm.RemoveVariableNode("Plant/Modbus/dev1/Speed", AddressSpaceRealm.Raw).ShouldBeTrue();

            item.Statuses.ShouldContain((StatusCode)StatusCodes.BadNodeIdUnknown);
            nm.LiveItemCount.ShouldBe(0, "the item's node is gone; the map must not keep re-authorizing it");
            nm.IsNodeMonitored(nodeId).ShouldBeFalse();
        }
        finally { await host.DisposeAsync(); }
    }

    /// <summary>A rebuild sweeps every stood-down item.</summary>
    [Fact]
    public async Task A_rebuild_tells_and_forgets_every_stood_down_item()
    {
        var (host, server) = await BootAsync();
        try
        {
            var nm = server.NodeManager!;
            var (item, _) = await StandDownAsync(nm, "Plant/Modbus/dev1/Speed");

            nm.RebuildAddressSpace();
            nm.CompleteAddressSpaceApply();

            item.Statuses.ShouldContain((StatusCode)StatusCodes.BadNodeIdUnknown);
            nm.LiveItemCount.ShouldBe(0);
        }
        finally { await host.DisposeAsync(); }
    }

    /// <summary>
    ///     Positive control for the sweep: a stood-down item on a SURVIVING node is left alone by a surgical
    ///     remove of a sibling, and the next permitted pass restores it.
    /// </summary>
    [Fact]
    public async Task A_stood_down_item_on_a_surviving_node_is_untouched_and_still_restorable()
    {
        var (host, server) = await BootAsync();
        try
        {
            var nm = server.NodeManager!;
            nm.EnsureVariable("Plant/Modbus/dev1/Other", null, "Other", "Float", writable: false, realm: AddressSpaceRealm.Raw);
            var (item, _) = await StandDownAsync(nm, "Plant/Modbus/dev1/Speed");

            nm.RemoveVariableNode("Plant/Modbus/dev1/Other", AddressSpaceRealm.Raw).ShouldBeTrue();

            item.Statuses.ShouldNotContain((StatusCode)StatusCodes.BadNodeIdUnknown);
            nm.LiveItemCount.ShouldBe(1);

            // Grant restored ⇒ the pass re-attaches it (a second stand-down proves the restore happened).
            nm.Authorizer = Authorizer(permits: true);
            nm.RevalidateMonitoredItems();
            nm.Authorizer = Authorizer(permits: false);
            nm.RevalidateMonitoredItems();
            item.Statuses.Count(s => s == StatusCodes.BadUserAccessDenied).ShouldBe(2);
        }
        finally { await host.DisposeAsync(); }
    }

    /// <summary>Registers a stub item on <paramref name="rawPath"/> and stands it down through a denying pass.</summary>
    private static async Task<(StubItem Item, NodeId NodeId)> StandDownAsync(OtOpcUaNodeManager nm, string rawPath)
    {
        nm.EnsureVariable(rawPath, null, rawPath, "Float", writable: false, realm: AddressSpaceRealm.Raw);
        var nodeId = nm.TryGetVariable(rawPath, AddressSpaceRealm.Raw)!.NodeId;
        var handle = (NodeHandle)nm.GetManagerHandle(nodeId);
        var item = new StubItem(handle, Identity());
        nm.TrackLiveMonitoredItem(handle, item);

        nm.Authorizer = Authorizer(permits: false);
        nm.RevalidateMonitoredItems();
        item.Statuses.ShouldContain((StatusCode)StatusCodes.BadUserAccessDenied, "non-vacuity: the item really was stood down");
        await Task.CompletedTask;
        return (item, nodeId);
    }

    private static DataPlaneAuthorizer Authorizer(bool permits)
    {
        var state = new DataPlaneAuthorityState();
        var grants = permits
            ? new[]
            {
                new NodeAcl
                {
                    NodeAclId = "acl-cluster", ClusterId = Cluster, Principal = Principal,
                    ScopeKind = NodeAclScopeKind.Cluster, PermissionFlags = NodePermissions.Subscribe,
                },
            }
            : [];
        state.Apply(Cluster, "rev-1", [], grants, new Dictionary<AclScopeRef, IReadOnlyList<NodeAclPath>>());
        return new DataPlaneAuthorizer(state, new TriePermissionEvaluator(state.Tries), enabled: true, NullLogger.Instance);
    }

    private static RoleCarryingUserIdentity Identity() =>
        new(new UserNameIdentityToken { UserName = "apikey" }, [], Principal, apiKeyId: null);

    private async Task<(OpcUaApplicationHost Host, OtOpcUaSdkServer Server)> BootAsync() =>
        await OpcUaHostStart.StartAsync(
            port => new OpcUaApplicationHost(
                new OpcUaApplicationHostOptions
                {
                    ApplicationName = "OtOpcUa.StaleTest",
                    ApplicationUri = $"urn:OtOpcUa.StaleTest:{Guid.NewGuid():N}",
                    OpcUaPort = port,
                    PublicHostname = "localhost",
                    PkiStoreRoot = _pkiRoot,
                },
                NullLogger<OpcUaApplicationHost>.Instance),
            () => new OtOpcUaSdkServer(), Ct);

    public void Dispose()
    {
        if (Directory.Exists(_pkiRoot)) Directory.Delete(_pkiRoot, recursive: true);
    }

    /// <summary>The minimum of a sampled item the removal path touches: its handle, identity and value queue.</summary>
    private sealed class StubItem(NodeHandle handle, IUserIdentity identity) : ISampledDataChangeMonitoredItem
    {
        public List<StatusCode> Statuses { get; } = [];
        public IUserIdentity EffectiveIdentity => identity;
        public object ManagerHandle => handle;
        public NodeId NodeId => handle.NodeId;
        public void QueueValue(DataValue value, ServiceResult error, bool ignoreFilters) => Statuses.Add(error?.StatusCode ?? value.StatusCode);
        public void QueueValue(DataValue value, ServiceResult error) => QueueValue(value, error, false);
        public void Dispose() { }

        public INodeManager NodeManager => throw new NotSupportedException();
        public ISession Session => throw new NotSupportedException();
        public uint Id => throw new NotSupportedException();
        public uint SubscriptionId => throw new NotSupportedException();
        public bool IsDurable => throw new NotSupportedException();
        public uint ClientHandle => throw new NotSupportedException();
        public ISubscription SubscriptionCallback { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
        public int MonitoredItemType => throw new NotSupportedException();
        public bool IsReadyToPublish => throw new NotSupportedException();
        public bool IsReadyToTrigger { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
        public bool IsResendData => throw new NotSupportedException();
        public MonitoringMode MonitoringMode => throw new NotSupportedException();
        public double SamplingInterval => throw new NotSupportedException();
        public DataChangeFilter DataChangeFilter => throw new NotSupportedException();
        public uint AttributeId => throw new NotSupportedException();
        public NumericRange IndexRange => throw new NotSupportedException();
        public QualifiedName DataEncoding => throw new NotSupportedException();
        public bool AlwaysReportUpdates { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
        public DiagnosticsMasks DiagnosticsMasks => throw new NotSupportedException();
        public uint QueueSize => throw new NotSupportedException();
        public double MinimumSamplingInterval => throw new NotSupportedException();
        public int TimeToNextSample => throw new NotSupportedException();
        public void SetupResendDataTrigger() => throw new NotSupportedException();
        public ServiceResult GetCreateResult(out MonitoredItemCreateResult result) => throw new NotSupportedException();
        public ServiceResult GetModifyResult(out MonitoredItemModifyResult result) => throw new NotSupportedException();
        public IStoredMonitoredItem ToStorableMonitoredItem() => throw new NotSupportedException();
        public MonitoringMode SetMonitoringMode(MonitoringMode monitoringMode) => throw new NotSupportedException();
        public bool Publish(OperationContext context, Queue<MonitoredItemNotification> notifications, Queue<DiagnosticInfo> diagnostics, uint maxNotificationsPerPublish, ILogger logger) => throw new NotSupportedException();
        public void SetSemanticsChanged() => throw new NotSupportedException();
        public void SetStructureChanged() => throw new NotSupportedException();
        public bool SamplingIntervalExpired() => throw new NotSupportedException();
        public ReadValueId GetReadValueId() => throw new NotSupportedException();
        public ServiceResult ModifyAttributes(DiagnosticsMasks diagnosticsMasks, TimestampsToReturn timestampsToReturn, uint clientHandle, MonitoringFilter originalFilter, MonitoringFilter filterToUse, Opc.Ua.Range range, double samplingInterval, uint queueSize, bool discardOldest) => throw new NotSupportedException();
        public void SetSamplingInterval(double samplingInterval) => throw new NotSupportedException();
    }
}