/* ========================================================================
 * Copyright (c) 2005-2026 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
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 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
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 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * The complete license agreement can be found here:
 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System;
using System.Buffers.Binary;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging.Abstractions;
using NUnit.Framework;
using Opc.Ua.Bindings;
using Opc.Ua.Pcap.Dissection;
using Opc.Ua.Pcap.Frame;

namespace Opc.Ua.Pcap.Tests.Dissection
{
    /// <summary>
    /// Tests for the <see cref="ServiceCallReassembler"/> public surface —
    /// input validation, control-message paths, and asymmetric
    /// OpenSecureChannel reporting (none of which require loaded key
    /// material).
    /// </summary>
    [TestFixture]
    public sealed class ServiceCallReassemblerTests
    {
        [Test]
        public void ConstructorRejectsNullLoggerFactory()
        {
            Assert.That(
                () => new ServiceCallReassembler(loggerFactory: null!),
                Throws.TypeOf<ArgumentNullException>()
                    .With.Property("ParamName").EqualTo("loggerFactory"));
        }

        [Test]
        public void DefaultConstructorDoesNotThrow()
        {
            ServiceCallReassembler reassembler = new();

            // Brand-new reassembler reports no completed calls.
            IReadOnlyList<DecodedServiceCall> empty = reassembler.DrainCompleted();
            Assert.That(empty, Is.Empty);
        }

        [Test]
        public void LoadKeyMaterialRejectsNull()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);

            Assert.That(
                () => reassembler.LoadKeyMaterial(material: null!),
                Throws.TypeOf<ArgumentNullException>()
                    .With.Property("ParamName").EqualTo("material"));
        }

        [Test]
        public void ProcessAllRejectsNullFrames()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);

            Assert.That(
                () => reassembler.ProcessAll(frames: null!),
                Throws.TypeOf<ArgumentNullException>()
                    .With.Property("ParamName").EqualTo("frames"));
        }

        [Test]
        public void ProcessAllAsyncRejectsNullFrames()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);

            Assert.That(
                async () => await reassembler.ProcessAllAsync(
                    frames: null!,
                    CancellationToken.None).ConfigureAwait(false),
                Throws.TypeOf<ArgumentNullException>()
                    .With.Property("ParamName").EqualTo("frames"));
        }

        [Test]
        public void PushIgnoresFrameShorterThanFourBytes()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.ClientToServer,
                "client:1",
                "server:1",
                new byte[] { 1, 2, 3 });

            reassembler.Push(frame);

            Assert.That(reassembler.DrainCompleted(), Is.Empty,
                "A frame shorter than the 4-byte message-type marker must be skipped.");
        }

        [Test]
        public void PushIgnoresFrameWithInvalidMessageType()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = new byte[24];
            BinaryPrimitives.WriteUInt32LittleEndian(payload, 0xDEADBEEF);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.ClientToServer,
                "client:1",
                "server:1",
                payload);

            reassembler.Push(frame);

            Assert.That(reassembler.DrainCompleted(), Is.Empty,
                "Frames whose first 4 bytes do not encode a recognised TcpMessageType must be ignored.");
        }

        [Test]
        public void PushIgnoresFrameWithUnknownDirection()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = BuildOpnChunk(channelId: 1, tokenId: 2, size: 64);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.Unknown,
                clientEndpoint: string.Empty,
                serverEndpoint: string.Empty,
                payload);

            reassembler.Push(frame);

            Assert.That(reassembler.DrainCompleted(), Is.Empty,
                "Frames with Unknown direction must be skipped — we cannot decide " +
                "client vs server keys.");
        }

        [Test]
        public void PushOpenChunkFromClientProducesOpenSecureChannelRequestCall()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = BuildOpnChunk(channelId: 0x0A0B0C0D, tokenId: 0x12345678, size: 64);
            var timestamp = new DateTimeOffset(2026, 3, 4, 5, 6, 7, TimeSpan.Zero);
            var frame = new CaptureFrame(
                timestamp,
                CaptureFrameDirection.ClientToServer,
                clientEndpoint: "10.0.0.1:55000",
                serverEndpoint: "10.0.0.2:4840",
                payload);

            reassembler.Push(frame);
            IReadOnlyList<DecodedServiceCall> completed = reassembler.DrainCompleted();

            Assert.That(completed, Has.Count.EqualTo(1));
            DecodedServiceCall call = completed[0];
            Assert.That(call.RequestName, Is.EqualTo("OpenSecureChannelRequest"));
            Assert.That(call.ChannelId, Is.EqualTo(0x0A0B0C0DU));
            Assert.That(call.TokenId, Is.EqualTo(0x12345678U));
            Assert.That(call.RequestTimestamp, Is.EqualTo(timestamp));
            Assert.That(call.RequestBodySize, Is.EqualTo(payload.Length));
            Assert.That(call.RequestSummary, Is.EqualTo("(asymmetric OpenSecureChannel chunk)"));
        }

        [Test]
        public void PushOpenChunkFromServerProducesOpenSecureChannelResponseCall()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = BuildOpnChunk(channelId: 0x99999999, tokenId: 0x77777777, size: 64);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.ServerToClient,
                string.Empty,
                string.Empty,
                payload);

            reassembler.Push(frame);
            IReadOnlyList<DecodedServiceCall> completed = reassembler.DrainCompleted();

            Assert.That(completed, Has.Count.EqualTo(1));
            Assert.That(completed[0].RequestName, Is.EqualTo("OpenSecureChannelResponse"));
        }

        [Test]
        public void DrainCompletedClearsInternalList()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = BuildOpnChunk(channelId: 1, tokenId: 2, size: 64);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.ClientToServer,
                string.Empty,
                string.Empty,
                payload);

            reassembler.Push(frame);
            IReadOnlyList<DecodedServiceCall> first = reassembler.DrainCompleted();
            IReadOnlyList<DecodedServiceCall> second = reassembler.DrainCompleted();

            Assert.That(first, Has.Count.EqualTo(1));
            Assert.That(second, Is.Empty,
                "DrainCompleted must clear the internal list so the next call sees " +
                "only freshly completed entries.");
        }

        [Test]
        public void ProcessAllFeedsEveryFrameThenReturnsCompleted()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var frames = new List<CaptureFrame>
            {
                MakeOpenFrame(channelId: 1, tokenId: 10, fromClient: true),
                MakeOpenFrame(channelId: 2, tokenId: 20, fromClient: false)
            };

            IReadOnlyList<DecodedServiceCall> calls = reassembler.ProcessAll(frames);

            Assert.That(calls, Has.Count.EqualTo(2));
            Assert.That(calls[0].ChannelId, Is.EqualTo(1U));
            Assert.That(calls[0].TokenId, Is.EqualTo(10U));
            Assert.That(calls[0].RequestName, Is.EqualTo("OpenSecureChannelRequest"));
            Assert.That(calls[1].ChannelId, Is.EqualTo(2U));
            Assert.That(calls[1].TokenId, Is.EqualTo(20U));
            Assert.That(calls[1].RequestName, Is.EqualTo("OpenSecureChannelResponse"));
        }

        [Test]
        public async Task ProcessAllAsyncFeedsEveryFrameThenReturnsCompleted()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var frames = new List<CaptureFrame>
            {
                MakeOpenFrame(channelId: 5, tokenId: 6, fromClient: true),
                MakeOpenFrame(channelId: 7, tokenId: 8, fromClient: true)
            };

            IReadOnlyList<DecodedServiceCall> calls = await reassembler.ProcessAllAsync(
                AsAsyncEnumerable(frames),
                CancellationToken.None).ConfigureAwait(false);

            Assert.That(calls, Has.Count.EqualTo(2));
            Assert.That(calls[0].ChannelId, Is.EqualTo(5U));
            Assert.That(calls[1].ChannelId, Is.EqualTo(7U));
        }

        [Test]
        public void PushUnknownMessageTypeBaseDoesNotThrow()
        {
            // A 4-byte type that passes IsValid but whose masked base is none
            // of HEL/ACK/ERR/RHE/OPN/MSG/CLO — defensively ensure nothing
            // crashes. The Final-flag (0x46000000) combined with a fabricated
            // 3-byte tail "ZZZ" yields 0x465A5A5A which IsValid rejects, so
            // build a recognized-but-unhandled type instead: Hello.
            // NOTE: due to the bug in Push() (mask vs case label mismatch),
            // Hello control messages produce no DecodedServiceCall today.
            // The test pins the current behaviour so we can spot regressions
            // — if the production bug is fixed, this assertion needs to flip
            // to expect a completed control-message entry.
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] payload = new byte[32];
            // Hello = 0x464C4548 ("HELF" with little-endian read).
            BinaryPrimitives.WriteUInt32LittleEndian(payload, 0x464C4548U);
            var frame = new CaptureFrame(
                DateTimeOffset.UtcNow,
                CaptureFrameDirection.ClientToServer,
                string.Empty,
                string.Empty,
                payload);

            Assert.That(() => reassembler.Push(frame), Throws.Nothing);
            Assert.That(reassembler.DrainCompleted(), Is.Empty,
                "Current production code drops Hello/Ack/Error/ReverseHello because " +
                "ServiceCallReassembler.Push masks the type with MessageTypeMask but " +
                "compares against the un-masked case labels. Document the behaviour.");
        }

        [Test]
        public void PrivateAddControlMessageProducesCompletedEntry()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var timestamp = new DateTimeOffset(2026, 4, 5, 6, 7, 8, TimeSpan.Zero);
            CaptureFrame frame = MakeControlFrame(TcpMessageType.Hello, timestamp);

            InvokeInstance<object?>(reassembler, "AddControlMessage", frame, "Hello");

            IReadOnlyList<DecodedServiceCall> completed = reassembler.DrainCompleted();

            Assert.That(completed, Has.Count.EqualTo(1));
            Assert.That(completed[0].RequestName, Is.EqualTo("Hello"));
            Assert.That(completed[0].RequestTimestamp, Is.EqualTo(timestamp));
            Assert.That(completed[0].RequestBodySize, Is.EqualTo(8));
        }

        [Test]
        public void PushMessageWithoutKeyMaterialIsSkipped()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            byte[] chunk = BuildMsgChunk(channelId: 0x12345678, tokenId: 0x42, body: [1, 2, 3]);

            Assert.That(
                () => reassembler.Push(
                    new CaptureFrame(
                        DateTimeOffset.UtcNow,
                        CaptureFrameDirection.ClientToServer,
                        string.Empty,
                        string.Empty,
                        chunk)),
                Throws.Nothing);
            Assert.That(reassembler.DrainCompleted(), Is.Empty);
        }

        /// <summary>
        /// Verifies request summaries include service-specific counts and use the fallback body size for unknown kinds.
        /// </summary>
        [Test]
        [SetCulture("en-US")]
        public void PrivateRequestSummaryFormatsKnownRequestKinds()
        {
            Assert.That(
                InvokeCreateRequestSummary(
                    new ReadRequest
                    {
                        RequestHeader = new RequestHeader { RequestHandle = 10, AuditEntryId = "audit" },
                        NodesToRead = [new ReadValueId { NodeId = ObjectIds.Server }],
                        MaxAge = 12.5
                    },
                    "ReadRequest",
                    100),
                Is.EqualTo("handle=10 audit=audit 1 nodes, maxAge=12.5"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new BrowseRequest
                    {
                        View = new ViewDescription(),
                        NodesToBrowse = [new BrowseDescription { NodeId = ObjectIds.ObjectsFolder }]
                    },
                    "BrowseRequest",
                    101),
                Is.EqualTo("handle=0 audit= 1 nodes, view=default"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new WriteRequest { NodesToWrite = [new WriteValue()] },
                    "WriteRequest",
                    102),
                Is.EqualTo("handle=0 audit= 1 nodes"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new CallRequest { MethodsToCall = [new CallMethodRequest()] },
                    "CallRequest",
                    103),
                Is.EqualTo("handle=0 audit= 1 methods"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new HistoryReadRequest { NodesToRead = [new HistoryReadValueId()] },
                    "HistoryReadRequest",
                    104),
                Is.EqualTo("handle=0 audit= 1 nodes"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new CreateMonitoredItemsRequest { ItemsToCreate = [new MonitoredItemCreateRequest()] },
                    "CreateMonitoredItemsRequest",
                    105),
                Is.EqualTo("handle=0 audit= 1 items"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new DeleteMonitoredItemsRequest { MonitoredItemIds = [1U, 2U] },
                    "DeleteMonitoredItemsRequest",
                    106),
                Is.EqualTo("handle=0 audit= 2 items"));
            Assert.That(
                InvokeCreateRequestSummary(
                    new PublishRequest { SubscriptionAcknowledgements = [new SubscriptionAcknowledgement()] },
                    "PublishRequest",
                    107),
                Is.EqualTo("handle=0 audit= 1 acks"));
            Assert.That(
                InvokeCreateRequestSummary(new RegisterNodesRequest(), "RegisterNodesRequest", 108),
                Is.EqualTo("handle=0 audit= RegisterNodesRequest body=108B"));
        }

        /// <summary>
        /// Verifies request summary display values use the current culture's decimal separator.
        /// </summary>
        [Test]
        [SetCulture("de-DE")]
        public void RequestSummaryFormatsNumericDisplayValuesUsingCurrentCulture()
        {
            Assert.That(
                InvokeCreateRequestSummary(
                    new ReadRequest
                    {
                        RequestHeader = new RequestHeader { RequestHandle = 10, AuditEntryId = "audit" },
                        NodesToRead = [new ReadValueId { NodeId = ObjectIds.Server }],
                        MaxAge = 12.5
                    },
                    "ReadRequest",
                    100),
                Is.EqualTo("handle=10 audit=audit 1 nodes, maxAge=12,5"));
        }

        [Test]
        public void PrivateRequestSummaryFormatsNonDefaultBrowseView()
        {
            Assert.That(
                InvokeCreateRequestSummary(
                    new BrowseRequest
                    {
                        View = new ViewDescription { ViewId = new NodeId(1234, 2) },
                        NodesToBrowse = [new BrowseDescription { NodeId = ObjectIds.ObjectsFolder }]
                    },
                    "BrowseRequest",
                    101),
                Is.EqualTo("handle=0 audit= 1 nodes, view=ns=2;i=1234"));
        }

        [Test]
        public void PrivateFormattingHelpersHandleCollectionsAndMissingProperties()
        {
            var encodeable = new EncodeableWithCollections();

            Assert.That(
                InvokeStatic<string>("FormatCount", encodeable, "Items", "items"),
                Is.EqualTo("2 items"));
            Assert.That(
                InvokeStatic<string>("FormatCount", encodeable, "Missing", "items"),
                Is.EqualTo(string.Empty));
            Assert.That(
                InvokeStatic<string>("FormatCount", encodeable, "Value", "items"),
                Is.EqualTo(string.Empty));
            Assert.That(
                InvokeStatic<string>("FormatCount", encodeable, "ConvertibleItems", "items"),
                Is.EqualTo("3 items"));
            Assert.That(
                InvokeStatic<string>("FormatCountAndValue", encodeable, "Items", "items", "Value", "value"),
                Is.EqualTo("2 items, value=42"));
            Assert.That(
                InvokeStatic<string>("FormatCountAndValue", encodeable, "Items", "items", "NullValue", "value"),
                Is.EqualTo("2 items, value=null"));
            Assert.That(
                InvokeStatic<string>("FormatCountAndValue", encodeable, "Missing", "items", "Value", "value"),
                Is.EqualTo(string.Empty));
        }

        [Test]
        public void PrivateDecodedMessageHelpersCoverResponsesAndAnnotations()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var response = new ReadResponse
            {
                ResponseHeader = new ResponseHeader
                {
                    ServiceResult = StatusCodes.BadUnexpectedError,
                    Timestamp = new DateTime(2026, 1, 2, 3, 4, 5, DateTimeKind.Utc)
                }
            };
            object decodedResponse = InvokeInstance<object>(
                reassembler,
                "CreateDecodedMessage",
                response,
                10);
            object decodedEncodeable = InvokeInstance<object>(
                reassembler,
                "CreateDecodedMessage",
                new Argument { Name = "Input" },
                11);
            var annotations = new Dictionary<string, string?>();

            InvokeStatic<object?>(
                "AddRequestAnnotations",
                annotations,
                new ReadRequest
                {
                    RequestHeader = new RequestHeader { RequestHandle = 123, AuditEntryId = "audit" }
                });
            InvokeStatic<object?>("AddRequestAnnotations", annotations, new Argument());

            Assert.That(GetProperty<string?>(decodedResponse, "Name"), Is.EqualTo("ReadResponse"));
            Assert.That(GetProperty<StatusCode?>(decodedResponse, "ResponseStatus"), Is.EqualTo(StatusCodes.BadUnexpectedError));
            Assert.That(GetProperty<string?>(decodedResponse, "Summary"), Does.Contain("status=BadUnexpectedError"));
            Assert.That(GetProperty<string?>(decodedEncodeable, "Name"), Is.EqualTo("Argument"));
            Assert.That(GetProperty<string?>(decodedEncodeable, "Summary"), Is.EqualTo("Argument body=11B"));
            Assert.That(annotations["RequestHandle"], Is.EqualTo("123"));
            Assert.That(annotations["AuditEntryId"], Is.EqualTo("audit"));
            Assert.That(annotations, Has.Count.EqualTo(2));
        }

        [Test]
        public void PrivateDecodeMessageReturnsUndecodedForMalformedBody()
        {
            var reassembler = new ServiceCallReassembler(NullLoggerFactory.Instance);
            var chunks = new List<byte[]> { new byte[] { 0xFF, 0x00 }, new byte[] { 0xAA } };

            object decoded = InvokeInstance<object>(reassembler, "DecodeMessage", chunks);

            Assert.That(GetProperty<string?>(decoded, "Name"), Is.EqualTo("3B"));
            Assert.That(GetProperty<string?>(decoded, "Summary"), Is.EqualTo("(undecoded: 3 bytes)"));
        }

        // ---- helpers ----

        private static CaptureFrame MakeControlFrame(uint messageType, DateTimeOffset timestamp)
        {
            byte[] payload = new byte[8];
            BinaryPrimitives.WriteUInt32LittleEndian(payload, messageType);
            BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(4), (uint)payload.Length);
            return new CaptureFrame(
                timestamp,
                CaptureFrameDirection.ClientToServer,
                string.Empty,
                string.Empty,
                payload);
        }

        private static byte[] BuildMsgChunk(uint channelId, uint tokenId, byte[] body)
        {
            int size = 24 + body.Length;
            byte[] chunk = new byte[size];
            BinaryPrimitives.WriteUInt32LittleEndian(chunk, TcpMessageType.MessageFinal);
            BinaryPrimitives.WriteUInt32LittleEndian(chunk.AsSpan(4), (uint)size);
            BinaryPrimitives.WriteUInt32LittleEndian(chunk.AsSpan(8), channelId);
            BinaryPrimitives.WriteUInt32LittleEndian(chunk.AsSpan(12), tokenId);
            BinaryPrimitives.WriteUInt32LittleEndian(chunk.AsSpan(16), 1);
            BinaryPrimitives.WriteUInt32LittleEndian(chunk.AsSpan(20), 2);
            body.CopyTo(chunk.AsSpan(24));
            return chunk;
        }

        private static string InvokeCreateRequestSummary(IServiceRequest request, string typeName, int byteCount)
        {
            return InvokeStatic<string>("CreateRequestSummary", request, typeName, byteCount);
        }

        private static T InvokeInstance<T>(ServiceCallReassembler reassembler, string methodName, params object?[] parameters)
        {
            MethodInfo method = typeof(ServiceCallReassembler).GetMethod(
                methodName,
                BindingFlags.NonPublic | BindingFlags.Instance)!;
            return (T)method.Invoke(reassembler, parameters)!;
        }

        private static T InvokeStatic<T>(string methodName, params object?[] parameters)
        {
            MethodInfo method = typeof(ServiceCallReassembler).GetMethod(
                methodName,
                BindingFlags.NonPublic | BindingFlags.Static)!;
            return (T)method.Invoke(null, parameters)!;
        }

        private static T GetProperty<T>(object value, string name)
        {
            return (T)value.GetType().GetProperty(name, BindingFlags.Public | BindingFlags.Instance)!.GetValue(value)!;
        }

        private sealed class EncodeableWithCollections : IEncodeable
        {
            public ExpandedNodeId TypeId => ExpandedNodeId.Null;

            public ExpandedNodeId BinaryEncodingId => ExpandedNodeId.Null;

            public ExpandedNodeId XmlEncodingId => ExpandedNodeId.Null;

            public ICollection Items { get; } = new ArrayList { 1, 2 };

            public IConvertableToArray ConvertibleItems { get; } = new ConvertableCollection();

            public int Value => 42;

            public string? NullValue => null;

            public void Encode(IEncoder encoder)
            {
            }

            public void Decode(IDecoder decoder)
            {
            }

            public bool IsEqual(IEncodeable? encodeable)
            {
                return ReferenceEquals(this, encodeable);
            }

            public object Clone()
            {
                return new EncodeableWithCollections();
            }
        }

        private sealed class ConvertableCollection : IConvertableToArray
        {
            public int Count => 3;

            public Array? ToArray()
            {
                throw new InvalidOperationException("Collection count must not allocate an array.");
            }
        }

        private static byte[] BuildOpnChunk(uint channelId, uint tokenId, int size)
        {
            if (size < 16)
            {
                throw new ArgumentOutOfRangeException(nameof(size));
            }

            byte[] data = new byte[size];
            // "OPNF" little-endian = 0x464E504F (Open + Final flag).
            BinaryPrimitives.WriteUInt32LittleEndian(data, 0x464E504FU);
            BinaryPrimitives.WriteUInt32LittleEndian(data.AsSpan(4), (uint)size);
            BinaryPrimitives.WriteUInt32LittleEndian(data.AsSpan(8), channelId);
            BinaryPrimitives.WriteUInt32LittleEndian(data.AsSpan(12), tokenId);
            return data;
        }

        private static CaptureFrame MakeOpenFrame(uint channelId, uint tokenId, bool fromClient)
        {
            return new CaptureFrame(
                DateTimeOffset.UtcNow,
                fromClient ? CaptureFrameDirection.ClientToServer : CaptureFrameDirection.ServerToClient,
                string.Empty,
                string.Empty,
                BuildOpnChunk(channelId, tokenId, size: 32));
        }

        private static async IAsyncEnumerable<CaptureFrame> AsAsyncEnumerable(IEnumerable<CaptureFrame> source)
        {
            foreach (CaptureFrame frame in source)
            {
                yield return frame;
                await Task.Yield();
            }
        }
    }
}