fix(net): conform character entry and session shutdown

tests/AcDream.Core.Net.Tests/WorldSessionNegotiationShutdownTests.cs

@@ -0,0 +1,77 @@
+using System.Buffers.Binary;
+using System.Net;
+using System.Net.Sockets;
+using AcDream.Core.Net.Cryptography;
+using AcDream.Core.Net.Packets;
+
+namespace AcDream.Core.Net.Tests;
+
+public sealed class WorldSessionNegotiationShutdownTests
+{
+    [Fact]
+    public async Task ThrowingServerTimeSubscriber_StillDisposesWithNegotiatedDisconnect()
+    {
+        using var server = new UdpClient(new IPEndPoint(IPAddress.Loopback, 0));
+        var serverEndpoint = (IPEndPoint)server.Client.LocalEndPoint!;
+        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+
+        Task<byte[]> serverFlow = Task.Run(async () =>
+        {
+            UdpReceiveResult login = await server.ReceiveAsync(timeout.Token);
+            byte[] connectRequest = BuildConnectRequest(
+                clientId: 0x1234,
+                iteration: 7,
+                serverTime: 12345.5);
+            await server.SendAsync(connectRequest, login.RemoteEndPoint, timeout.Token);
+
+            UdpReceiveResult disconnect = await server.ReceiveAsync(timeout.Token);
+            return disconnect.Buffer;
+        }, timeout.Token);
+
+        using var session = new WorldSession(serverEndpoint);
+        session.ServerTimeUpdated += _ =>
+            throw new InvalidOperationException("subscriber failed");
+
+        Assert.Throws<InvalidOperationException>(() =>
+            session.Connect("typed-account", "password", TimeSpan.FromSeconds(3)));
+
+        session.Dispose();
+        byte[] datagram = await serverFlow;
+        PacketCodec.PacketDecodeResult decoded =
+            PacketCodec.TryDecode(datagram, inboundIsaac: null);
+
+        Assert.True(decoded.IsOk, decoded.Error.ToString());
+        Assert.True(decoded.Packet!.Header.HasFlag(PacketHeaderFlags.Disconnect));
+        Assert.Equal((ushort)0x1234, decoded.Packet.Header.Id);
+        Assert.Equal((ushort)7, decoded.Packet.Header.Iteration);
+        Assert.Equal(WorldSession.State.Disconnected, session.CurrentState);
+    }
+
+    private static byte[] BuildConnectRequest(
+        ushort clientId,
+        ushort iteration,
+        double serverTime)
+    {
+        byte[] body = new byte[32];
+        BinaryPrimitives.WriteInt64LittleEndian(
+            body,
+            BitConverter.DoubleToInt64Bits(serverTime));
+        BinaryPrimitives.WriteUInt64LittleEndian(body.AsSpan(8), 0xFEEDFACECAFEBABEUL);
+        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(16), clientId);
+        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(20), 0xAABBCCDDu);
+        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(24), 0x01020304u);
+
+        var header = new PacketHeader
+        {
+            Flags = PacketHeaderFlags.ConnectRequest,
+            DataSize = (ushort)body.Length,
+            Iteration = iteration,
+        };
+        header.Checksum = header.CalculateHeaderHash32() + Hash32.Calculate(body);
+
+        byte[] datagram = new byte[PacketHeader.Size + body.Length];
+        header.Pack(datagram);
+        body.CopyTo(datagram.AsSpan(PacketHeader.Size));
+        return datagram;
+    }
+}