Launcher milestone 2: player list, kick/ban, live stats

Adds an admin-protocol client (token-authed TCP JSON on 127.0.0.1:AdminPort,
reusing the server's .admin-token) that polls connected players and status
every 3s, plus Kick/Ban on the selected player and a players/uptime readout.

host/Services/AdminClient.cs

@@ -0,0 +1,67 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace CommonwealthOnline.Host.Services;
+
+// Speaks the server's token-authenticated admin protocol on 127.0.0.1:AdminPort:
+// read .admin-token, send {..,"adminToken"}\n, read one newline-terminated JSON reply.
+public sealed class AdminClient
+{
+    private const int MaxResponseBytes = 1_000_000;
+
+    private readonly int _port;
+    private readonly string _tokenPath;
+
+    public AdminClient(int adminPort, string tokenPath)
+    {
+        _port = adminPort;
+        _tokenPath = tokenPath;
+    }
+
+    public async Task<JsonObject?> SendAsync(JsonObject request, CancellationToken ct = default)
+    {
+        var token = (await File.ReadAllTextAsync(_tokenPath, ct).ConfigureAwait(false)).Trim();
+        var authenticated = (JsonObject)request.DeepClone();
+        authenticated["adminToken"] = token;
+        var payload = JsonSerializer.SerializeToUtf8Bytes(authenticated);
+
+        using var client = new TcpClient();
+        await client.ConnectAsync(IPAddress.Loopback, _port, ct).ConfigureAwait(false);
+        var stream = client.GetStream();
+        await stream.WriteAsync(payload, ct).ConfigureAwait(false);
+        await stream.WriteAsync(new byte[] { (byte)'\n' }, ct).ConfigureAwait(false);
+
+        using var buffer = new MemoryStream();
+        var one = new byte[1];
+        while (buffer.Length < MaxResponseBytes)
+        {
+            var read = await stream.ReadAsync(one, ct).ConfigureAwait(false);
+            if (read == 0 || one[0] == (byte)'\n')
+            {
+                break;
+            }
+
+            buffer.WriteByte(one[0]);
+        }
+
+        return JsonNode.Parse(buffer.ToArray()) as JsonObject;
+    }
+
+    public Task<JsonObject?> StatusAsync(CancellationToken ct = default) =>
+        SendAsync(new JsonObject { ["cmd"] = "status" }, ct);
+
+    public Task<JsonObject?> ClientsAsync(CancellationToken ct = default) =>
+        SendAsync(new JsonObject { ["cmd"] = "clients" }, ct);
+
+    public Task<JsonObject?> KickAsync(uint playerId, string reason, CancellationToken ct = default) =>
+        SendAsync(new JsonObject { ["cmd"] = "kick", ["playerId"] = playerId, ["reason"] = reason }, ct);
+
+    public Task<JsonObject?> BanAsync(uint playerId, string reason, CancellationToken ct = default) =>
+        SendAsync(new JsonObject { ["cmd"] = "ban", ["playerId"] = playerId, ["reason"] = reason }, ct);
+}

host/ViewModels/MainWindowViewModel.cs

@@ -1,5 +1,8 @@
+using System;
 using System.Collections.ObjectModel;
 using System.IO;
+using System.Text.Json.Nodes;
+using System.Threading.Tasks;
 using Avalonia.Threading;
 using CommonwealthOnline.Host.Services;
 using CommunityToolkit.Mvvm.ComponentModel;
@@ -12,9 +15,11 @@ public partial class MainWindowViewModel : ObservableObject
     private const int MaxLogLines = 2000;
 
     private readonly ServerController _controller = new();
-    private readonly string _serverDir = System.IO.Directory.GetCurrentDirectory();
+    private readonly string _serverDir = Directory.GetCurrentDirectory();
     private readonly string _configPath =
-        Path.Combine(System.IO.Directory.GetCurrentDirectory(), "commonwealth-server.json");
+        Path.Combine(Directory.GetCurrentDirectory(), "commonwealth-server.json");
+    private readonly DispatcherTimer _pollTimer;
+    private bool _polling;
 
     [ObservableProperty] private string _serverName;
     [ObservableProperty] private string _host;
@@ -25,8 +30,15 @@ public partial class MainWindowViewModel : ObservableObject
     [ObservableProperty] private bool _enableGnsTransport;
     [ObservableProperty] private bool _isRunning;
     [ObservableProperty] private string _statusText = "Stopped";
+    [ObservableProperty] private string _statsText = string.Empty;
+
+    [ObservableProperty]
+    [NotifyCanExecuteChangedFor(nameof(KickCommand))]
+    [NotifyCanExecuteChangedFor(nameof(BanCommand))]
+    private PlayerRow? _selectedPlayer;
 
     public ObservableCollection<string> Log { get; } = new();
+    public ObservableCollection<PlayerRow> Players { get; } = new();
 
     public string[] VerbosityOptions { get; } = { "error", "warning", "info", "debug" };
 
@@ -50,7 +62,100 @@ public partial class MainWindowViewModel : ObservableObject
                 StatusText = running ? "Running" : "Stopped";
                 StartCommand.NotifyCanExecuteChanged();
                 StopCommand.NotifyCanExecuteChanged();
+                if (!running)
+                {
+                    Players.Clear();
+                    StatsText = string.Empty;
+                }
             });
+
+        _pollTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(3) };
+        _pollTimer.Tick += async (_, _) => await PollAsync();
+        _pollTimer.Start();
+    }
+
+    private AdminClient CreateAdminClient()
+    {
+        var tokenPath = Path.Combine(Path.GetDirectoryName(_configPath) ?? _serverDir, ".admin-token");
+        return new AdminClient(AdminPort, tokenPath);
+    }
+
+    private async Task PollAsync()
+    {
+        if (!IsRunning || _polling)
+        {
+            return;
+        }
+
+        _polling = true;
+        try
+        {
+            var admin = CreateAdminClient();
+            var clients = await admin.ClientsAsync().ConfigureAwait(true);
+            ApplyClients(clients);
+
+            var status = await admin.StatusAsync().ConfigureAwait(true);
+            ApplyStatus(status);
+        }
+        catch (Exception)
+        {
+            // Server still starting, admin port not up yet, or token not written — ignore this tick.
+        }
+        finally
+        {
+            _polling = false;
+        }
+    }
+
+    private void ApplyClients(JsonObject? response)
+    {
+        if (response?["clients"] is not JsonArray array)
+        {
+            return;
+        }
+
+        var previouslySelected = SelectedPlayer?.PlayerId;
+        Players.Clear();
+        foreach (var node in array)
+        {
+            if (node is not JsonObject client)
+            {
+                continue;
+            }
+
+            Players.Add(new PlayerRow
+            {
+                PlayerId = (uint)(client["player_id"]?.GetValue<long>() ?? 0),
+                Label = client["label"]?.GetValue<string>() ?? string.Empty,
+                Address = client["address"]?.GetValue<string>() ?? string.Empty,
+                PacketsReceived = client["packets_received"]?.GetValue<long>() ?? 0,
+                PacketsSent = client["packets_sent"]?.GetValue<long>() ?? 0,
+            });
+        }
+
+        if (previouslySelected is { } id)
+        {
+            foreach (var row in Players)
+            {
+                if (row.PlayerId == id)
+                {
+                    SelectedPlayer = row;
+                    break;
+                }
+            }
+        }
+    }
+
+    private void ApplyStatus(JsonObject? response)
+    {
+        if (response is null)
+        {
+            return;
+        }
+
+        var connected = response["connected_clients"]?.GetValue<long>() ?? Players.Count;
+        var uptime = response["uptime_seconds"]?.GetValue<long>() ?? 0;
+        StatsText = $"{connected}/{MaxPlayers} players · up {uptime}s";
     }
 
     private void Append(string line)
@@ -94,4 +199,45 @@ public partial class MainWindowViewModel : ObservableObject
     }
 
     private bool CanStop() => IsRunning;
+
+    [RelayCommand(CanExecute = nameof(CanActOnPlayer))]
+    private async Task Kick()
+    {
+        if (SelectedPlayer is not { } player)
+        {
+            return;
+        }
+
+        await RunAdminAction(admin => admin.KickAsync(player.PlayerId, "Kicked by host"),
+            $"[host] kick #{player.PlayerId}").ConfigureAwait(true);
+    }
+
+    [RelayCommand(CanExecute = nameof(CanActOnPlayer))]
+    private async Task Ban()
+    {
+        if (SelectedPlayer is not { } player)
+        {
+            return;
+        }
+
+        await RunAdminAction(admin => admin.BanAsync(player.PlayerId, "Banned by host"),
+            $"[host] ban #{player.PlayerId}").ConfigureAwait(true);
+    }
+
+    private bool CanActOnPlayer() => IsRunning && SelectedPlayer is not null;
+
+    private async Task RunAdminAction(Func<AdminClient, Task<JsonObject?>> action, string label)
+    {
+        try
+        {
+            var response = await action(CreateAdminClient()).ConfigureAwait(true);
+            var message = response?["message"]?.GetValue<string>();
+            Append(string.IsNullOrEmpty(message) ? $"{label} sent" : $"{label}: {message}");
+            await PollAsync().ConfigureAwait(true);
+        }
+        catch (Exception ex)
+        {
+            Append($"{label} failed: {ex.Message}");
+        }
+    }
 }

host/ViewModels/PlayerRow.cs

@@ -0,0 +1,13 @@
+namespace CommonwealthOnline.Host.ViewModels;
+
+public sealed class PlayerRow
+{
+    public uint PlayerId { get; init; }
+    public string Label { get; init; } = string.Empty;
+    public string Address { get; init; } = string.Empty;
+    public long PacketsReceived { get; init; }
+    public long PacketsSent { get; init; }
+
+    public string Display =>
+        $"#{PlayerId}   {(string.IsNullOrEmpty(Label) ? "player" : Label)}   {Address}   ↓{PacketsReceived} ↑{PacketsSent}";
+}

host/Views/MainWindow.axaml

@@ -3,14 +3,14 @@
         xmlns:vm="clr-namespace:CommonwealthOnline.Host.ViewModels"
         x:Class="CommonwealthOnline.Host.Views.MainWindow"
         x:DataType="vm:MainWindowViewModel"
-        Width="920" Height="640"
+        Width="960" Height="700"
-        MinWidth="760" MinHeight="520"
+        MinWidth="820" MinHeight="600"
         Title="Commonwealth Online — Server Host"
         Background="{StaticResource CoBackgroundBrush}">
 
   <Grid RowDefinitions="Auto,*,Auto" Margin="18">
 
-    <Image Grid.Row="0" Source="/Assets/logo.png" Height="88"
+    <Image Grid.Row="0" Source="/Assets/logo.png" Height="84"
            HorizontalAlignment="Left" Margin="0,0,0,14" />
 
     <Grid Grid.Row="1" ColumnDefinitions="330,*">
@@ -38,7 +38,9 @@
                 HorizontalAlignment="Stretch" />
       </StackPanel>
 
-      <Border Grid.Column="1" Background="{StaticResource CoSurfaceBrush}"
+      <Grid Grid.Column="1" RowDefinitions="*,Auto">
+
+        <Border Grid.Row="0" Background="{StaticResource CoSurfaceBrush}"
                 CornerRadius="4" Padding="10">
           <ScrollViewer>
             <ItemsControl ItemsSource="{Binding Log}">
@@ -53,6 +55,35 @@
           </ScrollViewer>
         </Border>
 
+        <Border Grid.Row="1" Background="{StaticResource CoSurfaceBrush}"
+                CornerRadius="4" Padding="10" Margin="0,10,0,0" Height="188">
+          <Grid RowDefinitions="Auto,*,Auto">
+            <DockPanel Grid.Row="0" Margin="0,0,0,6">
+              <TextBlock DockPanel.Dock="Left" Text="PLAYERS"
+                         Foreground="{StaticResource CoAccentBrush}" FontWeight="Bold" FontSize="12" />
+              <TextBlock DockPanel.Dock="Right" Text="{Binding StatsText}"
+                         Foreground="{StaticResource CoTextBrush}" FontSize="11"
+                         HorizontalAlignment="Right" />
+            </DockPanel>
+            <ListBox Grid.Row="1" Background="Transparent"
+                     ItemsSource="{Binding Players}" SelectedItem="{Binding SelectedPlayer}">
+              <ListBox.ItemTemplate>
+                <DataTemplate>
+                  <TextBlock Text="{Binding Display}" Foreground="{StaticResource CoTextBrush}"
+                             FontFamily="Cascadia Mono,Consolas,monospace" FontSize="12" />
+                </DataTemplate>
+              </ListBox.ItemTemplate>
+            </ListBox>
+            <StackPanel Grid.Row="2" Orientation="Horizontal" Spacing="8" Margin="0,6,0,0">
+              <Button Content="Kick" Command="{Binding KickCommand}" Padding="18,4" />
+              <Button Content="Ban" Command="{Binding BanCommand}" Padding="18,4"
+                      Background="{StaticResource CoDangerBrush}" Foreground="White" />
+            </StackPanel>
+          </Grid>
+        </Border>
+
+      </Grid>
+
     </Grid>
 
     <Grid Grid.Row="2" ColumnDefinitions="Auto,*,Auto,Auto" Margin="0,14,0,0">