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/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}");
+        }
+    }
 }