voice-cat/clients/apple/dotnet/VoiceCat.Mac/ConnectWindowController.cs

using AppKit;
using CoreGraphics;
using Foundation;
using VoiceCat.Core;
using VoiceCat.Crypto;

namespace VoiceCat.Mac;

internal sealed class ConnectWindowController : NSWindowController
{
    private readonly NSTextField host = new(new CGRect(120, 180, 280, 26)) { StringValue = "127.0.0.1:8384", PlaceholderString = "Host:port" };
    private readonly NSTextField nickname = new(new CGRect(120, 140, 280, 26)) { StringValue = Environment.UserName, PlaceholderString = "Nickname" };
    private readonly NSTextField status = NSTextField.CreateLabel("Ready to connect");
    private readonly NSButton connect = new(new CGRect(300, 55, 100, 32)) { Title = "Connect", BezelStyle = NSBezelStyle.Rounded };
    private VoiceCatClient? client;
    private MainWindowController? main;

    internal ConnectWindowController() : base(new NSWindow(new CGRect(0, 0, 520, 260), NSWindowStyle.Titled | NSWindowStyle.Closable,
        NSBackingStore.Buffered, false))
    {
        Window!.Title = "Connect to VoiceCat"; Window.Center();
        var view = Window.ContentView!;
        var hostLabel = NSTextField.CreateLabel("Server"); hostLabel.Frame = new CGRect(30, 185, 80, 20); view.AddSubview(hostLabel); view.AddSubview(host);
        var nicknameLabel = NSTextField.CreateLabel("Nickname"); nicknameLabel.Frame = new CGRect(30, 145, 80, 20); view.AddSubview(nicknameLabel); view.AddSubview(nickname);
        status.Frame = new CGRect(30, 95, 370, 22); status.AccessibilityLabel = "Connection status"; view.AddSubview(status);
        ((INSAccessibility)connect).AccessibilityLabel = "Connect to server"; connect.Activated += Connect; view.AddSubview(connect);
        Window.DefaultButtonCell = connect.Cell;
    }

    private async void Connect(object? sender, EventArgs args)
    {
        if (client is not null) return;
        try
        {
            connect.Enabled = false; status.StringValue = "Connecting…";
            (string serverHost, ushort port) = ParseEndpoint(host.StringValue);
            string pins = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VoiceCat", "tofu.txt");
            client = new("VoiceCat macOS", "0.1.0", pins);
            await client.ConnectAsync(serverHost, port, ConfirmIdentity);
            var auth = await client.AuthenticateGuestAsync(nickname.StringValue);
            if (!auth.Ok) throw new InvalidOperationException(auth.Error);
            main = new(client, auth.Self.Id, nickname.StringValue);
            client = null; main.ShowWindow(this); Window.Close();
        }
        catch (Exception exception)
        {
            if (client is not null) await client.DisposeAsync(); client = null;
            status.StringValue = exception.Message; connect.Enabled = true;
        }
    }

    private ValueTask<bool> ConfirmIdentity(ServerIdentityChallenge challenge, CancellationToken cancellationToken)
    {
        var completion = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
        NSApplication.SharedApplication.InvokeOnMainThread(() =>
        {
            var alert = new NSAlert { MessageText = challenge.Status == TofuStatus.FirstConnect ? "Trust this VoiceCat server?" : "Server identity changed",
                InformativeText = $"{challenge.Host}:{challenge.Port}\n\nCertificate SHA-256:\n{challenge.CertificateFingerprint}", AlertStyle = challenge.Status == TofuStatus.Mismatch ? NSAlertStyle.Critical : NSAlertStyle.Informational };
            alert.AddButton("Trust and connect"); alert.AddButton("Cancel"); completion.TrySetResult(alert.RunModal() == 1000);
        });
        return new(completion.Task.WaitAsync(cancellationToken));
    }

    private static (string Host, ushort Port) ParseEndpoint(string value)
    {
        int separator = value.LastIndexOf(':');
        if (separator <= 0 || !ushort.TryParse(value[(separator + 1)..], out ushort port) || port == 0) throw new ArgumentException("Enter a server as host:port.");
        return (value[..separator].Trim('[', ']'), port);
    }
}