v0.5: TCP STT client with PTT on/off, server endpoint in config + UI

Robovoice.Stt.Tcp/Robovoice.Stt.Tcp.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <ItemGroup>
+    <ProjectReference Include="..\Robovoice.Core\Robovoice.Core.csproj" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Robovoice.Stt.Tcp/TcpSttSource.cs

@@ -0,0 +1,253 @@
+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Robovoice.Core;
+
+namespace Robovoice.Stt.Tcp;
+
+public sealed class TcpSttSource : ISttSource
+{
+    private TcpClient? _tcp;
+    private NetworkStream? _stream;
+    private StreamReader? _reader;
+    private StreamWriter? _writer;
+    private CancellationTokenSource? _cts;
+    private Task? _runTask;
+    private readonly object _sendLock = new();
+    private bool _disposed;
+
+    public string ServerEndpoint { get; set; } = "127.0.0.1:5210";
+
+    public bool IsRunning => _cts is not null;
+
+    public Action<string>? Log { get; set; }
+
+    public event TranscriptEventHandler? TranscriptReceived;
+
+    public Task StartAsync(CancellationToken ct = default)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        if (_cts is not null)
+            return Task.CompletedTask;
+
+        _cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        _runTask = RunAsync(_cts.Token);
+        return Task.CompletedTask;
+    }
+
+    public async Task StopAsync(CancellationToken ct = default)
+    {
+        if (_cts is not null)
+            _cts.Cancel();
+
+        CleanupConnection();
+
+        if (_runTask is not null)
+        {
+            try { await _runTask.WaitAsync(ct); }
+            catch { }
+            _runTask = null;
+        }
+
+        _cts?.Dispose();
+        _cts = null;
+    }
+
+    private async Task RunAsync(CancellationToken ct)
+    {
+        while (!ct.IsCancellationRequested)
+        {
+            IPEndPoint? endpoint = ParseEndpoint(ServerEndpoint);
+            if (endpoint is null)
+            {
+                Log?.Invoke($"STT: invalid endpoint '{ServerEndpoint}'");
+                try { await Task.Delay(3000, ct); } catch { break; }
+                continue;
+            }
+
+            try
+            {
+                _tcp = new TcpClient();
+                using var connectCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+                connectCts.CancelAfter(TimeSpan.FromSeconds(5));
+                await _tcp.ConnectAsync(endpoint.Address, endpoint.Port, connectCts.Token);
+
+                _stream = _tcp.GetStream();
+                _reader = new StreamReader(_stream, System.Text.Encoding.UTF8);
+                _writer = new StreamWriter(_stream, System.Text.Encoding.UTF8) { AutoFlush = true };
+
+                Log?.Invoke($"STT: connected to {ServerEndpoint}");
+
+                await ReceiveLoopAsync(ct);
+            }
+            catch (OperationCanceledException)
+            {
+                break;
+            }
+            catch (Exception ex)
+            {
+                Log?.Invoke($"STT: connection failed ({ex.Message}), retrying...");
+            }
+            finally
+            {
+                CleanupConnection();
+            }
+
+            if (!ct.IsCancellationRequested)
+            {
+                try { await Task.Delay(3000, ct); }
+                catch (OperationCanceledException) { break; }
+            }
+        }
+    }
+
+    private async Task ReceiveLoopAsync(CancellationToken ct)
+    {
+        while (!ct.IsCancellationRequested && _reader is not null)
+        {
+            string? line;
+            try
+            {
+                line = await _reader.ReadLineAsync(ct);
+            }
+            catch
+            {
+                break;
+            }
+
+            if (line is null)
+                break;
+
+            TranscriptMessage? message = ParseTranscriptLine(line);
+            if (message is null)
+                continue;
+
+            TranscriptReceived?.Invoke(this, new TranscriptEventArgs
+            {
+                Message = message,
+            });
+        }
+    }
+
+    public void SendOn()
+    {
+        SendControl("on");
+    }
+
+    public void SendOff()
+    {
+        SendControl("off");
+    }
+
+    public async Task ReconnectAsync(CancellationToken ct = default)
+    {
+        if (_cts is null)
+            return;
+
+        Log?.Invoke("STT: reconnecting...");
+        CleanupConnection();
+
+        try { await Task.Delay(500, ct); }
+        catch (OperationCanceledException) { return; }
+    }
+
+    private void SendControl(string evt)
+    {
+        lock (_sendLock)
+        {
+            if (_writer is null)
+                return;
+
+            try
+            {
+                _writer.WriteLine(JsonSerializer.Serialize(new ControlDto { Event = evt }));
+            }
+            catch
+            {
+                Log?.Invoke($"STT: failed to send '{evt}' (not connected?)");
+            }
+        }
+    }
+
+    private void CleanupConnection()
+    {
+        lock (_sendLock)
+        {
+            _writer?.Dispose();
+            _reader?.Dispose();
+            _stream?.Dispose();
+            _tcp?.Dispose();
+            _writer = null;
+            _reader = null;
+            _stream = null;
+            _tcp = null;
+        }
+    }
+
+    private static IPEndPoint? ParseEndpoint(string endpoint)
+    {
+        int colon = endpoint.LastIndexOf(':');
+        if (colon <= 0)
+            return null;
+
+        string host = endpoint[..colon];
+        if (!int.TryParse(endpoint[(colon + 1)..], out int port))
+            return null;
+
+        if (IPAddress.TryParse(host, out var addr))
+            return new IPEndPoint(addr, port);
+
+        try
+        {
+            var addresses = Dns.GetHostAddresses(host);
+            addr = addresses.FirstOrDefault(a => a.AddressFamily == AddressFamily.InterNetwork);
+            if (addr is null)
+                return null;
+            return new IPEndPoint(addr, port);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static TranscriptMessage? ParseTranscriptLine(string line)
+    {
+        if (string.IsNullOrWhiteSpace(line))
+            return null;
+
+        try
+        {
+            var dto = JsonSerializer.Deserialize<TransmitDto>(line);
+            if (dto is null)
+                return null;
+
+            var type = dto.Final ? TranscriptType.Final : TranscriptType.Partial;
+            return new TranscriptMessage(type, dto.Text ?? string.Empty);
+        }
+        catch (JsonException)
+        {
+            return null;
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_disposed) return;
+        await StopAsync();
+        _disposed = true;
+    }
+}
+
+internal sealed class ControlDto
+{
+    [JsonPropertyName("event")]
+    public string Event { get; set; } = string.Empty;
+}
+
+internal sealed class TransmitDto
+{
+    public bool Final { get; set; }
+    public string Text { get; set; } = string.Empty;
+}