Add xToys pattern import via URL paste

- XToysPattern.cs: fetch pattern from xtoys.app API (one call), parse
  script-v3 JSON, resolve slider defaults, evaluate sine/straight steps
  to WaveFrames at 100ms resolution
- Frequency mapping: 0%=1000ms deep, 100%=10ms buzzy
- MainForm: Pattern button + input dialog, continuously enqueues pattern
  frames as a loop, Stop All cancels
- Fix: handle JSON values that are numbers vs strings (end/start fields)
- NOTES.md: xToys slider parameter intel + frequency mapping docs

MainForm.cs

@@ -50,11 +50,13 @@ public class MainForm : Form
 
     readonly Button _btnMusic;
     readonly Button _btnLive;
+    readonly Button _btnPattern;
     readonly Label _lblTrack;
     readonly Label _lblAudioDev;
     readonly ComboBox _cboAudioDev;
     bool _isMusicRunning;
     bool _isLiveRunning;
+    bool _isPatternRunning;
     WaveOutEvent? _audioOut;
     Stopwatch? _musicStopwatch;
     LiveCapture? _liveCapture;
@@ -123,31 +125,39 @@ public class MainForm : Form
         {
             Text = "Test",
             Location = new Point(16, 96),
-            Size = new Size(80, 32)
+            Size = new Size(68, 32)
         };
         _btnTest.Click += OnTest;
 
         _btnMusic = new Button
         {
             Text = "Music",
-            Location = new Point(104, 96),
-            Size = new Size(80, 32)
+            Location = new Point(92, 96),
+            Size = new Size(68, 32)
         };
         _btnMusic.Click += OnMusic;
 
         _btnLive = new Button
         {
             Text = "Live",
-            Location = new Point(192, 96),
-            Size = new Size(80, 32)
+            Location = new Point(168, 96),
+            Size = new Size(68, 32)
         };
         _btnLive.Click += OnLive;
 
+        _btnPattern = new Button
+        {
+            Text = "Pattern",
+            Location = new Point(244, 96),
+            Size = new Size(68, 32)
+        };
+        _btnPattern.Click += OnPattern;
+
         _btnStop = new Button
         {
             Text = "Stop All",
-            Location = new Point(280, 96),
-            Size = new Size(80, 32)
+            Location = new Point(320, 96),
+            Size = new Size(76, 32)
         };
         _btnStop.Click += OnStop;
 
@@ -297,7 +307,7 @@ public class MainForm : Form
         _chkScaleB.CheckedChanged += OnLimitChanged;
         OnLimitChanged(null, EventArgs.Empty);
 
-        Controls.AddRange(new Control[] { _lblBle, _lblWs, _lblDeviceName, _txtDeviceName, _btnConnect, _chkSwap, _btnTest, _btnMusic, _btnLive, _btnStop, _lblAudioDev, _cboAudioDev, _lblTrack, _lblSendA, _heatA, _lblSendB, _heatB, _lblRecvA, _gaugeRecvA, _lblRecvB, _gaugeRecvB, _lblLimitA, _limitBarA, _lblLimitValA, _chkScaleA, _lblLimitB, _limitBarB, _lblLimitValB, _chkScaleB });
+        Controls.AddRange(new Control[] { _lblBle, _lblWs, _lblDeviceName, _txtDeviceName, _btnConnect, _chkSwap, _btnTest, _btnMusic, _btnLive, _btnPattern, _btnStop, _lblAudioDev, _cboAudioDev, _lblTrack, _lblSendA, _heatA, _lblSendB, _heatB, _lblRecvA, _gaugeRecvA, _lblRecvB, _gaugeRecvB, _lblLimitA, _limitBarA, _lblLimitValA, _chkScaleA, _lblLimitB, _limitBarB, _lblLimitValB, _chkScaleB });
 
         // Tray icon — three cached variants: neutral=gray, active=gold, hot=red-orange
         _iconNeutral = CreateVoltageIcon(Color.Gray);
@@ -465,9 +475,11 @@ public class MainForm : Form
 
     void RefreshButtonStates()
     {
-        _btnTest.Enabled = !_server.HasClient && !IsTestRunning && !_isMusicRunning && !_isLiveRunning;
-        _btnMusic.Enabled = !_server.HasClient && !_isMusicRunning && !IsTestRunning && !_isLiveRunning;
-        _btnLive.Enabled = !_server.HasClient && !_isLiveRunning && !IsTestRunning && !_isMusicRunning;
+        bool busy = IsTestRunning || _isMusicRunning || _isLiveRunning || _isPatternRunning;
+        _btnTest.Enabled = !_server.HasClient && !busy;
+        _btnMusic.Enabled = !_server.HasClient && !busy;
+        _btnLive.Enabled = !_server.HasClient && !busy;
+        _btnPattern.Enabled = !_server.HasClient && !busy;
         _btnStop.Enabled = true;
     }
 
@@ -484,6 +496,10 @@ public class MainForm : Form
         {
             _lblTrack.Text = "Live capture";
         }
+        else if (_isPatternRunning)
+        {
+            _lblTrack.Text = $"Pattern: {_patternName}";
+        }
 
         UpdateTrayIcon();
     }
@@ -550,6 +566,7 @@ public class MainForm : Form
     {
         StopMusic();
         StopLive();
+        StopPattern();
         _state.SetStrength('A', 0);
         _state.SetStrength('B', 0);
         _state.Stop('A');
@@ -732,6 +749,102 @@ public class MainForm : Form
         }
     }
 
+    string _patternName = "";
+    CancellationTokenSource? _patternCts;
+
+    void OnPattern(object? sender, EventArgs e)
+    {
+        if (_isPatternRunning || _server.HasClient) return;
+
+        var url = ShowInputDialog("Paste xToys pattern URL:", "Pattern Import");
+        if (string.IsNullOrWhiteSpace(url)) return;
+
+        _isPatternRunning = true;
+        _btnPattern.Enabled = false;
+        _lblTrack.Text = "Loading pattern...";
+
+        _patternCts = new CancellationTokenSource();
+        Task.Run(() => RunPatternAsync(url, _patternCts.Token));
+    }
+
+    async Task RunPatternAsync(string url, CancellationToken ct)
+    {
+        XToysPattern? pattern = null;
+        try
+        {
+            pattern = await XToysPatternImporter.ImportAsync(url);
+        }
+        catch (Exception ex)
+        {
+            BeginInvoke(() =>
+            {
+                _lblTrack.Text = $"Pattern failed: {ex.Message?.Split('\n')[0]}";
+                _isPatternRunning = false;
+                RefreshButtonStates();
+            });
+            return;
+        }
+
+        _patternName = pattern.Name;
+
+        _state.SetStrength('A', 60);
+        _state.SetStrength('B', 60);
+        _state.Stop('A');
+        _state.Stop('B');
+
+        BeginInvoke(() => _lblTrack.Text = $"Pattern: {_patternName}");
+
+        // Continuously enqueue pattern frames at 100ms per frame
+        int idx = 0;
+        while (!ct.IsCancellationRequested && _isPatternRunning)
+        {
+            var frameA = pattern.ChannelA[idx];
+            var frameB = pattern.ChannelB[idx];
+            _state.EnqueueStream('A', new[] { frameA });
+            _state.EnqueueStream('B', new[] { frameB });
+            idx = (idx + 1) % pattern.ChannelA.Count;
+
+            try { await Task.Delay(100, ct); } catch (OperationCanceledException) { break; }
+        }
+    }
+
+    void StopPattern()
+    {
+        _patternCts?.Cancel();
+        _patternCts = null;
+
+        if (_isPatternRunning)
+        {
+            _isPatternRunning = false;
+            if (!IsDisposed)
+            {
+                _lblTrack.Text = "";
+                RefreshButtonStates();
+            }
+        }
+    }
+
+    string ShowInputDialog(string prompt, string title)
+    {
+        using var dlg = new Form
+        {
+            Text = title,
+            FormBorderStyle = FormBorderStyle.FixedDialog,
+            ClientSize = new Size(380, 100),
+            StartPosition = FormStartPosition.CenterParent,
+            MaximizeBox = false,
+            MinimizeBox = false
+        };
+        var lbl = new Label { Text = prompt, Location = new Point(12, 12), Size = new Size(356, 20) };
+        var txt = new TextBox { Location = new Point(12, 36), Size = new Size(356, 22) };
+        var ok = new Button { Text = "OK", DialogResult = DialogResult.OK, Location = new Point(200, 66), Size = new Size(80, 24) };
+        var cancel = new Button { Text = "Cancel", DialogResult = DialogResult.Cancel, Location = new Point(288, 66), Size = new Size(80, 24) };
+        dlg.Controls.AddRange(new Control[] { lbl, txt, ok, cancel });
+        dlg.AcceptButton = ok;
+        dlg.CancelButton = cancel;
+        return dlg.ShowDialog(this) == DialogResult.OK ? txt.Text.Trim() : "";
+    }
+
     void UpdateTrayIcon()
     {
         var newState = _state.IsSignaling ? "hot"

NOTES.md

@@ -129,3 +129,28 @@ web game / userscript  ──WS──>  Substation  ──BLE──>  Coyote 3.0
 ```
 
 Build: `dotnet run -c Release`
+
+## xToys pattern import
+
+Paste a URL like `https://xtoys.app/patterns/-OuhuHOuY1AlPPoCJlzc` into the Pattern dialog.
+The app fetches the pattern once from `https://xtoys.app/api/getPatternv2`, evaluates it
+locally, and plays it as a continuous loop. No ongoing API calls.
+
+### xToys script-v3 slider parameters
+
+From pattern analysis:
+
+- **A CH** (0.5–10): Divides the pattern between channels. If A=1 and B=2, then 2/3 of
+  the pattern goes to channel B. Controls the "hold" duration on channel A.
+- **B CH** (0.5–10): Same division for channel B. Controls the "pause" duration.
+- **Ramp** (0.5–5): Applies a smoothness filter to transitions. Higher = slower ramps.
+- **Min Freq** (0–100): Low cutoff on frequency values. No idea why.
+- **Min Level** (0–100): Low cutoff on intensity values. Floor that's held during "pause".
+
+### Frequency mapping
+
+xToys frequency is 0–100 (percentage). Mapped to e-stim period:
+- 0% = 1000ms (1Hz, deep thump)
+- 100% = 10ms (100Hz, buzzy)
+
+Formula: `period_ms = 1000 - 9.9 * freq_pct`

XToysPattern.cs

@@ -0,0 +1,162 @@
+using System.Net.Http;
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+
+namespace Substation;
+
+public record XToysPattern(string Name, List<WaveFrame> ChannelA, List<WaveFrame> ChannelB);
+
+public static class XToysPatternImporter
+{
+    static readonly HttpClient Http = new();
+
+    public static async Task<XToysPattern> ImportAsync(string url)
+    {
+        var patternId = ExtractPatternId(url);
+        if (patternId == null)
+            throw new ArgumentException("Could not extract pattern ID from URL. Expected format: https://xtoys.app/patterns/<ID>");
+
+        var body = JsonSerializer.Serialize(new { data = new { patternID = patternId } });
+        var content = new StringContent(body, Encoding.UTF8, "application/json");
+        var response = await Http.PostAsync("https://xtoys.app/api/getPatternv2", content);
+        response.EnsureSuccessStatusCode();
+
+        var json = await response.Content.ReadAsStringAsync();
+        return Parse(json);
+    }
+
+    static int FreqPctToMs(byte freqPct)
+    {
+        // xToys frequency: 0% = deep (1000ms), 100% = buzzy (10ms)
+        // freqPct is the raw 0-100 value from the pattern (already clamped in EvaluatePattern)
+        return (int)Math.Round(1000 - 9.9 * freqPct);
+    }
+
+    static string? ExtractPatternId(string url)
+    {
+        var match = Regex.Match(url, @"/patterns/([A-Za-z0-9_-]+)");
+        return match.Success ? match.Groups[1].Value : null;
+    }
+
+    static XToysPattern Parse(string json)
+    {
+        using var doc = JsonDocument.Parse(json);
+
+        var pattern = doc.RootElement.GetProperty("result").GetProperty("pattern");
+        var name = pattern.GetProperty("name").GetString() ?? "Unknown";
+        var patternData = pattern.GetProperty("patternData");
+
+        // Resolve slider defaults
+        var sliders = new Dictionary<string, double>();
+        if (patternData.TryGetProperty("ma", out var ma))
+        {
+            foreach (var slider in ma.EnumerateArray())
+            {
+                var key = slider.GetProperty("key").GetString()!;
+                var value = slider.GetProperty("value").GetDouble();
+                sliders[key] = value;
+            }
+        }
+
+        // Evaluate patterns to per-tick value arrays
+        var int1 = EvaluatePattern(patternData, "Int1", sliders);
+        var int2 = EvaluatePattern(patternData, "Int2", sliders);
+        var freq1 = EvaluatePattern(patternData, "Freq1", sliders);
+        var freq2 = EvaluatePattern(patternData, "Freq2", sliders);
+
+        // All patterns in a group should have the same total duration.
+        // Use the max length to be safe.
+        int tickCount = Math.Max(int1.Length, Math.Max(int2.Length, Math.Max(freq1.Length, freq2.Length)));
+
+        var channelA = new List<WaveFrame>(tickCount);
+        var channelB = new List<WaveFrame>(tickCount);
+
+        for (int i = 0; i < tickCount; i++)
+        {
+            byte intA = i < int1.Length ? int1[i] : (byte)0;
+            byte intB = i < int2.Length ? int2[i] : (byte)0;
+            // Freq patterns output 0-100 (percentage). Map: 0% = 1000ms deep, 100% = 10ms buzzy.
+            byte freqA = i < freq1.Length ? Freq.Compress(FreqPctToMs(freq1[i])) : Freq.Compress(10);
+            byte freqB = i < freq2.Length ? Freq.Compress(FreqPctToMs(freq2[i])) : Freq.Compress(10);
+
+            channelA.Add(new WaveFrame(
+                new[] { freqA, freqA, freqA, freqA },
+                new[] { intA, intA, intA, intA }));
+
+            channelB.Add(new WaveFrame(
+                new[] { freqB, freqB, freqB, freqB },
+                new[] { intB, intB, intB, intB }));
+        }
+
+        return new XToysPattern(name, channelA, channelB);
+    }
+
+    static byte[] EvaluatePattern(JsonElement patternData, string patternName, Dictionary<string, double> sliders)
+    {
+        if (!patternData.TryGetProperty("patterns", out var patterns))
+            return Array.Empty<byte>();
+        if (!patterns.TryGetProperty(patternName, out var patternArr))
+            return Array.Empty<byte>();
+
+        var values = new List<byte>();
+        double lastEnd = 0;
+
+        foreach (var loop in patternArr.EnumerateArray())
+        {
+            var steps = loop.GetProperty("steps");
+            foreach (var step in steps.EnumerateArray())
+            {
+                var type = step.GetProperty("type").GetString() ?? "straight";
+                var time = ResolveExpr(GetStepValue(step, "time"), sliders);
+                var startVal = step.TryGetProperty("start", out var s)
+                    ? (s.ValueKind == JsonValueKind.Null ? lastEnd : ResolveExpr(GetStepValue(step, "start"), sliders))
+                    : lastEnd;
+                var endVal = ResolveExpr(GetStepValue(step, "end"), sliders);
+
+                int ticks = Math.Max(1, (int)Math.Round(time / 0.1));
+
+                for (int t = 0; t < ticks; t++)
+                {
+                    double frac = (double)t / ticks;
+                    double v;
+                    if (type == "sine")
+                        v = startVal + (endVal - startVal) * (1 - Math.Cos(frac * Math.PI)) / 2;
+                    else
+                        v = startVal + (endVal - startVal) * frac;
+
+                    values.Add((byte)Math.Clamp((int)Math.Round(v), 0, 100));
+                }
+
+                lastEnd = endVal;
+            }
+        }
+
+        return values.ToArray();
+    }
+
+    static string GetStepValue(JsonElement step, string propName)
+    {
+        if (!step.TryGetProperty(propName, out var el))
+            return "0";
+        return el.ValueKind switch
+        {
+            JsonValueKind.String => el.GetString() ?? "0",
+            JsonValueKind.Number => el.GetDouble().ToString(),
+            _ => "0"
+        };
+    }
+
+    static double ResolveExpr(string expr, Dictionary<string, double> sliders)
+    {
+        // Replace {var} references, then evaluate simple expressions like "ramp/2"
+        var resolved = Regex.Replace(expr, @"\{(\w+)\}", m =>
+            sliders.TryGetValue(m.Groups[1].Value, out var val) ? val.ToString() : "0");
+
+        // Parse simple arithmetic: number, or number/number
+        var parts = resolved.Split('/');
+        if (parts.Length == 2 && double.TryParse(parts[0], out var a) && double.TryParse(parts[1], out var b))
+            return a / b;
+        return double.TryParse(resolved, out var result) ? result : 0;
+    }
+}