feat(scoreboard): unit 5 — tile selection and the cached strip presenter

ScoreboardTiles decides which of the eight facts appear and shapes their text (money uses the session's dominant currency and flags a second one rather than converting; watch hours carry 'as of {date}' because Analytics is a daily aggregate). Tiles are OPT-IN, so 'None' really means the layer draws nothing, and 'Default' is the six session facts. ScoreboardPresenter owns the raster cache: ScoreboardRecorder.Changed fires only on a visible change, so the strip rebuilds only then — a per-tick raster would be the compositor's most expensive layer for identical pixels. Guard: ScoreboardPresenterTests asserts the cache identity (same instance when nothing moved, a new frame when a value moved, reuse when a recipient-side gift event arrives) and that an empty selection returns no frame at all.
2026-10-30 14:38:59 -07:00
parent fbcccea0f7
commit 41b0cd6e98
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+using System.Collections.Generic;
+using ytLive.Models;
+
+namespace ytLive.Services.Compositor;
+
+/// <summary>Turns the session's tallies into the strip frame, and keeps the raster until a displayed
+/// value actually moves.
+///
+/// <para>The cache is the point: a strip re-rasterised every tick would be the most expensive layer
+/// the compositor carries, for pixels that did not change. `ScoreboardRecorder.Changed` only fires
+/// on a visible change, so the presenter rebuilds only then.</para></summary>
+public sealed class ScoreboardPresenter
+{
+    private readonly ScoreboardRecorder _recorder;
+    private VideoFrame? _frame;
+    private string? _tilesFingerprint;
+    private ScoreboardStyle _style;
+    private ScoreboardTiles _tiles = ScoreboardTiles.None;
+
+    public ScoreboardPresenter(ScoreboardRecorder recorder, ScoreboardStyle style)
+    {
+        _recorder = recorder;
+        _style = style;
+        _recorder.Changed += Invalidate;
+    }
+
+    /// <summary>The strip frame for the current tallies, or null when nothing is enabled/shown.</summary>
+    public VideoFrame? Frame
+    {
+        get
+        {
+            var tiles = _tiles.Build(_recorder.State);
+            var fingerprint = $"{_tiles.CacheKey}|{string.Join('|', tiles)}|{_style}";
+            if (_frame != null && fingerprint == _tilesFingerprint) return _frame;
+
+            _tilesFingerprint = fingerprint;
+            _frame = ScoreboardRenderer.Render(tiles, _style);
+            return _frame;
+        }
+    }
+
+    public void SetTiles(ScoreboardTiles tiles)
+    {
+        _tiles = tiles;
+        Invalidate();
+    }
+
+    public void SetStyle(ScoreboardStyle style)
+    {
+        _style = style;
+        Invalidate();
+    }
+
+    /// <summary>Drops the cached raster so the next read rebuilds it.</summary>
+    public void Invalidate()
+    {
+        _frame = null;
+        _tilesFingerprint = null;
+    }
+}