BadNote/lib/editor/engine/stroke_store.dart

// lib/editor/engine/stroke_store.dart
//
// Mutable, revision-tracked store for committed EditorStrokes.
//
// Every mutation bumps [revision] (monotonic int). Consumers use the revision
// as an O(1) repaint gate: if revision has not changed since the last paint,
// nothing needs to be redrawn (StaticInkPainter.shouldRepaint).

import 'stroke_model.dart';

/// Holds the ordered list of committed [EditorStroke]s for one ink host (e.g.
/// a page or annotation layer). Every mutating operation bumps [revision].
///
/// This class is intentionally NOT a ChangeNotifier / Listenable — callers
/// poll the revision number from within CustomPainter.shouldRepaint, so no
/// subscription machinery is needed here.
class StrokeStore {
  final List<EditorStroke> _strokes = [];
  int _revision = 0;

  /// Monotonically increasing counter. Bumped on every mutation.
  int get revision => _revision;

  /// Unmodifiable ordered list of committed strokes.
  List<EditorStroke> get committed => List.unmodifiable(_strokes);

  /// Appends [stroke] and bumps the revision.
  void add(EditorStroke stroke) {
    _strokes.add(stroke);
    _revision++;
  }

  /// Removes the stroke with the given [id] (no-op if not found) and bumps
  /// the revision only when a stroke was actually removed.
  void removeById(String id) {
    final before = _strokes.length;
    _strokes.removeWhere((s) => s.id == id);
    if (_strokes.length != before) {
      _revision++;
    }
  }

  /// Replaces the entire stroke list and bumps the revision.
  void replaceAll(List<EditorStroke> strokes) {
    _strokes
      ..clear()
      ..addAll(strokes);
    _revision++;
  }

  /// Clears all strokes and bumps the revision.
  void clear() {
    _strokes.clear();
    _revision++;
  }
}