import '../flight_model.dart';
import 'state/parse.dart';

/// Routes the bridge's telemetry-bearing events into [FlightModel]'s sub-models
/// (plan P1). Kept out of the widget tree so it can be unit-tested against
/// recorded events.
///
/// A `telemetry` event is the native [TelemetryHub]'s full snapshot: the flight
/// controller's flat keys plus one nested group per subsystem (`battery`,
/// `links`, `rc`, `storage`, `cameraSettings`, `gimbal`, `vision`). It arrives at
/// up to 10 Hz with the slow groups repeated unchanged between their 2 Hz
/// refreshes, so each group is compared with the last one seen and its
/// sub-model only notified when it actually moved. A group missing from the
/// snapshot was never reported by this aircraft and leaves its sub-model empty.
class TelemetryReducer {
  TelemetryReducer(this.model);

  final FlightModel model;

  final Map<String, Object?> _lastGroups = <String, Object?>{};

  static const List<String> _groups = <String>['battery', 'links', 'rc', 'storage', 'cameraSettings', 'gimbal', 'vision'];

  /// Applies [event] if it is one of the telemetry types; returns whether it was.
  bool apply(Map<String, dynamic> event) {
    switch (event['type'] as String?) {
      case 'telemetry':
        // Stray packets trailing a disconnect would repopulate what was cleared.
        if (model.connected) model.batch(() => _telemetry(event));
        return true;
      case 'camera':
        if (model.connected) model.camera.applySystem(event);
        return true;
      case 'exposure':
        if (model.connected) model.camera.applyExposure(event);
        return true;
      case 'diagnostics':
        if (model.connected) model.alerts.apply(asMapList(event['items']));
        return true;
      case 'mission':
        model.mission.apply(event);
        return true;
    }
    return false;
  }

  /// Forgets the last-seen groups, so the next aircraft's first tick applies in full.
  void reset() => _lastGroups.clear();

  void _telemetry(Map<String, dynamic> t) {
    // Flight-controller keys change every tick; absent until the FC first reports.
    if (t.containsKey('satelliteCount')) model.aircraft.apply(t);

    final Set<String> changed = <String>{};
    for (final String g in _groups) {
      final Object? v = t[g];
      if (_lastGroups.containsKey(g) && deepEquals(_lastGroups[g], v)) continue;
      _lastGroups[g] = v;
      changed.add(g);
    }
    if (changed.isEmpty) return;

    if (changed.contains('battery')) {
      final Map<String, dynamic>? b = asMap(t['battery']);
      b == null ? model.battery.clear() : model.battery.apply(b);
    }
    if (changed.contains('links') || changed.contains('rc')) {
      model.links.apply(links: asMap(t['links']), rc: asMap(t['rc']));
    }
    if (changed.contains('storage') || changed.contains('cameraSettings')) {
      model.camera.applyTelemetry(storage: asMap(t['storage']), settings: asMap(t['cameraSettings']));
    }
    if (changed.contains('gimbal')) {
      final Map<String, dynamic>? g = asMap(t['gimbal']);
      g == null ? model.gimbal.clear() : model.gimbal.apply(g);
    }
    if (changed.contains('vision')) model.vision.apply(asMap(t['vision']));
  }
}