import 'dart:ui' show Size;

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`, `ssd`, `thermal`, `cameraSettings`, `gimbal`,
/// `gimbalSettings`, `vision`, `calibration`, `perception`, `obstacleSensors`,
/// `airSense`, `airSenseAvoidance`, `flyZone`). 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', 'ssd', 'thermal', 'cameraSettings', 'gimbal', 'gimbalSettings', 'vision', 'calibration', 'palmControl', 'perception', 'obstacleSensors', 'airSense', 'airSenseAvoidance', 'flyZone'];

  /// 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 'histogram':
        if (model.connected) model.camera.applyHistogram(event);
        return true;
      case 'diagnostics':
        if (model.connected) model.alerts.apply(asMapList(event['items']));
        return true;
      case 'key':
        final String? id = asString(event['id']);
        if (model.connected && id != null) model.keys.apply(id, event['value']);
        return true;
      case 'mission':
        model.mission.apply(event);
        return true;
      case 'flySafe':
        // The GEO system is app-level: its notices count with or without an aircraft.
        model.flyZones.applyNotice(event);
        return true;
      case 'flyZoneDbProgress':
        model.flyZones.applyUpgradeProgress(finite(event['progress']));
        return true;
      case 'videoSize':
        final int? w = asInt(event['width']), h = asInt(event['height']);
        if (w != null && h != null && w > 0 && h > 0) model.videoSize.value = Size(w.toDouble(), h.toDouble());
        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 (const <String>['storage', 'ssd', 'thermal', 'cameraSettings'].any(changed.contains)) {
      model.camera.applyTelemetry(
        storage: asMap(t['storage']),
        ssd: asMap(t['ssd']),
        thermal: asMap(t['thermal']),
        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('gimbalSettings')) model.gimbal.applySettings(asMap(t['gimbalSettings']));
    if (changed.contains('vision')) model.vision.apply(asMap(t['vision']));
    if (changed.contains('calibration')) model.calibration.apply(asMap(t['calibration']));
    if (changed.contains('palmControl')) model.vision.applyPalm(asString(t['palmControl']));
    if (changed.contains('perception')) model.vision.applyPerception(asMap(t['perception']));
    if (changed.contains('obstacleSensors')) model.vision.applyHealth(asMap(t['obstacleSensors']));
    if (changed.contains('airSense')) model.airSense.apply(asMap(t['airSense']));
    if (changed.contains('airSenseAvoidance')) model.airSense.applyAvoidance(asMap(t['airSenseAvoidance']));
    if (changed.contains('flyZone')) model.flyZones.applyState(asMap(t['flyZone']));
  }
}