import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../domain/wind/wind_math.dart';
import '../../services/wind/wind_service.dart';
import 'current_mission_provider.dart';
import 'map_controller_provider.dart';

final windServiceProvider = Provider<WindService>((ref) => WindService());

/// Zustand der Kopfleisten-Wind-Pille (Doku 3.8).
class HeaderWindState {
  const HeaderWindState({
    this.sample,
    this.loading = false,
    this.showPerWaypoint = false,
  });

  final WindSample? sample;
  final bool loading;

  /// Umschaltbar per Antippen der Pille (HTML-Demonstrator:
  /// showPerWaypointWind) - blendet Wind-Marker an jedem Wegpunkt ein/aus.
  final bool showPerWaypoint;

  HeaderWindState copyWith({
    WindSample? sample,
    bool? loading,
    bool? showPerWaypoint,
  }) {
    return HeaderWindState(
      sample: sample ?? this.sample,
      loading: loading ?? this.loading,
      showPerWaypoint: showPerWaypoint ?? this.showPerWaypoint,
    );
  }
}

/// Haelt den fuer die Kopfleiste interpolierten Wind (120 m AGL ueber dem
/// Referenzort: erster Wegpunkt, sonst aktuelles Kartenzentrum) - analog
/// refreshHeaderWind()/headerWindLocation() im HTML-Demonstrator.
class HeaderWindNotifier extends Notifier<HeaderWindState> {
  @override
  HeaderWindState build() => const HeaderWindState();

  Future<void> refresh() async {
    final waypoints = ref.read(currentMissionProvider);
    (double, double)? location;
    if (waypoints.isNotEmpty) {
      location = (waypoints.first.lat, waypoints.first.lon);
    } else {
      try {
        final center = ref.read(mapControllerProvider).camera.center;
        location = (center.latitude, center.longitude);
      } catch (_) {
        // Kamera noch nicht bereit (Karte noch nicht gemountet/gelayoutet).
        location = null;
      }
    }
    if (location == null) return;

    state = state.copyWith(loading: true);
    final sample =
        await ref.read(windServiceProvider).fetchHeaderWind(location.$1, location.$2);
    state = state.copyWith(loading: false, sample: sample);
  }

  void toggleShowPerWaypoint() {
    state = state.copyWith(showPerWaypoint: !state.showPerWaypoint);
  }
}

final headerWindProvider =
    NotifierProvider<HeaderWindNotifier, HeaderWindState>(HeaderWindNotifier.new);

/// Referenzort fuer Windabfragen ohne festen Bezugspunkt (Wind-
/// Validierungspanel aus der Wegpunktliste): erster Wegpunkt, sonst
/// aktuelles Kartenzentrum - analog headerWindLocation() im HTML-
/// Demonstrator. Null, wenn die Karte noch nicht gemountet/gelayoutet ist.
(double, double)? windReferenceLocation(WidgetRef ref) {
  final waypoints = ref.read(currentMissionProvider);
  if (waypoints.isNotEmpty) {
    final first = waypoints.first;
    return (first.lat, first.lon);
  }
  try {
    final center = ref.read(mapControllerProvider).camera.center;
    return (center.latitude, center.longitude);
  } catch (_) {
    return null;
  }
}