import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:dmc_app/domain/waypoint/flat_waypoint_list.dart';
import 'package:dmc_app/services/wind/wind_service.dart';
import 'package:dmc_app/ui/providers/current_mission_provider.dart';
import 'package:dmc_app/ui/providers/wind_provider.dart';

/// Zaehlt fetchWindForWaypoints()-Aufrufe statt echte HTTP-Requests zu
/// stellen - schreibt synthetische Winddaten zurueck, damit
/// ensurePerWaypointWind()s "bereits vorhanden"-Kurzschluss (siehe dortige
/// Doku) bei einem zweiten Aufruf greifen kann.
class _CountingWindService extends WindService {
  int fetchCalls = 0;

  @override
  Future<List<Waypoint>> fetchWindForWaypoints(List<Waypoint> waypoints) async {
    fetchCalls++;
    return [
      for (final w in waypoints) w.copyWith(windSpeedMs: 5, windDirFromDeg: 200),
    ];
  }
}

Waypoint _wp(double lat, double lon, {double? windSpeedMs}) => Waypoint(
      lat: lat,
      lon: lon,
      altitudeM: 60,
      speedMs: 15,
      catchRadiusM: 60,
      windSpeedMs: windSpeedMs,
      windDirFromDeg: windSpeedMs != null ? 180 : null,
    );

void main() {
  test('ensurePerWaypointWind() fetches once for a list without wind data', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    container.read(currentMissionProvider.notifier).addWaypoint(_wp(0, 0));

    await container.read(headerWindProvider.notifier).ensurePerWaypointWind();

    expect(service.fetchCalls, 1);
    expect(container.read(currentMissionProvider).single.windSpeedMs, 5);
  });

  test('ensurePerWaypointWind() does not fetch when every waypoint already '
      'has wind data (e.g. loaded from a saved mission)', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    container.read(currentMissionProvider.notifier).addWaypoint(_wp(0, 0, windSpeedMs: 3));

    await container.read(headerWindProvider.notifier).ensurePerWaypointWind();

    expect(service.fetchCalls, 0);
  });

  test('a second ensurePerWaypointWind() call for the unchanged list does '
      'not fetch again', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    container.read(currentMissionProvider.notifier).addWaypoint(_wp(0, 0));

    final notifier = container.read(headerWindProvider.notifier);
    await notifier.ensurePerWaypointWind();
    await notifier.ensurePerWaypointWind();

    expect(service.fetchCalls, 1);
  });

  test('toggleShowPerWaypoint() fetches when turning on, not when turning off', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    container.read(currentMissionProvider.notifier).addWaypoint(_wp(0, 0));

    final notifier = container.read(headerWindProvider.notifier);
    notifier.toggleShowPerWaypoint(); // an
    await Future<void>.delayed(Duration.zero);
    expect(container.read(headerWindProvider).showPerWaypoint, isTrue);
    expect(service.fetchCalls, 1);

    notifier.toggleShowPerWaypoint(); // aus
    await Future<void>.delayed(Duration.zero);
    expect(container.read(headerWindProvider).showPerWaypoint, isFalse);
    expect(service.fetchCalls, 1, reason: 'Ausschalten loest keinen Abruf aus');
  });

  test('after activation, changing the waypoint list (e.g. adding a point) '
      'triggers an automatic refetch', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    final missionNotifier = container.read(currentMissionProvider.notifier);
    missionNotifier.addWaypoint(_wp(0, 0));

    await container.read(headerWindProvider.notifier).ensurePerWaypointWind();
    expect(service.fetchCalls, 1);

    missionNotifier.addWaypoint(_wp(0, 0.01));
    await Future<void>.delayed(Duration.zero);

    expect(service.fetchCalls, 2,
        reason: 'die veraenderte Wegpunktliste loest automatisch neu aus');
  });

  test('after activation, editing only altitude (position unchanged) does '
      'NOT trigger a refetch', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    final missionNotifier = container.read(currentMissionProvider.notifier);
    missionNotifier.addWaypoint(_wp(0, 0));

    await container.read(headerWindProvider.notifier).ensurePerWaypointWind();
    expect(service.fetchCalls, 1);

    missionNotifier.setAltitude(0, 150);
    await Future<void>.delayed(Duration.zero);

    expect(service.fetchCalls, 1,
        reason: 'nur die Position ist Teil der Aenderungs-Signatur, nicht die Hoehe');
  });

  test('before activation (menu never opened, pill never toggled), list '
      'changes trigger no fetch at all', () async {
    final service = _CountingWindService();
    final container = ProviderContainer(overrides: [
      windServiceProvider.overrideWithValue(service),
    ]);
    addTearDown(container.dispose);
    // Beobachtet headerWindProvider, ohne ensurePerWaypointWind() oder
    // toggleShowPerWaypoint() aufzurufen - build() registriert den Listener
    // zwar, er soll aber inaktiv bleiben.
    container.read(headerWindProvider);

    container.read(currentMissionProvider.notifier).addWaypoint(_wp(0, 0));
    await Future<void>.delayed(Duration.zero);

    expect(service.fetchCalls, 0);
  });
}