import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:latlong2/latlong.dart';

import '../../../domain/mission/mission_stats.dart';
import '../../../domain/mission/mission_warnings.dart';
import '../../../domain/mission/route_geometry.dart';
import '../../../domain/wind/wind_math.dart';
import '../../providers/active_drone_profile_provider.dart';
import '../../providers/current_mission_provider.dart';
import '../../providers/map_controller_provider.dart';
import '../../providers/telemetry_provider.dart';
import '../../providers/terrain_provider.dart';
import '../settings/settings_screen.dart';
import '../../widgets/drone_marker_icon.dart';
import '../../widgets/mission_footer_bar.dart';
import '../../widgets/mission_map.dart';
import '../../widgets/waypoint_list_panel.dart';
import '../../widgets/warnings_panel.dart';

/// Fly-Modus (Architektur-Doku 3.10/3.11): zeigt dieselbe Karte + Fusszeile
/// wie der Plan-Modus, aber ohne Reticle/Draeder - im Flug wird die Route
/// beobachtet statt neu geplant. Der Kartencontroller ist derselbe
/// app-lebenslange Provider wie im Plan-Modus (Doku: mapControllerProvider),
/// die Kameraposition bleibt also beim Umschalten erhalten. Wegpunkte lassen
/// sich weiterhin ueber die Liste anpassen (z.B. spontane Hoehenaenderung),
/// nur das Karten-Reticle zum Anlegen/Verschieben entfaellt hier.
class FlyScreen extends ConsumerWidget {
  const FlyScreen({super.key});

  void _onCenterOnWaypoint(WidgetRef ref, int index) {
    final waypoints = ref.read(currentMissionProvider);
    if (index < 0 || index >= waypoints.length) return;
    final wp = waypoints[index];
    final controller = ref.read(mapControllerProvider);
    controller.move(LatLng(wp.lat, wp.lon), controller.camera.zoom);
  }

  void _openWaypointList(
    BuildContext context,
    WidgetRef ref, {
    PanelTab initialTab = PanelTab.list,
  }) {
    Navigator.of(context).push(
      PageRouteBuilder<void>(
        opaque: true,
        transitionDuration: const Duration(milliseconds: 150),
        reverseTransitionDuration: const Duration(milliseconds: 150),
        pageBuilder: (routeContext, animation, secondaryAnimation) {
          return FadeTransition(
            opacity: animation,
            child: WaypointListPanel(
              activeIndex: -1,
              initialTab: initialTab,
              onClose: () => Navigator.of(routeContext).pop(),
              onCenterOnWaypoint: (index) {
                _onCenterOnWaypoint(ref, index);
                Navigator.of(routeContext).pop();
              },
              onDelete: (index) =>
                  ref.read(currentMissionProvider.notifier).removeAt(index),
              onAltitudeChanged: (index, value) => ref
                  .read(currentMissionProvider.notifier)
                  .setAltitude(index, value),
              onSpeedChanged: (index, value) =>
                  ref.read(currentMissionProvider.notifier).setSpeed(index, value),
              onCatchRadiusChanged: (index, value) => ref
                  .read(currentMissionProvider.notifier)
                  .setCatchRadius(index, value),
              onActionChanged: (index, action) =>
                  ref.read(currentMissionProvider.notifier).setAction(index, action),
            ),
          );
        },
      ),
    );
  }

  void _openWarningsPanel(
    BuildContext context,
    WidgetRef ref,
    List<MissionWarning> warnings,
  ) {
    Navigator.of(context).push(MaterialPageRoute<void>(
      builder: (routeContext) => WarningsPanel(
        warnings: warnings,
        onClose: () => Navigator.of(routeContext).pop(),
        onWarningTap: (warning) {
          Navigator.of(routeContext).pop();
          switch (warning.action) {
            case WarningAction.altitude:
              _openWaypointList(context, ref, initialTab: PanelTab.altitude);
            case WarningAction.speed:
              _openWaypointList(context, ref, initialTab: PanelTab.speed);
            case WarningAction.map:
              fitMapToWaypoints(ref, ref.read(currentMissionProvider));
          }
        },
      ),
    ));
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final waypoints = ref.watch(currentMissionProvider);
    final droneProfile = ref.watch(activeDroneProfileProvider);
    final telemetry = ref.watch(telemetryProvider).value;

    final routeGeometry = buildRouteGeometry(
      waypoints,
      minTurnRadius: droneProfile.minTurnRadius,
      maxClimbRate: droneProfile.maxClimbRate,
      maxDescentRate: droneProfile.maxDescentRate,
    );
    final missionStats = computeMissionStats(waypoints);
    final safeEdgeInset = math.max(
      MediaQuery.of(context).padding.left,
      MediaQuery.of(context).padding.right,
    );
    final terrainProfile = ref.watch(terrainProvider).profile;
    final warnings = computeMissionWarnings(
      waypoints: waypoints,
      routeGeometry: routeGeometry,
      legWindBad: computeLegWindBad(waypoints, droneProfile.maxSpeed),
      droneProfile: droneProfile,
      totalDistanceM: missionStats.distanceM,
      totalDurationSec: missionStats.durationSec,
      terrain: terrainProfile,
    );

    // Vor der ersten Telemetrie (Verbindungsaufbau laeuft noch, oder Mock
    // hat noch nicht getickt) und ohne GPS-Fix (TelemetryFrame wird bewusst
    // nicht auf einen Fix gegated, siehe dortige Doku - ohne Fix meldet der
    // FC aber oft (0,0) oder eine veraltete Position) auf dem ersten
    // Wegpunkt statt an einer erfundenen Stelle anzeigen.
    final droneMarker = telemetry != null && telemetry.hasFix
        ? Marker(
            point: LatLng(telemetry.lat, telemetry.lon),
            width: 28,
            height: 28,
            alignment: Alignment.center,
            child: DroneMarkerIcon(headingDeg: telemetry.headingDeg),
          )
        : waypoints.isEmpty
            ? null
            : Marker(
                point: LatLng(waypoints.first.lat, waypoints.first.lon),
                width: 28,
                height: 28,
                alignment: Alignment.center,
                child: const DroneMarkerIcon(),
              );

    return Stack(
      children: [
        MissionMap(
          mapController: ref.watch(mapControllerProvider),
          routeSegments: routeGeometry.segments,
          waypointMarkers: [
            for (var i = 0; i < waypoints.length; i++)
              CircleMarker(
                point: LatLng(waypoints[i].lat, waypoints[i].lon),
                radius: 6,
                color: i < routeGeometry.vertexBad.length && routeGeometry.vertexBad[i]
                    ? const Color(0xFFE2574A)
                    : const Color(0xFF2B2B28),
                borderStrokeWidth: 1.5,
                borderColor: Colors.white,
              ),
          ],
          droneMarker: droneMarker,
        ),
        // Live-Hoehe/-Geschwindigkeit aus der Telemetrie (HTML-Demonstrator:
        // #altReadout/#spdReadout im Fly-Modus) - anders als dort keine
        // SET-Zeile, weil es im Waypoint-Fly-Modus kein editierbares
        // Rad-Widget (curAlt/curSpeed) gibt, dessen Wert sinnvoll waere.
        Positioned(
          top: 56,
          left: 14 + safeEdgeInset,
          child: _liveReadout('Alt', telemetry?.altitudeM, 'm'),
        ),
        Positioned(
          top: 56,
          right: 14 + safeEdgeInset,
          child: _liveReadout('Speed', telemetry?.speedMs, 'm/s'),
        ),
        Positioned(
          left: 0,
          right: 0,
          bottom: 0,
          child: MissionFooterBar(
            waypoints: waypoints,
            legClimbBad: routeGeometry.legClimbBad,
            vertexBad: routeGeometry.vertexBad,
            activeIndex: -1,
            totalDistanceM: missionStats.distanceM,
            totalDurationSec: missionStats.durationSec,
            warnings: warnings,
            onDetailsTap: () => _openWaypointList(context, ref),
            onWarningsTap: () => _openWarningsPanel(context, ref, warnings),
            onSettingsTap: () => Navigator.of(context).push(MaterialPageRoute(
              builder: (_) => const SettingsScreen(),
            )),
          ),
        ),
      ],
    );
  }

  Widget _liveReadout(String label, double? value, String unit) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      decoration: BoxDecoration(
        color: Colors.black.withValues(alpha: 0.7),
        borderRadius: BorderRadius.circular(6),
      ),
      child: Text(
        '$label: ${value != null ? '${value.round()} $unit' : '—'}',
        style: const TextStyle(
          color: Colors.white,
          fontSize: 15,
          fontWeight: FontWeight.w500,
        ),
      ),
    );
  }
}