import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import '../../../dji_service.dart';

import '../../../flight_model.dart';
import '../../../fly/state/aircraft_state.dart';
import '../../../fly/state/alert_state.dart';
import '../../../fly/state/battery_state.dart';
import '../../../fly/state/camera_state.dart';
import '../../../fly/state/vision_state.dart';
import '../../../theme.dart';
import '../../pv_icons.dart';

/// Debug screen for the telemetry foundation (plan P1): every field the bridge
/// now reports, grouped by sub-model, each section rebuilt only by its own
/// sub-model — the same listening pattern the P2 HUD uses — with the age of
/// its last update so a stalled source is obvious. The header starts and stops
/// the flight controller's simulator, where P1's fields are verified.
class TelemetryInspectorPage extends StatelessWidget {
  const TelemetryInspectorPage({super.key, required this.model, required this.dji});

  final FlightModel model;
  final DjiService dji;

  Future<void> _toggleSimulator(BuildContext context) async {
    final bool active = model.aircraft.simulatorActive == true;
    if (!active) {
      final bool? go = await showDialog<bool>(
        context: context,
        builder: (BuildContext context) => AlertDialog(
          title: const Text('Start the simulator?'),
          content: const Text('Remove the propellers first: the motors can spin while the simulator runs. '
              'The aircraft must be on the ground with motors off.'),
          actions: <Widget>[
            TextButton(onPressed: () => Navigator.of(context).pop(false), child: const Text('Cancel')),
            TextButton(onPressed: () => Navigator.of(context).pop(true), child: const Text('Propellers are off — start')),
          ],
        ),
      );
      if (go != true) return;
    }
    try {
      if (active) {
        await dji.stopSimulator();
      } else {
        // Start where the pilot is, so the map and home distance make sense.
        await dji.startSimulator(
          latitude: model.phoneLatitude ?? model.aircraft.latitude ?? 55.6761,
          longitude: model.phoneLongitude ?? model.aircraft.longitude ?? 12.5683,
        );
      }
    } catch (e) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(context)
        ..clearSnackBars()
        ..showSnackBar(SnackBar(content: Text('Simulator: ${e is PlatformException ? (e.message ?? e.code) : e}')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFF0A1120),
      body: SafeArea(
        child: Column(crossAxisAlignment: CrossAxisAlignment.stretch, children: <Widget>[
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 10, 10, 6),
            child: Row(children: <Widget>[
              const Expanded(
                child: Text('Telemetry inspector',
                    style: TextStyle(fontFamily: PV.fontSans, fontSize: 15, fontWeight: FontWeight.w700, color: Glass.ink)),
              ),
              ListenableBuilder(
                listenable: Listenable.merge(<Listenable>[model, model.aircraft]),
                builder: (BuildContext context, _) {
                  final bool active = model.aircraft.simulatorActive == true;
                  final bool canStart = model.connected && model.profile.hasSimulator && model.aircraft.motorsOn != true;
                  return TextButton.icon(
                    onPressed: active || canStart ? () => _toggleSimulator(context) : null,
                    icon: Icon(active ? Icons.stop_circle_outlined : Icons.play_circle_outline, size: 18),
                    label: Text(active ? 'Stop simulator' : 'Simulator'),
                    style: TextButton.styleFrom(foregroundColor: active ? const Color(0xFFD9852B) : Glass.sat),
                  );
                },
              ),
              IconButton(
                onPressed: () => Navigator.of(context).maybePop(),
                icon: const PVIcon('close', size: 17, color: Glass.ink),
              ),
            ]),
          ),
          Expanded(child: TelemetryInspector(model: model)),
        ]),
      ),
    );
  }
}

/// The inspector body, separate from the page so widget tests can pump it.
class TelemetryInspector extends StatefulWidget {
  const TelemetryInspector({super.key, required this.model});

  final FlightModel model;

  @override
  State<TelemetryInspector> createState() => _TelemetryInspectorState();
}

class _TelemetryInspectorState extends State<TelemetryInspector> {
  /// Ticks the "updated … ago" labels; sections otherwise rebuild on their own data.
  final ValueNotifier<DateTime> _clock = ValueNotifier<DateTime>(DateTime.now());
  Timer? _timer;

  @override
  void initState() {
    super.initState();
    _timer = Timer.periodic(const Duration(milliseconds: 500), (_) => _clock.value = DateTime.now());
  }

  @override
  void dispose() {
    _timer?.cancel();
    _clock.dispose();
    super.dispose();
  }

  FlightModel get _m => widget.model;

  @override
  Widget build(BuildContext context) {
    return ListView(padding: const EdgeInsets.fromLTRB(16, 0, 16, 24), children: <Widget>[
      _Section(
        title: 'Aircraft · 10 Hz',
        listenable: _m.aircraft,
        clock: _clock,
        updatedAt: () => _m.aircraft.updatedAt,
        rows: () => _aircraftRows(_m.aircraft),
      ),
      _Section(
        title: 'Return to home',
        listenable: _m.aircraft,
        clock: _clock,
        updatedAt: () => _m.aircraft.updatedAt,
        rows: () => _goHomeRows(_m.aircraft),
      ),
      _Section(
        title: 'Battery · 2 Hz',
        listenable: _m.battery,
        clock: _clock,
        updatedAt: () => _m.battery.updatedAt,
        rows: () => _batteryRows(_m.battery),
      ),
      _Section(
        title: 'Links · 2 Hz',
        listenable: _m.links,
        clock: _clock,
        updatedAt: () => _m.links.updatedAt,
        rows: () => <(String, String)>[
          ('Kind', _s(_m.links.kind)),
          ('Uplink (RC)', _q(_m.links.uplinkQuality)),
          ('Downlink (HD)', _q(_m.links.downlinkQuality)),
          ('RC battery', _m.links.rcBatteryPercent == null
              ? '—'
              : '${_m.links.rcBatteryPercent}% · ${_m.links.rcBatteryMah ?? '—'} mAh${_m.links.rcCharging == true ? ' · charging' : ''}'),
        ],
      ),
      _Section(
        title: 'Camera · 2 Hz',
        listenable: _m.camera,
        clock: _clock,
        updatedAt: () => _m.camera.updatedAt,
        rows: () => _cameraRows(_m.camera),
      ),
      _Section(
        title: 'Gimbal · 10 Hz',
        listenable: _m.gimbal,
        clock: _clock,
        updatedAt: () => _m.gimbal.updatedAt,
        rows: () => <(String, String)>[
          ('Pitch / roll / yaw', '${_deg(_m.gimbal.pitch)} / ${_deg(_m.gimbal.roll)} / ${_deg(_m.gimbal.yaw)}'),
        ],
      ),
      _Section(
        title: 'Vision · 10 Hz',
        listenable: _m.vision,
        clock: _clock,
        updatedAt: () => _m.vision.updatedAt,
        rows: () => _visionRows(_m.vision),
      ),
      _Section(
        title: 'Diagnostics',
        listenable: _m.alerts,
        clock: _clock,
        updatedAt: () => _m.alerts.updatedAt,
        rows: () => _alertRows(_m.alerts),
      ),
    ]);
  }

  static List<(String, String)> _aircraftRows(AircraftState a) => <(String, String)>[
        ('Flight mode', '${_s(a.flightMode)}  (${_s(a.flightModeEnum)})'),
        ('Flying / motors', '${_b(a.isFlying)} / ${_b(a.motorsOn)}'),
        ('GPS', '${a.satellites ?? '—'} sats · level ${a.gpsSignalLevel ?? '—'}'),
        ('Attitude p/r/y', '${_deg(a.pitch)} / ${_deg(a.roll)} / ${_deg(a.heading)}'),
        ('Height', _m1(a.altitude)),
        ('VPS', a.vpsHeight == null
            ? 'not in use${a.ultrasonicError == true ? ' · ERROR' : ''}'
            : '${_m1(a.vpsHeight)}${a.ultrasonicError == true ? ' · ERROR' : ''}'),
        ('Vision positioning', _b(a.visionPositioningBeingUsed)),
        ('H / V speed', '${_ms(a.horizontalSpeed)} / ${_ms(a.verticalSpeed)}'),
        ('Position', a.latitude == null ? '—' : '${a.latitude!.toStringAsFixed(6)}, ${a.longitude!.toStringAsFixed(6)}'),
        ('Home', a.homeLatitude == null ? 'not set' : '${_m1(a.homeDistance)} away'),
        ('Flight time', _mmss(a.flightTimeSeconds)),
        ('Landing confirm', _b(a.landingConfirmationNeeded)),
        ('Low / serious low', '${_b(a.lowBattery)} / ${_b(a.seriousLowBattery)} · ${_s(a.batteryThresholdBehavior)}'),
        ('Wind', _s(a.windWarning)),
        ('Max height / radius hit', '${_b(a.reachedMaxHeight)} / ${_b(a.reachedMaxRadius)}'),
        ('IMU preheating', _b(a.imuPreheating)),
        ('Orientation', _s(a.orientationMode)),
        ('Simulator', _b(a.simulatorActive)),
      ];

  static List<(String, String)> _goHomeRows(AircraftState a) {
    final GoHomeAssessment? g = a.goHome;
    return <(String, String)>[
      ('Going home', '${_b(a.goingHome)} · ${_s(a.goHomeExecutionState)}'),
      ('RTH height', _m1(a.goHomeHeight)),
      ('Remaining flight', _mmss(g?.remainingFlightTime)),
      ('Needed to go home', g == null ? '—' : '${g.batteryNeededToGoHome ?? '—'}% · ${_mmss(g.timeNeededToGoHome)}'),
      ('Needed to land', g == null ? '—' : '${g.batteryNeededToLand ?? '—'}% · ${_mmss(g.timeNeededToLand)}'),
      ('Max radius & return', _m1(g?.maxRadiusCanFlyAndGoHome)),
      ('Smart RTH', g == null ? '—' : '${_s(g.smartRTHState)} · ${g.smartRTHCountdown ?? '—'} s'),
    ];
  }

  static List<(String, String)> _batteryRows(BatteryState b) => <(String, String)>[
        ('Weakest pack', b.percent == null ? '—' : '${b.percent}% · ${_v(b.voltage)} · ${_c(b.temperature)}'),
        ('Thresholds', 'low ${b.lowWarningThreshold ?? '—'}% · serious ${b.seriousLowWarningThreshold ?? '—'}%'),
        for (final BatteryPack p in b.packs) ...<(String, String)>[
          ('Pack ${p.index}', '${p.percent ?? '—'}% · ${_v(p.voltage)} · ${p.current?.toStringAsFixed(2) ?? '—'} A · ${_c(p.temperature)}'),
          ('  charge', '${p.chargeRemainingMah ?? '—'} / ${p.fullChargeCapacityMah ?? '—'} mAh (design ${p.designCapacityMah ?? '—'})'),
          ('  cells', p.cellVoltages.isEmpty
              ? '—'
              : '${p.cellVoltages.map((double v) => v.toStringAsFixed(2)).join(' ')} V · Δ ${(p.cellDeviation! * 1000).round()} mV'),
          ('  health', '${p.discharges ?? '—'} cycles · life ${p.lifetimePercent ?? '—'}% · ${_s(p.connectionState)}'),
        ],
      ];

  static List<(String, String)> _cameraRows(CameraState c) {
    final StorageInfo? s = c.storage;
    return <(String, String)>[
      ('Mode', '${_s(c.mode)}${c.isRecording ? ' · REC ${_mmss(c.recordSeconds)}' : ''}'),
      ('Exposure', 'ISO ${_s(c.iso)} · ${_s(c.shutter)} · ${_s(c.aperture)} · EV ${_s(c.ev)}'),
      ('Storage', s == null ? '—' : '${s.status} · ${_s(s.location)}'),
      ('Space', s == null ? '—' : '${s.remainingMB ?? '—'} / ${s.totalMB ?? '—'} MB'),
      ('Remaining', s == null ? '—' : '${s.availableCaptureCount ?? '—'} shots · ${_mmss(s.availableRecordingSeconds)}'),
      ('AE lock / focus', '${_b(c.aeLock)} / ${_s(c.focusMode)}'),
      ('Photo', '${_s(c.photoAspectRatio)} · ${_s(c.photoFileFormat)}'),
      ('Video', '${_s(c.videoResolution)} · ${_s(c.videoFrameRate)} · ${_s(c.videoFileFormat)}'),
      ('Colour', _s(c.colorProfile)),
    ];
  }

  static List<(String, String)> _visionRows(VisionState v) {
    if (v.sensors.isEmpty) return const <(String, String)>[('Sensors', 'none reporting')];
    return <(String, String)>[
      ('Closest', _m1(v.closest)),
      for (final VisionReading r in v.sensors.values)
        (
          r.position,
          '${r.isSensorBeingUsed ? 'active' : 'idle'}${r.isDisabled ? ' · disabled' : ''} · ${_s(r.systemWarning)} · '
              '${_m1(r.distance)} · [${r.sectors.map((VisionSector s) => s.distance?.toStringAsFixed(1) ?? '·').join(' ')}]'
        ),
    ];
  }

  static List<(String, String)> _alertRows(AlertState a) {
    if (a.all.isEmpty) return const <(String, String)>[('Active', 'none')];
    return <(String, String)>[
      for (final DiagnosticAlert d in a.all) ('${d.severity.name} · ${d.component} ${d.code}', '${d.reason}${d.solution == null ? '' : ' — ${d.solution}'}'),
    ];
  }

  static String _s(String? v) => v ?? '—';
  static String _b(bool? v) => v == null ? '—' : (v ? 'yes' : 'no');
  static String _q(int? v) => v == null ? '—' : '$v / 100';
  static String _deg(double? v) => v == null ? '—' : '${v.toStringAsFixed(1)}°';
  static String _m1(double? v) => v == null ? '—' : '${v.toStringAsFixed(1)} m';
  static String _ms(double? v) => v == null ? '—' : '${v.toStringAsFixed(1)} m/s';
  static String _v(double? v) => v == null ? '—' : '${v.toStringAsFixed(2)} V';
  static String _c(double? v) => v == null ? '—' : '${v.toStringAsFixed(1)} °C';
  static String _mmss(int? s) => s == null || s < 0 ? '—' : '${s ~/ 60}:${(s % 60).toString().padLeft(2, '0')}';
}

class _Section extends StatelessWidget {
  const _Section({
    required this.title,
    required this.listenable,
    required this.clock,
    required this.updatedAt,
    required this.rows,
  });

  final String title;
  final Listenable listenable;
  final ValueNotifier<DateTime> clock;
  final DateTime? Function() updatedAt;
  final List<(String, String)> Function() rows;

  static const TextStyle _label = TextStyle(fontFamily: PV.fontSans, fontSize: 12, color: Glass.ink);
  static const TextStyle _value = TextStyle(fontFamily: PV.fontMono, fontSize: 11, color: Color(0xCCEAF0FA));
  static const TextStyle _eyebrow =
      TextStyle(fontFamily: PV.fontMono, fontSize: 10, letterSpacing: 1.4, color: Color(0x8CEAF0FA));

  @override
  Widget build(BuildContext context) {
    return Column(crossAxisAlignment: CrossAxisAlignment.stretch, children: <Widget>[
      Padding(
        padding: const EdgeInsets.only(top: 18, bottom: 6),
        child: Row(children: <Widget>[
          Expanded(child: Text(title.toUpperCase(), style: _eyebrow)),
          ListenableBuilder(
            listenable: Listenable.merge(<Listenable>[listenable, clock]),
            builder: (BuildContext context, _) {
              final DateTime? at = updatedAt();
              final int? ms = at == null ? null : clock.value.difference(at).inMilliseconds;
              final bool stale = ms == null || ms > 3000;
              return Text(
                ms == null ? 'no data' : (ms < 1000 ? 'live' : '${(ms / 1000).toStringAsFixed(0)} s ago'),
                style: _eyebrow.copyWith(color: stale ? const Color(0xFFD9852B) : Glass.sat),
              );
            },
          ),
        ]),
      ),
      ListenableBuilder(
        listenable: listenable,
        builder: (BuildContext context, _) => Column(children: <Widget>[
          for (final (String, String) r in rows())
            Container(
              padding: const EdgeInsets.symmetric(vertical: 5),
              decoration: const BoxDecoration(border: Border(bottom: BorderSide(color: Color(0x12FFFFFF)))),
              child: Row(crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[
                SizedBox(width: 150, child: Text(r.$1, style: _label)),
                Expanded(child: Text(r.$2, style: _value)),
              ]),
            ),
        ]),
      ),
    ]);
  }
}