import 'package:flutter/material.dart';

import '../../../../dji_service.dart';
import '../../../../fly/sensing_distances.dart';
import '../../hud_kit.dart';
import '../camera_menu/camera_rows.dart';

/// Settings → Vision → obstacle distances (plan P8): where the aircraft brakes
/// and how far it looks, per direction the aircraft reports. Read once when the
/// tab opens; a step writes at once and rolls back if the aircraft refuses.
class SensingDistanceRows extends StatefulWidget {
  const SensingDistanceRows({super.key, required this.dji, required this.connected, required this.onError});

  final DjiService dji;
  final bool connected;
  final void Function(String label, Object error) onError;

  @override
  State<SensingDistanceRows> createState() => _SensingDistanceRowsState();
}

class _SensingDistanceRowsState extends State<SensingDistanceRows> {
  SensingDistances? _d;
  bool _loading = false;
  final Set<(SensingKind, SensingDirection)> _pending = <(SensingKind, SensingDirection)>{};

  @override
  void initState() {
    super.initState();
    _load();
  }

  @override
  void didUpdateWidget(SensingDistanceRows old) {
    super.didUpdateWidget(old);
    if (widget.connected && !old.connected) _load();
  }

  Future<void> _load() async {
    if (!widget.connected || _loading) return;
    _loading = true;
    try {
      final SensingDistances d = SensingDistances.fromBridge(await widget.dji.getSensingDistances());
      if (mounted) setState(() => _d = d);
    } catch (_) {
      if (mounted) setState(() => _d = const SensingDistances());
    } finally {
      _loading = false;
    }
  }

  Future<void> _step(SensingKind k, SensingDirection dir, int steps) async {
    final SensingDistances? before = _d;
    final double? v = before?.value(k, dir);
    if (before == null || v == null) return;
    final double next = SensingDistances.stepped(k, dir, v, steps);
    if (next == v) return;
    setState(() {
      _d = before.withValue(k, dir, next);
      _pending.add((k, dir));
    });
    try {
      await (k == SensingKind.avoidance
          ? widget.dji.setAvoidanceDistance(dir.sdk, next)
          : widget.dji.setMaxPerceptionDistance(dir.sdk, next));
    } catch (e) {
      if (mounted) setState(() => _d = before);
      widget.onError(k == SensingKind.avoidance ? 'Braking distance' : 'Sensing range', e);
    } finally {
      if (mounted) setState(() => _pending.remove((k, dir)));
    }
  }

  @override
  Widget build(BuildContext context) {
    final SensingDistances? d = _d;
    // Nothing reported (or not connected): the rows stay out of the way.
    if (d == null || d.isEmpty) return const SizedBox.shrink();
    Widget row(SensingKind k, SensingDirection dir) {
      final double? v = d.value(k, dir);
      if (v == null) return const SizedBox.shrink();
      final ({double min, double max, double step}) r = SensingDistances.range(k, dir);
      final String what = k == SensingKind.avoidance ? 'braking distance' : 'sensing range';
      return StepperTile(
        key: ValueKey<String>('row-sensing-${k.name}-${dir.name}'),
        id: 'sensing-${k.name}-${dir.name}',
        label: '${dir.label} $what',
        hint: k == SensingKind.avoidance ? 'The aircraft brakes this far from an obstacle' : 'Obstacles closer than this are reported',
        shown: '${v.toStringAsFixed(r.step < 1 ? 1 : 0)} m',
        canDown: v > r.min,
        canUp: v < r.max,
        pending: _pending.contains((k, dir)),
        onStep: (int s) => _step(k, dir, s),
      );
    }

    return Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.stretch, children: <Widget>[
      Padding(
        padding: const EdgeInsets.fromLTRB(16, 10, 16, 2),
        child: Text('OBSTACLE DISTANCES', style: HudText.label),
      ),
      for (final SensingKind k in SensingKind.values)
        for (final SensingDirection dir in SensingDirection.values) row(k, dir),
    ]);
  }
}