import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:sensors_plus/sensors_plus.dart';
import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:my_app/appeditor/custom/AppEditorWidgetContext.dart';

// Includes an optional horizontal magnetic compass for Android/iOS.
Widget buildCustomWidget(BuildContext context, AppEditorWidgetContext app) {
  return app.params['sensor'] == true
      ? MagneticCompass(app: app)
      : CompassWidget(app: app);
}

class CompassWidget extends StatefulWidget {
  const CompassWidget({super.key, required this.app});
  final AppEditorWidgetContext app;
  @override
  State<CompassWidget> createState() => _CompassWidgetState();
}

class _CompassWidgetState extends State<CompassWidget> {
  late String _variable;
  late Stream<dynamic> _headings;

  void _bind() {
    _variable =
        widget.app.params['headingVariable'] as String? ?? 'compass_heading';
    _headings = widget.app.watchVar(_variable);
  }

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

  @override
  void didUpdateWidget(covariant CompassWidget oldWidget) {
    super.didUpdateWidget(oldWidget);
    final name =
        widget.app.params['headingVariable'] as String? ?? 'compass_heading';
    if (name != _variable || !identical(widget.app, oldWidget.app)) _bind();
  }

  double _number(dynamic value, double fallback) {
    final result = value is num ? value.toDouble() : double.tryParse('$value');
    return result != null && result.isFinite ? result : fallback;
  }

  Future<void> _publish(double value, {bool notify = false}) async {
    try {
      await widget.app.addVar(name: _variable, value: value, overwrite: true);
      if (notify && mounted && widget.app.hasAction('onHeadingChanged')) {
        await widget.app.runAction('onHeadingChanged');
      }
    } catch (error) {
      widget.app.showMessage('تغییر جهت ممکن نشد: $error');
    }
  }

  @override
  Widget build(BuildContext context) {
    final args = widget.app.params;
    final manual = args['manual'] != false;
    return StreamBuilder<dynamic>(
      stream: _headings,
      builder: (context, snapshot) {
        final initial = _number(args['initialHeading'], 0);
        final heading = _number(snapshot.data, initial) % 360;
        return Card(
          child: Padding(
            padding: const EdgeInsets.all(16),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(
                  args['title'] as String? ?? 'قطب‌نما',
                  style: Theme.of(context).textTheme.titleLarge,
                ),
                const SizedBox(height: 12),
                Text(
                  manual
                      ? 'حالت دستی — داده سنسور خوانده نمی‌شود'
                      : 'جهت از متغیر اپ',
                ),
                const SizedBox(height: 12),
                SizedBox.square(
                  dimension: 210,
                  child: Stack(
                    alignment: Alignment.center,
                    children: [
                      Container(
                        decoration: BoxDecoration(
                          shape: BoxShape.circle,
                          border: Border.all(
                            color: Theme.of(context).colorScheme.outline,
                          ),
                        ),
                      ),
                      const Positioned(top: 8, child: Text('N · شمال')),
                      const Positioned(bottom: 8, child: Text('S · جنوب')),
                      const Positioned(right: 8, child: Text('E')),
                      const Positioned(left: 8, child: Text('W')),
                      Transform.rotate(
                        // If the device points east, north is to its left.
                        angle: -heading * math.pi / 180,
                        child: const Icon(
                          Icons.navigation,
                          size: 100,
                          color: Colors.red,
                        ),
                      ),
                    ],
                  ),
                ),
                const SizedBox(height: 12),
                Text(
                  '${heading.toStringAsFixed(1)}°',
                  textDirection: TextDirection.ltr,
                ),
                if (!snapshot.hasData && !manual)
                  const Text(
                    'هنوز داده‌ای دریافت نشده؛ مقدار اولیه نمایش داده می‌شود.',
                  ),
                if (manual)
                  Directionality(
                    textDirection: TextDirection.ltr,
                    child: Slider(
                      min: 0,
                      max: 359,
                      value: heading.clamp(0, 359),
                      onChanged: (value) => _publish(value),
                      onChangeEnd: (value) => _publish(value, notify: true),
                    ),
                  ),
              ],
            ),
          ),
        );
      },
    );
  }
}


/// Magnetic north for a portrait phone held flat, screen facing upward.
/// No tilt compensation or geographic declination correction is applied.
class MagneticCompass extends StatefulWidget {
  const MagneticCompass({super.key, required this.app});
  final AppEditorWidgetContext app;
  @override
  State<MagneticCompass> createState() => _MagneticCompassState();
}

class _MagneticCompassState extends State<MagneticCompass>
    with WidgetsBindingObserver {
  StreamSubscription<MagnetometerEvent>? _subscription;
  Timer? _timeout;
  double? _heading;
  String _status = 'در انتظار دادهٔ مغناطیسی';
  int _epoch = 0;
  bool _visible = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) _sync();
    });
  }

  @override
  void didUpdateWidget(covariant MagneticCompass oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (!identical(oldWidget.app, widget.app)) {
      _stop();
      _heading = null;
      _sync();
    }
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) => _sync();

  void _stop() {
    _epoch++;
    _timeout?.cancel();
    _timeout = null;
    final subscription = _subscription;
    _subscription = null;
    if (subscription != null) unawaited(subscription.cancel());
  }

  void _sync() {
    if (!mounted) return;
    final lifecycle = WidgetsBinding.instance.lifecycleState;
    if (!_visible || !widget.app.mounted ||
        (lifecycle != null && lifecycle != AppLifecycleState.resumed)) {
      _stop();
      setState(() => _status = 'دریافت متوقف است');
      return;
    }
    if (_subscription != null) return;
    if (kIsWeb || (defaultTargetPlatform != TargetPlatform.android &&
        defaultTargetPlatform != TargetPlatform.iOS)) {
      setState(() => _status = 'قطب‌نمای مغناطیسی این نمونه فقط روی Android/iOS اجرا می‌شود');
      return;
    }
    final epoch = ++_epoch;
    setState(() {
      _heading = null;
      _status = 'در انتظار دادهٔ مغناطیسی';
    });
    void fail() {
      if (!mounted || epoch != _epoch) return;
      _stop();
      setState(() {
        _heading = null;
        _status = 'سنسور مغناطیسی در دسترس نیست؛ دریافت را دوباره شروع کنید';
      });
    }
    _timeout = Timer(const Duration(seconds: 5), fail);
    try {
      _subscription = magnetometerEventStream(
        samplingPeriod: const Duration(milliseconds: 200),
      ).listen((event) {
        if (!mounted || epoch != _epoch) return;
        if (!event.x.isFinite || !event.y.isFinite ||
            event.x * event.x + event.y * event.y < 0.01) return;
        _timeout?.cancel();
        final offset = (widget.app.params['headingOffset'] as num?)?.toDouble() ?? 0;
        final angle = (math.atan2(-event.x, event.y) * 180 / math.pi + offset) % 360;
        if (!angle.isFinite) return;
        setState(() {
          _heading = angle;
          _status = 'شمال مغناطیسی؛ گوشی افقی و بالای آن رو به جلو';
        });
      }, onError: (Object error) => fail(), onDone: fail, cancelOnError: true);
    } catch (_) {
      fail();
    }
  }

  @override
  void dispose() {
    _stop();
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // TickerMode is disabled by Flutter when this route is covered.
    final visible = TickerMode.of(context);
    if (visible != _visible) {
      _visible = visible;
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (mounted) _sync();
      });
    }
    return Card(child: Padding(
      padding: const EdgeInsets.all(16),
      child: Column(mainAxisSize: MainAxisSize.min, children: [
        Text(widget.app.params['title'] as String? ?? 'قطب‌نمای مغناطیسی',
            style: Theme.of(context).textTheme.titleLarge),
        const SizedBox(height: 12),
        Text(_status, textAlign: TextAlign.center),
        const SizedBox(height: 16),
        if (_heading != null) ...[
          SizedBox.square(dimension: 210, child: Stack(
            alignment: Alignment.center, children: [
              const Positioned(top: 0, child: Text('N · شمال')),
              const Positioned(bottom: 0, child: Text('S · جنوب')),
              const Positioned(right: 0, child: Text('E')),
              const Positioned(left: 0, child: Text('W')),
              Transform.rotate(angle: -_heading! * math.pi / 180,
                  child: const Icon(Icons.navigation, size: 100, color: Colors.red)),
            ],
          )),
          Text('${_heading!.toStringAsFixed(1)}°', textDirection: TextDirection.ltr),
        ],
        TextButton(onPressed: () { _stop(); _sync(); },
            child: const Text('شروع مجدد دریافت')),
      ]),
    ));
  }
}