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

import '../dji_service.dart';
import '../flight_model.dart';
import '../theme.dart';
import 'flight_overlay_scaffold.dart';
import 'pv_icons.dart';

/// Pro exposure controls — mirrors the v2 "Camera settings" mockup. Auto/Pro
/// tabs switch exposure program; the five dials (ISO / shutter / aperture / EV /
/// WB) each drive the matching SDK setter, and the value scrubber picks a value.
class CameraSettingsPage extends StatefulWidget {
  const CameraSettingsPage({super.key, required this.model, required this.dji});

  final FlightModel model;
  final DjiService dji;

  @override
  State<CameraSettingsPage> createState() => _CameraSettingsPageState();
}

class _CameraSettingsPageState extends State<CameraSettingsPage> {
  DjiService get _dji => widget.dji;
  FlightModel get _m => widget.model;

  // (key, icon, values). Values mirror the kit scrubber; the SDK rejects any it
  // doesn't support (surfaced as a snackbar), so a superset is safe.
  static const List<(String, String, List<String>)> _dials = <(String, String, List<String>)>[
    ('ISO', 'iso', <String>['AUTO', '100', '200', '400', '800', '1600', '3200', '6400']),
    ('Shutter', 'shutter', <String>['1/2000', '1/1000', '1/500', '1/240', '1/120', '1/60', '1/30', '1/15', '1/8']),
    ('Aperture', 'aperture', <String>['f/2.8', 'f/4', 'f/5.6', 'f/8', 'f/11']),
    ('EV', 'ev', <String>['-2.0', '-1.3', '-0.7', '-0.3', '0.0', '+0.3', '+0.7', '+1.3', '+2.0']),
    ('WB', 'wb', <String>['AUTO', '2700K', '4000K', '5200K', '5800K', '6500K']),
  ];

  int _active = 0; // selected dial

  bool get _pro => _m.exposureProgram == ExposureProgram.pro;

  void _snack(String msg) {
    ScaffoldMessenger.of(context)
      ..clearSnackBars()
      ..showSnackBar(SnackBar(content: Text(msg)));
  }

  Future<void> _run(String label, Future<void> Function() action) async {
    try {
      await action();
    } catch (e) {
      _snack('$label: ${e is PlatformException ? (e.message ?? e.code) : e}');
    }
  }

  String? _valueFor(String key) => switch (key) {
        'ISO' => _m.iso,
        'Shutter' => _m.shutter,
        'Aperture' => _m.aperture,
        'EV' => _m.ev,
        'WB' => _m.whiteBalance,
        _ => null,
      };

  Future<void> _setValue(String key, String value) async {
    setState(() {
      switch (key) {
        case 'ISO':
          _m.iso = value;
        case 'Shutter':
          _m.shutter = value;
        case 'Aperture':
          _m.aperture = value;
        case 'EV':
          _m.ev = value;
        case 'WB':
          _m.whiteBalance = value;
      }
    });
    switch (key) {
      case 'ISO':
        await _run('ISO', () => _dji.setISO(value));
      case 'Shutter':
        await _run('Shutter', () => _dji.setShutterSpeed(value));
      case 'Aperture':
        await _run('Aperture', () => _dji.setAperture(value));
      case 'EV':
        await _run('EV', () => _dji.setEV(value));
      case 'WB':
        await _run('White balance', () => _dji.setWhiteBalance(value));
    }
  }

  Future<void> _setProgram(bool pro) async {
    setState(() => _m.exposureProgram = pro ? ExposureProgram.pro : ExposureProgram.auto);
    await _run('Exposure', () => _dji.setExposureProgram(pro ? 'pro' : 'auto'));
  }

  @override
  Widget build(BuildContext context) {
    return FlightOverlayScaffold(
      title: 'Camera settings',
      trailing: _autoProTabs(),
      body: Column(
        children: <Widget>[
          Align(
            alignment: Alignment.centerRight,
            child: Container(
              width: 132, height: 48,
              padding: const EdgeInsets.all(6),
              decoration: BoxDecoration(color: Glass.pill, borderRadius: BorderRadius.circular(10)),
              child: const CustomPaint(size: Size.infinite, painter: _HistogramPainter()),
            ),
          ),
          const Spacer(),
          _dialRail(),
        ],
      ),
    );
  }

  Widget _autoProTabs() {
    return Container(
      padding: const EdgeInsets.all(3),
      decoration: BoxDecoration(color: Glass.pill, borderRadius: BorderRadius.circular(10)),
      child: Row(mainAxisSize: MainAxisSize.min, children: <Widget>[
        _tab('Auto', !_pro, () => _setProgram(false)),
        _tab('Pro', _pro, () => _setProgram(true)),
      ]),
    );
  }

  Widget _tab(String label, bool active, VoidCallback onTap) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        height: 28,
        padding: const EdgeInsets.symmetric(horizontal: 16),
        decoration: BoxDecoration(color: active ? Glass.accent : Colors.transparent, borderRadius: BorderRadius.circular(7)),
        alignment: Alignment.center,
        child: Text(label, style: const TextStyle(fontFamily: PV.fontSans, fontSize: 12, fontWeight: FontWeight.w700, color: Glass.ink)),
      ),
    );
  }

  Widget _dialRail() {
    final (String key, _, List<String> values) = _dials[_active];
    final String? current = _valueFor(key);
    return Container(
      padding: const EdgeInsets.fromLTRB(8, 12, 8, 12),
      decoration: BoxDecoration(
        color: Glass.pill,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: const Color(0x1AFFFFFF)),
      ),
      child: Column(children: <Widget>[
        Row(mainAxisAlignment: MainAxisAlignment.spaceAround, children: <Widget>[
          for (int i = 0; i < _dials.length; i++) _dial(i),
        ]),
        const SizedBox(height: 12),
        Opacity(
          opacity: _pro ? 1 : 0.4,
          child: IgnorePointer(
            ignoring: !_pro,
            child: SizedBox(
              height: 30,
              child: ListView(
                scrollDirection: Axis.horizontal,
                children: <Widget>[
                  for (final String v in values) _scrubValue(key, v, v == current),
                ],
              ),
            ),
          ),
        ),
      ]),
    );
  }

  Widget _dial(int i) {
    final (String key, String icon, _) = _dials[i];
    final bool sel = i == _active;
    final String value = _valueFor(key) ?? '—';
    return GestureDetector(
      onTap: () => setState(() => _active = i),
      child: Column(mainAxisSize: MainAxisSize.min, children: <Widget>[
        PVIcon(icon, size: 17, color: sel ? const Color(0xFF8FB4F6) : const Color(0xFF8FA0BE)),
        const SizedBox(height: 4),
        Text(key, style: const TextStyle(fontFamily: PV.fontMono, fontSize: 9.5, letterSpacing: 0.8, color: Color(0x99EAF0FA))),
        Text(value, style: TextStyle(fontFamily: PV.fontMono, fontSize: 15, fontWeight: FontWeight.w700, color: sel ? const Color(0xFF8FB4F6) : Glass.ink)),
      ]),
    );
  }

  Widget _scrubValue(String key, String v, bool sel) {
    return GestureDetector(
      onTap: () => _setValue(key, v),
      child: Container(
        alignment: Alignment.center,
        padding: const EdgeInsets.symmetric(horizontal: 12),
        child: Text(v,
            style: TextStyle(
              fontFamily: PV.fontMono,
              fontSize: sel ? 14 : 12,
              fontWeight: sel ? FontWeight.w700 : FontWeight.w400,
              color: sel ? const Color(0xFF5B93F5) : const Color(0x99EAF0FA),
            )),
      ),
    );
  }
}

class _HistogramPainter extends CustomPainter {
  const _HistogramPainter();
  @override
  void paint(Canvas canvas, Size size) {
    final Path p = Path()
      ..moveTo(0, size.height)
      ..quadraticBezierTo(size.width * 0.2, size.height * 0.2, size.width * 0.4, size.height * 0.6)
      ..quadraticBezierTo(size.width * 0.6, size.height * 0.05, size.width * 0.8, size.height * 0.5)
      ..quadraticBezierTo(size.width * 0.9, size.height * 0.8, size.width, size.height * 0.9);
    canvas.drawPath(
      Path.from(p)
        ..lineTo(size.width, size.height)
        ..lineTo(0, size.height)
        ..close(),
      Paint()..color = const Color(0x407FE0B0),
    );
    canvas.drawPath(p, Paint()
      ..color = const Color(0xFF7FE0B0)
      ..style = PaintingStyle.stroke
      ..strokeWidth = 1.4);
  }

  @override
  bool shouldRepaint(covariant _HistogramPainter oldDelegate) => false;
}