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

/// Display units. `auto` follows the scooter's own imperial bit.
///
/// ASSUMPTION (INFERRED, ride verification pending): native protocol speed and
/// distance values are kilometres. Imperial display converts from km.
enum UnitPreference { auto, metric, imperial }

/// Dashboard layouts the rider can pick from.
enum ClusterLayout {
  arc('Arc', 'Speed inside a round gauge'),
  digital('Digital', 'Big number with a speed bar'),
  tiles('Tiles', 'Everything as cards');

  const ClusterLayout(this.label, this.description);
  final String label;
  final String description;
}

/// Accent colour presets. Blue is the OpenScooter default.
enum AccentColor {
  blue('Blue', Color(0xFF3D8BFF)),
  cyan('Cyan', Color(0xFF22C1D8)),
  green('Green', Color(0xFF34C77B)),
  lime('Lime', Color(0xFFB4E33D)),
  amber('Amber', Color(0xFFFFB020)),
  orange('Orange', Color(0xFFFF6B2C)),
  red('Red', Color(0xFFFF4D5E)),
  pink('Pink', Color(0xFFFF5CA8)),
  purple('Purple', Color(0xFF9B6CFF)),
  white('White', Color(0xFFF2F4F8));

  const AccentColor(this.label, this.color);
  final String label;
  final Color color;
}

/// App-wide user preferences, persisted with shared_preferences.
class AppSettings extends ChangeNotifier {
  AppSettings._();
  static final AppSettings instance = AppSettings._();

  static const _kAccent = 'accent';
  static const _kLayout = 'layout';
  static const _kUnits = 'units';

  SharedPreferences? _prefs;

  AccentColor _accent = AccentColor.blue;
  ClusterLayout _layout = ClusterLayout.arc;
  UnitPreference _units = UnitPreference.auto;

  AccentColor get accent => _accent;
  ClusterLayout get layout => _layout;
  UnitPreference get units => _units;

  Future<void> load() async {
    try {
      _prefs = await SharedPreferences.getInstance();
      _accent = _byName(AccentColor.values, _prefs!.getString(_kAccent)) ?? _accent;
      _layout = _byName(ClusterLayout.values, _prefs!.getString(_kLayout)) ?? _layout;
      _units = _byName(UnitPreference.values, _prefs!.getString(_kUnits)) ?? _units;
    } catch (_) {
      // Defaults are fine if preferences are unavailable.
    }
    notifyListeners();
  }

  set accent(AccentColor v) {
    _accent = v;
    _prefs?.setString(_kAccent, v.name);
    notifyListeners();
  }

  set layout(ClusterLayout v) {
    _layout = v;
    _prefs?.setString(_kLayout, v.name);
    notifyListeners();
  }

  set units(UnitPreference v) {
    _units = v;
    _prefs?.setString(_kUnits, v.name);
    notifyListeners();
  }

  static T? _byName<T extends Enum>(List<T> values, String? name) {
    if (name == null) return null;
    for (final v in values) {
      if (v.name == name) return v;
    }
    return null;
  }
}