import 'dart:convert';

import 'package:shared_preferences/shared_preferences.dart';

import '../../core/theme/accent_choice.dart';
import '../../core/theme/theme_preference.dart';
import '../models/slot_assignment.dart';
import '../models/slot_type.dart';

/// Persists launcher configuration. This is the single source of truth for
/// appearance, home-button visibility, the automatic night window, and pinned
/// apps as well as the three fixed slots.
class SettingsRepository {
  SettingsRepository(this._prefs);

  final SharedPreferences _prefs;

  static const _themeKey = 'settings.theme';
  static const _nightStartKey = 'settings.nightStartMinutes';
  static const _nightEndKey = 'settings.nightEndMinutes';
  static const _accentKey = 'settings.accent';
  static const _showBatteryKey = 'settings.showBattery';
  static const _slotPrefix = 'slot';
  static const _pinnedKey = 'home.pinned';
  static const _firstLaunchAtKey = 'onboarding.firstLaunchAt';
  static const _homeRoleHintShownKey = 'onboarding.homeRoleHintShown';
  static const _obdAddressKey = 'obd.adapterAddress';
  static const _weatherTemperatureKey = 'weather.locationTemperature';
  static const _keepScreenOnKey = 'display.keepScreenOn';
  static const _speedEnabledKey = 'carData.speedEnabled';
  static const _speedUseObdKey = 'carData.speedUseObd';
  static const _temperatureEnabledKey = 'carData.temperatureEnabled';
  static const _temperatureUseObdKey = 'carData.temperatureUseObd';

  ThemePreference get themePreference {
    return ThemePreference.fromStorage(_prefs.getString(_themeKey));
  }

  int get nightStartMinutes => _prefs.getInt(_nightStartKey) ?? 19 * 60;

  int get nightEndMinutes => _prefs.getInt(_nightEndKey) ?? 7 * 60;

  AccentChoice get accent {
    return AccentChoice.fromStorage(_prefs.getString(_accentKey));
  }

  bool get showBattery => _prefs.getBool(_showBatteryKey) ?? true;

  /// When CarDash first ran after this installation. Older installs are
  /// migrated to the epoch so onboarding copy cannot reappear after an update.
  DateTime? get firstLaunchAt {
    final millis = _prefs.getInt(_firstLaunchAtKey);
    return millis == null ? null : DateTime.fromMillisecondsSinceEpoch(millis);
  }

  /// Records the first launch once. Existing preferences mean this is an
  /// upgraded install, so the onboarding window is treated as already over.
  Future<DateTime> ensureFirstLaunchAt(DateTime now) async {
    final stored = firstLaunchAt;
    if (stored != null) return stored;
    final first = _prefs.getKeys().isEmpty
        ? now
        : DateTime.fromMillisecondsSinceEpoch(0);
    await _prefs.setInt(_firstLaunchAtKey, first.millisecondsSinceEpoch);
    return first;
  }

  /// Freezes the one-time migration default for temperature. Existing installs
  /// that configured OBD-II or location weather keep the feature; a fresh
  /// install starts off so it cannot fetch weather without an explicit choice.
  Future<void> ensureTelemetryDefaults() async {
    if (_prefs.containsKey(_temperatureEnabledKey)) return;
    final wasUsingCarData =
        (_prefs.getBool(_weatherTemperatureKey) ?? false) ||
        obdAdapterAddress != null;
    await _prefs.setBool(_temperatureEnabledKey, wasUsingCarData);
  }

  bool get homeRoleHintShown {
    return _prefs.getBool(_homeRoleHintShownKey) ?? false;
  }

  /// Whether the speed card may be shown on Home.
  bool get speedEnabled => _prefs.getBool(_speedEnabledKey) ?? true;

  /// OBD-II is preferred for speed when it is connected; GPS is the fallback.
  bool get speedUseObd => _prefs.getBool(_speedUseObdKey) ?? true;

  /// Fresh installs start with temperature off. [ensureTelemetryDefaults]
  /// preserves it for an upgrade that already had OBD or weather configured.
  bool get temperatureEnabled =>
      _prefs.getBool(_temperatureEnabledKey) ?? false;

  /// OBD-II ambient is preferred when available; weather is the fallback.
  bool get temperatureUseObd => _prefs.getBool(_temperatureUseObdKey) ?? true;

  String? get obdAdapterAddress {
    final value = _prefs.getString(_obdAddressKey)?.trim();
    return value == null || value.isEmpty ? null : value;
  }

  bool get weatherLocationTemperature {
    return _prefs.getBool(_weatherTemperatureKey) ?? false;
  }

  /// The dashboard keeps the display awake by default.
  bool get keepScreenOn {
    return _prefs.getBool(_keepScreenOnKey) ?? true;
  }

  Future<void> setThemePreference(ThemePreference preference) {
    return _prefs.setString(_themeKey, preference.storageValue);
  }

  Future<void> setAccent(AccentChoice accent) {
    return _prefs.setString(_accentKey, accent.storageValue);
  }

  Future<void> setShowBattery(bool show) {
    return _prefs.setBool(_showBatteryKey, show);
  }

  Future<void> setSpeedEnabled(bool enabled) {
    return _prefs.setBool(_speedEnabledKey, enabled);
  }

  Future<void> setSpeedUseObd(bool enabled) {
    return _prefs.setBool(_speedUseObdKey, enabled);
  }

  Future<void> setTemperatureEnabled(bool enabled) {
    return _prefs.setBool(_temperatureEnabledKey, enabled);
  }

  Future<void> setTemperatureUseObd(bool enabled) {
    return _prefs.setBool(_temperatureUseObdKey, enabled);
  }

  Future<void> setHomeRoleHintShown(bool shown) {
    return _prefs.setBool(_homeRoleHintShownKey, shown);
  }

  Future<void> setObdAdapterAddress(String? address) async {
    if (address == null || address.isEmpty) {
      await _prefs.remove(_obdAddressKey);
    } else {
      await _prefs.setString(_obdAddressKey, address);
    }
  }

  Future<void> setWeatherLocationTemperature(bool enabled) {
    return _prefs.setBool(_weatherTemperatureKey, enabled);
  }

  Future<void> setKeepScreenOn(bool enabled) {
    return _prefs.setBool(_keepScreenOnKey, enabled);
  }

  Future<void> setNightWindow({
    required int startMinutes,
    required int endMinutes,
  }) async {
    await _prefs.setInt(_nightStartKey, startMinutes);
    await _prefs.setInt(_nightEndKey, endMinutes);
  }

  bool slotEnabled(SlotType slot) {
    return _prefs.getBool('$_slotPrefix.${slot.key}.enabled') ?? true;
  }

  Future<void> setSlotEnabled(SlotType slot, bool enabled) {
    return _prefs.setBool('$_slotPrefix.${slot.key}.enabled', enabled);
  }

  SlotAssignment? slot(SlotType slot) {
    final packageName = _prefs.getString('$_slotPrefix.${slot.key}.package');
    final activityName = _prefs.getString('$_slotPrefix.${slot.key}.activity');
    final label = _prefs.getString('$_slotPrefix.${slot.key}.label');
    if (packageName == null || activityName == null) return null;
    return SlotAssignment(
      packageName: packageName,
      activityName: activityName,
      label: label ?? packageName,
    );
  }

  Future<void> setSlot(SlotType slot, SlotAssignment assignment) async {
    await _prefs.setString(
      '$_slotPrefix.${slot.key}.package',
      assignment.packageName,
    );
    await _prefs.setString(
      '$_slotPrefix.${slot.key}.activity',
      assignment.activityName,
    );
    await _prefs.setString('$_slotPrefix.${slot.key}.label', assignment.label);
  }

  Future<void> clearSlot(SlotType slot) async {
    await _prefs.remove('$_slotPrefix.${slot.key}.package');
    await _prefs.remove('$_slotPrefix.${slot.key}.activity');
    await _prefs.remove('$_slotPrefix.${slot.key}.label');
  }

  /// Apps explicitly pinned to the home screen via All Apps. The three
  /// predefined slots are stored separately.
  List<SlotAssignment> get pinnedApps {
    final raw = _prefs.getString(_pinnedKey);
    if (raw == null || raw.isEmpty) return const <SlotAssignment>[];
    try {
      final decoded = jsonDecode(raw);
      if (decoded is! List) return const <SlotAssignment>[];
      return decoded
          .whereType<Map>()
          .map((entry) => SlotAssignment.fromMap(entry))
          .where(
            (entry) =>
                entry.packageName.isNotEmpty && entry.activityName.isNotEmpty,
          )
          .toList(growable: false);
    } catch (_) {
      return const <SlotAssignment>[];
    }
  }

  Future<void> setPinnedApps(List<SlotAssignment> apps) {
    return _prefs.setString(
      _pinnedKey,
      jsonEncode(apps.map((app) => app.toMap()).toList(growable: false)),
    );
  }
}