import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../../../core/api/api_client.dart';
import '../../../../core/constants.dart';
import '../../../../core/database/app_database.dart';

/// ThemeMode provider, watched by PrivacyMapsApp.
final themeModeProvider =
    StateNotifierProvider<ThemeModeNotifier, ThemeMode>((ref) {
  return ThemeModeNotifier(ref.watch(appDatabaseProvider));
});

class ThemeModeNotifier extends StateNotifier<ThemeMode> {
  final AppDatabase _db;

  ThemeModeNotifier(this._db) : super(ThemeMode.system) {
    _load();
  }

  Future<void> _load() async {
    final value = await _db.getSetting(AppConstants.settingThemeMode);
    if (value != null && mounted) {
      state = _parse(value);
    }
  }

  Future<void> setThemeMode(ThemeMode mode) async {
    state = mode;
    await _db.setSetting(AppConstants.settingThemeMode, mode.name);
  }

  ThemeMode _parse(String value) {
    switch (value) {
      case 'light':
        return ThemeMode.light;
      case 'dark':
        return ThemeMode.dark;
      default:
        return ThemeMode.system;
    }
  }
}

class SettingsScreen extends ConsumerStatefulWidget {
  const SettingsScreen({super.key});

  @override
  ConsumerState<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends ConsumerState<SettingsScreen> {
  late final TextEditingController _backendUrlController;
  bool _urlSaved = false;

  @override
  void initState() {
    super.initState();
    _backendUrlController = TextEditingController();
    _loadBackendUrl();
  }

  Future<void> _loadBackendUrl() async {
    final db = ref.read(appDatabaseProvider);
    final url = await db.getSetting(AppConstants.settingBackendUrl);
    _backendUrlController.text = url ?? AppConstants.defaultBackendUrl;
  }

  @override
  void dispose() {
    _backendUrlController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final themeMode = ref.watch(themeModeProvider);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Settings'),
      ),
      body: ListView(
        children: [
          // Backend URL
          Padding(
            padding: const EdgeInsets.all(16),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  'Backend Server',
                  style: Theme.of(context).textTheme.titleSmall,
                ),
                const SizedBox(height: 8),
                TextField(
                  controller: _backendUrlController,
                  decoration: InputDecoration(
                    labelText: 'Server URL',
                    hintText: AppConstants.defaultBackendUrl,
                    suffixIcon: _urlSaved
                        ? const Icon(Icons.check, color: Colors.green)
                        : null,
                  ),
                  keyboardType: TextInputType.url,
                  onChanged: (_) {
                    if (_urlSaved) setState(() => _urlSaved = false);
                  },
                ),
                const SizedBox(height: 8),
                FilledButton(
                  onPressed: _saveBackendUrl,
                  child: const Text('Save'),
                ),
              ],
            ),
          ),
          const Divider(),

          // Theme
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            child: Text(
              'Appearance',
              style: Theme.of(context).textTheme.titleSmall,
            ),
          ),
          RadioListTile<ThemeMode>(
            title: const Text('System default'),
            value: ThemeMode.system,
            groupValue: themeMode,
            onChanged: (v) =>
                ref.read(themeModeProvider.notifier).setThemeMode(v!),
          ),
          RadioListTile<ThemeMode>(
            title: const Text('Day (light)'),
            value: ThemeMode.light,
            groupValue: themeMode,
            onChanged: (v) =>
                ref.read(themeModeProvider.notifier).setThemeMode(v!),
          ),
          RadioListTile<ThemeMode>(
            title: const Text('Night (dark)'),
            value: ThemeMode.dark,
            groupValue: themeMode,
            onChanged: (v) =>
                ref.read(themeModeProvider.notifier).setThemeMode(v!),
          ),
          const Divider(),

          // About
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            child: Text(
              'About',
              style: Theme.of(context).textTheme.titleSmall,
            ),
          ),
          const ListTile(
            leading: Icon(Icons.info_outline),
            title: Text('Privacy Maps'),
            subtitle: Text('Version 1.0.0'),
          ),
          const Padding(
            padding: EdgeInsets.symmetric(horizontal: 16),
            child: Text(
              'A privacy-first maps application. No tracking, no analytics, '
              'no third-party SDKs. All data stays on your device or your '
              'own server.',
            ),
          ),
          const SizedBox(height: 16),

          // Attributions
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            child: Text(
              'Open Source Attributions',
              style: Theme.of(context).textTheme.titleSmall,
            ),
          ),
          const _AttributionTile(
            name: 'OpenStreetMap',
            description: 'Map data',
            license: 'ODbL 1.0',
          ),
          const _AttributionTile(
            name: 'OSRM',
            description: 'Open Source Routing Machine',
            license: 'BSD 2-Clause',
          ),
          const _AttributionTile(
            name: 'Photon',
            description: 'Geocoding / search powered by Komoot',
            license: 'Apache License 2.0',
          ),
          const _AttributionTile(
            name: 'Martin',
            description: 'Vector tile server',
            license: 'Apache License 2.0 / MIT',
          ),
          const SizedBox(height: 32),
        ],
      ),
    );
  }

  Future<void> _saveBackendUrl() async {
    final url = _backendUrlController.text.trim();
    if (url.isEmpty) return;

    final db = ref.read(appDatabaseProvider);
    await db.setSetting(AppConstants.settingBackendUrl, url);

    ref.read(apiClientProvider).updateBaseUrl(url);

    setState(() => _urlSaved = true);

    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Backend URL saved.')),
      );
    }
  }
}

class _AttributionTile extends StatelessWidget {
  final String name;
  final String description;
  final String license;

  const _AttributionTile({
    required this.name,
    required this.description,
    required this.license,
  });

  @override
  Widget build(BuildContext context) {
    return ListTile(
      dense: true,
      title: Text(name),
      subtitle: Text(description),
      trailing: Text(
        license,
        style: Theme.of(context).textTheme.labelSmall?.copyWith(
              color: Theme.of(context).colorScheme.outline,
            ),
      ),
    );
  }
}