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

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

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

class _SettingsScreenState extends State<SettingsScreen> {
  final _urlController = TextEditingController();
  final _keyController = TextEditingController();
  bool _isSaving = false;
  bool _obscureKey = true;

  static const _urlPrefKey = 'server_url';
  static const _apiKeyPrefKey = 'api_key';

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

  @override
  void dispose() {
    _urlController.dispose();
    _keyController.dispose();
    super.dispose();
  }

  Future<void> _loadSettings() async {
    final prefs = await SharedPreferences.getInstance();
    _urlController.text = prefs.getString(_urlPrefKey) ?? '';
    _keyController.text = prefs.getString(_apiKeyPrefKey) ?? '';
  }

  Future<void> _saveSettings() async {
    setState(() => _isSaving = true);
    try {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(_urlPrefKey, _urlController.text.trim());
      await prefs.setString(_apiKeyPrefKey, _keyController.text.trim());
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Settings saved')),
        );
        Navigator.pop(context, true); // true = settings changed
      }
    } finally {
      if (mounted) setState(() => _isSaving = false);
    }
  }

  Future<void> _clearSettings() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('Clear settings?'),
        content: const Text('Server URL and API key will be removed.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('Clear', style: TextStyle(color: Colors.red)),
          ),
        ],
      ),
    );

    if (confirmed == true) {
      final prefs = await SharedPreferences.getInstance();
      await prefs.remove(_urlPrefKey);
      await prefs.remove(_apiKeyPrefKey);
      _urlController.clear();
      _keyController.clear();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Settings cleared')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Backup settings'),
        actions: [
          IconButton(
            icon: const Icon(Icons.delete_outline),
            tooltip: 'Clear settings',
            onPressed: _clearSettings,
          ),
        ],
      ),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Container(
            padding: const EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: Theme.of(context).colorScheme.secondaryContainer,
              borderRadius: BorderRadius.circular(8),
            ),
            child: Row(
              children: [
                Icon(
                  Icons.info_outline,
                  color: Theme.of(context).colorScheme.onSecondaryContainer,
                  size: 20,
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: Text(
                    'Point to your running Python server. '
                    'Leave blank to use local storage only.',
                    style: TextStyle(
                      color: Theme.of(context).colorScheme.onSecondaryContainer,
                      fontSize: 13,
                    ),
                  ),
                ),
              ],
            ),
          ),

          const SizedBox(height: 24),

          TextField(
            controller: _urlController,
            keyboardType: TextInputType.url,
            autocorrect: false,
            decoration: const InputDecoration(
              labelText: 'Server URL',
              hintText: 'http://192.168.1.x:8000',
              prefixIcon: Icon(Icons.dns_outlined),
              border: OutlineInputBorder(),
            ),
          ),

          const SizedBox(height: 16),

          TextField(
            controller: _keyController,
            obscureText: _obscureKey,
            autocorrect: false,
            enableSuggestions: false,
            decoration: InputDecoration(
              labelText: 'API Key',
              hintText: 'Your X-API-Key value',
              prefixIcon: const Icon(Icons.key_outlined),
              border: const OutlineInputBorder(),
              suffixIcon: IconButton(
                icon: Icon(
                  _obscureKey
                      ? Icons.visibility_outlined
                      : Icons.visibility_off_outlined,
                ),
                onPressed: () => setState(() => _obscureKey = !_obscureKey),
              ),
            ),
          ),

          const SizedBox(height: 32),

          FilledButton.icon(
            onPressed: _isSaving ? null : _saveSettings,
            icon: _isSaving
                ? const SizedBox(
                    width: 16,
                    height: 16,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  )
                : const Icon(Icons.save_outlined),
            label: Text(_isSaving ? 'Saving...' : 'Save'),
          ),
        ],
      ),
    );
  }
}

class AppSettings {
  static const _urlPrefKey = 'server_url';
  static const _apiKeyPrefKey = 'api_key';

  static Future<({String url, String apiKey})> load() async {
    final prefs = await SharedPreferences.getInstance();
    return (
      url: prefs.getString(_urlPrefKey) ?? '',
      apiKey: prefs.getString(_apiKeyPrefKey) ?? '',
    );
  }

  static bool isConfigured({required String url, required String apiKey}) {
    return url.isNotEmpty && apiKey.isNotEmpty;
  }
}