import 'dart:convert';

import 'package:convert/convert.dart';
import 'package:crypto/crypto.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:geolocator/geolocator.dart';
import 'package:provider/provider.dart';
import '../config/api.dart';
import '../providers/auth_provider.dart';
import '../services/settings_service.dart';

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

  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen>
    with SingleTickerProviderStateMixin {
  late TabController _tabController;
  final TextEditingController _loginController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();
  final TextEditingController _secretKeyController = TextEditingController();
  final TextEditingController _serverUrlController = TextEditingController();

  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 2, vsync: this);
    _tabController.addListener(() {
      setState(() {});
    });
    final settings = context.read<SettingsService>();
    _serverUrlController.text = settings.baseUrl;
  }

  @override
  void dispose() {
    _tabController.dispose();
    _loginController.dispose();
    _passwordController.dispose();
    _secretKeyController.dispose();
    _serverUrlController.dispose();
    super.dispose();
  }

  static const String _secretKey = 'FtracKer*1405.';

  @override
  Widget build(BuildContext context) {
    final authProvider = context.watch<AuthProvider>();
    final settings = context.read<SettingsService>();

    return Scaffold(
      resizeToAvoidBottomInset: true,
      body: SingleChildScrollView(
        child: Center(
          child: Card(
            margin: const EdgeInsets.all(24),
            child: Padding(
              padding: const EdgeInsets.all(24),
              child: ConstrainedBox(
                constraints: const BoxConstraints(maxWidth: 400),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    const Text(
                      'Family Safety',
                      textAlign: TextAlign.center,
                      style: TextStyle(
                        fontSize: 32,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                    const SizedBox(height: 24),
                    if (!kIsWeb) ...[
                      TextField(
                        controller: _serverUrlController,
                        decoration: const InputDecoration(
                          labelText: 'Server URL',
                          hintText: 'https://example.com/api',
                          border: OutlineInputBorder(),
                          prefixIcon: Icon(Icons.cloud_outlined),
                        ),
                        keyboardType: TextInputType.url,
                      ),
                      const SizedBox(height: 16),
                    ],
                    TabBar(
                      controller: _tabController,
                      tabs: const [
                        Tab(text: 'Login'),
                        Tab(text: 'Register'),
                      ],
                    ),
                    const SizedBox(height: 24),
                    TextField(
                      controller: _loginController,
                      decoration: const InputDecoration(
                        labelText: 'Login',
                        border: OutlineInputBorder(),
                      ),
                    ),
                    const SizedBox(height: 16),
                    TextField(
                      controller: _passwordController,
                      decoration: const InputDecoration(
                        labelText: 'Password',
                        border: OutlineInputBorder(),
                      ),
                      obscureText: true,
                    ),
                    if (_tabController.index == 1) ...[
                      const SizedBox(height: 16),
                      TextField(
                        controller: _secretKeyController,
                        decoration: const InputDecoration(
                          labelText: 'Secret Key',
                          border: OutlineInputBorder(),
                        ),
                        obscureText: true,
                      ),
                    ],
                    const SizedBox(height: 16),
                    if (authProvider.error.isNotEmpty)
                      Text(
                        authProvider.error,
                        style: const TextStyle(color: Colors.red),
                      ),
                    const SizedBox(height: 16),
                    ElevatedButton(
                      onPressed: authProvider.isLoading
                          ? null
                          : () async {
                              if (!kIsWeb) {
                                final status =
                                    await Geolocator.checkPermission();
                                if (status == LocationPermission.denied) {
                                  final requested =
                                      await Geolocator.requestPermission();
                                  if (requested == LocationPermission.denied) {
                                    authProvider.setError(
                                      'Location permission denied',
                                    );
                                    return;
                                  }
                                }
                                if (status ==
                                    LocationPermission.deniedForever) {
                                  authProvider.setError(
                                    'Location permission permanently denied. Please enable it in settings.',
                                  );
                                  return;
                                }
                              }
                              if (!kIsWeb) {
                                final newUrl = _serverUrlController.text.trim();
                                if (newUrl.isNotEmpty &&
                                    newUrl != settings.baseUrl) {
                                  ApiConfig.setBaseUrl(newUrl);
                                  await settings.setBaseUrl(newUrl);
                                }
                              }
                              if (_tabController.index == 0) {
                                try {
                                  await authProvider.login(
                                    _loginController.text,
                                    _passwordController.text,
                                  );
                                  if (!context.mounted) return;
                                  Navigator.of(
                                    context,
                                  ).pushReplacementNamed('/map');
                                } catch (e) {
                                  // Error is handled by provider
                                }
                              } else {
                                if (_secretKeyController.text != _secretKey) {
                                  authProvider.setError('Invalid secret key');
                                  return;
                                }
                                Digest digest = md5.convert(
                                  utf8.encode(_secretKeyController.text),
                                );
                                String secretKeyHash = hex.encode(digest.bytes);
                                try {
                                  await authProvider.register(
                                    _loginController.text,
                                    _passwordController.text,
                                    secretKeyHash,
                                  );
                                } catch (e) {
                                  // Error is handled by provider
                                }
                              }
                            },
                      child: authProvider.isLoading
                          ? const SizedBox(
                              height: 20,
                              width: 20,
                              child: CircularProgressIndicator(strokeWidth: 2),
                            )
                          : Text(
                              _tabController.index == 0 ? 'Login' : 'Register',
                            ),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}