import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../data/sources/localiser/realtime_data_client.dart';
import '../../providers.dart';

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

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

class _LoginScreenState extends ConsumerState<LoginScreen> {
  final _usernameController = TextEditingController();
  final _passwordController = TextEditingController();
  bool _loading = false;
  String? _error;

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

  @override
  void dispose() {
    _usernameController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  Future<void> _tryAutoLogin() async {
    final store = ref.read(credentialStoreProvider);
    final saved = await store.load();
    if (saved == null || !mounted) return;

    _usernameController.text = saved.username;
    _passwordController.text = saved.password;
    await _login(saved.username, saved.password, saveCredentials: false);
  }

  Future<void> _login(String username, String password,
      {bool saveCredentials = true}) async {
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final client = ref.read(sessionClientProvider);
      final tokenResponse = await client.login(username, password);
      final token = tokenResponse.token;

      ref.read(authTokenProvider.notifier).state = token;

      final config = ref.read(serverConfigProvider)!;
      final realtime = RealtimeDataClient(config: config, token: token);
      await realtime.connect();
      ref.read(realtimeDataClientProvider.notifier).state = realtime;

      if (saveCredentials) {
        await ref
            .read(credentialStoreProvider)
            .save((username: username, password: password));
      }

      if (mounted) context.go('/floorplan');
    } on Exception catch (e) {
      setState(() => _error = e.toString());
    } finally {
      if (mounted) setState(() => _loading = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Sign In')),
      body: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            TextField(
              controller: _usernameController,
              decoration: const InputDecoration(
                labelText: 'Username',
                border: OutlineInputBorder(),
              ),
              textInputAction: TextInputAction.next,
              autofillHints: const [AutofillHints.username],
            ),
            const SizedBox(height: 12),
            TextField(
              controller: _passwordController,
              decoration: const InputDecoration(
                labelText: 'Password',
                border: OutlineInputBorder(),
              ),
              obscureText: true,
              textInputAction: TextInputAction.done,
              autofillHints: const [AutofillHints.password],
              onSubmitted: _loading
                  ? null
                  : (_) => _login(
                        _usernameController.text.trim(),
                        _passwordController.text,
                      ),
            ),
            const SizedBox(height: 16),
            if (_error != null)
              Padding(
                padding: const EdgeInsets.only(bottom: 12),
                child: Text(
                  _error!,
                  style: TextStyle(color: Theme.of(context).colorScheme.error),
                ),
              ),
            FilledButton(
              onPressed: _loading
                  ? null
                  : () => _login(
                        _usernameController.text.trim(),
                        _passwordController.text,
                      ),
              child: _loading
                  ? const SizedBox.square(
                      dimension: 20,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Text('Sign in'),
            ),
          ],
        ),
      ),
    );
  }
}