import 'package:flutter/material.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:webview_flutter/webview_flutter.dart';

/// Login screen that loads wp-login.php in a WebView.
///
/// When the user successfully logs in, WordPress redirects to /twp-phone/.
/// We detect that URL change and report login success to the parent.
class LoginScreen extends StatefulWidget {
  final void Function(String serverUrl) onLoginSuccess;

  const LoginScreen({super.key, required this.onLoginSuccess});

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

class _LoginScreenState extends State<LoginScreen> {
  static const _storage = FlutterSecureStorage();

  final _formKey = GlobalKey<FormState>();
  final _serverController = TextEditingController();
  bool _showWebView = false;
  bool _webViewLoading = true;
  String? _error;
  late WebViewController _webViewController;

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

  Future<void> _loadSavedServer() async {
    final saved = await _storage.read(key: 'server_url');
    if (saved != null && mounted) {
      _serverController.text = saved;
    }
  }

  void _startLogin() {
    if (!_formKey.currentState!.validate()) return;

    var serverUrl = _serverController.text.trim();
    if (!serverUrl.startsWith('http')) {
      serverUrl = 'https://$serverUrl';
    }
    // Remove trailing slash
    serverUrl = serverUrl.replaceAll(RegExp(r'/+$'), '');

    setState(() {
      _showWebView = true;
      _webViewLoading = true;
      _error = null;
    });

    final loginUrl =
        '$serverUrl/wp-login.php?redirect_to=${Uri.encodeComponent('$serverUrl/twp-phone/')}';

    _webViewController = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setNavigationDelegate(
        NavigationDelegate(
          onPageStarted: (url) {
            // Check if we've been redirected to the phone page (login success)
            if (url.contains('/twp-phone/') || url.endsWith('/twp-phone')) {
              _onLoginComplete(serverUrl);
            }
          },
          onPageFinished: (url) {
            if (mounted) {
              setState(() => _webViewLoading = false);
            }
            // Also check on page finish in case redirect was instant
            if (url.contains('/twp-phone/') || url.endsWith('/twp-phone')) {
              _onLoginComplete(serverUrl);
            }
          },
          onWebResourceError: (error) {
            if (mounted) {
              setState(() {
                _showWebView = false;
                _error =
                    'Could not connect to server: ${error.description}';
              });
            }
          },
        ),
      )
      ..setUserAgent('TWPMobile/2.0 (Android; WebView)')
      ..loadRequest(Uri.parse(loginUrl));
  }

  Future<void> _onLoginComplete(String serverUrl) async {
    // Save server URL for next launch
    await _storage.write(key: 'server_url', value: serverUrl);
    if (mounted) {
      widget.onLoginSuccess(serverUrl);
    }
  }

  void _cancelLogin() {
    setState(() {
      _showWebView = false;
      _error = null;
    });
  }

  @override
  Widget build(BuildContext context) {
    if (_showWebView) {
      return Scaffold(
        appBar: AppBar(
          leading: IconButton(
            icon: const Icon(Icons.arrow_back),
            onPressed: _cancelLogin,
          ),
          title: const Text('Sign In'),
        ),
        body: Stack(
          children: [
            WebViewWidget(controller: _webViewController),
            if (_webViewLoading)
              const Center(child: CircularProgressIndicator()),
          ],
        ),
      );
    }

    return Scaffold(
      body: SafeArea(
        child: Center(
          child: SingleChildScrollView(
            padding: const EdgeInsets.all(24),
            child: Form(
              key: _formKey,
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Icon(
                    Icons.phone_in_talk,
                    size: 64,
                    color: Theme.of(context).colorScheme.primary,
                  ),
                  const SizedBox(height: 16),
                  Text(
                    'TWP Softphone',
                    style: Theme.of(context).textTheme.headlineMedium,
                  ),
                  const SizedBox(height: 32),
                  TextFormField(
                    controller: _serverController,
                    decoration: const InputDecoration(
                      labelText: 'Server URL',
                      hintText: 'https://your-site.com',
                      prefixIcon: Icon(Icons.dns),
                      border: OutlineInputBorder(),
                    ),
                    keyboardType: TextInputType.url,
                    autofillHints: const [AutofillHints.url],
                    validator: (v) =>
                        v == null || v.trim().isEmpty ? 'Required' : null,
                  ),
                  if (_error != null) ...[
                    const SizedBox(height: 16),
                    Text(
                      _error!,
                      style: TextStyle(
                          color: Theme.of(context).colorScheme.error),
                    ),
                  ],
                  const SizedBox(height: 24),
                  SizedBox(
                    width: double.infinity,
                    height: 48,
                    child: FilledButton(
                      onPressed: _startLogin,
                      child: const Text('Connect'),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

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