import 'package:flutter/material.dart';
import 'package:app_links/app_links.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:hl_lieferservice/feature/authentication/bloc/auth_bloc.dart';
import 'package:hl_lieferservice/feature/authentication/bloc/auth_event.dart';
import 'package:hl_lieferservice/feature/authentication/bloc/auth_state.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:hl_lieferservice/util.dart';
import 'dart:async';

class LoginPage extends StatefulWidget {
  final bool sessionExpired;

  const LoginPage({super.key, this.sessionExpired = false});

  @override
  State<StatefulWidget> createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  final _loginFormKey = GlobalKey<FormState>();
  bool _isLoading = false;
  late AppLinks _appLinks;
  StreamSubscription<Uri>? _linkSubscription;

  @override
  void initState() {
    super.initState();
    _appLinks = AppLinks();
  }

  @override
  void dispose() {
    _linkSubscription?.cancel();
    super.dispose();
  }

  void _onPressLogin() async {
    setState(() => _isLoading = true);

    try {
      debugPrint("🔵 Setting up deep link listener...");

      final completer = Completer<Uri>();

      // Listen for deep links BEFORE opening browser
      _linkSubscription = _appLinks.uriLinkStream.listen(
            (Uri uri) {
          debugPrint("🟢 Deep link received: $uri");
          if (uri.scheme == 'myapp' && !completer.isCompleted) {
            completer.complete(uri);
          }
        },
        onError: (err) {
          debugPrint("🔴 Deep link error: $err");
          if (!completer.isCompleted) {
            completer.completeError(err);
          }
        },
      );

      // Small delay to ensure listener is ready
      await Future.delayed(const Duration(milliseconds: 500));

      final loginUrl = Uri.parse('${getConfig().backendUrl}/login');
      final launched = await launchUrl(
        loginUrl,
        mode: LaunchMode.externalApplication,
      );

      if (!launched) {
        throw Exception('Could not launch browser');
      }

      debugPrint("🔵 Browser opened. Waiting for callback...");

      // Wait for the deep link callback
      final callbackUri = await completer.future.timeout(
        const Duration(minutes: 5),
        onTimeout: () {
          debugPrint("⏱️ Timeout - no callback received");
          throw TimeoutException('Login timeout');
        },
      );

      final sessionId = callbackUri.queryParameters['session_id']!;

      debugPrint("✅ Success! Callback: $callbackUri");
      debugPrint("✅ Session ID: $sessionId");

      await _linkSubscription?.cancel();
      _linkSubscription = null;

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Login erfolgreich!'),
            backgroundColor: Colors.green,
          ),
        );
        
        context.read<AuthBloc>().add(SetAuthenticatedEvent(sessionId: sessionId));
      }

    } on TimeoutException {
      debugPrint("❌ Timeout");
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Login Timeout')),
        );
      }
    } catch (e) {
      debugPrint("❌ Error: $e");
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Fehler: $e')),
        );
      }
    } finally {
      await _linkSubscription?.cancel();
      _linkSubscription = null;
      if (mounted) {
        setState(() => _isLoading = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        children: [
          if (widget.sessionExpired)
            MaterialBanner(
              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
              content: const Text(
                "Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.",
                style: TextStyle(color: Colors.white),
              ),
              backgroundColor: Colors.orange.shade800,
              leading: const Icon(Icons.warning_amber_rounded, color: Colors.white),
              actions: [const SizedBox.shrink()],
            ),
          Expanded(
          child: Center(
          child: Column(
          mainAxisAlignment: MainAxisAlignment.start,
          children: [
            Padding(
              padding: const EdgeInsets.all(50),
              child: Column(
                children: [
                  Image.asset(
                    "assets/holzleitner_Logo_2017_RZ_transparent.png",
                  ),
                  const Padding(
                    padding: EdgeInsets.only(top: 20),
                    child: Text(
                      "Auslieferservice",
                      style: TextStyle(
                        fontWeight: FontWeight.w400,
                        fontSize: 20,
                      ),
                    ),
                  ),
                ],
              ),
            ),
            Form(
              key: _loginFormKey,
              child: FractionallySizedBox(
                widthFactor: 0.8,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Padding(
                      padding: const EdgeInsets.only(top: 15, bottom: 15),
                      child: BlocBuilder<AuthBloc, AuthState>(
                        builder: (context, authState) {
                          final isBusy =
                              _isLoading || authState is Authenticating;
                          if (!isBusy) {
                            return OutlinedButton(
                              onPressed: _onPressLogin,
                              child: const Text(
                                "Anmelden mit Holzleitner Login",
                              ),
                            );
                          }
                          return Column(
                            children: [
                              const CircularProgressIndicator(),
                              const SizedBox(height: 16),
                              Text(
                                authState is Authenticating
                                    ? 'Anmeldung wird abgeschlossen…'
                                    : 'Warte auf Login...',
                              ),
                            ],
                          );
                        },
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
        ),
        ),
        ],
      ),
    );
  }
}