import 'dart:async';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:telemednet/data/services/navigation_service.dart';
import 'package:telemednet/route_names.dart';
import 'package:telemednet/screens/authentication/sign_up_screen.dart';
import 'package:telemednet/widgets/primary_button.dart';

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

  @override
  State<LaunchScreen> createState() => _LaunchScreenState();
}

class _LaunchScreenState extends State<LaunchScreen> {
  String? selectedUserType;

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        decoration: const BoxDecoration(
          image: DecorationImage(
            image: AssetImage('images/cover-picture.jpg'),
            fit: BoxFit.cover,
          ),
        ),
        child: Center(
          child: SingleChildScrollView(
            padding: const EdgeInsets.all(24.0),
            child: Card(
              elevation: 4,
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(16),
              ),
              child: Padding(
                padding: const EdgeInsets.all(24.0),
                child: StreamBuilder(
                  stream: FirebaseAuth.instance.authStateChanges(),
                  builder: (context, snapshot) {
                    if (snapshot.connectionState == ConnectionState.waiting) {
                      return _buildLoadingWidget();
                    } else if (snapshot.hasData) {
                      _fetchProfileAndNavigate(context);
                      return _buildLoadingWidget();
                    } else {
                      return Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          const Text(
                            'Register',
                            style: TextStyle(
                              fontSize: 24,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          const SizedBox(height: 16),
                          const Text(
                            'Who are you?',
                            style: TextStyle(
                              color: Colors.grey,
                              fontSize: 16,
                            ),
                          ),
                          const SizedBox(height: 24),
                          _buildUserTypeSelection(context),
                        ],
                      );
                    }
                  },
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildLoadingWidget() {
    return const SizedBox(
      height: 120,
      child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            CircularProgressIndicator(),
            SizedBox(height: 12),
            Text('Please wait...'),
          ],
        ),
      ),
    );
  }

  Widget _buildUserTypeSelection(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        _buildSelectionCard(
          title: 'Doctor',
          description: 'Can organise and approve appointments',
          icon: Icons.medical_services,
          isSelected: selectedUserType == 'doctor',
          onTap: () => setState(() => selectedUserType = 'doctor'),
        ),
        const SizedBox(height: 12),
        _buildSelectionCard(
          title: 'Patient',
          description: 'Can book appointments',
          icon: Icons.person,
          isSelected: selectedUserType == 'patient',
          onTap: () => setState(() => selectedUserType = 'patient'),
        ),
        const SizedBox(height: 24),
        SizedBox(
          width: double.infinity,
          child: PrimaryButton(
            onPressed: selectedUserType != null
                ? () => Navigator.of(context).push(
                      MaterialPageRoute(
                        builder: (context) => SignUpScreen(
                          selectedUserType: selectedUserType!,
                        ),
                      ),
                    )
                : null,
            text: 'Next',
          ),
        ),
        const SizedBox(height: 16),
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('Already have an account?'),
            TextButton(
              onPressed: () {
                Navigator.of(context).pushNamed(RouteNames.signIn);
              },
              child: const Text(
                'Login',
                style: TextStyle(color: Colors.blue),
              ),
            ),
          ],
        ),
      ],
    );
  }

  Widget _buildSelectionCard({
    required String title,
    required String description,
    required IconData icon,
    required bool isSelected,
    required VoidCallback onTap,
  }) {
    return InkWell(
      onTap: onTap,
      borderRadius: BorderRadius.circular(12),
      child: Container(
        decoration: BoxDecoration(
          border: Border.all(
            color: isSelected ? Colors.blue : Colors.grey.shade300,
            width: isSelected ? 2 : 1,
          ),
          borderRadius: BorderRadius.circular(12),
          color: isSelected ? Colors.blue.shade50 : Colors.white,
        ),
        padding: const EdgeInsets.all(16),
        child: Row(
          children: [
            Container(
              padding: const EdgeInsets.all(8),
              decoration: BoxDecoration(
                color: Colors.blue.shade100,
                borderRadius: BorderRadius.circular(8),
              ),
              child: Icon(icon, color: Colors.blue, size: 24),
            ),
            const SizedBox(width: 16),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    title,
                    style: const TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                  const SizedBox(height: 4),
                  Text(
                    description,
                    style: TextStyle(
                      fontSize: 14,
                      color: Colors.grey.shade600,
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _fetchProfileAndNavigate(BuildContext context) async {
    if (mounted) {
      await NavigationService.handleUserNavigation(context);
    }
  }
}