import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../widgets/input_field.dart';
import 'login_screen.dart';

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

  @override
  State<RegisterScreen> createState() => _RegisterScreenState();
}

class _RegisterScreenState extends State<RegisterScreen> {
  final usernameController = TextEditingController();
  final emailController = TextEditingController();
  final passwordController = TextEditingController();
  final confirmPasswordController = TextEditingController();

  Future<void> register() async {
    String username = usernameController.text.trim();
    String email = emailController.text.trim();
    String password = passwordController.text.trim();
    String confirmPassword = confirmPasswordController.text.trim();

    if (username.isEmpty || email.isEmpty || password.isEmpty || confirmPassword.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('All fields are required')),
      );
      return;
    }

    if (!RegExp(r'^[^@]+@[^@]+\.[^@]+').hasMatch(email)) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Invalid email format')),
      );
      return;
    }

    if (password != confirmPassword) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Passwords do not match')),
      );
      return;
    }

    final prefs = await SharedPreferences.getInstance();

    // Check if the username or email is already taken
    String? existingUser = prefs.getString(username);
    String? existingEmail = prefs.getString(email);
    if (existingUser != null || existingEmail != null) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Username or Email already exists. Choose another.')),
      );
      return;
    }

    // Save user credentials in SharedPreferences
    await prefs.setString(username, password);
    await prefs.setString(email, username); // Store email linked to the username

    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(content: Text('Registration Successful! Please Login')),
    );

    // Redirect to Login Screen
    Navigator.pushReplacement(
      context,
      MaterialPageRoute(builder: (context) => const LoginScreen()),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              /// Logo
              Image.asset(
                'assets/logo.png',
                width: 1000,
                height: 150,
              ),
              const SizedBox(height: 40),

              /// Username Field
              InputField(
                hintText: 'Username',
                icon: Icons.person,
                controller: usernameController,
              ),
              const SizedBox(height: 16),

              /// Email Field
              InputField(
                hintText: 'Email',
                icon: Icons.email,
                controller: emailController,
              ),
              const SizedBox(height: 16),

              /// Password Field
              InputField(
                hintText: 'Password',
                icon: Icons.lock,
                obscureText: true,
                controller: passwordController,
              ),
              const SizedBox(height: 16),

              /// Confirm Password Field
              InputField(
                hintText: 'Confirm Password',
                icon: Icons.lock,
                obscureText: true,
                controller: confirmPasswordController,
              ),
              const SizedBox(height: 24),

              /// Register Button
              ElevatedButton(
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.grey[800], // Match Login Button
                  foregroundColor: Colors.white,
                  minimumSize: const Size.fromHeight(50),
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(8),
                  ),
                ),
                onPressed: register,
                child: const Text('Register', style: TextStyle(fontSize: 18)),
              ),
              const SizedBox(height: 16),

              /// Horizontal Line with "or" (optional, in case Google Sign-Up is added)
              Row(
                children: const [
                  Expanded(
                    child: Divider(color: Colors.grey, thickness: 1),
                  ),
                  Padding(
                    padding: EdgeInsets.symmetric(horizontal: 8),
                    child: Text("or", style: TextStyle(color: Colors.grey, fontSize: 16)),
                  ),
                  Expanded(
                    child: Divider(color: Colors.grey, thickness: 1),
                  ),
                ],
              ),
              const SizedBox(height: 16),

              /// Login Navigation (Styled in Blue)
              GestureDetector(
                onTap: () {
                  Navigator.pushReplacement(
                    context,
                    MaterialPageRoute(builder: (context) => const LoginScreen()),
                  );
                },
                child: const Text(
                  "Already have an account? Login",
                  style: TextStyle(
                    fontSize: 16,
                    fontWeight: FontWeight.w500,
                    color: Colors.grey, // Styled for better visibility
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}