import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:mileograph_flutter/services/authservice.dart';
import 'package:provider/provider.dart';

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

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

class _LoginScreenState extends State<LoginScreen> {
  bool _checkingSession = true;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) => _checkExistingSession());
  }

  Future<void> _checkExistingSession() async {
    final auth = context.read<AuthService>();
    try {
      final valid = await auth.validateStoredToken();
      if (!valid) return;
      await auth.tryRestoreSession();
      if (!mounted) return;
      context.go('/');
    } finally {
      if (mounted) setState(() => _checkingSession = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      resizeToAvoidBottomInset: true,
      body: Container(
        color: Theme.of(context).scaffoldBackgroundColor,
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text.rich(
                TextSpan(
                  children: [
                    TextSpan(
                      text: "Mile",
                      style: TextStyle(
                        color: Theme.of(context).textTheme.bodyLarge?.color,
                      ),
                    ),
                    const TextSpan(
                      text: "O",
                      style: TextStyle(color: Colors.red),
                    ),
                    TextSpan(
                      text: "graph",
                      style: TextStyle(
                        color: Theme.of(context).textTheme.bodyLarge?.color,
                      ),
                    ),
                  ],
                  style: const TextStyle(
                    decoration: TextDecoration.none,
                    color: Colors.white,
                    fontFamily: "Tomatoes",
                    fontSize: 50,
                  ),
                ),
              ),
              if (_checkingSession)
                const Padding(
                  padding: EdgeInsets.only(top: 12),
                  child: SizedBox(
                    height: 24,
                    width: 24,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  ),
                ),
              const SizedBox(height: 50),
              const LoginPanel(),
            ],
          ),
        ),
      ),
    );
  }
}

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

  @override
  State<LoginPanel> createState() => _LoginPanelState();
}

class _LoginPanelState extends State<LoginPanel> {
  bool registerMode = false;

  void toggleMode() {
    setState(() {
      registerMode = !registerMode;
    });
  }

  @override
  Widget build(BuildContext context) {
    final authService = context.read<AuthService>();

    return Center(
      child: SizedBox(
        width: 400,
        child: Card(
          child: Padding(
            padding: EdgeInsets.all(20),
            child: registerMode
                ? RegisterPanelContent(
                    onBack: toggleMode,
                    authService: authService,
                  )
                : LoginPanelContent(
                    registerCb: toggleMode,
                    authService: authService,
                  ),
          ),
        ),
      ),
    );
  }
}

class LoginPanelContent extends StatefulWidget {
  const LoginPanelContent({
    required this.registerCb,
    required this.authService,
    super.key,
  });

  final VoidCallback registerCb;
  final AuthService authService;

  @override
  State<LoginPanelContent> createState() => _LoginPanelContentState();
}

class _LoginPanelContentState extends State<LoginPanelContent> {
  final _usernameController = TextEditingController();
  final _passwordController = TextEditingController();

  bool _loggingIn = false;

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

  Future<void> login() async {
    final username = _usernameController.text;
    final password = _passwordController.text;

    final auth = context.read<AuthService>();

    setState(() {
      _loggingIn = true;
    });
    try {
      await auth.login(username, password);
      if (!mounted) return;
      setState(() {
        _loggingIn = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _loggingIn = false;
      });
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Login failed: $e')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    Widget loginButtonContent = Text("Login");
    if (_loggingIn) {
      loginButtonContent = Padding(
        padding: const EdgeInsets.all(8.0),
        child: SizedBox(
          height: 10,
          width: 10,
          child: CircularProgressIndicator(
            color: Theme.of(context).textTheme.bodyLarge?.color,
            strokeWidth: 2,
          ),
        ),
      );
    } else {
      loginButtonContent = Text("Login");
    }
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      mainAxisSize: MainAxisSize.min,
      children: [
        Padding(
          padding: const EdgeInsets.symmetric(vertical: 0, horizontal: 50),
          child: Text(
            "Login",
            style: TextStyle(fontWeight: FontWeight.bold, fontSize: 20),
          ),
        ),
        const SizedBox(height: 8),
        TextFormField(
          controller: _usernameController,
          decoration: InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Username",
          ),
          onFieldSubmitted: (_) => login(),
        ),
        const SizedBox(height: 8),
        TextFormField(
          controller: _passwordController,
          obscureText: true,
          decoration: InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Password",
          ),
          onFieldSubmitted: (_) => login(),
        ),
        const SizedBox(height: 12),
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            FilledButton(onPressed: login, child: loginButtonContent),
            const SizedBox(width: 10),
            ElevatedButton(
              onPressed: widget.registerCb,
              child: Text("Register"),
            ),
          ],
        ),
      ],
    );
  }
}

class RegisterPanelContent extends StatefulWidget {
  const RegisterPanelContent({
    super.key,
    required this.onBack,
    required this.authService,
  });
  final VoidCallback onBack;
  final AuthService authService;
  @override
  State<RegisterPanelContent> createState() => _RegisterPanelContentState();
}

class _RegisterPanelContentState extends State<RegisterPanelContent> {
  final _usernameController = TextEditingController();
  final _displayNameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  final _inviteController = TextEditingController();
  bool _registering = false;

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

  Future<void> _register() async {
    setState(() => _registering = true);
    try {
      await widget.authService.register(
        username: _usernameController.text.trim(),
        email: _emailController.text.trim(),
        fullName: _displayNameController.text.trim(),
        password: _passwordController.text,
        inviteCode: _inviteController.text.trim(),
      );
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Registration successful. Please log in.')),
      );
      widget.onBack();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Registration failed: $e')),
      );
    } finally {
      if (mounted) setState(() => _registering = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      mainAxisSize: MainAxisSize.min,
      children: [
        Row(
          children: [
            IconButton(
              icon: const Icon(Icons.arrow_back),
              onPressed: widget.onBack,
              tooltip: 'Back to login',
            ),
            Expanded(
              child: Center(
                child: Text(
                  "Register",
                  style: TextStyle(fontWeight: FontWeight.bold, fontSize: 20),
                ),
              ),
            ),
            const SizedBox(width: 48),
          ],
        ),
        const SizedBox(height: 16),
        TextField(
          controller: _usernameController,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Username",
          ),
        ),
        const SizedBox(height: 8),
        TextField(
          controller: _displayNameController,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Display Name",
          ),
        ),
        const SizedBox(height: 8),
        TextField(
          controller: _emailController,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Email",
          ),
        ),
        const SizedBox(height: 8),
        TextField(
          controller: _passwordController,
          obscureText: true,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Password",
          ),
        ),
        const SizedBox(height: 8),
        TextField(
          controller: _inviteController,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: "Invite Code",
          ),
        ),
        const SizedBox(height: 12),
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            FilledButton(
              onPressed: _registering ? null : _register,
              child: _registering
                  ? const SizedBox(
                      height: 14,
                      width: 14,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Text("Register"),
            ),
          ],
        ),
      ],
    );
  }
}