import 'package:flutter/material.dart';
import '../../data/session/session_service.dart';
import '../../data/firebase/firebase_service.dart';

/// Screen for user session management (login/logout).
class SessionScreen extends StatefulWidget {
  final SessionService? sessionService;
  final FirebaseService? firebaseService;
  final VoidCallback? onSessionChanged;

  const SessionScreen({
    super.key,
    this.sessionService,
    this.firebaseService,
    this.onSessionChanged,
  });

  @override
  State<SessionScreen> createState() => _SessionScreenState();
}

class _SessionScreenState extends State<SessionScreen> {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _userIdController = TextEditingController();
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();
  bool _isLoading = false;
  bool _useFirebaseAuth = false;

  @override
  void initState() {
    super.initState();
    // Check if Firebase Auth is available
    _useFirebaseAuth = widget.firebaseService?.isEnabled == true &&
        widget.firebaseService?.config.authEnabled == true;
  }

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

  Future<void> _handleLogin() async {
    if (widget.sessionService == null) return;

    setState(() {
      _isLoading = true;
    });

    try {
      if (_useFirebaseAuth && widget.firebaseService != null) {
        // Use Firebase Auth for authentication
        final email = _emailController.text.trim();
        final password = _passwordController.text.trim();

        if (email.isEmpty || password.isEmpty) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(
                content: Text('Please enter email and password'),
              ),
            );
          }
          return;
        }

        // Authenticate with Firebase
        final firebaseUser = await widget.firebaseService!.loginWithEmailPassword(
          email: email,
          password: password,
        );

        // Create session with Firebase user info
        await widget.sessionService!.login(
          id: firebaseUser.uid,
          username: firebaseUser.email?.split('@').first ?? firebaseUser.uid,
          token: await firebaseUser.getIdToken(),
        );

        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('Login successful'),
            ),
          );
          setState(() {});
          // Notify parent that session state changed
          widget.onSessionChanged?.call();
        }
      } else {
        // Simple validation mode (no Firebase Auth)
        final username = _usernameController.text.trim();
        final userId = _userIdController.text.trim();

        if (username.isEmpty || userId.isEmpty) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(
                content: Text('Please enter username and user ID'),
              ),
            );
          }
          return;
        }

        // Basic validation: require minimum length
        if (userId.length < 3) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(
                content: Text('User ID must be at least 3 characters'),
              ),
            );
          }
          return;
        }

        if (username.length < 2) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(
                content: Text('Username must be at least 2 characters'),
              ),
            );
          }
          return;
        }

        // Create session (demo mode - no real authentication)
        await widget.sessionService!.login(
          id: userId,
          username: username,
        );

        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text('Login successful (demo mode)'),
              backgroundColor: Colors.orange,
            ),
          );
          setState(() {});
          // Notify parent that session state changed
          widget.onSessionChanged?.call();
        }
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Login failed: ${e.toString().replaceAll('FirebaseException: ', '').replaceAll('SessionException: ', '')}'),
            backgroundColor: Colors.red,
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  Future<void> _handleLogout() async {
    if (widget.sessionService == null) return;

    setState(() {
      _isLoading = true;
    });

    try {
      // Logout from session service first
      await widget.sessionService!.logout();

      // Also logout from Firebase Auth if enabled
      if (_useFirebaseAuth && widget.firebaseService != null) {
        try {
          await widget.firebaseService!.logout();
        } catch (e) {
          // Log error but don't fail logout - session is already cleared
          debugPrint('Warning: Firebase logout failed: $e');
        }
      }

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Logout successful'),
          ),
        );
        setState(() {});
        // Notify parent that session state changed
        widget.onSessionChanged?.call();
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Logout failed: ${e.toString().replaceAll('SessionException: ', '')}'),
            backgroundColor: Colors.red,
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final isLoggedIn = widget.sessionService?.isLoggedIn ?? false;
    final currentUser = widget.sessionService?.currentUser;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Session'),
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : SingleChildScrollView(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  if (isLoggedIn && currentUser != null) ...[
                    Card(
                      child: Padding(
                        padding: const EdgeInsets.all(16),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            const Text(
                              'Current Session',
                              style: TextStyle(
                                fontSize: 18,
                                fontWeight: FontWeight.bold,
                              ),
                            ),
                            const SizedBox(height: 12),
                            Text('User ID: ${currentUser.id}'),
                            Text('Username: ${currentUser.username}'),
                            Text(
                              'Created: ${DateTime.fromMillisecondsSinceEpoch(currentUser.createdAt).toString().split('.')[0]}',
                            ),
                          ],
                        ),
                      ),
                    ),
                    const SizedBox(height: 16),
                    ElevatedButton(
                      onPressed: _handleLogout,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: Colors.red,
                        foregroundColor: Colors.white,
                      ),
                      child: const Text('Logout'),
                    ),
                  ] else ...[
                    const Icon(
                      Icons.person_outline,
                      size: 64,
                      color: Colors.grey,
                    ),
                    const SizedBox(height: 16),
                    const Text(
                      'Login',
                      style: TextStyle(
                        fontSize: 24,
                        fontWeight: FontWeight.bold,
                      ),
                      textAlign: TextAlign.center,
                    ),
                    if (!_useFirebaseAuth) ...[
                      const SizedBox(height: 8),
                      Container(
                        padding: const EdgeInsets.all(12),
                        decoration: BoxDecoration(
                          color: Colors.orange.shade50,
                          borderRadius: BorderRadius.circular(8),
                          border: Border.all(color: Colors.orange.shade200),
                        ),
                        child: Row(
                          children: [
                            Icon(Icons.info_outline, color: Colors.orange.shade700, size: 20),
                            const SizedBox(width: 8),
                            Expanded(
                              child: Text(
                                'Demo mode: No authentication required. Enter any valid user ID and username.',
                                style: TextStyle(
                                  fontSize: 12,
                                  color: Colors.orange.shade700,
                                ),
                              ),
                            ),
                          ],
                        ),
                      ),
                    ],
                    const SizedBox(height: 24),
                    if (_useFirebaseAuth) ...[
                      TextField(
                        controller: _emailController,
                        decoration: const InputDecoration(
                          labelText: 'Email',
                          hintText: 'Enter your email',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType: TextInputType.emailAddress,
                        autofillHints: const [AutofillHints.email],
                      ),
                      const SizedBox(height: 16),
                      TextField(
                        controller: _passwordController,
                        decoration: const InputDecoration(
                          labelText: 'Password',
                          hintText: 'Enter your password',
                          border: OutlineInputBorder(),
                        ),
                        obscureText: true,
                        autofillHints: const [AutofillHints.password],
                      ),
                    ] else ...[
                      TextField(
                        controller: _userIdController,
                        decoration: const InputDecoration(
                          labelText: 'User ID',
                          hintText: 'Enter user ID (min 3 characters)',
                          border: OutlineInputBorder(),
                        ),
                      ),
                      const SizedBox(height: 16),
                      TextField(
                        controller: _usernameController,
                        decoration: const InputDecoration(
                          labelText: 'Username',
                          hintText: 'Enter username (min 2 characters)',
                          border: OutlineInputBorder(),
                        ),
                      ),
                    ],
                    const SizedBox(height: 24),
                    ElevatedButton(
                      onPressed: _isLoading ? null : _handleLogin,
                      child: _isLoading
                          ? const SizedBox(
                              width: 20,
                              height: 20,
                              child: CircularProgressIndicator(strokeWidth: 2),
                            )
                          : const Text('Login'),
                    ),
                  ],
                ],
              ),
            ),
    );
  }
}