// lib/screens/login_screen.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../services/api_service.dart';
import '../services/session_manager.dart';
import 'main_screen.dart';

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

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

class _LoginScreenState extends State<LoginScreen> {
  final _usernameController = TextEditingController(text: 'gast');
  final _passwordController = TextEditingController(text: 'gast');
  bool _isLoading = false;
  bool _obscurePassword = true;

  Future<void> _login() async {
    if (_usernameController.text.isEmpty || _passwordController.text.isEmpty) {
      _showError('Bitte Benutzername und Passwort eingeben');
      return;
    }

    setState(() => _isLoading = true);

    try {
      final apiService = ApiService();
      final response = await apiService.login(
        _usernameController.text.trim(),
        _passwordController.text,
      );

      if (response['success'] == true && 
          response['userID'] != null && 
          response['session'] != null) {
        
        final sessionManager = Provider.of<SessionManager>(context, listen: false);
        sessionManager.setSession(response['userID'], response['session']);
        
        if (mounted) {
          Navigator.pushReplacement(
            context,
            MaterialPageRoute(builder: (_) => const MainScreen()),
          );
        }
      } else {
        _showError(response['error'] ?? 'Anmeldung fehlgeschlagen');
      }
    } catch (e) {
      _showError('Verbindungsfehler: $e');
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _showError(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(message), backgroundColor: Colors.red),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Icon(Icons.school, size: 80, color: Colors.blue),
              const SizedBox(height: 16),
              const Text(
                'DÜSK',
                style: TextStyle(fontSize: 48, fontWeight: FontWeight.bold),
              ),
              const Text(
                'Düsseldorfer Schülerinventar',
                style: TextStyle(fontSize: 16, color: Colors.grey),
              ),
              const SizedBox(height: 48),
              TextField(
                controller: _usernameController,
                decoration: const InputDecoration(
                  labelText: 'Benutzername',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.person),
                ),
                enabled: !_isLoading,
              ),
              const SizedBox(height: 16),
              TextField(
                controller: _passwordController,
                decoration: InputDecoration(
                  labelText: 'Passwort',
                  border: const OutlineInputBorder(),
                  prefixIcon: const Icon(Icons.lock),
                  suffixIcon: IconButton(
                    icon: Icon(_obscurePassword ? Icons.visibility_off : Icons.visibility),
                    onPressed: () => setState(() => _obscurePassword = !_obscurePassword),
                  ),
                ),
                obscureText: _obscurePassword,
                enabled: !_isLoading,
              ),
              const SizedBox(height: 24),
              SizedBox(
                width: double.infinity,
                height: 50,
                child: ElevatedButton(
                  onPressed: _isLoading ? null : _login,
                  child: _isLoading
                      ? const CircularProgressIndicator()
                      : const Text('Anmelden', style: TextStyle(fontSize: 16)),
                ),
              ),
              const SizedBox(height: 24),
              const Text(
                'Server: paul-koop.org | Demozugang: gast/gast',
                style: TextStyle(fontSize: 12, color: Colors.grey),
              ),
            ],
          ),
        ),
      ),
    );
  }
}