import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:permission_handler/permission_handler.dart';
import 'dart:async';

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

  @override
  State<BluetoothScreen> createState() => _BluetoothScreenState();
}

class _BluetoothScreenState extends State<BluetoothScreen> {
  List<ScanResult> _scanResults = [];
  bool _isScanning = false;
  StreamSubscription? _scanResultsSubscription;
  StreamSubscription? _isScanningSubscription;

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

    _scanResultsSubscription = FlutterBluePlus.scanResults.listen((results) {
      if (mounted) {
        setState(() {
          _scanResults = results;
        });
      }
    });

    _isScanningSubscription = FlutterBluePlus.isScanning.listen((state) {
      if (mounted) {
        setState(() {
          _isScanning = state;
        });
      }
    });
  }

  @override
  void dispose() {
    _scanResultsSubscription?.cancel();
    _isScanningSubscription?.cancel();
    super.dispose();
  }

  Future<void> startScan() async {
    // 1. Pedir permissões
    Map<Permission, PermissionStatus> statuses = await [
      Permission.bluetoothScan,
      Permission.bluetoothConnect,
      Permission.location,
    ].request();

    if (statuses[Permission.bluetoothScan]!.isGranted &&
        statuses[Permission.bluetoothConnect]!.isGranted) {
      
      try {
        // 2. Iniciar Scan
        await FlutterBluePlus.startScan(
          timeout: const Duration(seconds: 15),
        );

        // Se não encontrar nada (ex: no emulador), avisa o usuário
        Future.delayed(const Duration(seconds: 5), () {
          if (mounted && _scanResults.isEmpty && _isScanning) {
            _showSnackBar("Nenhum dispositivo encontrado (Verifique se o Bluetooth/GPS estão ligados)", Colors.orange);
          }
        });

      } catch (e) {
        _showSnackBar("Erro ao iniciar busca: $e", Colors.red);
      }
    } else {
      _showSnackBar("Permissões de Bluetooth negadas", Colors.orange);
    }
  }

  Future<void> connectToDevice(BluetoothDevice device) async {
    try {
      String name = device.platformName.isEmpty ? 'Dispositivo' : device.platformName;
      _showSnackBar("Conectando a $name...", Colors.blue);
      await device.connect();
      _showSnackBar("Conectado com sucesso!", Colors.green);
    } catch (e) {
      _showSnackBar("Falha ao conectar: $e", Colors.red);
    }
  }

  void _showSnackBar(String message, Color color) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: color,
        duration: const Duration(seconds: 3),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Conexão Bluetooth'),
        backgroundColor: Colors.black87,
        foregroundColor: Colors.white,
      ),
      backgroundColor: Colors.grey[900],
      body: Column(
        children: [
          const SizedBox(height: 20),
          Center(
            child: Column(
              children: [
                const Icon(Icons.bluetooth, size: 80, color: Colors.blue),
                const SizedBox(height: 10),
                ElevatedButton.icon(
                  onPressed: _isScanning ? null : startScan,
                  icon: _isScanning
                      ? const SizedBox(
                          width: 18,
                          height: 18,
                          child: CircularProgressIndicator(strokeWidth: 2, color: Colors.black),
                        )
                      : const Icon(Icons.search),
                  label: Text(_isScanning ? 'Buscando...' : 'Procurar Dispositivos'),
                  style: ElevatedButton.styleFrom(
                    backgroundColor: Colors.white,
                    foregroundColor: Colors.black,
                    padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
                  ),
                ),
              ],
            ),
          ),
          const SizedBox(height: 20),
          Expanded(
            child: _scanResults.isEmpty && !_isScanning
                ? const Center(
                    child: Text(
                      "Clique em Procurar para encontrar dispositivos.\n(Nota: Requer telemóvel físico para Bluetooth real)",
                      textAlign: TextAlign.center,
                      style: TextStyle(color: Colors.white54),
                    ),
                  )
                : ListView.builder(
                    itemCount: _scanResults.length,
                    itemBuilder: (context, index) {
                      final r = _scanResults[index];
                      final name = r.device.platformName.isEmpty
                          ? "Dispositivo Desconhecido"
                          : r.device.platformName;
                      return Card(
                        margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
                        color: Colors.white10,
                        child: ListTile(
                          leading: const Icon(Icons.bluetooth, color: Colors.blue),
                          title: Text(
                            name,
                            style: const TextStyle(
                              color: Colors.white,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          subtitle: Text(
                            r.device.remoteId.toString(),
                            style: const TextStyle(color: Colors.white70),
                          ),
                          trailing: ElevatedButton(
                            onPressed: () => connectToDevice(r.device),
                            child: const Text("Conectar"),
                          ),
                        ),
                      );
                    },
                  ),
          ),
        ],
      ),
    );
  }
}