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 BluetoothConnectionScreen extends StatefulWidget {
  const BluetoothConnectionScreen({super.key});

  @override
  State<BluetoothConnectionScreen> createState() => _BluetoothConnectionScreenState();
}

class _BluetoothConnectionScreenState extends State<BluetoothConnectionScreen> {
  List<ScanResult> scanResults = [];
  bool isScanning = false;
  StreamSubscription? scanSubscription;
  StreamSubscription? isScanningSubscription;

  @override
  void initState() {
    super.initState();
    // Monitorar se o sistema está escaneando
    isScanningSubscription = FlutterBluePlus.isScanning.listen((scanning) {
      if (mounted) {
        setState(() {
          isScanning = scanning;
        });
      }
    });

    // Ouvir os resultados do scan globalmente
    scanSubscription = FlutterBluePlus.scanResults.listen((results) {
      if (mounted) {
        setState(() {
          scanResults = results;
        });
      }
    });
  }

  @override
  void dispose() {
    scanSubscription?.cancel();
    isScanningSubscription?.cancel();
    super.dispose();
  }

  Future<void> startScan() async {
    // 1. Pedir permissões (necessário no Android)
    Map<Permission, PermissionStatus> statuses = await [
      Permission.bluetoothScan,
      Permission.bluetoothConnect,
      Permission.location,
    ].request();

    if (statuses[Permission.bluetoothScan]!.isGranted &&
        statuses[Permission.bluetoothConnect]!.isGranted &&
        statuses[Permission.location]!.isGranted) {
      
      setState(() {
        scanResults.clear();
      });

      // 2. Iniciar o scan
      try {
        await FlutterBluePlus.startScan(timeout: const Duration(seconds: 15));
      } catch (e) {
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text('Erro ao buscar: $e')),
          );
        }
      }
    } else {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Permissões negadas')),
        );
      }
    }
  }

  Future<void> connectToDevice(BluetoothDevice device) async {
    try {
      await device.connect();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Conectado a ${device.platformName.isEmpty ? 'Dispositivo' : device.platformName}')),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Falha ao conectar: $e')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Conexão Bluetooth'),
        backgroundColor: Colors.grey[850],
        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.white,
                ),
                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: 20, vertical: 15),
                    textStyle: const TextStyle(fontSize: 18),
                  ),
                ),
              ],
            ),
          ),
          const SizedBox(height: 20),
          Expanded(
            child: scanResults.isEmpty && !isScanning
                ? const Center(
                    child: Text(
                      "Nenhum dispositivo encontrado.\nClique em procurar.",
                      textAlign: TextAlign.center,
                      style: TextStyle(color: Colors.white70),
                    ),
                  )
                : ListView.builder(
                    itemCount: scanResults.length,
                    itemBuilder: (context, index) {
                      final device = scanResults[index].device;
                      final name = device.platformName.isEmpty ? 'Desconhecido' : device.platformName;
                      return Card(
                        color: Colors.white10,
                        margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                        child: ListTile(
                          title: Text(name, style: const TextStyle(color: Colors.white)),
                          subtitle: Text(device.remoteId.toString(), style: const TextStyle(color: Colors.white70)),
                          trailing: const Icon(Icons.link, color: Colors.blue),
                          onTap: () => connectToDevice(device),
                        ),
                      );
                    },
                  ),
          ),
        ],
      ),
    );
  }
}