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

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();

    // Ouvir os resultados da busca e ordenar
    _scanResultsSubscription = FlutterBluePlus.scanResults.listen((results) {
      if (mounted) {
        // Criar uma cópia da lista e ordenar
        List<ScanResult> sortedResults = List.from(results);
        sortedResults.sort((a, b) {
          bool aHasName = _hasRealName(a);
          bool bHasName = _hasRealName(b);
          
          if (aHasName && !bHasName) return -1; // 'a' vem primeiro
          if (!aHasName && bHasName) return 1;  // 'b' vem primeiro
          return 0; // Mantém a ordem original entre iguais
        });

        setState(() {
          _scanResults = sortedResults;
        });
      }
    });

    // Ouvir o estado da busca
    _isScanningSubscription = FlutterBluePlus.isScanning.listen((state) {
      if (mounted) {
        setState(() {
          _isScanning = state;
        });
      }
    });
  }

  // Função auxiliar para verificar se tem nome real
  bool _hasRealName(ScanResult r) {
    return r.advertisementData.advName.isNotEmpty || r.device.platformName.isNotEmpty;
  }

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

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

    if (statuses[Permission.bluetoothScan]!.isGranted &&
        statuses[Permission.bluetoothConnect]!.isGranted) {
      
      try {
        _scanResults.clear();
        await FlutterBluePlus.startScan(
          timeout: const Duration(seconds: 15),
          androidUsesFineLocation: true,
          continuousUpdates: true, 
        );

        Future.delayed(const Duration(seconds: 8), () {
          if (mounted && _scanResults.isEmpty && _isScanning) {
            _showSnackBar("Nenhum dispositivo encontrado.", AppColors.coral);
          }
        });

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

  Future<void> stopScan() async {
    try {
      await FlutterBluePlus.stopScan();
    } catch (e) {
      _showSnackBar("Erro ao parar busca: $e", Colors.red);
    }
  }

  Future<void> connectToDevice(BluetoothDevice device) async {
    try {
      String name = device.platformName.isNotEmpty ? device.platformName : "Dispositivo";
      _showSnackBar("Conectando a $name...", Colors.white70);
      await device.connect();
      _showSnackBar("Conectado com sucesso!", Colors.green);
    } catch (e) {
      _showSnackBar("Falha ao conectar: $e", Colors.red);
    }
  }

  // Lógica para capturar o nome
  String _getDeviceName(ScanResult r) {
    if (r.advertisementData.advName.isNotEmpty) {
      return r.advertisementData.advName;
    } else if (r.device.platformName.isNotEmpty) {
      return r.device.platformName;
    } else {
      String id = r.device.remoteId.toString();
      return "Disp. [${id.length > 5 ? id.substring(id.length - 5) : id}]";
    }
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Bluetooth', style: TextStyle(fontWeight: FontWeight.bold)),
        centerTitle: true,
        backgroundColor: Colors.transparent,
        elevation: 0,
        foregroundColor: AppColors.white,
      ),
      extendBodyBehindAppBar: true,
      backgroundColor: AppColors.background,
      body: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topCenter,
            end: Alignment.bottomCenter,
            colors: [
              AppColors.coral.withOpacity(0.1),
              AppColors.background,
            ],
          ),
        ),
        child: Column(
          children: [
            const SizedBox(height: 100),
            
            Center(
              child: Column(
                children: [
                  Container(
                    padding: const EdgeInsets.all(25),
                    decoration: BoxDecoration(
                      shape: BoxShape.circle,
                      color: _isScanning 
                        ? AppColors.coral.withOpacity(0.1) 
                        : AppColors.backgroundGrey.withOpacity(0.3),
                      border: Border.all(
                        color: _isScanning ? AppColors.coral : AppColors.backgroundGrey,
                        width: 2,
                      ),
                    ),
                    child: Icon(
                      _isScanning ? Icons.bluetooth_searching : Icons.bluetooth,
                      size: 60,
                      color: _isScanning ? AppColors.coral : AppColors.white.withOpacity(0.7),
                    ),
                  ),
                  const SizedBox(height: 30),
                  
                  SizedBox(
                    width: 220,
                    height: 50,
                    child: ElevatedButton(
                      onPressed: _isScanning ? stopScan : startScan,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: _isScanning ? AppColors.backgroundGrey : AppColors.white,
                        foregroundColor: _isScanning ? AppColors.white : AppColors.background,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(25),
                        ),
                        elevation: 0,
                      ),
                      child: Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          if (_isScanning)
                            const Padding(
                              padding: EdgeInsets.only(right: 10),
                              child: SizedBox(
                                width: 18,
                                height: 18,
                                child: CircularProgressIndicator(
                                  strokeWidth: 2,
                                  color: AppColors.white,
                                ),
                              ),
                            ),
                          Text(
                            _isScanning ? 'PARAR BUSCA' : 'BUSCAR AGORA',
                            style: const TextStyle(
                              fontSize: 14,
                              fontWeight: FontWeight.bold,
                              letterSpacing: 1.2,
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
            
            const SizedBox(height: 40),
            
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 24),
              child: Row(
                children: [
                  Text(
                    _isScanning ? "Procurando..." : "Dispositivos próximos",
                    style: const TextStyle(
                      color: AppColors.white,
                      fontSize: 14,
                      fontWeight: FontWeight.w500,
                    ),
                  ),
                  const Spacer(),
                  if (_isScanning)
                    Container(
                      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
                      decoration: BoxDecoration(
                        color: AppColors.coral.withOpacity(0.2),
                        borderRadius: BorderRadius.circular(10),
                      ),
                      child: const Text(
                        "ATIVO",
                        style: TextStyle(color: AppColors.coral, fontSize: 10, fontWeight: FontWeight.bold),
                      ),
                    ),
                ],
              ),
            ),
            const SizedBox(height: 15),

            Expanded(
              child: _scanResults.isEmpty && !_isScanning
                  ? Center(
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          Icon(Icons.bluetooth_disabled, size: 40, color: AppColors.white.withOpacity(0.1)),
                          const SizedBox(height: 16),
                          Text(
                            "Inicie a busca para conectar",
                            style: TextStyle(color: AppColors.white.withOpacity(0.3)),
                          ),
                        ],
                      ),
                    )
                  : ListView.builder(
                      padding: const EdgeInsets.only(top: 0, bottom: 20),
                      itemCount: _scanResults.length,
                      itemBuilder: (context, index) {
                        final r = _scanResults[index];
                        final name = _getDeviceName(r);
                        final isUnknown = name.startsWith("Disp. [");
                        
                        return Container(
                          margin: const EdgeInsets.symmetric(horizontal: 20, vertical: 6),
                          decoration: BoxDecoration(
                            color: AppColors.backgroundGrey.withOpacity(0.2),
                            borderRadius: BorderRadius.circular(15),
                          ),
                          child: ListTile(
                            contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                            leading: CircleAvatar(
                              backgroundColor: AppColors.backgroundGrey.withOpacity(0.3),
                              child: Icon(
                                isUnknown ? Icons.devices_other : Icons.bluetooth, 
                                color: isUnknown ? AppColors.white.withOpacity(0.4) : AppColors.white, 
                                size: 20
                              ),
                            ),
                            title: Text(
                              name,
                              style: TextStyle(
                                color: isUnknown ? AppColors.white.withOpacity(0.5) : AppColors.white,
                                fontWeight: FontWeight.w600,
                                fontSize: 15,
                              ),
                            ),
                            subtitle: Text(
                              r.device.remoteId.toString(),
                              style: TextStyle(color: AppColors.white.withOpacity(0.3), fontSize: 11),
                            ),
                            trailing: ElevatedButton(
                              onPressed: () => connectToDevice(r.device),
                              style: ElevatedButton.styleFrom(
                                backgroundColor: AppColors.coral,
                                foregroundColor: AppColors.white,
                                padding: const EdgeInsets.symmetric(horizontal: 12),
                                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
                                elevation: 0,
                              ),
                              child: const Text("CONECTAR", style: TextStyle(fontSize: 11, fontWeight: FontWeight.bold)),
                            ),
                          ),
                        );
                      },
                    ),
            ),
          ],
        ),
      ),
    );
  }
}