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

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

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

class _BluetoothConnectionScreenState extends State<BluetoothConnectionScreen> {
  List<ScanResult> _scanResults = [];
  bool _isScanning = false;
  BluetoothDevice? _connectedDevice;
  late StreamSubscription<List<ScanResult>> _scanResultsSubscription;
  late StreamSubscription<bool> _isScanningSubscription;

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

    _scanResultsSubscription = FlutterBluePlus.scanResults.listen((results) {
      if (mounted) {
        setState(() {
          // Filtra os dispositivos para mostrar apenas aqueles que possuem um nome identificado
          _scanResults = results.where((r) => r.device.platformName.isNotEmpty).toList();
        });
      }
    });

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

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

  Future<void> _requestPermissionsAndStartScan() async {
    if (Platform.isAndroid) {
      Map<Permission, PermissionStatus> statuses = await [
        Permission.bluetoothScan,
        Permission.bluetoothConnect,
        Permission.bluetoothAdvertise,
        Permission.location,
      ].request();

      bool allGranted = true;
      if (statuses[Permission.bluetoothScan]?.isDenied ?? true) allGranted = false;
      if (statuses[Permission.bluetoothConnect]?.isDenied ?? true) allGranted = false;

      final bool scanPermanentlyDenied = statuses[Permission.bluetoothScan]?.isPermanentlyDenied ?? false;
      final bool connectPermanentlyDenied = statuses[Permission.bluetoothConnect]?.isPermanentlyDenied ?? false;

      if (scanPermanentlyDenied || connectPermanentlyDenied) {
        if (mounted) {
          _showSettingsDialog();
        }
        return;
      }

      if (allGranted) {
        _startScan();
      } else {
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text(AppStrings.permissionsDenied),
              behavior: SnackBarBehavior.floating,
            ),
          );
        }
      }
    } else {
      _startScan();
    }
  }

  void _showSettingsDialog() {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(AppStrings.permissionsNeeded),
        content: Text(AppStrings.permissionsDeniedPermanent),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(AppStrings.btnCancel),
          ),
          TextButton(
            onPressed: () {
              openAppSettings();
              Navigator.pop(context);
            },
            child: Text(AppStrings.settingsTitle),
          ),
        ],
      ),
    );
  }

  Future<void> _startScan() async {
    try {
      if (await FlutterBluePlus.adapterState.first != BluetoothAdapterState.on) {
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text(AppStrings.turnOnBluetooth),
              behavior: SnackBarBehavior.floating,
            ),
          );
        }
        return;
      }

      await FlutterBluePlus.startScan(
        timeout: const Duration(seconds: 15),
      );
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('${AppStrings.scanError}$e'),
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
    }
  }

  Future<void> _stopScan() async {
    try {
      await FlutterBluePlus.stopScan();
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('${AppStrings.stopScanError}$e'),
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
    }
  }

  Future<void> _connectToDevice(BluetoothDevice device) async {
    try {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('${AppStrings.connectingTo}${device.platformName.isEmpty ? AppStrings.unknownDevice : device.platformName}...'),
          duration: const Duration(seconds: 2),
          behavior: SnackBarBehavior.floating,
        ),
      );

      await device.connect();
      if (mounted) {
        setState(() {
          _connectedDevice = device;
          _isScanning = false;
        });
        FlutterBluePlus.stopScan();
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(AppStrings.connectedSuccess),
            backgroundColor: AppColors.success,
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('${AppStrings.connectFail}$e'),
            backgroundColor: AppColors.error,
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
    }
  }

  Future<void> _disconnectDevice() async {
    if (_connectedDevice != null) {
      await _connectedDevice!.disconnect();
      setState(() {
        _connectedDevice = null;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: AppBar(
        title: Text(
          AppStrings.bluetoothTitle,
          style: const TextStyle(
            fontWeight: FontWeight.w900,
            letterSpacing: 2,
            color: Colors.white,
          ),
        ),
        centerTitle: true,
        backgroundColor: Colors.transparent,
        elevation: 0,
        leading: IconButton(
          icon: const Icon(Icons.arrow_back_ios_new, color: Colors.white, size: 20),
          onPressed: () => Navigator.pop(context),
        ),
      ),
      body: Stack(
        children: [
          Column(
            children: [
              const SizedBox(height: 20),
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 25),
                child: Container(
                  padding: const EdgeInsets.all(25),
                  decoration: BoxDecoration(
                    color: AppColors.backgroundGrey,
                    borderRadius: BorderRadius.circular(30),
                    border: Border.all(color: Colors.white.withValues(alpha: 0.05)),
                    boxShadow: [
                      BoxShadow(
                        color: Colors.black.withValues(alpha: 0.3),
                        blurRadius: 20,
                        offset: const Offset(0, 10),
                      ),
                    ],
                  ),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            _connectedDevice != null
                                ? AppStrings.statusConnected
                                : (_isScanning ? AppStrings.searching : AppStrings.statusReady),
                            style: TextStyle(
                              color: _connectedDevice != null ? Colors.greenAccent : (_isScanning ? AppColors.coral : Colors.white54),
                              fontSize: 10,
                              fontWeight: FontWeight.w900,
                              letterSpacing: 1,
                            ),
                          ),
                          const SizedBox(height: 8),
                          Text(
                            _connectedDevice != null
                                ? AppStrings.oneDevice
                                : '${_scanResults.length} ${AppStrings.foundDevices}',
                            style: const TextStyle(
                              color: Colors.white,
                              fontSize: 22,
                              fontWeight: FontWeight.w900,
                            ),
                          ),
                        ],
                      ),
                      if (_connectedDevice == null)
                        GestureDetector(
                          onTap: _isScanning ? _stopScan : _requestPermissionsAndStartScan,
                          child: Container(
                            padding: const EdgeInsets.all(15),
                            decoration: BoxDecoration(
                              color: _isScanning ? Colors.red.withValues(alpha: 0.1) : AppColors.coral.withValues(alpha: 0.1),
                              shape: BoxShape.circle,
                              border: Border.all(
                                color: _isScanning ? Colors.red.withValues(alpha: 0.5) : AppColors.coral.withValues(alpha: 0.5),
                                width: 2,
                              ),
                            ),
                            child: Icon(
                              _isScanning ? Icons.stop_rounded : Icons.search_rounded,
                              color: _isScanning ? Colors.red : AppColors.coral,
                              size: 28,
                            ),
                          ),
                        )
                      else
                        GestureDetector(
                          onTap: _disconnectDevice,
                          child: Container(
                            padding: const EdgeInsets.all(15),
                            decoration: BoxDecoration(
                              color: Colors.red.withValues(alpha: 0.1),
                              shape: BoxShape.circle,
                              border: Border.all(
                                color: Colors.red.withValues(alpha: 0.5),
                                width: 2,
                              ),
                            ),
                            child: const Icon(
                              Icons.close_rounded,
                              color: Colors.red,
                              size: 28,
                            ),
                          ),
                        ),
                    ],
                  ),
                ),
              ),
              const SizedBox(height: 30),
              Expanded(
                child: ListView.builder(
                  itemCount: _connectedDevice != null ? 1 : _scanResults.length,
                  padding: const EdgeInsets.symmetric(horizontal: 25),
                  physics: const BouncingScrollPhysics(),
                  itemBuilder: (context, index) {
                    final BluetoothDevice device = _connectedDevice ?? _scanResults[index].device;
                    final name = device.platformName.isEmpty ? AppStrings.unknownDevice : device.platformName;

                    return Padding(
                      padding: const EdgeInsets.only(bottom: 18),
                      child: Container(
                        padding: const EdgeInsets.all(20),
                        decoration: BoxDecoration(
                          color: AppColors.backgroundGrey.withValues(alpha: 0.4),
                          borderRadius: BorderRadius.circular(25),
                          border: Border.all(color: Colors.white.withValues(alpha: 0.03)),
                        ),
                        child: Row(
                          children: [
                            Container(
                              padding: const EdgeInsets.all(12),
                              decoration: BoxDecoration(
                                color: AppColors.background.withValues(alpha: 0.8),
                                borderRadius: BorderRadius.circular(15),
                              ),
                              child: Icon(
                                  Icons.bluetooth_audio_rounded,
                                  color: _connectedDevice != null ? Colors.greenAccent : AppColors.coral.withValues(alpha: 0.8),
                                  size: 24
                              ),
                            ),
                            const SizedBox(width: 20),
                            Expanded(
                              child: Column(
                                crossAxisAlignment: CrossAxisAlignment.start,
                                children: [
                                  Text(
                                    name,
                                    style: const TextStyle(
                                        color: Colors.white,
                                        fontSize: 16,
                                        fontWeight: FontWeight.w900
                                    ),
                                  ),
                                  const SizedBox(height: 4),
                                  Text(
                                    device.remoteId.toString(),
                                    style: const TextStyle(
                                        color: Colors.white38,
                                        fontSize: 11,
                                        fontWeight: FontWeight.bold
                                    ),
                                  ),
                                ],
                              ),
                            ),
                            if (_connectedDevice == null)
                              GestureDetector(
                                onTap: () => _connectToDevice(device),
                                child: const Icon(Icons.add_link_rounded, color: Colors.white24),
                              )
                            else
                              const Icon(Icons.check_circle_rounded, color: Colors.greenAccent),
                          ],
                        ),
                      ),
                    );
                  },
                ),
              ),
            ],
          ),
          if (_isScanning)
            const Positioned(
              bottom: 0,
              left: 0,
              right: 0,
              child: LinearProgressIndicator(
                backgroundColor: Colors.transparent,
                valueColor: AlwaysStoppedAnimation<Color>(AppColors.coral),
                minHeight: 2,
              ),
            ),
        ],
      ),
    );
  }
}