import 'dart:async';
import 'package:flutter/material.dart';
import 'package:bluetooth_print/bluetooth_print_model.dart';
import '../services/bluetooth_service.dart';

class BluetoothScanDialog extends StatefulWidget {
  final BluetoothService bluetoothService;
  final void Function(BluetoothDevice device, bool success)? onDeviceConnected;

  const BluetoothScanDialog({
    super.key,
    required this.bluetoothService,
    this.onDeviceConnected,
  });

  @override
  State<BluetoothScanDialog> createState() => _BluetoothScanDialogState();
}

class _BluetoothScanDialogState extends State<BluetoothScanDialog> {
  bool _isScanning = false;
  List<BluetoothDevice> _scannedDevices = [];
  String? _connectingAddress;

  StreamSubscription<List<BluetoothDevice>>? _scanResultsSub;
  StreamSubscription<bool>? _isScanningSub;

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

    // 1. Langsung berlangganan ke stream hasil scan agar perangkat yang ditemukan seketika tampil di UI
    _scanResultsSub = widget.bluetoothService.scanResults.listen((devices) {
      if (mounted) {
        setState(() {
          _scannedDevices = devices;
        });
      }
    });

    // 2. Berlangganan ke stream status scan untuk sinkronisasi indikator loading
    _isScanningSub = widget.bluetoothService.isScanning.listen((scanning) {
      if (mounted) {
        setState(() {
          _isScanning = scanning;
        });
      }
    });

    // 3. Mulai pemindaian perdana tepat 1 kali saat dialog dibuka
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) {
        _startScan();
      }
    });
  }

  @override
  void dispose() {
    _scanResultsSub?.cancel();
    _isScanningSub?.cancel();
    widget.bluetoothService.stopScan();
    super.dispose();
  }

  Future<void> _startScan() async {
    if (_connectingAddress != null) return;

    if (mounted) {
      setState(() {
        _isScanning = true;
        _scannedDevices.clear();
      });
    }

    try {
      await widget.bluetoothService.startScan(timeout: const Duration(seconds: 5));
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Gagal memindai: $e')),
        );
      }
    }
  }

  Future<void> _connect(BluetoothDevice device) async {
    if (_connectingAddress != null) return;

    setState(() {
      _connectingAddress = device.address;
    });

    // Hentikan pemindaian terlebih dahulu sebelum menyambungkan ke BLE device
    await widget.bluetoothService.stopScan();

    final ok = await widget.bluetoothService.connectToDevice(device);

    if (mounted) {
      widget.onDeviceConnected?.call(device, ok);
      Navigator.of(context).pop();
    }
  }

  @override
  Widget build(BuildContext context) {
    return PopScope(
      canPop: true,
      onPopInvokedWithResult: (didPop, _) {
        if (didPop) {
          widget.bluetoothService.stopScan();
        }
      },
      child: AlertDialog(
        title: Row(
          children: [
            const Icon(Icons.bluetooth_searching, color: Colors.blue),
            const SizedBox(width: 8),
            const Expanded(
              child: Text(
                'Pindai Printer Bluetooth',
                style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold),
              ),
            ),
            if (_isScanning)
              const SizedBox(
                width: 16,
                height: 16,
                child: CircularProgressIndicator(strokeWidth: 2),
              ),
          ],
        ),
        content: SizedBox(
          width: MediaQuery.of(context).size.width,
          height: 320,
          child: Column(
            children: [
              if (_isScanning)
                const Padding(
                  padding: EdgeInsets.symmetric(vertical: 6.0),
                  child: Text(
                    'Mencari printer thermal di sekitar...',
                    style: TextStyle(color: Colors.grey, fontSize: 12),
                  ),
                ),
              Expanded(
                child: _scannedDevices.isEmpty
                    ? Center(
                        child: _isScanning
                            ? const Text('Sedang memindai perangkat...')
                            : const Text(
                                'Tidak ada perangkat Bluetooth ditemukan.\nPastikan Bluetooth & printer aktif.',
                                textAlign: TextAlign.center,
                                style: TextStyle(color: Colors.grey),
                              ),
                      )
                    : ListView.builder(
                        itemCount: _scannedDevices.length,
                        itemBuilder: (context, index) {
                          final dev = _scannedDevices[index];
                          final isConnectingThis = _connectingAddress == dev.address;

                          return Card(
                            margin: const EdgeInsets.symmetric(vertical: 4),
                            child: ListTile(
                              leading: const Icon(Icons.print, color: Colors.blue),
                              title: Text(
                                dev.name ?? 'Perangkat Bluetooth',
                                style: const TextStyle(fontWeight: FontWeight.w600),
                              ),
                              subtitle: Text(dev.address ?? ''),
                              trailing: ElevatedButton(
                                onPressed: (_connectingAddress != null)
                                    ? null
                                    : () => _connect(dev),
                                child: isConnectingThis
                                    ? const SizedBox(
                                        width: 16,
                                        height: 16,
                                        child: CircularProgressIndicator(strokeWidth: 2),
                                      )
                                    : const Text('Hubungkan'),
                              ),
                            ),
                          );
                        },
                      ),
              ),
            ],
          ),
        ),
        actions: [
          TextButton(
            onPressed: (_isScanning || _connectingAddress != null)
                ? null
                : () => _startScan(),
            child: const Text('Pindai Ulang'),
          ),
          TextButton(
            onPressed: () {
              Navigator.of(context).pop();
            },
            child: const Text('Tutup'),
          ),
        ],
      ),
    );
  }
}