Connecting to a Microcontroller using Bluetooth (BLE).

import 'package:flutter/foundation.dart';
import 'dart:convert';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';

Future<bool> connectDeviceUsingQR(String jsonString) async {
  try {
    // Parse the JSON string
    final Map<String, dynamic> decodedJson = jsonDecode(jsonString);
    final String? deviceId = decodedJson['deviceId'];
    final String? serviceUuid = decodedJson['serviceUuid'];

    if (deviceId == null || serviceUuid == null) {
      debugPrint('Error: deviceId or serviceUuid is missing');
      return false;
    }

    // Get the Bluetooth device using its ID
    final device = BluetoothDevice.fromId(deviceId);
    bool hasWriteCharacteristic = false;

    // Attempt to connect to the device with a timeout
    try {
      if (!await device.isConnected) {
        await device.connect().timeout(
          const Duration(seconds: 2),
          onTimeout: () {
            debugPrint('Error: Connection timed out');
            throw Exception('Connection timed out');
          },
        );
      }
    } catch (e) {
      debugPrint('Error connecting to device: $e');
      return false;
    }

    // Discover services and characteristics
    final services = await device.discoverServices();
    for (var service in services) {
      if (service.uuid.toString() == serviceUuid) {
        // Match with provided UUID
        for (var characteristic in service.characteristics) {
          if (characteristic.properties.write) {
            hasWriteCharacteristic = true;
            debugPrint('Found writable characteristic: ${characteristic.uuid}');
          }
        }
      }
    }

    return hasWriteCharacteristic;
  } catch (e) {
    debugPrint('Unexpected error: $e');
    return false;
  }
}