BLECheck.swift

class BLECheck {
    private static var manager: CBCentralManager?
    private static func getManager() -> CBCentralManager {
        if (manager == nil) {
            manager = CBCentralManager(delegate: nil, queue: nil, options: [CBCentralManagerOptionShowPowerAlertKey: false])
        }
        
        return manager!
    }
    
    static func getState() -> CBManagerState? {
        if (!isBluetoothPermissionGranted()) {
            return nil
        }
        
        return getManager().state
    }
    
    private static func isBluetoothPermissionGranted() -> Bool {
        if (!getIfUsageSet()) {
            return false
        }
        
        if #available(iOS 13.1, *) {
            return CBCentralManager.authorization == .allowedAlways
        } else if #available(iOS 13.0, *) {
            return getManager().authorization == .allowedAlways
        }
        // Before iOS 13, Bluetooth permissions are not required to check permission
        return true
    }
    
    private static func getIfUsageSet() -> Bool {
        if #available(iOS 13.0, *) {
            return Bundle.main.object(forInfoDictionaryKey: "NSBluetoothAlwaysUsageDescription") != nil
        } else {
            return Bundle.main.object(forInfoDictionaryKey: "NSBluetoothPeripheralUsageDescription") != nil
        }
        
    }
}