Companion Gists to the Introduction to Core Bluetooth Class

01-SecondStep-00.swift

extension ITCB_SDK_Device_Peripheral: CBPeripheralDelegate {
    public func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
        if let error = error {
            print("Encountered an error \(error) for the Peripheral \(peripheral.name ?? "ERROR")")
            owner?._sendErrorMessageToAllObservers(error: ITCB_Errors.coreBluetooth(error))
            return
        }
        print("Successfully Discovered \(peripheral.services?.count ?? 0) Services for \(peripheral.name ?? "ERROR").")
        peripheral.services?.forEach {
            print("Discovered Service: \($0.uuid.uuidString)")
            peripheral.discoverCharacteristics([_static_ITCB_SDK_8BallService_Question_UUID,
                                                _static_ITCB_SDK_8BallService_Answer_UUID], for: $0)
        }
    }
}

01-SecondStep-01.swift

    public func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        if let error = error {
            print("Encountered an error \(error) for the Peripheral \(peripheral.name ?? "ERROR")")
            owner?._sendErrorMessageToAllObservers(error: ITCB_Errors.coreBluetooth(error))
            return
        }
        print("Successfully Discovered \(service.characteristics?.count ?? 0) Characteristics for the Service \(service.uuid.uuidString), on the Peripheral \(peripheral.name ?? "ERROR").")
        service.characteristics?.forEach {
            print("Discovered Characteristic: \($0.uuid.uuidString)")
        }
        owner.peripheralServicesUpdated(self)
    }

01-SecondStep-02.swift

extension ITCB_SDK_Device_Peripheral {
    public func sendQuestion(_ inQuestion: String) {
        question = nil
        if  let peripheral = _peerInstance as? CBPeripheral,
            let service = peripheral.services?[_static_ITCB_SDK_8BallServiceUUID.uuidString],
            let answerCharacteristic = service.characteristics?[_static_ITCB_SDK_8BallService_Answer_UUID.uuidString] {
            _timeoutTimer = Timer.scheduledTimer(withTimeInterval: _timeoutLengthInSeconds, repeats: false) { [unowned self] (_) in
                self._timeoutTimer = nil
                self.owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_RejectionReason.deviceOffline))
            }
            _interimQuestion = inQuestion
        
            print("We have received the question \"\(inQuestion)\", and are setting it aside, as we ask the Peripheral to set the notify to true for the answer Characteristic.")
            peripheral.setNotifyValue(true, for: answerCharacteristic)
        } else {
            self.owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_RejectionReason.deviceOffline))
        }
    }
}

01-SecondStep-03.swift

    public func peripheral(_ peripheral: CBPeripheral, didUpdateNotificationStateFor characteristic: CBCharacteristic, error: Error?) {
        if let error = error {
            _timeoutTimer?.invalidate()
            _timeoutTimer = nil
            owner?._sendErrorMessageToAllObservers(error: ITCB_Errors.coreBluetooth(error))
            return
        }

        if  let question = _interimQuestion,
            let data = question.data(using: .utf8),
            characteristic.isNotifying,
            let service = peripheral.services?[_static_ITCB_SDK_8BallServiceUUID.uuidString],
            let questionCharacteristic = service.characteristics?[_static_ITCB_SDK_8BallService_Question_UUID.uuidString] {
            print("The Peripheral's answer Characteristic is now notifying.")
            print("Asking the Peripheral \(peripheral.name ?? "ERROR") the question \"\(_interimQuestion ?? "ERROR")\".")
            peripheral.writeValue(data, for: questionCharacteristic, type: .withResponse)
        }
    }

01-SecondStep-04.swift

    public func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
        guard let error = error else {
            print("Characteristic \(characteristic.uuid.uuidString) reports that its value was accepted by the Peripheral.")
            if let questionString = _interimQuestion {
                _interimQuestion = nil
                question = questionString
            } else {
                owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_RejectionReason.peripheralError(nil)))
            }
            
            return
        }
        
        _timeoutTimer?.invalidate()
        _timeoutTimer = nil
        
        if let error = error as? CBATTError {
            print("Encountered an error \(error) for the Peripheral \(peripheral.name ?? "ERROR")")
            switch error {
            case CBATTError.unlikelyError:
                owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_Errors.coreBluetooth(ITCB_RejectionReason.questionPlease)))

            default:
                owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_Errors.coreBluetooth(ITCB_RejectionReason.peripheralError(error))))
            }
        } else {
            owner?._sendErrorMessageToAllObservers(error: .sendFailed(ITCB_RejectionReason.unknown(error)))
        }
    }

01-SecondStep-05.swift

    public func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
        _timeoutTimer?.invalidate()
        _timeoutTimer = nil
        if let error = error {
            print("Encountered an error \(error) for the Peripheral \(peripheral.name ?? "ERROR")")
            owner?._sendErrorMessageToAllObservers(error: ITCB_Errors.coreBluetooth(error))
            return
        }
        print("Characteristic \(characteristic.uuid.uuidString) Updated its value to \(String(describing: characteristic.value)).")
        if  let answerData = characteristic.value,
            let answerString = String(data: answerData, encoding: .utf8),
            !answerString.isEmpty {
            peripheral.setNotifyValue(false, for: characteristic)
            answer = answerString
        }
    }

01-SecondStep-ArrayExtension.swift

extension Array where Element: CBAttribute {
    public subscript(_ inUUIDString: String) -> Element! {
        for element in self where element.uuid.uuidString == inUUIDString {
            return element
        }
        
        return nil
    }
}