SmsReaderUtil.kt

class SmsReaderUtil @Inject constructor() {

    private var smsReceiver: SmsReceiver? = null

    fun register(activity: Activity?) {
        smsReceiver = SmsReceiver()
        activity?.let {
            val intentFilter = IntentFilter(SmsRetriever.SMS_RETRIEVED_ACTION)
            activity.registerReceiver(smsReceiver, intentFilter)
        }
    }

    fun setup(activity: Activity?, success: (intent: Intent) -> Unit) {
        activity?.let {
            smsReceiver?.success = success

            try {
                val client = SmsRetriever.getClient(activity)
                val task = client?.startSmsUserConsent(NUMBER_OTP_SMS_SERVICE)

                task?.addOnCanceledListener {
                    log("OTP Retriever Canceled")
                }

                task?.addOnFailureListener {
                    log("OTP Retriever Failed ${it.message}")
                }

            } catch (e: Exception) {
                unRegister(activity)
            }
        }
    }

    fun handleOnResult(data: Intent?, isSixDigit: Boolean, success: (code: String) -> Unit, error: () -> Unit) {
        val message = data?.getStringExtra(SmsRetriever.EXTRA_SMS_MESSAGE)

        if (message != null && message.toLowerCase().contains(SMS_OTP_KEY)) {
            val code = /** Parse SMS to get Code */

            if(code != null) {
              success.invoke(code)
            } else {
              error.invoke()
            }
        }
    }

    fun unRegister(activity: Activity?) {
        activity?.let {
            if (smsReceiver != null) {
                activity.unregisterReceiver(smsReceiver)
                smsReceiver = null
            }
        }
    }

    private fun log(message: String) {
        if (BuildConfig.DEBUG) Log.e(this.javaClass.name, message)
    }

}