ios – Learn how to name an API at precisely 00 and half-hour each hour in Swift?

I’m making an attempt to implement a repeating API name in my iOS app (Swift), and I would like the decision to occur at precisely 00 and half-hour of each hour (e.g., 1:00, 1:30, 2:00, and so on.).

• On launch (when app is in foreground), I wish to make the primary API name to examine if a slot is offered.
• Then, I wish to schedule the API to run at each hour and half-hour mark.
• This must be correct to the clock (not simply each 1800 seconds), so the API ought to hearth precisely at hh:00 and hh:30.

Utilizing this strategy, the API is known as 30–40 occasions per minute inside a single view controller. The API name is triggered from a customized navigation bar (ENavigationBar), which is subclass of UIView.

func scheduleFunctionCall() {
    if UIApplication.shared.applicationState == .background { return }

    // We examine the physician appointment the primary time to see if it is obtainable.
    self.drTimer?.invalidate()
    self.drTimer = nil
    
    if !GlobalConstant.appCONSTANT.isDrAppointmentCheckedFirstTime {
        checkDrAppointmentAvailable()
    } else {
        if GlobalConstant.appCONSTANT.roomName != "" {
            showNeedHelpDrButton()
        } else {
            hideNeedHelpDrView()
        }
    }

    // Get the present time
    let calendar = Calendar.present
    let now = Date()
    let minute = calendar.part(.minute, from: now)
    let second = calendar.part(.second, from: now)
    var fireInSeconds: TimeInterval = 0

    if minute < 1 || (minute >= 31 && minute < 32) {
        // If it is already at :00 or :30, simply look ahead to the subsequent second alignment
        fireInSeconds = TimeInterval(60 - second)
    } else if minute < 31 {
        fireInSeconds = TimeInterval((31 - minute) * 60 - second)
    } else {
        fireInSeconds = TimeInterval((61 - minute) * 60 - second)
    }

    Timer.scheduledTimer(withTimeInterval: fireInSeconds, repeats: false) { _ in
        self.checkDrAppointmentAvailable()
        
        // Now arrange the repeating timer each half-hour
        self.drTimer = Timer.scheduledTimer(withTimeInterval: 1800, repeats: true) { _ in
            self.checkDrAppointmentAvailable()
            let nextMinute = minute < 31 ? "00" : "30"
            print("Operate known as at (calendar.part(.hour, from: Date())):(nextMinute)")
        }
    }
}