how to set local notifications between 8am and 8pm every day - swift

Question

So I am very new to Swift and I'm currently setting a repeating timer every 30 min after the app was launched, but i would like to only send notification between 8 am and 8 pm. Is it possible to do this without setting a reminder for each specific time?
This is how I'm currently doing this.
override func viewDidLoad(){
let notificationCenter = UNUserNotificationCenter.current()
notificationCenter.requestAuthorization(options: [.alert, .sound]) { (granted, error ) in
// enable or disable if needed.
if granted {
print("We have permission to send notifications")
} else {
print("We don't have the option to send notifications")
}
}
notificationCenter.removeAllDeliveredNotifications()
notificationCenter.removeAllPendingNotificationRequests()
// The actual notification the user will receive
let notification = UNMutableNotificationContent()
notification.title = "You should have some water"
notification.body = "It has been a long time since you had some water, why don't you have some."
notification.categoryIdentifier = "reminder"
notification.sound = .default
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: (60*30), repeats: true)
let uuidString = UUID().uuidString
let request = UNNotificationRequest(identifier: uuidString, content: notification, trigger: trigger)
notificationCenter.add(request, withCompletionHandler: nil)
}

Answer 1

Unfortunately you do need to add a notification request for each 30 minute interval in the 8am-8pm window. What is your aversion to this approach? It's a simple for-loop. Instead of using a UNTimeIntervalNotificationTrigger you would use a UNCalendarNotificationTrigger.
let notificationCenter = UNUserNotificationCenter.current()
notificationCenter.removeAllDeliveredNotifications()
notificationCenter.removeAllPendingNotificationRequests()
let startHour = 8
let totalHours = 12
let totalHalfHours = totalHours * 2
for i in 0...totalHalfHours {
var date = DateComponents()
date.hour = startHour + i / 2
date.minute = 30 * (i % 2)
print("\(date.hour!):\(date.minute!)")
let notification = UNMutableNotificationContent()
notification.title = "You should have some water"
notification.body = "It has been a long time since you had some water, why don't you have some."
notification.categoryIdentifier = "reminder"
notification.sound = .default
let trigger = UNCalendarNotificationTrigger(dateMatching: date, repeats: true)
let uuidString = UUID().uuidString
let request = UNNotificationRequest(identifier: uuidString, content: notification, trigger: trigger)
notificationCenter.add(request, withCompletionHandler: nil)
}