I’m trying to implement a feature in my iOS app where I need to schedule local notifications that repeat at different intervals “weekly“, “monthly“, or “yearly“, starting from a specified date. I’m using the UNCalendarNotificationTrigger with the repeats parameter set to true, but I’m not sure if it handles different repeating periods as expected.

Here’s the function I’ve written:

func scheduleNotifications(startDate: Date?, remindersDayBefore: Int16, periodType: PeriodType) {

    // Calculate the reminder date based on the start date and reminders day before
    let calendar = Calendar.current
    var reminderDate = calendar.date(byAdding: .day, value: 0, to: startDate)!

    let currentDate = Date()

    // If the reminder date is in the past, calculate the next occurrence
    if reminderDate < currentDate {
        switch periodType {
        case .weekly:
            reminderDate = calendar.date(byAdding: .day, value: 0, to: reminderDate)!
        case .monthly:
            reminderDate = calendar.date(byAdding: .month, value: 0, to: reminderDate)!
        case .yearly:
            reminderDate = calendar.date(byAdding: .year, value: 0, to: reminderDate)!
            return
        }
    }

    // Extract date components for the trigger
    var reminderComponents = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: reminderDate)

    // Create the notification content
    let content = UNMutableNotificationContent()
    switch remindersDayBefore {
case 0:
    content.title = "Reminder: Event today"
    content.body = "This is a reminder that your event is today."
case 1:
    content.title = "Reminder: Event tomorrow"
    content.body = "This is a reminder that your event is tomorrow."
default:
    content.title = "Reminder: Event in (remindersDayBefore) days"
    content.body = "This is a reminder that your event is scheduled in (remindersDayBefore) days."
}

    content.sound = .default

    // Create the calendar notification trigger
    let trigger = UNCalendarNotificationTrigger(dateMatching: reminderComponents, repeats: true)

    // Create the notification request
    let notificationRequest = UNNotificationRequest(identifier: subscription.id.uuidString, content: content, trigger: trigger)

    // Add the notification request
    UNUserNotificationCenter.current().add(notificationRequest) { (error) in
        if let error = error {
            print("Error adding notification: (error)")
        } else {
            print("Notification scheduled successfully.")
        }
    }
}

My Questions:

1. Will this setup correctly handle notifications that repeat weekly,
   monthly, or yearly? Specifically, I’m concerned about the
   UNCalendarNotificationTrigger and whether it will continue to work
   correctly for these different intervals after the initial trigger.

2. How can I test these notifications to make sure they work as
   expected for future dates and different repeating periods? I’ve had
   trouble testing on a real device and the iOS simulator is tied to
   the macOS system date.

Thanks in advance!