I tried something like this:
var calendar = Calendar.current
var dayFutureComponents = DateComponents()
dayFutureComponents.day = 1 // aka 1 day
var d = calendar.date(byAdding: dayFutureComponents, to: Date())
...//setting of d.hour, d.minute, d.second to zero and finding the difference between 2 dates
The problem is for example my current GMT is +3. So the result differs from one I need to achieve by 3 hours. How to fix this issue?
First create a Calendar for the UTC timezone. Second get the startOfDay using the UTC calendar. Third add one day to that date. Then you can useDatemethodtimeIntervalSince(_ Date)` to calculate the amount of seconds between those two dates:
extension Calendar {
static let iso8601UTC: Calendar = {
var calendar = Calendar(identifier: .iso8601)
calendar.timeZone = TimeZone(identifier: "UTC")!
return calendar
}()
}
extension Date {
var secondsUntilStartOfDayTomorrowAtUTC: TimeInterval {
return startOfDayTomorrowAtUTC.timeIntervalSince(self)
}
var startOfDayTomorrowAtUTC: Date {
return Calendar.current.date(byAdding: .day, value: 1, to: startOfDayAtUTC)!
}
var startOfDayAtUTC: Date {
return Calendar.iso8601UTC.startOfDay(for: self)
}
}
Playground Testing:
TimeZone.current.secondsFromGMT(for: Date()) / 3600 // -2 hours
Date().startOfDayAtUTC // "Jan 18, 2018 at 10:00 PM"
let finalDate = Date().startOfDayTomorrowAtUTC // "Jan 19, 2018 at 10:00 PM"
print(finalDate) // "2018-01-20 00:00:00 +0000\n"
let seconds = Date().secondsUntilStartOfDayTomorrowAtUTC // 29282.42592203617
let minutes = seconds / 60 // 488.0404320339362
let hours = seconds / 3600 // 8.134007200565604
Missed out that when I for example set hour to 0 - it displayed according to GMT (in my case it is 3 hours of difference). And When I calculate the difference between 2 dates - both dates has the same "displacement" so final result should be the same
