How to calculate the difference in days for two Date in Swift as days start at 6 a.m. instead of 0 - swift

Question

I'm trying to get the difference in two Date objects.
I know how to do it basically, which is like this:
let date = Date()
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale.current
print(count)
// print(history[count - 1].value(forKey: "multipleURLs") as! [String])
let latestDate = history[count - 1].value(forKey: "date") as! Date
let calendar = Calendar.current
let components = calendar.dateComponents([.year, .month, .day, .hour], from: date)
let nowDate = calendar.startOfDay(for: date)
let lastDate = calendar.startOfDay(for: latestDate)
let diffDateComponent = (calendar as NSCalendar).components([NSCalendar.Unit.year, NSCalendar.Unit.month, NSCalendar.Unit.day], from: lastDate, to: nowDate, options: NSCalendar.Options.init(rawValue: 0))
print("Status Checked" + String(describing: diffDateComponent.day))
But I'm trying to get the result as a day start from 6 a.m. in the morning instead of 0.
So I did something like this:
let nowDate = calendar.startOfDay(for: date.addingTimeInterval(-3600))
let lastDate = calendar.startOfDay(for: latestDate.addingTimeInterval(-3600))
But it doesn't seem to be working, can anyone help me with this?

Answer 1

This will set each date to 6 AM (in the current locale of the Date):
import Foundation
// set up dates
let calendar = Calendar.current
let date = Date()
if let latestDate = calendar.date(byAdding: .day, value: -5, to: date) {
// set each day to 6 AM
if let nowDate = calendar.date(bySettingHour: 6, minute: 0, second: 0, of: date ),
let lastDate = calendar.date(bySettingHour: 6, minute: 0, second: 0, of: latestDate) {
print( date.description(with: .current),
nowDate.description(with: .current),
lastDate.description(with: .current),
separator: "\n")
// calculate difference in days
if let days = calendar.dateComponents([.day], from: lastDate, to: nowDate).day {
print("Days since: \(days)")
}
}
}
// Thursday, June 8, 2017 at 7:59:42 AM Eastern Daylight Time
// Thursday, June 8, 2017 at 6:00:00 AM Eastern Daylight Time
// Saturday, June 3, 2017 at 6:00:00 AM Eastern Daylight Time
// Days since: 5

Answer 2

Thanks guy, I finally figured it out. In case anyone need it, this is how it's done:
let date = Date()
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale.current
let latestDate = history[count - 1].value(forKey: "date") as! Date
let calendar = Calendar.current
let nowDate = calendar.date(byAdding: .hour, value: -6, to: date)
let lastDate = calendar.date(byAdding: .hour, value: -6, to: latestDate)
let finalNowDate = calendar.startOfDay(for: nowDate!)
let finalLastDate = calendar.startOfDay(for: lastDate!)
let diffDateComponent = calendar.dateComponents([.day], from: finalLastDate, to: finalNowDate)
print("dif\(diffDateComponent.day)")