NSDateComponents / NSDate : get the last sunday

Question

I know there are some questions similar to this one, but I just can't find what's wrong with my code.

Basically what I want is if today is not sunday, currentDate is set to the last sunday. If today is sunday I currentDate is set to the sunday before.

Here's how I'm trying to do it.

  NSDateComponents *components = [[NSCalendar currentCalendar] components:  NSWeekCalendarUnit | NSYearCalendarUnit | NSWeekdayCalendarUnit fromDate:currentDate];

    if (components.weekday == 1) { //Its sunday. We just need to subtract a week
        [components setWeek: -1];
        currentDate = [[NSCalendar currentCalendar] dateByAddingComponents:components toDate:currentDate options:0];

    }else{ //If its not sunday we just go to sunday
        [components setWeekday: 1];
        currentDate = [[NSCalendar currentCalendar] dateFromComponents:components];

    }

The first time this part of the code is executed I get the right answer. After the first time I get weird dates, like 02 Dec. 4026, and the year keeps going up.

Here's the code that made it work:

   NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components: ( NSWeekCalendarUnit | NSWeekdayCalendarUnit | NSYearCalendarUnit) fromDate:currentDate];
    int weekday = components.weekday;

    if (weekday == 1) {
        [components setWeek:components.week -1];
    }else{
        [components setWeekday:1];
    }
    currentDate = [calendar dateFromComponents:components];

Answer 1

Use nextDateAfterDate with the .SearchBackwards option if you are using iOS 8.0+

let calendar = NSCalendar.currentCalendar()
let options: NSCalendarOptions = [.MatchPreviousTimePreservingSmallerUnits, .SearchBackwards]
calendar.nextDateAfterDate(NSDate(), matchingUnit: .Weekday, value: 1, options: options)