JDTimeIntervalExtension

extension TimeInterval {

    func asHoursMinutesSeconds () -> (Int, Int, Int) {
        let interval = Int(self)
        return ( interval / 3600, interval % 3600 / 60, (interval % 3600) % 60)
    }
    
    
    /// Creates a string with hours, minutes, seconds,
    /// divided by the given separator.
    /// For example: "1:23:59"
    ///
    /// - Parameters:
    ///   - separator: separator between time units
    /// - Returns: <#return value description#>
    func asHoursMinutesSecondsString(_ separator:String) -> String {
        let interval = Int(self)
        let (h, m, s) = self.asHoursMinutesSeconds ()
        
        let strHours = String(format: "%02d", h)
        let strMinutes = String(format: "%02d", m)
        let strSeconds = String(format: "%02d", s)

        if (interval < 3600) {
            return "\(strMinutes)\(separator)\(strSeconds)"
        }
        else {
            return "\(strHours)\(separator)\(strMinutes):\(strSeconds)"
        }
    }
}