/**
 * 計算上次日期距離現在多久
 *
 * @param lastTime  上次日期(需要和格式對應)
 * @param format1   上次日期格式
 * @param currentTime 最近日期(需要和格式對應)
 * @param format2   最近日期格式
 *
 * @return xx分鐘前、xx小時前、xx天前
 */
+ (NSString *)timeIntervalFromLastTime:(NSString *)lastTime
            lastTimeFormat:(NSString *)format1
             ToCurrentTime:(NSString *)currentTime
           currentTimeFormat:(NSString *)format2{
  //上次時間
  NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc]init];
  dateFormatter1.dateFormat = format1;
  NSDate *lastDate = [dateFormatter1 dateFromString:lastTime];
  //當前時間
  NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc]init];
  dateFormatter2.dateFormat = format2;
  NSDate *currentDate = [dateFormatter2 dateFromString:currentTime];
  return [Utilities timeIntervalFromLastTime:lastDate ToCurrentTime:currentDate];
}
 
+ (NSString *)timeIntervalFromLastTime:(NSDate *)lastTime ToCurrentTime:(NSDate *)currentTime{
  NSTimeZone *timeZone = [NSTimeZone systemTimeZone];
  //上次時間
  NSDate *lastDate = [lastTime dateByAddingTimeInterval:[timeZone secondsFromGMTForDate:lastTime]];
  //當前時間
  NSDate *currentDate = [currentTime dateByAddingTimeInterval:[timeZone secondsFromGMTForDate:currentTime]];
  //時間間隔
  NSInteger intevalTime = [currentDate timeIntervalSinceReferenceDate] - [lastDate timeIntervalSinceReferenceDate];
 
  //秒、分、小時、天、月、年
  NSInteger minutes = intevalTime / 60;
  NSInteger hours = intevalTime / 60 / 60;
  NSInteger day = intevalTime / 60 / 60 / 24;
  NSInteger month = intevalTime / 60 / 60 / 24 / 30;
  NSInteger yers = intevalTime / 60 / 60 / 24 / 365;
 
  if (minutes <= 10) {
    return @"剛剛";
  }else if (minutes < 60){
    return [NSString stringWithFormat: @"%ld分鐘前",(long)minutes];
  }else if (hours < 24){
    return [NSString stringWithFormat: @"%ld小時前",(long)hours];
  }else if (day < 30){
    return [NSString stringWithFormat: @"%ld天前",(long)day];
  }else if (month < 12){
    NSDateFormatter * df =[[NSDateFormatter alloc]init];
    df.dateFormat = @"M月d日";
    NSString * time = [df stringFromDate:lastDate];
    return time;
  }else if (yers >= 1){
    NSDateFormatter * df =[[NSDateFormatter alloc]init];
    df.dateFormat = @"yyyy年M月d日";
    NSString * time = [df stringFromDate:lastDate];
    return time;
  }
  return @"";
}
 

NSLog(@"\n\nresult: %@", [Utilities timeIntervalFromLastTime:@"2015年12月8日 15:50"
                      lastTimeFormat:@"yyyy年MM月dd日 HH:mm"
                      ToCurrentTime:@"2015/12/08 16:12"
                    currentTimeFormat:@"yyyy/MM/dd HH:mm"]);