class DateFormat {
  static const num ONE_MINUTE = 60000;
  static const num ONE_HOUR = 3600000;
  static const num ONE_DAY = 86400000;
  static const num ONE_WEEK = 604800000;

  static const String ONE_SECOND_AGO = "秒前";
  static const String ONE_MINUTE_AGO = "分钟前";
  static const String ONE_HOUR_AGO = "小时前";
  static const String ONE_DAY_AGO = "天前";
  static const String ONE_MONTH_AGO = "月前";
  static const String ONE_YEAR_AGO = "年前";

  static String formatCreateAtHHmm(String date) {
    if(date == null)
      return '';
    var time =DateTime.parse(date);
    return "${time.hour.toString().padLeft(2, '0')}:${time.minute.toString().padLeft(2, '0')}";
  }

  static String formatCreateAt(String date) {
    if(date == null)
      return '';
    return format(DateTime.parse(date));
  }

  static String format(DateTime date) {
    return formatTime(date.millisecondsSinceEpoch ~/ 1000);
  }

  static String formatTime(num time) {
    num delta = DateTime.now().millisecondsSinceEpoch - time * 1000;
    if(delta<=1000){
      return "刚刚";
    }
    if (delta < 1 * ONE_MINUTE) {
      num seconds = toSeconds(delta);
      return (seconds <= 0 ? 1 : seconds).toInt().toString() + ONE_SECOND_AGO;
    }
    if (delta < 60 * ONE_MINUTE) {
      num minutes = toMinutes(delta);
      return (minutes <= 0 ? 1 : minutes).toInt().toString() + ONE_MINUTE_AGO;
    }
    if (delta < 24 * ONE_HOUR) {
      num hours = toHours(delta);
      return (hours <= 0 ? 1 : hours).toInt().toString() + ONE_HOUR_AGO;
    }
    var date = DateTime.fromMillisecondsSinceEpoch(time * 1000);
    return "${date.year}-${date.month}-${date.day}";
    // if (delta < 48 * ONE_HOUR) {
    //   return "昨天";
    // }
    // if (delta < 30 * ONE_DAY) {
    //   num days = toDays(delta);
    //   return (days <= 0 ? 1 : days).toInt().toString() + ONE_DAY_AGO;
    // }
    // if (delta < 12 * 4 * ONE_WEEK) {
    //   num months = toMonths(delta);
    //   return (months <= 0 ? 1 : months).toInt().toString() + ONE_MONTH_AGO;
    // } else {
    //   num years = toYears(delta);
    //   return (years <= 0 ? 1 : years).toInt().toString() + ONE_YEAR_AGO;
    // }
  }

  static num toSeconds(num date) {
    return date / 1000;
  }

  static num toMinutes(num date) {
    return toSeconds(date) / 60;
  }

  static num toHours(num date) {
    return toMinutes(date) / 60;
  }

  static num toDays(num date) {
    return toHours(date) / 24;
  }

  static num toMonths(num date) {
    return toDays(date) / 30;
  }

  static num toYears(num date) {
    return toMonths(date) / 365;
  }
}