class SkyTimeTool {

  static String getTimeZone() {
    final offset = DateTime.now().timeZoneOffset;
    final hours = offset.inHours;
    final minutes = offset.inMinutes.remainder(60).abs();
    final sign = hours >= 0 ? '+' : '-';
    final formatted =
        'GMT$sign${hours.abs().toString().padLeft(2, '0')}:${minutes.toString().padLeft(2, '0')}';
    return formatted;
  }

  //格式化数字，带单位 k / m，可自定义小数位和千分位分隔符
  static String formatNum(
      num value, {
        int decimalDigits = 1,
        String separator = ',',
        String unit = 'k',
      }) {
    String removeTrailingZeros(String str) {
      if (str.contains('.')) {
        str = str.replaceAll(RegExp(r'0+$'), ''); // 去掉末尾 0
        str = str.replaceAll(RegExp(r'\.$'), ''); // 去掉末尾小数点
      }
      return str;
    }

    String addSeparator(String str) {
      final parts = str.split('.');
      final intPart = parts[0];
      final decPart = parts.length > 1 ? '.${parts[1]}' : '';
      final regex = RegExp(r'(\d+)(\d{3})');
      var formatted = intPart;
      while (regex.hasMatch(formatted)) {
        formatted = formatted.replaceAllMapped(
          regex,
              (m) => '${m[1]}$separator${m[2]}',
        );
      }
      return '$formatted$decPart';
    }

    if (value < 1000) {
      return addSeparator(value.toStringAsFixed(0));
    } else if (value < 1000000) {
      int mu = unit=='w' ? 10000 : 1000;
      final formatted = (value / mu).toStringAsFixed(decimalDigits);
      return '${removeTrailingZeros(formatted)}$unit';
    } else {
      final formatted = (value / 1000000).toStringAsFixed(decimalDigits);
      return '${removeTrailingZeros(formatted)}m';
    }
  }
}