using System;

namespace FL
{
    public static class StringUtils
    {
        /// <summary>
        /// 毫秒转指定格式的时间字符串
        /// </summary>
        /// <param name="milliseconds"></param>
        /// <param name="format">字符串格式, 例: @"mm\:ss"</param>
        /// <returns></returns>
        public static string ToTimeString(this long milliseconds, string format)
        {
            var timeData = TimeSpan.FromMilliseconds(milliseconds);
            return timeData.ToString(format);
        }
        private const string MILLION = "M";
        private const string THOUSAND = "K";
        /// <summary>
        /// 货币、战力数字转字符串
        /// >=百万，以M结尾
        /// >=万，以K结尾
        /// </summary>
        /// <param name="number"></param>
        /// <param name="decimals">保留小数点位数</param>
        /// <returns></returns>
        public static string FormatNumber(this long number, int decimals = 1)
        {
            const int million = 1000000;
            const int thousand = 1000;
            var format = $"{{0:N{decimals}}}";
            if (number >= million)
            {
                return string.Format(format, (double)number / million) + MILLION;
            }
            if (number >= thousand * 10)
            {
                return string.Format(format, (double)number / thousand) + THOUSAND;
            }
            return number.ToString();
        }
    }
}