using System;

namespace CompressorXN_HelperLib
{
    public class DateTimeHelper
    {
        /// <summary>
        /// 取得当前年第一天
        /// </summary>
        /// <param name="datetime">要取得年份第一天的时间</param>
        /// <returns></returns>
        public static DateTime FirstDayOfYear(DateTime datetime)
        {
            return new DateTime(datetime.Year, 1, 1);
        }

        /// <summary>
        /// 取得当前年最后一天
        /// </summary>
        /// <param name="datetime">要取得年份最后一天的时间</param>
        /// <returns></returns>
        public static DateTime LastDayOfYear(DateTime datetime)
        {
            return new DateTime(datetime.Year + 1, 1, 1, 23, 59, 59).AddDays(-1);
        }

        /// <summary>
        /// 获取当前月第一天
        /// </summary>
        /// <param name="datetime">要取得月份第一天的时间</param>
        /// <returns></returns>
        public static DateTime FirstDayOfMonth(DateTime datetime)
        {
            return new DateTime(datetime.Year, datetime.Month, 1);
        }

        /// <summary>
        /// 获取当前月最后一天
        /// </summary>
        /// <param name="datetime">要取得月份最后一天的时间</param>
        /// <returns></returns>
        public static DateTime LastDayOfMonth(DateTime datetime)
        {
            return new DateTime(datetime.Year, datetime.Month, 1, 23, 59, 59).AddMonths(1).AddDays(-1);
        }

        /// <summary>
        /// 获取当天开始时间
        /// </summary>
        /// <param name="datetime">要取得当天开始时间的时间</param>
        /// <returns></returns>
        public static DateTime StartOfDay(DateTime datetime)
        {
            return new DateTime(datetime.Year, datetime.Month, datetime.Day);
        }

        /// <summary>
        /// 获取当天结束时间
        /// </summary>
        /// <param name="datetime">要取得当天结束时间的时间</param>
        /// <returns></returns>
        public static DateTime EndOfDay(DateTime datetime)
        {
            return new DateTime(datetime.Year, datetime.Month, datetime.Day, 23, 59, 59);
        }
    }
}