using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace IStation.Untity
{
    /// <summary>
    /// 时间辅助类
    /// </summary>
    public static class DateTimeHelper
    {
        /// <summary>
        /// 获取两个时间的TimeSpan
        /// </summary>
        /// <param name="dt1"></param>
        /// <param name="dt2"></param>
        /// <returns></returns>
        public static TimeSpan CalcuDiff(DateTime d1, DateTime d2)
        {
            TimeSpan ts;
            if (d1 > d2)
            {
                ts = d1 - d2;
            }
            else
            {
                ts = d2 - d1;
            }
            return ts;
        }

        /// <summary>
        /// 获取最大时间
        /// </summary>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DateTime GetMax(IEnumerable<DateTime> list)
        {
            if (list == null || list.Count() < 1)
                return DateTime.MaxValue;
            return list.Max();
        }

        /// <summary>
        /// 获取最大时间
        /// </summary>
        public static DateTime GetMax(DateTime dt1, DateTime dt2)
        {
            if (dt1 < dt2)
                return dt2;
            return dt1;
        }

        /// <summary>
        /// 获取最小时间
        /// </summary>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DateTime GetMin(IEnumerable<DateTime> list)
        {
            if (list == null || list.Count() < 1)
                return DateTime.MinValue;
            return list.Min();
        }

        /// <summary>
        /// 获取最小时间
        /// </summary>
        public static DateTime GetMin(DateTime dt1, DateTime dt2)
        {
            if (dt1 < dt2)
                return dt1;
            return dt2;
        }

        /// <summary>
        /// 计算相差年数
        /// </summary>
        /// <param name="d1"></param>
        /// <param name="d2"></param>
        /// <returns></returns>
        public static int CalcuDiffYear(DateTime d1, DateTime d2)
        {
            return Math.Abs(d1.Year - d2.Year);
        }

        /// <summary>
        /// 计算相差月份
        /// </summary>
        /// <param name="d1"></param>
        /// <param name="d2"></param>
        /// <returns></returns>
        public static int CalcuDiffMonth(DateTime d1, DateTime d2)
        {
            var max = GetMax(new List<DateTime>() { d1, d2 });
            var min = GetMin(new List<DateTime>() { d1, d2 });
            var year = max.Year - min.Year;
            var month = max.Month - min.Month;
            if (month < 0)
            {
                year -= 1;
                month += 12;
            }
            return year * 12 + month;
        }



    }

}