using System;

namespace Hncore.Infrastructure.Extension
{
    public static class DateTimeExtension
    {
        public static string Format(this DateTime time, string format = "yyyy-MM-dd")
        {
            return time.ToString(format);
        }


        private static DateTime Jan1st1970 = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

        public static long CurrentTimeMillis()
        {
            return (long) ((DateTime.UtcNow - Jan1st1970).TotalMilliseconds);
        }

        public static long CurrentTimeMillis(DateTime time)
        {
            return (long) ((time.ToUniversalTime() - Jan1st1970).TotalMilliseconds);
        }

        public static string Format(this DateTime? dateTime, string format = "yyyy-MM-dd")
        {
            return Convert.ToDateTime(dateTime).ToString(format);
        }

        public static DateTime ToDateTime(this DateTime? dateTime, DateTime defaultTime)
        {
            if (dateTime != null)
            {
                return Convert.ToDateTime(dateTime);
            }

            return defaultTime;
        }

        public static bool Between(this DateTime time, DateTime beginTime, DateTime endTime)
        {
            return time >= beginTime && time <= endTime;
        }

        /// <summary>
        /// 取得某月的第一天
        /// </summary>
        /// <param name="datetime">要取得月份第一天的时间</param>
        /// <returns></returns>
        public static DateTime FirstDayOfMonth(this DateTime datetime)
        {
            return datetime.AddDays(1 - datetime.Day);
        }

        /**/
        /// <summary>
        /// 取得某月的最后一天
        /// </summary>
        /// <param name="datetime">要取得月份最后一天的时间</param>
        /// <returns></returns>
        public static DateTime LastDayOfMonth(this DateTime datetime)
        {
            return datetime.AddDays(1 - datetime.Day).AddMonths(1).AddDays(-1);
        }

        /**/
        /// <summary>
        /// 取得上个月第一天
        /// </summary>
        /// <param name="datetime">要取得上个月第一天的当前时间</param>
        /// <returns></returns>
        public static DateTime FirstDayOfPreviousMonth(this DateTime datetime)
        {
            return datetime.AddDays(1 - datetime.Day).AddMonths(-1);
        }

        /**/
        /// <summary>
        /// 取得上个月的最后一天
        /// </summary>
        /// <param name="datetime">要取得上个月最后一天的当前时间</param>
        /// <returns></returns>
        public static DateTime LastDayOfPrdviousMonth(this DateTime datetime)
        {
            return datetime.AddDays(1 - datetime.Day).AddDays(-1);
        }

        /// <summary>
        /// 获取时间的Unix时间戳
        /// </summary>
        /// <param name="tm">时间对象</param>
        /// <returns>Unix时间戳</returns>
        /// 
        public static long GetUnixTimeStamp(this DateTime tm)
        {
            long result = (tm.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
            return result;
        }

        /// <summary>
        /// 从Uninx转换时间
        /// </summary>
        /// <param name="tm">时间对象</param>
        /// <param name="timeStamp">时间戳</param>
        /// <returns>新时间对象</returns>
        /// 
        public static DateTime LoadFromUnixTimeStamp(this DateTime tm,double timeStamp)
        {
            DateTime startTime=TimeZoneInfo.ConvertTime(new System.DateTime(1970, 1, 1),TimeZoneInfo.Local);
            DateTime result=startTime.AddSeconds(timeStamp);
            return result;
        }

        public static DateTime LoadFromUnixTimeStamp(this long timeStamp)
        {
            DateTime startTime = TimeZoneInfo.ConvertTime(new System.DateTime(1970, 1, 1), TimeZoneInfo.Local);
            DateTime result = startTime.AddSeconds(timeStamp);
            return result;
        }

        /// <summary>
        /// 时间戳转换成时间
        /// </summary>
        /// <param name="timestamp">时间戳</param>
        /// <param name="millisecond">是否毫秒级,true毫秒级(默认值)</param>
        /// <param name="localTime">是否输出本地时间,true本地时间(默认值)</param>
        /// <returns></returns>
        public static DateTime? LoadFromUnixTimeStamp(this string timestamp)
        {
            if (long.TryParse(timestamp, out long ts))
            {
                return ts.LoadFromUnixTimeStamp();
            }
            return null;
        }

        /// <summary>
        /// 1970 到现在的秒数
        /// </summary>
        /// <param name="time"></param>
        /// <returns></returns>
        public static int TimestampFrom19700101(this DateTime time)
        {
            return (int)(time - new DateTime(1970, 01, 01)).TotalSeconds;
        }


        #region 获取日期、明天
        public static DateTime Date(this DateTime? time)
        {
            return Convert.ToDateTime(time).Date;
        }
        public static DateTime NextDate(this DateTime? time)
        {
            return Convert.ToDateTime(time).Date.AddDays(1);
        }
        public static DateTime Date(this DateTime time)
        {
            return time.Date;
        }
        public static DateTime NextDate(this DateTime time)
        {
            return time.Date.AddDays(1);
        }
        #endregion

        public static DateTime Begin(this DateTime time)
        {
            return new DateTime(time.Year, time.Month, time.Day);
        }

        public static DateTime End(this DateTime time)
        {
            return new DateTime(time.Year, time.Month, time.Day,23,59,59);
        }
    }
}