using System;
using System.Globalization;

namespace learun.util
{
	/// <summary>
	/// 版 本 EasyCode EC管理后台
	/// Copyright (c) 2019-present EC管理有限公司
	/// 创建人：tobin
	/// 日 期：2019.10.25
	/// 描 述：时间操作
	/// </summary>
	public static class Time
	{
		#region 当前时间

		/// <summary>
		/// 当前时间
		/// </summary>
		public static DateTime Now
		{
			get
			{
				return DateTime.Now;
			}
		}

		/// <summary>
		/// 短日期格式(yyyy/MM/dd)
		/// </summary>
		public static string ShortDate
		{
			get
			{
				return Now.ToString("yyyy/MM/dd");
			}
		}

		/// <summary>
		/// 长日期格式(yyyy月MM日dd日)
		/// </summary>
		public static string LongDate
		{
			get
			{
				return Now.ToString("yyyy月MM日dd日");
			}
		}

		/// <summary>
		/// 日期时间(yyyy/MM/dd HH:mm)
		/// </summary>
		public static string ShortDateTime
		{
			get
			{
				return Now.ToString("yyyy/MM/dd HH:mm");
			}
		}

		/// <summary>
		/// 日期时间(yyyy年MM月dd日 HH时mm分)
		/// </summary>
		public static string LongDateTime
		{
			get
			{
				return Now.ToString("yyyy年MM月dd日 HH时mm分");
			}
		}

		/// <summary>
		/// 日期时间(yyyy年MM月dd日 HH时mm分)
		/// </summary>
		public static string LongTime
		{
			get
			{
				return Now.ToString("HH时mm分");
			}
		}

		/// <summary>
		/// 日期时间(yyyy年MM月dd日 HH时mm分)
		/// </summary>
		public static string ShortTime
		{
			get
			{
				return Now.ToString("HH:mm");
			}
		}

		/// <summary>
		/// 当前日期
		/// </summary>
		/// <returns></returns>
		public static string GetToday()
		{
			return DateTime.Now.ToString("yyyy-MM-dd");
		}

		/// <summary>
		/// 当前日期自定义格式
		/// </summary>
		/// <param name="format"></param>
		/// <returns></returns>
		public static string GetToday(string format)
		{
			return DateTime.Now.ToString(format);
		}

		/// <summary>
		/// 当前日期 加添加，减天数 -1、1
		/// </summary>
		/// <param name="i"></param>
		/// <returns></returns>
		public static string GetDate(int i)
		{
			DateTime dt = DateTime.Now;
			dt = dt.AddDays(i);
			return dt.ToString("yyyy-MM-dd");
		}

		/// <summary>
		///  当前日期 加添加，减天数 -1、1
		/// </summary>
		/// <param name="i"></param>
		/// <param name="dateformat">返回的时间格式</param>
		/// <returns></returns>
		public static string GetDate(int i, string dateformat)
		{
			DateTime dt = DateTime.Now;
			dt = dt.AddDays(i);
			return dt.ToString(dateformat);
		}

		#endregion 当前时间

		#region 返回本年有多少天

		/// <summary>返回本年有多少天</summary>
		/// <param name="iYear">年份</param>
		/// <returns>本年的天数</returns>
		public static int GetDaysOfYear(int iYear)
		{
			return IsRuYear(iYear) ? 366 : 365;
		}

		/// <summary>本年有多少天</summary>
		/// <param name="dt">日期</param>
		/// <returns>本天在当年的天数</returns>
		public static int GetDaysOfYear(DateTime dt)
		{
			return IsRuYear(dt.Year) ? 366 : 365;
		}

		#endregion 返回本年有多少天

		#region 返回本月有多少天

		/// <summary>本月有多少天</summary>
		/// <param name="iYear">年</param>
		/// <param name="Month">月</param>
		/// <returns>天数</returns>
		public static int GetDaysOfMonth(int iYear, int Month)
		{
			var days = 0;
			switch (Month)
			{
				case 1:
					days = 31;
					break;

				case 2:
					days = IsRuYear(iYear) ? 29 : 28;
					break;

				case 3:
					days = 31;
					break;

				case 4:
					days = 30;
					break;

				case 5:
					days = 31;
					break;

				case 6:
					days = 30;
					break;

				case 7:
					days = 31;
					break;

				case 8:
					days = 31;
					break;

				case 9:
					days = 30;
					break;

				case 10:
					days = 31;
					break;

				case 11:
					days = 30;
					break;

				case 12:
					days = 31;
					break;
			}

			return days;
		}

		/// <summary>本月有多少天</summary>
		/// <param name="dt">日期</param>
		/// <returns>天数</returns>
		public static int GetDaysOfMonth(DateTime dt)
		{
			//--------------------------------//
			//--从dt中取得当前的年，月信息  --//
			//--------------------------------//
			int days = 0;
			int year = dt.Year;
			int month = dt.Month;

			//--利用年月信息，得到当前月的天数信息。
			switch (month)
			{
				case 1:
					days = 31;
					break;

				case 2:
					days = IsRuYear(year) ? 29 : 28;
					break;

				case 3:
					days = 31;
					break;

				case 4:
					days = 30;
					break;

				case 5:
					days = 31;
					break;

				case 6:
					days = 30;
					break;

				case 7:
					days = 31;
					break;

				case 8:
					days = 31;
					break;

				case 9:
					days = 30;
					break;

				case 10:
					days = 31;
					break;

				case 11:
					days = 30;
					break;

				case 12:
					days = 31;
					break;
			}
			return days;
		}

		#endregion 返回本月有多少天

		#region 返回当前日期的 （星期名称or星期编号）

		/// <summary>返回当前日期的星期名称</summary>
		/// <param name="dt">日期</param>
		/// <returns>星期名称</returns>
		public static string GetWeekNameOfDay(DateTime dt)
		{
			string week = string.Empty;
			switch (dt.DayOfWeek)
			{
				case DayOfWeek.Monday:
					week = "星期一";
					break;

				case DayOfWeek.Tuesday:
					week = "星期二";
					break;

				case DayOfWeek.Wednesday:
					week = "星期三";
					break;

				case DayOfWeek.Thursday:
					week = "星期四";
					break;

				case DayOfWeek.Friday:
					week = "星期五";
					break;

				case DayOfWeek.Saturday:
					week = "星期六";
					break;

				case DayOfWeek.Sunday:
					week = "星期日";
					break;
			}
			return week;
		}

		/// <summary>返回当前日期的星期编号</summary>
		/// <param name="dt">日期</param>
		/// <returns>星期数字编号</returns>
		public static int GetWeekNumberOfDay(DateTime dt)
		{
			int week = 0;
			switch (dt.DayOfWeek)
			{
				case DayOfWeek.Monday:
					week = 1;
					break;

				case DayOfWeek.Tuesday:
					week = 2;
					break;

				case DayOfWeek.Wednesday:
					week = 3;
					break;

				case DayOfWeek.Thursday:
					week = 4;
					break;

				case DayOfWeek.Friday:
					week = 5;
					break;

				case DayOfWeek.Saturday:
					week = 6;
					break;

				case DayOfWeek.Sunday:
					week = 7;
					break;
			}
			return week;
		}

		#endregion 返回当前日期的 （星期名称or星期编号）

		#region 获取某一年有多少周

		/// <summary>
		/// 获取某一年有多少周
		/// </summary>
		/// <param name="year">年份</param>
		/// <returns>该年周数</returns>
		public static int GetWeekAmount(int year)
		{
			var end = new DateTime(year, 12, 31); //该年最后一天
			var gc = new GregorianCalendar();
			return gc.GetWeekOfYear(end, CalendarWeekRule.FirstDay, DayOfWeek.Monday); //该年星期数
		}

		#endregion 获取某一年有多少周

		#region 获取某一日期是该年中的第几周

		/// <summary>
		/// 获取某一日期是该年中的第几周
		/// </summary>
		/// <param name="dt">日期</param>
		/// <returns>该日期在该年中的周数</returns>
		public static int GetWeekOfYear(DateTime dt)
		{
			var gc = new GregorianCalendar();
			return gc.GetWeekOfYear(dt, CalendarWeekRule.FirstDay, DayOfWeek.Monday);
		}

		#endregion 获取某一日期是该年中的第几周

		#region 根据某年的第几周获取这周的起止日期

		/// <summary>
		/// 根据某年的第几周获取这周的起止日期
		/// </summary>
		/// <param name="year"></param>
		/// <param name="weekOrder"></param>
		/// <param name="firstDate"></param>
		/// <param name="lastDate"></param>
		/// <returns></returns>
		public static void WeekRange(int year, int weekOrder, ref DateTime firstDate, ref DateTime lastDate)
		{
			//当年的第一天
			var firstDay = new DateTime(year, 1, 1);

			//当年的第一天是星期几
			int firstOfWeek = Convert.ToInt32(firstDay.DayOfWeek);

			//计算当年第一周的起止日期，可能跨年
			int dayDiff = (-1) * firstOfWeek + 1;
			int dayAdd = 7 - firstOfWeek;

			firstDate = firstDay.AddDays(dayDiff).Date;
			lastDate = firstDay.AddDays(dayAdd).Date;

			//如果不是要求计算第一周
			if (weekOrder != 1)
			{
				int addDays = (weekOrder - 1) * 7;
				firstDate = firstDate.AddDays(addDays);
				lastDate = lastDate.AddDays(addDays);
			}
		}

		#endregion 根据某年的第几周获取这周的起止日期

		#region 返回两个日期之间相差的天数

		/// <summary>
		/// 返回两个日期之间相差的天数
		/// </summary>
		/// <param name="dtfrm">两个日期参数</param>
		/// <param name="dtto">两个日期参数</param>
		/// <returns>天数</returns>
		public static int DiffDays(DateTime dtfrm, DateTime dtto)
		{
			TimeSpan tsDiffer = dtto.Date - dtfrm.Date;
			return tsDiffer.Days;
		}

		#endregion 返回两个日期之间相差的天数

		#region 返回两个日期之间相差的小时数

		/// <summary>
		/// 返回两个日期之间相差的小时数
		/// </summary>
		/// <param name="dtfrm">两个日期参数</param>
		/// <param name="dtto">两个日期参数</param>
		/// <returns>小时数</returns>
		public static int DiffHours(DateTime dtfrm, DateTime dtto)
		{
			TimeSpan tsDiffer = dtto.Date - dtfrm.Date;
			return tsDiffer.TotalHours.ToInt();
		}

		#endregion 返回两个日期之间相差的小时数

		#region 返回两个日期之间相差的分钟数

		/// <summary>
		/// 返回两个日期之间相差的分钟数
		/// </summary>
		/// <param name="dtfrm">两个日期参数</param>
		/// <param name="dtto">两个日期参数</param>
		/// <returns>分钟数</returns>
		public static int DiffMinutes(DateTime dtfrm, DateTime dtto)
		{
			TimeSpan tsDiffer = dtto.Date - dtfrm.Date;
			return tsDiffer.TotalMinutes.ToInt();
		}

		#endregion 返回两个日期之间相差的分钟数

		#region 判断当前年份是否是闰年

		/// <summary>判断当前年份是否是闰年，私有函数</summary>
		/// <param name="iYear">年份</param>
		/// <returns>是闰年：True ，不是闰年：False</returns>
		private static bool IsRuYear(int iYear)
		{
			//形式参数为年份
			//例如：2003
			int n = iYear;
			return (n % 400 == 0) || (n % 4 == 0 && n % 100 != 0);
		}

		#endregion 判断当前年份是否是闰年

		#region 将输入的字符串转化为日期。如果字符串的格式非法，则返回当前日期

		/// <summary>
		/// 将输入的字符串转化为日期。如果字符串的格式非法，则返回当前日期。
		/// </summary>
		/// <param name="strInput">输入字符串</param>
		/// <returns>日期对象</returns>
		public static DateTime ToDate(string strInput)
		{
			DateTime oDateTime;

			try
			{
				oDateTime = DateTime.Parse(strInput);
			}
			catch (Exception)
			{
				oDateTime = DateTime.Today;
			}

			return oDateTime;
		}

		#endregion 将输入的字符串转化为日期。如果字符串的格式非法，则返回当前日期

		#region 将日期对象转化为格式字符串

		/// <summary>
		/// 将日期对象转化为格式字符串
		/// </summary>
		/// <param name="oDateTime">日期对象</param>
		/// <param name="strFormat">
		/// 格式：
		///		"SHORTDATE"===短日期
		///		"LONGDATE"==长日期
		///		其它====自定义格式
		/// </param>
		/// <returns>日期字符串</returns>
		public static string ToString(DateTime oDateTime, string strFormat)
		{
			string strDate;

			try
			{
				switch (strFormat.ToUpper())
				{
					case "SHORTDATE":
						strDate = oDateTime.ToShortDateString();
						break;

					case "LONGDATE":
						strDate = oDateTime.ToLongDateString();
						break;

					default:
						strDate = oDateTime.ToString(strFormat);
						break;
				}
			}
			catch (Exception)
			{
				strDate = oDateTime.ToShortDateString();
			}

			return strDate;
		}

		#endregion 将日期对象转化为格式字符串

		/// <summary>
		/// 获取当前日期是星期几
		/// </summary>
		/// <param name="dt">时间对象</param>
		/// <returns></returns>
		public static int GetNumberWeekDay(DateTime dt)
		{
			return (int)dt.DayOfWeek;
		}

		/// <summary>
		/// 获取中式星期信息
		/// </summary>
		/// <param name="y">年</param>
		/// <param name="m">月</param>
		/// <param name="d">日</param>
		/// <returns></returns>
		public static string GetChineseWeekDay(int y, int m, int d)
		{
			string[] weekstr = { "日", "一", "二", "三", "四", "五", "六" };
			if (m < 3)
			{
				m += 12;
				y--;
			}
			if (y % 400 == 0 || y % 100 != 0 && y % 4 == 0)
				d--;
			else
				d += 1;
			return "星期" + weekstr[(d + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y / 400) % 7];
		}

		/// <summary>
		/// 获取中国时间
		/// </summary>
		/// <param name="dt">时间对象</param>
		/// <returns></returns>
		public static string GetChineseDateTime(DateTime dt)
		{
			string dateTime = dt.ToString("yyyy-MM-dd");
			dateTime = dateTime + string.Format("({0})", GetChineseWeekDay(dt.Year, dt.Month, dt.Day));
			string time = string.Format("{0:  tt hh:mm:ss }", dt);
			time = time.Replace("am", "上午").Replace("pm", "下午");
			dateTime = dateTime + time;
			return dateTime;
		}
	}
}