using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace MSCL
{
  /// summary>
  /// 時間日期處理類
  /// /summary>
  public class DateTimeHelper
  {
    #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>本年的天數/returns>
    public static int GetDaysOfYear(int iYear)
    {
      int cnt = 0;
      if (IsRuYear(iYear))
      {
        //閏年多 1 天 即：2 月為 29 天
        cnt = 366;
      }
      else
      {
        //--非閏年少1天 即：2 月為 28 天
        cnt = 365;
      }
      return cnt;
    }
    #endregion
    #region 返回本年有多少天
    /// summary>本年有多少天/summary>
    /// param name="dt">日期/param>
    /// returns>本天在當年的天數/returns>
    public static int GetDaysOfYear(DateTime idt)
    {
      int n;
      //取得傳入參數的年份部分，用來判斷是否是閏年
      n = idt.Year;
      if (IsRuYear(n))
      {
        //閏年多 1 天 即：2 月為 29 天
        return 366;
      }
      else
      {
        //--非閏年少1天 即：2 月為 28 天
        return 365;
      }
    }
    #endregion
    #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>天數/returns>
    public static int GetDaysOfMonth(int iYear, int Month)
    {
      int days = 0;
      switch (Month)
      {
        case 1:
          days = 31;
          break;
        case 2:
          if (IsRuYear(iYear))
          {
            //閏年多 1 天 即：2 月為 29 天
            days = 29;
          }
          else
          {
            //--非閏年少1天 即：2 月為 28 天
            days = 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
    #region 返回本月有多少天
    /// summary>本月有多少天/summary>
    /// param name="dt">日期/param>
    /// returns>天數/returns>
    public static int GetDaysOfMonth(DateTime dt)
    {
      //--------------------------------//
      //--從dt中取得當前的年，月信息 --//
      //--------------------------------//
      int year, month, days = 0;
      year = dt.Year;
      month = dt.Month;
      //--利用年月信息，得到當前月的天數信息。
      switch (month)
      {
        case 1:
          days = 31;
          break;
        case 2:
          if (IsRuYear(year))
          {
            //閏年多 1 天 即：2 月為 29 天
            days = 29;
          }
          else
          {
            //--非閏年少1天 即：2 月為 28 天
            days = 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
    #region 返回當前日期的星期名稱
    /// summary>返回當前日期的星期名稱/summary>
    /// param name="dt">日期/param>
    /// returns>星期名稱/returns>
    public static string GetWeekNameOfDay(DateTime idt)
    {
      string dt, week = "";
      dt = idt.DayOfWeek.ToString();
      switch (dt)
      {
        case "Mondy":
          week = "星期一";
          break;
        case "Tuesday":
          week = "星期二";
          break;
        case "Wednesday":
          week = "星期三";
          break;
        case "Thursday":
          week = "星期四";
          break;
        case "Friday":
          week = "星期五";
          break;
        case "Saturday":
          week = "星期六";
          break;
        case "Sunday":
          week = "星期日";
          break;
      }
      return week;
    }
    #endregion
    #region 返回當前日期的星期編號
    /// summary>返回當前日期的星期編號/summary>
    /// param name="dt">日期/param>
    /// returns>星期數字編號/returns>
    public static string GetWeekNumberOfDay(DateTime idt)
    {
      string dt, week = "";
      dt = idt.DayOfWeek.ToString();
      switch (dt)
      {
        case "Mondy":
          week = "1";
          break;
        case "Tuesday":
          week = "2";
          break;
        case "Wednesday":
          week = "3";
          break;
        case "Thursday":
          week = "4";
          break;
        case "Friday":
          week = "5";
          break;
        case "Saturday":
          week = "6";
          break;
        case "Sunday":
          week = "7";
          break;
      }
      return week;
    }
    #endregion
    #region 判斷當前日期所屬的年份是否是閏年，私有函數
    /// summary>判斷當前日期所屬的年份是否是閏年，私有函數/summary>
    /// param name="dt">日期/param>
    /// returns>是閏年：True ，不是閏年：False/returns>
    private static bool IsRuYear(DateTime idt)
    {
      //形式參數為日期類型
      //例如：2003-12-12
      int n;
      n = idt.Year;
      if ((n % 400 == 0) || (n % 4 == 0  n % 100 != 0))
      {
        return true;
      }
      else
      {
        return false;
      }
    }
    #endregion
    #region 判斷當前年份是否是閏年，私有函數
    /// summary>判斷當前年份是否是閏年，私有函數/summary>
    /// param name="dt">年份/param>
    /// returns>是閏年：True ，不是閏年：False/returns>
    private static bool IsRuYear(int iYear)
    {
      //形式參數為年份
      //例如：2003
      int n;
      n = iYear;
      if ((n % 400 == 0) || (n % 4 == 0  n % 100 != 0))
      {
        return true;
      }
      else
      {
        return false;
      }
    }
    #endregion
    #region 將輸入的字符串轉化為日期。如果字符串的格式非法，則返回當前日期
    /// summary>
    /// 將輸入的字符串轉化為日期。如果字符串的格式非法，則返回當前日期。
    /// /summary>
    /// param name="strInput">輸入字符串/param>
    /// returns>日期對象/returns>
    public static DateTime ConvertStringToDate(string strInput)
    {
      DateTime oDateTime;
      try
      {
        oDateTime = DateTime.Parse(strInput);
      }
      catch (Exception)
      {
        oDateTime = DateTime.Today;
      }
      return oDateTime;
    }
    #endregion
    #region 將日期對象轉化為格式字符串
    /// summary>
    /// 將日期對象轉化為格式字符串
    /// /summary>
    /// param name="oDateTime">日期對象/param>
    /// param name="strFormat">
    /// 格式：
    ///    "SHORTDATE"===短日期
    ///    "LONGDATE"==長日期
    ///    其它====自定義格式
    /// /param>
    /// returns>日期字符串/returns>
    public static string ConvertDateToString(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
    #region 判斷是否為合法日期，必須大于1800年1月1日
    /// summary>
    /// 判斷是否為合法日期，必須大于1800年1月1日
    /// /summary>
    /// param name="strDate">輸入日期字符串/param>
    /// returns>True/False/returns>
    public static bool IsDateTime(string strDate)
    {
      try
      {
        DateTime oDate = DateTime.Parse(strDate);
        if (oDate.CompareTo(DateTime.Parse("1800-1-1")) > 0)
          return true;
        else
          return false;
      }
      catch (Exception)
      {
        return false;
      }
    }
    #endregion
    #region 獲取兩個日期之間的差值 可返回年 月 日 小時 分鐘 秒
    /// summary>
    /// 獲取兩個日期之間的差值
    /// /summary>
    /// param name="howtocompare">比較的方式可為：year month day hour minute second/param>
    /// param name="startDate">開始日期/param>
    /// param name="endDate">結束日期/param>
    /// returns>時間差/returns>
    public static double DateDiff(string howtocompare, DateTime startDate, DateTime endDate)
    {
      double diff = 0;
      try
      {
        TimeSpan TS = new TimeSpan(endDate.Ticks - startDate.Ticks);
        switch (howtocompare.ToLower())
        {
          case "year":
            diff = Convert.ToDouble(TS.TotalDays / 365);
            break;
          case "month":
            diff = Convert.ToDouble((TS.TotalDays / 365) * 12);
            break;
          case "day":
            diff = Convert.ToDouble(TS.TotalDays);
            break;
          case "hour":
            diff = Convert.ToDouble(TS.TotalHours);
            break;
          case "minute":
            diff = Convert.ToDouble(TS.TotalMinutes);
            break;
          case "second":
            diff = Convert.ToDouble(TS.TotalSeconds);
            break;
        }
      }
      catch (Exception)
      {
        diff = 0;
      }
      return diff;
    }
    #endregion
    #region 計算兩個日期之間相差的工作日天數
    /// summary>
    /// 計算兩個日期之間相差的工作日天數
    /// /summary>
    /// param name="dtStart">開始日期/param>
    /// param name="dtEnd">結束日期/param>
    /// param name="Flag">是否除去周六，周日/param>
    /// returns>Int/returns>
    public static int CalculateWorkingDays(DateTime dtStart, DateTime dtEnd, bool Flag)
    {
      int count = 0;
      for (DateTime dtTemp = dtStart; dtTemp  dtEnd; dtTemp = dtTemp.AddDays(1))
      {
        if (Flag)
        {
          if (dtTemp.DayOfWeek != DayOfWeek.Saturday  dtTemp.DayOfWeek != DayOfWeek.Sunday)
          {
            count++;
          }
        }
        else
        {
          count++;
        }
      }
      return count;
    }
    #endregion
  }
}