using System;

using System.Globalization;

using NUnit.Framework;



namespace Delta.Utilities.Helpers

{

	/// <summary>

	/// Date helper class, mostly used just to present date times in a common

	/// format (like ISO date strings), but also has some helper methods to

	/// check different dates and parse date strings.

	/// </summary>

	public static class DateHelper

	{

		#region GetTimeString (Static)

		/// <summary>

		/// GetTimeString

		/// </summary>

		/// <param name="time">Time</param>

		/// <returns>String</returns>

		public static string GetTimeString(this DateTime time)

		{

			return String.Format("{0:00}:{1:00}", time.Hour, time.Minute);

		}

		#endregion



		#region GetForumDateAndTime (Static)

		/// <summary>

		/// Get forum date and time in german format, day.month.year hour:minute

		/// </summary>

		/// <param name="date">Date</param>

		/// <returns>String</returns>

		public static string GetForumDateAndTime(this DateTime date)

		{

			string dateString =

				String.Format("{0:00}.{1:00}.{2}", date.Day, date.Month, date.Year);

			string timeString =

				// Skip time if it is 00:00 (which usually means no time is given)

				(date.Hour != 0 || date.Minute != 0

				 	? String.Format("{0:00}:{1:00}", date.Hour, date.Minute)

				 	: "");



			// Make bold if this was posted today!

			bool wasPostedToday =

				date.DayOfYear == DateTime.Now.DayOfYear &&

				date.Year == DateTime.Now.Year;

			if (wasPostedToday &&

			    String.IsNullOrEmpty(timeString) == false)

			{

				return String.Format("<b>{0}</b>", timeString);

			}

			else

			{

				return String.Format("{0} {1}", dateString, timeString);

			}

		}

		#endregion



		#region GetAtForumDateAndTime (Static)

		/// <summary>

		/// Get at forum date and time

		/// </summary>

		/// <param name="date">DateHelper</param>

		/// <returns>String</returns>

		public static string GetAtForumDateAndTime(this DateTime date)

		{

			string dateString =

				String.Format("{0:00}.{1:00}.{2}", date.Day, date.Month, date.Year);

			string timeString =

				// Skip time if it is 00:00 (which usually means no time is given)

				(date.Hour != 0 || date.Minute != 0

				 	? String.Format("{0:00}:{1:00}", date.Hour, date.Minute)

				 	: "");



			// Make bold if this was posted today!

			bool wasPostedToday =

				date.DayOfYear == DateTime.Now.DayOfYear &&

				date.Year == DateTime.Now.Year;

			if (wasPostedToday &&

			    String.IsNullOrEmpty(timeString) == false)

			{

				return String.Format("um <b>{0}</b>", timeString);

			}

			else

			{

				return String.Format("am {0} {1}", dateString, timeString);

			}

		}

		#endregion



		#region GetDateFromString (Static)

		/// <summary>

		/// Get date from string

		/// </summary>

		/// <param name="dateString">Date string</param>

		/// <returns>Date time</returns>

		public static DateTime GetDateFromString(string dateString)

		{

			// First check if this contains a space and might be a date + time

			if (dateString.Contains(" "))

			{

				return GetDateAndTimeFromString(dateString);

			}



			// Try to get it the normal way ^^

			DateTime ret = DateTime.Now;

			bool dateSucceeded = true;

			try

			{

				dateSucceeded = DateTime.TryParse(dateString,

					CultureInfo.InvariantCulture, DateTimeStyles.None, out ret);

			}

			catch

			{

			}



			if (dateSucceeded == false)

			{

				try

				{

					string[] dateParts = dateString.SplitAndTrim('.');

					if (dateParts.Length >= 3)

					{

						ret = new DateTime(

							Convert.ToInt32(dateParts[2]),

							Convert.ToInt32(dateParts[1]),

							Convert.ToInt32(dateParts[0]));

					}

					else if (dateParts.Length == 1)

					{

						// Support formats like "2011-07-27" as well (should already be

						// handled above, but sometimes it does not work).

						dateParts = dateString.SplitAndTrim('-');

						if (dateParts.Length >= 3)

						{

							ret = new DateTime(

								Convert.ToInt32(dateParts[0]),

								Convert.ToInt32(dateParts[1]),

								Convert.ToInt32(dateParts[2]));

						}

						else

						{

							// Finally check for American dates with / like "07/27/2011"

							dateParts = dateString.SplitAndTrim('/');

							if (dateParts.Length >= 3)

							{

								ret = new DateTime(

									Convert.ToInt32(dateParts[2]),

									Convert.ToInt32(dateParts[0]),

									Convert.ToInt32(dateParts[1]));

							}

							else

							{

								// Just grab the year, but even that might not work ..

								ret = new DateTime(

									Convert.ToInt32(dateParts[0]), 1, 1);

							}

						}

					}

				}

				catch { }

				// catch



				// If this did not work, then just use the current time.

				// This sometimes seems to happen with WebNews, but not often!

				if (ret.Year <= 1)

				{

					ret = DateTime.Now;

				}

			}



			return ret;

		}

		#endregion



		#region GetDateAndTimeFromString (Static)

		/// <summary>

		/// Get date and time from string

		/// </summary>

		/// <param name="dateString">Date string</param>

		/// <returns>Date time</returns>

		public static DateTime GetDateAndTimeFromString(string dateString)

		{

			if (dateString.Trim().Length == 0)

			{

				return DateTime.Now;

			}



			DateTime date = DateTime.Now;

			try

			{

				// You might ask yourself why go through all this trouble parsing

				// the date ourselves when DateTime.TryParse can do the same. Well,

				// this is several times faster and most dates are in this format :)

				string[] dateAndTime = dateString.Split(new[]

				{

					' ', ':'

				});

				date = GetDateFromString(dateAndTime[0]);

				if (dateAndTime.Length >= 3)

				{

					date = date.AddHours(Convert.ToInt32(dateAndTime[1]));

					date = date.AddMinutes(Convert.ToInt32(dateAndTime[2]));

					if (dateAndTime.Length >= 4)

					{

						date = date.AddSeconds(Convert.ToInt32(dateAndTime[3]));

					}

				}

			}

			catch

			{

				// Else just use the normal parser

				DateTime.TryParse(dateString, out date);

			}



			return date;

		}

		#endregion



		#region IsDateNewer (Static)

		/// <summary>

		/// Is date newer than the older date. Very useful for file comparisions.

		/// </summary>

		/// <param name="newerDate">Newer date</param>

		/// <param name="olderDate">Older date</param>

		/// <returns>True if the newer date is newer than the older date</returns>

		public static bool IsDateNewer(DateTime newerDate, DateTime olderDate)

		{

			return newerDate.CompareTo(olderDate) == 1;

		}

		#endregion



		#region IsDateInRange (Static)

		/// <summary>

		/// Is date in range. Will return true if currentData is between beginDate

		/// and endDate.

		/// </summary>

		/// <param name="currentDate">Current date</param>

		/// <param name="beginDate">Range begin</param>

		/// <param name="endDate">Range end</param>

		/// <returns>

		/// True if currentData is between beginDate and endDate.

		/// </returns>

		public static bool IsDateInRange(this DateTime currentDate,

			DateTime beginDate, DateTime endDate)

		{

			return

				beginDate.CompareTo(currentDate) < 1 &&

				endDate.CompareTo(currentDate) > -1;

		}

		#endregion



		#region AreSameDays (Static)

		/// <summary>

		/// Are day1 and day2 are the same day?

		/// </summary>

		/// <param name="day1">Day 1</param>

		/// <param name="day2">Day 2</param>

		/// <returns>

		/// True if the days are the same (ignoring all the other datetime values).

		/// </returns>

		public static bool AreSameDays(DateTime day1, DateTime day2)

		{

			return day1.Date.CompareTo(day2.Date) == 0;

		}

		#endregion



		#region GetIsoDate (Static)

		/// <summary>

		/// Returns the "Iso Date" stamp (Year-Month-Day).

		/// </summary>

		/// <param name="date">Date</param>

		/// <returns>"Iso Date" stamp (Year-Month-Day)</returns>

		public static string GetIsoDate(this DateTime date)

		{

			return date.Year + "-" +

			       date.Month.ToString("00") + "-" +

			       date.Day.ToString("00");

		}

		#endregion



		#region GetIsoTime (Static)

		/// <summary>

		/// Get Iso time stamp (Hour:Minute:Second)

		/// </summary>

		/// <param name="time">Datetime input</param>

		/// <returns>String with the time in hours:minutes:seconds</returns>

		public static string GetIsoTime(this DateTime time)

		{

			return time.Hour.ToString("00") + ":" +

			       time.Minute.ToString("00") + ":" +

			       time.Second.ToString("00");

		}

		#endregion



		#region GetIsoTimeWithMiliseconds (Static)

		/// <summary>

		/// Get iso time with miliseconds. Note: DateTime is not very accurate,

		/// use better timings with the Time or GameTime classes for ingame

		/// purposes (profiling, debugging, etc. otherwise strings should not be

		/// needed anyway). This is mostly 

		/// </summary>

		/// <param name="time">Time for output</param>

		/// <returns>

		/// Text with the time in hours:minutes:seconds.milliseconds format.

		/// </returns>

		public static string GetIsoTimeWithMiliseconds(this DateTime time)

		{

			return time.Hour.ToString("00") + ":" +

			       time.Minute.ToString("00") + ":" +

			       time.Second.ToString("00") + "." +

			       time.Millisecond.ToString("000");

		}

		#endregion



		#region GetIsoDateTime (Static)

		/// <summary>

		/// Get Iso date time stamp (Year-Month-Day Hour:Minute:Second)

		/// </summary>

		/// <param name="dateTime">Date Time</param>

		/// <returns>Date Time</returns>

		public static string GetIsoDateTime(this DateTime dateTime)

		{

			return GetIsoDate(dateTime) + " " + GetIsoTime(dateTime);

		}

		#endregion



		#region IsDate (Static)

		/// <summary>

		/// Is date, to check if for example the string contains DateTime value

		/// if not return false

		/// </summary>

		/// <param name="obj">Object to check if this is a date</param>

		/// <returns>True if this is a date, false otherwise</returns>

		public static bool IsDate(Object obj)

		{

			string dateString = obj.ToString();

			try

			{

				DateTime dateLocal = DateTime.Parse(dateString);

				if (dateLocal != DateTime.MinValue &&

				    dateLocal != DateTime.MaxValue)

				{

					return true;

				}

				return false;

			}

			catch

			{

				return false;

			}

		}

		#endregion



		/// <summary>

		/// Test

		/// </summary>

		internal class DateHelperTests

		{

			#region IsDateNewer

			/// <summary>

			/// Is date newer

			/// </summary>

			[Test]

			public void IsDateNewer()

			{

				DateTime newerDate = new DateTime(2007, 6, 21);

				DateTime olderDate = new DateTime(2007, 6, 20);



				Assert.True(DateHelper.IsDateNewer(newerDate, olderDate));

				Assert.False(DateHelper.IsDateNewer(newerDate, newerDate));



				DateTime notOlderDate = new DateTime(2008, 6, 21);

				Assert.False(DateHelper.IsDateNewer(newerDate, notOlderDate));

			}

			#endregion



			#region GetIsoDateTime

			/// <summary>

			/// Get iso date time stamp

			/// </summary>

			[Test]

			public void GetIsoDateTime()

			{

				Assert.Equal("2009-11-17 13:06:01",

					new DateTime(2009, 11, 17, 13, 6, 1).GetIsoDateTime());

				DateTime testTime = new DateTime(2009, 11, 17, 13, 6, 1);

				Assert.Equal(testTime, GetDateAndTimeFromString(

					testTime.GetIsoDateTime()));

			}

			#endregion

		}

	}

}