A TimeZone Aware DateTime Implementation

/*
 * Created by: Steinar Dragsnes
 * Created: 21.11.2008
 */

using System;

namespace DateTimeZone
{
	
	/// <summary>
	/// Contract for a simple time zone representation.
	/// </summary>
	public interface ITimeZone
	{
		/// <summary>
		/// This time zone's offset from GMT.
		/// </summary>
		double Offset { get; }

		/// <summary>
		/// Calculated hour offset derived from Offset.
		/// </summary>
		int HourOffset { get; }

		/// <summary>
		/// Calculated minute offset derived from Offset.
		/// </summary>
		int MinuteOffset { get; }

		/// <summary>
		/// The Id.
		/// </summary>
		string CanonicalID { get; }

		/// <summary>
		/// Location alias.
		/// </summary>
		string Aliases { get; }

		/// <summary>
		/// The definition of when a summer time zone change occurs.
		/// </summary>
		DaylightSavingTime SummerChange { get; }

		/// <summary>
		/// The definition of when a revertion to a standard time zone change occurs.
		/// </summary>
		DaylightSavingTime WinterChange { get; }

		///<summary>
		///Returns a <see cref="T:System.String"></see> that represents the current <see cref="T:System.Object"></see>.
		///</summary>
		///
		///<returns>
		///A <see cref="T:System.String"></see> that represents the current <see cref="T:System.Object"></see>.
		///</returns>
		///<filterpriority>2</filterpriority>
		string ToString();

		/// <summary>
		/// Printing the content of this
		/// </summary>
		/// <returns>A string formatted to print the c# code needed to define the TimeZone based on the values in this class</returns>
		string PrintValues();

		/// <summary>
		/// A convenience method that checks if the newly converted date for a time zone is within that
		/// time zone's definted DST rules.
		/// </summary>
		/// <param name="time"></param>
		/// <returns></returns>
		bool IsDST(System.DateTime time);

		/// <summary>
		/// Convenience getter for checking if a time zone has DST.
		/// </summary>
		bool HasDST { get; }

	    /// <summary>
	    /// Convenience method for calculating the point in time when the winter time starts.
	    /// </summary>
	    /// <param name="year">For which year to calculate the winter change.</param>
	    /// <returns>A point in time representing the winter change.</returns>
	    DateTime GetDSTEnd(int year);

	    /// <summary>
	    /// Convenience method for calculating the point in time when the summer time starts.
	    /// </summary>
	    /// <param name="year">For which year to calculate the summer change.</param>
	    /// <returns>A point in time representing the summer change.</returns>
	    DateTime GetDSTStart(int year);
	}
}