WCF over Twitter

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections;
using System.Windows.Threading;


namespace TwitterApi
{
	public class TwitterMessage
	{
		public int? Id
		{
			get;
			set;
		}
		public static TwitterChainMessage CreateMessages(TwitterMessageContext context, String message)
		{
			TwitterChainMessage chain = new TwitterChainMessage();
			String header = context.Header;
			string contentLeft = message;
			while(contentLeft != null)
			{
				var twitterMessage = TwitterMessage.Create(header, contentLeft, context.ContinuationString, context.MaxMessageSize, out contentLeft);
				chain.Append(twitterMessage);
			}
			return chain;
		}

		public Twit ToTwit()
		{
			return new Twit(this.FullMessage);
		}

		public static bool TryParseMessage(TwitterMessageContext context, String message, out TwitterMessage twitterMessage)
		{
			if(!context.IsConsistentWithContext(message))
			{
				twitterMessage = null;
				return false;
			}
			var header = context.Header;
			var content = message.Remove(0, context.Header.Length);
			String continuationString = "";
			if(content.EndsWith(context.ContinuationString))
			{
				content = content.Remove(content.Length - context.ContinuationString.Length);
				continuationString = context.ContinuationString;
			}
			twitterMessage = new TwitterMessage(header, content, continuationString, context.MaxMessageSize);
			return true;
		}

		public static TwitterMessage Create(String header, String content, String continuationString, int maxSize, out String contentLeft)
		{
			int currentSize = header.Length + content.Length;
			if(currentSize <= maxSize)
			{
				contentLeft = null;
				return new TwitterMessage(header, content, String.Empty, maxSize);
			}
			currentSize = currentSize + continuationString.Length;
			int numberCharToTrunc = currentSize - maxSize;
			contentLeft = content.Substring(content.Length - numberCharToTrunc);
			var truncatedContent = content.Substring(0, content.Length - contentLeft.Length);
			Debug.Assert(truncatedContent + contentLeft == content);
			return new TwitterMessage(header, truncatedContent, continuationString, maxSize);
		}

		private TwitterMessage(String header, String content, String continuationString, int maxSize)
		{
			Header = header;
			Content = content;
			Bottom = continuationString;
			if(FullMessage.Length > maxSize)
			{
				throw new InvalidOperationException("The twit is too big");
			}
		}



		string _FullMessage;
		public String FullMessage
		{
			get
			{
				return _FullMessage = _FullMessage ?? Header + Content + Bottom;
			}
		}
		public String Header
		{
			get;
			private set;
		}
		public String Content
		{
			get;
			private set;
		}
		public String Bottom
		{
			get;
			private set;
		}

		public bool IsFinalMessage
		{
			get
			{
				return String.IsNullOrEmpty(Bottom);
			}
		}
	}
}