STUN Client

using System;
using System.IO;
using System.Collections;
using System.Text;

using LumiSoft.Net.Mime;

namespace LumiSoft.Net.IMAP.Server
{
	/// <summary>
	/// FETCH command helper methods.
	/// </summary>
	internal class FetchHelper
	{				
		#region function ParseHeaderFields

		/// <summary>
		/// Returns requested header fields lines.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="fieldsStr">Header fields to get.</param>
		/// <param name="entity">Entity which header field lines to get.</param>
		/// <returns></returns>
		public static byte[] ParseHeaderFields(string fieldsStr,MimeEntity entity)
		{
			return ParseHeaderFields(fieldsStr,System.Text.Encoding.Default.GetBytes(entity.HeaderString));
		}

		/// <summary>
		/// Returns requested header fields lines.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="fieldsStr">Header fields to get.</param>
		/// <param name="data">Message data.</param>
		/// <returns></returns>
		public static byte[] ParseHeaderFields(string fieldsStr,byte[] data)
		{
			fieldsStr = fieldsStr.Trim();
			if(fieldsStr.StartsWith("(")){
				fieldsStr = fieldsStr.Substring(1,fieldsStr.Length - 1);
			}
			if(fieldsStr.EndsWith(")")){
				fieldsStr = fieldsStr.Substring(0,fieldsStr.Length - 1);
			}

			string retVal = "";

			string[] fields = fieldsStr.Split(' ');
            using(MemoryStream mStrm = new MemoryStream(data)){
				TextReader r = new StreamReader(mStrm);
				string line = r.ReadLine();
				
				bool fieldFound = false;
				// Loop all header lines
				while(line != null){ 
					// End of header
					if(line.Length == 0){
						break;
					}

					// Field continues
					if(fieldFound && line.StartsWith("\t")){
						retVal += line + "\r\n";
					}
					else{
						fieldFound = false;

						// Check if wanted field
						foreach(string field in fields){
							if(line.Trim().ToLower().StartsWith(field.Trim().ToLower())){
								retVal += line + "\r\n";
								fieldFound = true;
							}
						}
					}

					line = r.ReadLine();
				}
			}

			// Add header terminating blank line
			retVal += "\r\n"; 

			return System.Text.Encoding.ASCII.GetBytes(retVal);
		}

		#endregion

		#region function ParseHeaderFieldsNot

		/// <summary>
		/// Returns header fields lines except requested.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="fieldsStr">Header fields to skip.</param>
		/// <param name="entity">Entity which header field lines to get.</param>
		/// <returns></returns>
		public static byte[] ParseHeaderFieldsNot(string fieldsStr,MimeEntity entity)
		{
			return ParseHeaderFieldsNot(fieldsStr,System.Text.Encoding.Default.GetBytes(entity.HeaderString));
		}

		/// <summary>
		/// Returns header fields lines except requested.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="fieldsStr">Header fields to skip.</param>
		/// <param name="data">Message data.</param>
		/// <returns></returns>
		public static byte[] ParseHeaderFieldsNot(string fieldsStr,byte[] data)
		{
			fieldsStr = fieldsStr.Trim();
			if(fieldsStr.StartsWith("(")){
				fieldsStr = fieldsStr.Substring(1,fieldsStr.Length - 1);
			}
			if(fieldsStr.EndsWith(")")){
				fieldsStr = fieldsStr.Substring(0,fieldsStr.Length - 1);
			}

			string retVal = "";

			string[] fields = fieldsStr.Split(' ');
            using(MemoryStream mStrm = new MemoryStream(data)){
				TextReader r = new StreamReader(mStrm);
				string line = r.ReadLine();
				
				bool fieldFound = false;
				// Loop all header lines
				while(line != null){ 
					// End of header
					if(line.Length == 0){
						break;
					}

					// Filed continues
					if(fieldFound && line.StartsWith("\t")){
						retVal += line + "\r\n";
					}
					else{
						fieldFound = false;

						// Check if wanted field
						foreach(string field in fields){
							if(line.Trim().ToLower().StartsWith(field.Trim().ToLower())){								
								fieldFound = true;
							}
						}

						if(!fieldFound){
							retVal += line + "\r\n";
						}
					}

					line = r.ReadLine();
				}
			}

			return System.Text.Encoding.ASCII.GetBytes(retVal);
		}

		#endregion


		#region static method GetMimeEntity

		/// <summary>
		/// Gets specified mime entity. Returns null if specified mime entity doesn't exist.
		/// </summary>
		/// <param name="parser">Reference to mime parser.</param>
		/// <param name="mimeEntitySpecifier">Mime entity specifier. Nested mime entities are pointed by '.'. 
		/// For example: 1,1.1,2.1, ... .</param>
		/// <returns></returns>
		public static MimeEntity GetMimeEntity(LumiSoft.Net.Mime.Mime parser,string mimeEntitySpecifier)
		{
			// TODO: nested rfc 822 message

			// For single part message there is only one entity with value 1.
			// Example:
			//		header
			//		entity -> 1
			
			// For multipart message, entity counting starts from MainEntity.ChildEntities
			// Example:
			//		header
			//		multipart/mixed
			//			entity1  -> 1
			//			entity2  -> 2
			//          ...

			// Single part
			if((parser.MainEntity.ContentType & MediaType_enum.Multipart) == 0){
				if(mimeEntitySpecifier.Length == 1 && Convert.ToInt32(mimeEntitySpecifier) == 1){
					return parser.MainEntity;
				}
				else{
					return null;
				}
			}
			// multipart
			else{
				MimeEntity entity = parser.MainEntity;
				string[] parts = mimeEntitySpecifier.Split('.');
				foreach(string part in parts){
					int mEntryNo = Convert.ToInt32(part) - 1; // Enitites are zero base, mimeEntitySpecifier is 1 based.
					if(mEntryNo > -1 && mEntryNo < entity.ChildEntities.Count){
						entity = entity.ChildEntities[mEntryNo];
					}
					else{
						return null;
					}
				}

				return entity;
			}			
		}

		#endregion

		#region static method GetMimeEntityHeader

		/// <summary>
		/// Gets specified mime entity header.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="entity">Mime entity.</param>
		/// <returns></returns>
		public static byte[] GetMimeEntityHeader(MimeEntity entity)
		{
			return System.Text.Encoding.ASCII.GetBytes(entity.HeaderString + "\r\n");
		}

		/// <summary>
		/// Gets requested mime entity header. Returns null if specified mime entity doesn't exist.
		/// Note: Header terminator blank line is included.
		/// </summary>
		/// <param name="parser">Reference to mime parser.</param>
		/// <param name="mimeEntitySpecifier">Mime entity specifier. Nested mime entities are pointed by '.'. 
		/// For example: 1,1.1,2.1, ... .</param>
		/// <returns>Returns requested mime entity data or NULL if requested entry doesn't exist.</returns>
		public static byte[] GetMimeEntityHeader(LumiSoft.Net.Mime.Mime parser,string mimeEntitySpecifier)
		{
			MimeEntity mEntry = GetMimeEntity(parser,mimeEntitySpecifier);
			if(mEntry != null){
				return GetMimeEntityHeader(mEntry);
			}
			else{
				return null;
			}
		}

		#endregion

		#region static method GetMimeEntityData

		/// <summary>
		/// Gets requested mime entity data. Returns null if specified mime entity doesn't exist.
		/// </summary>
		/// <param name="parser">Reference to mime parser.</param>
		/// <param name="mimeEntitySpecifier">Mime entity specifier. Nested mime entities are pointed by '.'. 
		/// For example: 1,1.1,2.1, ... .</param>
		/// <returns>Returns requested mime entity data or NULL if requested entry doesn't exist.</returns>
		public static byte[] GetMimeEntityData(LumiSoft.Net.Mime.Mime parser,string mimeEntitySpecifier)
		{
			MimeEntity entity = GetMimeEntity(parser,mimeEntitySpecifier);
			if(entity != null){
				return entity.DataEncoded;
			}
			else{
				return null;
			}
		}

		#endregion


		#region static method Escape

		private static string Escape(string text)
		{
			text = text.Replace("\\","\\\\");
			text = text.Replace("\"","\\\"");

			return text;
		}

		#endregion

	}
}