using System;

using System.Text;

using System.IO;



namespace Westwind.InternetTools

{

	/// <summary>

	/// wwHttp Utility class to provide UrlEncoding without the need to use

	/// the System.Web libraries (too much overhead)

	/// </summary>

	public class wwHttpUtils 

	{

		/// <summary>

		/// UrlEncodes a string without the requirement for System.Web

		/// </summary>

		/// <param name="String"></param>

		/// <returns></returns>

		public static string UrlEncode(string InputString) 

		{

			StringReader sr = new StringReader( InputString);

			StringBuilder sb = new StringBuilder(  InputString.Length );



			while (true) 

			{

				int lnVal = sr.Read();

				if (lnVal == -1)

					break;

				char lcChar = (char) lnVal;



				if (lcChar >= 'a' && lcChar < 'z' || 

					lcChar >= 'A' && lcChar < 'Z' || 

					lcChar >= '0' && lcChar < '9')

					sb.Append(lcChar);

				else if (lcChar == ' ') 

					sb.Append("+");

				else

					sb.AppendFormat("%{0:X2}",lnVal);

			}



			return sb.ToString();

		}



		/// <summary>

		/// UrlDecodes a string without requiring System.Web

		/// </summary>

		/// <param name="InputString">String to decode.</param>

		/// <returns>decoded string</returns>

		public static string UrlDecode(string InputString)

		{

			char temp = ' ';

			StringReader sr = new StringReader(InputString);

			StringBuilder sb = new StringBuilder( InputString.Length );



			while (true) 

			{

				int lnVal = sr.Read();

				if (lnVal == -1)

					break;

				char TChar = (char) lnVal;

				if (TChar == '+')

					sb.Append(' ');

				else if(TChar == '%') 

				{

					// *** read the next 2 chars and parse into a char

					temp = (char) Int32.Parse(((char) sr.Read()).ToString() +  ((char) sr.Read()).ToString(),

												   System.Globalization.NumberStyles.HexNumber);

					sb.Append(temp);

				}

				else

					sb.Append(TChar);

			}



			return sb.ToString();

		}



		/// <summary>

		/// Retrieves a value by key from a UrlEncoded string.

		/// </summary>

		/// <param name="UrlEncodedString">UrlEncoded String</param>

		/// <param name="Key">Key to retrieve value for</param>

		/// <returns>returns the value or "" if the key is not found or the value is blank</returns>

		public static string GetUrlEncodedKey(string UrlEncodedString, string Key) 

		{

			UrlEncodedString = "&" + UrlEncodedString + "&";



			int Index = UrlEncodedString.ToLower().IndexOf("&" + Key.ToLower() + "=");

			if (Index < 0)

				return "";

	

			int lnStart = Index + 2 + Key.Length;



			int Index2 = UrlEncodedString.IndexOf("&",lnStart);

			if (Index2 < 0)

				 return "";



			string Result = wwHttpUtils.UrlDecode(  UrlEncodedString.Substring(lnStart,Index2 - lnStart) );



			return Result;

		}



	}

}