using System;
using System.Text;
using XYLEM.Communication;

namespace XYLEM.Communication.ValueEncoders {
	public static class StringEncoder {
		public static Encoding GetDefaultEncoding( ) {
			try {
				return Encoding.GetEncoding( "Windows-1252"/*Strings._CONFIG_STD_String_DefaultCharacterEncoding*/ );
			} catch (Exception ex) {
				throw new Exception( typeof( StringEncoder ).ToString( )+ "\n\rGetDefaultEncoding"+ "\n\rError when making default encoding with = "+ "\n\rWindows-1252"/*Strings._CONFIG_STD_String_DefaultCharacterEncoding*/, ex );
			}
			//Legacy code return Encoding.GetEncoding( 1252 );
		}

		/// <summary>
		/// Standard Windows iso-8859-1-encoding page.
		/// </summary>
		static Encoding s_Encoder = GetDefaultEncoding( ); // Default Fallback

		/// <summary>
		/// 
		/// </summary>
		/// <param name="value"></param>
		/// <param name="lenght"></param>
		/// <param name="CharacterSet">ex. "iso-8859-1"</param>
		/// <returns></returns>
		public static byte[] Encode(string value, int lenght, string CharacterSet) {
			if (value.Length > lenght) {
				throw new ArgumentException( "value.Length is too long", "value" );
			}
			var result = new byte[ lenght ];
			try {
				if (!String.IsNullOrEmpty( CharacterSet )) {
					Encoding.GetEncoding( CharacterSet ).GetBytes( value ).CopyTo( result, 0 );
					return result;
				}
			} catch (Exception ex) {
				throw new Exception( typeof( StringEncoder ).ToString( )+ "\n\rEncode"+ "\n\rWith = " + "iso-8859-1"/*Strings._CONFIG_STD_Email_DefaultCharacterEncoding*/ + Environment.NewLine + ex.Message );
			}
			// Use defalt
			s_Encoder.GetBytes( value ).CopyTo( result, 0 );
			return result;
		}

		/// <summary>
		/// Use default characterSet
		/// </summary>
		/// <param name="value"></param>
		/// <param name="lenght"></param>
		/// <returns></returns>
		public static byte[] Encode(string value, int lenght) { return Encode( value, lenght, null ); }

		/// <summary>
		/// 
		/// </summary>
		/// <param name="value"></param>
		/// <param name="lenght"></param>
		/// <param name="CharacterSet">ex. "iso-8859-1"</param>
		/// <returns></returns>
		public static string Decode(byte[] value, int lenght, string CharacterSet) {
			if (value.Length != lenght) {
				throw new ArgumentException( "value.Length wrong lenght", "value" );
			}
			string result = null;
			try {
				if (!String.IsNullOrEmpty( CharacterSet )) {
					result = Encoding.GetEncoding( CharacterSet ).GetString( value );
				}
			} catch (Exception ex) {
				throw new Exception( typeof( StringEncoder ).ToString( )+ "\n\rDecode()"+ "\n\rWith = " + "iso-8859-1"/*Strings._CONFIG_STD_Email_DefaultCharacterEncoding*/ + Environment.NewLine + ex.Message );
			}
			// Use defalt
			if (result == null) {
				result = s_Encoder.GetString( value );
			}
			var index = result.IndexOf( '\0' );
			if (index >= 0)
				return result.Substring( 0, result.IndexOf( '\0' ) );
			else
				return result;
		}

		/// <summary>
		/// Use default characterSet
		/// </summary>
		/// <param name="value"></param>
		/// <param name="lenght"></param>		
		/// <returns></returns>
		public static string Decode(byte[] value, int lenght) { return Decode( value, lenght, null ); }
	}
}