#region Using Directives

using System;
using System.ComponentModel;
using System.Globalization;
using System.Text;
using System.Text.RegularExpressions;

#endregion Using Directives


namespace ScintillaNET
{
    public class WhitespaceStringConverter : TypeConverter
    {
        #region Fields

        private static readonly Regex rr = new Regex("\\{0x([0123456789abcdef]{1,4})\\}", RegexOptions.IgnoreCase);

        #endregion Fields


        #region Methods

        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            if (sourceType == typeof(char) || sourceType == typeof(string))
                return true;

            return false;
        }


        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(char) || destinationType == typeof(string))
                return true;

            return false;
        }


        private string ConvertFrom(string value)
        {
            Match m = rr.Match(value);
            while (m.Success)
            {
                int val = int.Parse(m.Value.Substring(3, m.Length - 4), NumberStyles.AllowHexSpecifier);
                value = value.Replace(m.Value, ((char)val).ToString());
                m = rr.Match(value);
            }
            value = value.Replace("{TAB}", "\t").Replace("{LF}", "\r").Replace("{CR}", "\n").Replace("{SPACE}", " ");

            return value;
        }


        public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
        {
            string val = ConvertFrom(value.ToString());


            if (context.PropertyDescriptor.ComponentType == typeof(char))
                return val[0];

            return val;
        }


        private string ConvertTo(string nativeString)
        {
            StringBuilder sb = new StringBuilder();
            foreach (char c in nativeString)
            {
                if ((int)c > 32)
                {
                    sb.Append(c);
                    continue;
                }

                switch ((int)c)
                {
                    case 9:
                        sb.Append("{TAB}");
                        break;
                    case 10:
                        sb.Append("{LF}");
                        break;
                    case 13:
                        sb.Append("{CR}");
                        break;
                    case 32:
                        sb.Append("{SPACE}");
                        break;
                    default:
                        sb.Append("{0x" + ((int)c).ToString("x4") + "}");
                        break;
                }
            }
            return sb.ToString();
        }


        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        {
            string val = ConvertTo(value.ToString());

            if (destinationType == typeof(char))
                return val[0];

            return val;
        }


        public override bool IsValid(ITypeDescriptorContext context, object value)
        {
            return true;
        }

        #endregion Methods
    }
}