using System;
using sharp.extensions;
namespace sharp.parser
{
	public class CharGroup
	{
		public static readonly CharGroup digit = new CharGroup('0', '9');
		public static readonly CharGroup zero = new CharGroup('0');
		public static readonly CharGroup digit19 = new CharGroup('1', '9');
		public static readonly CharGroup plusminus = new CharGroup(new char[] { '+', '-' });
		public static readonly CharGroup minus = new CharGroup(new char[] { '+', '-' });
		public static readonly CharGroup plus = new CharGroup(new char[] { '+' });
		public static readonly CharGroup az = new CharGroup('a','z');
		public static readonly CharGroup AZ = new CharGroup('A','Z');
		public static readonly CharGroup aAzZ = az + AZ;
		public static readonly CharGroup LF = new CharGroup((char)0x0A);
		public static readonly CharGroup CR = new CharGroup((char)0x0D);
		public static readonly CharGroup HTAB = new CharGroup((char)0x09);
		public static readonly CharGroup WS = new CharGroup(new char[] { (char)0x09, (char)0x0A, (char)0x0B, (char)0x0C, (char)0x0D, (char)0x20});
		public static readonly CharGroup hexdigits = new CharGroup('a','f') + new CharGroup('A','F') + digit;

		char[] chars;

		public CharGroup(char ch)
		{
			chars = new char[] { ch };
		}
		public CharGroup(char[] chars)
		{
			this.chars = chars.Segment(0);
		}
		public CharGroup(char first,char last)
		{
			int l = (int)last - (int)first;
			this.chars = new char[l+1];

			for (int n = 0; n <= l;n++){
				this.chars[n] = (char)(first + n);
			}
		}

		public bool Contains(char ch){
			foreach (char c in chars){
				if (c == ch){
					return true;
				}
			}
			return false;
		}

		public bool Intersects(CharGroup other){
			foreach (char ch in chars){
				if (other.Contains(ch)){
					return true;
				}
			}
			return false;
		}



		public static CharGroup operator +(CharGroup cg1, CharGroup cg2)
		{
			return new CharGroup(cg1.chars.Combine(cg2.chars));
		}

		public static CharGroup operator -(CharGroup cg1, CharGroup cg2)
		{
			return new CharGroup(cg1.chars.Remove(cg2.chars));
		}

		public override string ToString()
		{
			return string.Format("[CharGroup '{0}']",new string(this.chars));
		}
	}
}