using System;
using lexer.buffer;
using System.Collections.Generic;
namespace lexer.match
{
	public abstract class Matchable
	{
		public event MatchedDelegate OnMatched;
		public String Name { get; private set; }

		public bool Grouping { get; set; }
		public bool Notice { get; set; }

		protected Matchable(String name = null)
		{
			this.Name = name;

			if (name != null)
			{
				namedMatchables.Add(name, this);
			}
		}

		public MatchedPart[] MatchNoticeable(CharacterBuffer chbuffer){
			MatchedPart[] mparts = Match(chbuffer);
			if (Grouping && (mparts != null)){
				MatchedPart mp = new MatchedPart(this, mparts.MatchingCharacters());
				return new MatchedPart[] { mp };
			}
			return mparts;
		}

		/**
		 * Match()	match this Matchable starting at current position of CharacterBuffer
		 * 
		 * if an successfull Match is found, return the matched characters as char[]
		 * returns null if no match is found
		 * 
		 **/
		public abstract MatchedPart[] Match(CharacterBuffer chbuffer);

		public override string ToString()
		{
			return ToString(false);
		}

		public virtual String ToString(bool useSymbol)
		{
			if (useSymbol && (this.Name != null))
			{
				return this.Name;
			}
			return ToString();
		}



		static Dictionary<string, Matchable> namedMatchables = new Dictionary<string, Matchable>();
		public static Matchable getNamedMatchable(String name)
		{
			if (!namedMatchables.ContainsKey(name)){
				return null;
			}
			return namedMatchables[name];
		}
		public static Matchable getNamedMatchable(char[] name)
		{
			return getNamedMatchable(new String(name));
		}

		public class DeferredMatchable : Matchable{

			Matchable matchable;

			public DeferredMatchable(char[] name)
				:this(new String(name)){}
			
			public DeferredMatchable(String name)
				:base(){
				Name = name;
				matchable = null;
			}

			public override MatchedPart[] Match(CharacterBuffer chbuffer)
			{
				if (matchable == null){
					matchable = getNamedMatchable(Name);
				}
				if (matchable == null)
				{
					throw new KeyNotFoundException(String.Format("Deferred matchable '{0}' was not found", Name));
				}
				return matchable.Match(chbuffer);
			}
		}

	}
}