package com.multitude.bless;

import org.antlr.runtime.Token;
import org.antlr.runtime.TokenStream;
import org.antlr.runtime.tree.Tree;
import org.antlr.runtime.tree.TreeNodeStream;
import org.antlr.runtime.IntStream;
import org.antlr.runtime.RecognitionException;
import org.antlr.runtime.MissingTokenException;
import org.antlr.runtime.UnwantedTokenException;
import org.antlr.runtime.MismatchedTokenException;
import org.antlr.runtime.NoViableAltException;

/**
 * BASTErrorNode is used in place of CommonErrorNode by BASTTreeAdaptor
 * 
 * @author brl
 * 
 */
public class BASTErrorNode extends BAST
{
public IntStream input;
public Token start;
public Token stop;
public RecognitionException trappedException;

public BASTErrorNode(TokenStream input, Token start, Token stop,
		RecognitionException e)
	{
	// System.out.println("start: "+start+", stop: "+stop);
	if (stop == null
			|| (stop.getTokenIndex() < start.getTokenIndex() && stop.getType() != Token.EOF))
		{
		// sometimes resync does not consume a token (when LT(1) is
		// in follow set. So, stop will be 1 to left to start. adjust.
		// Also handle case where start is the first token and no token
		// is consumed during recovery; LT(-1) will return null.
		stop = start;
		}
	this.input = input;
	this.start = start;
	this.stop = stop;
	this.trappedException = e;
	}

public boolean isNil()
	{
	return false;
	}

public int getType()
	{
	return Token.INVALID_TOKEN_TYPE;
	}

public String getText()
	{
	String badText = null;
	if (start instanceof Token)
		{
		int i = ((Token) start).getTokenIndex();
		int j = ((Token) stop).getTokenIndex();
		if (((Token) stop).getType() == Token.EOF)
			{
			j = ((TokenStream) input).size();
			}
		badText = ((TokenStream) input).toString(i, j);
		}
	else if (start instanceof Tree)
		{
		badText = ((TreeNodeStream) input).toString(start, stop);
		}
	else
		{
		// people should subclass if they alter the tree type so this
		// next one is for sure correct.
		badText = "<unknown>";
		}
	return badText;
	}

public String toString()
	{
	if (trappedException instanceof MissingTokenException)
		{
		return "<missing type: "
				+ ((MissingTokenException) trappedException).getMissingType() + ">";
		}
	else if (trappedException instanceof UnwantedTokenException)
		{
		return "<extraneous: "
				+ ((UnwantedTokenException) trappedException).getUnexpectedToken()
				+ ", resync=" + getText() + ">";
		}
	else if (trappedException instanceof MismatchedTokenException)
		{
		return "<mismatched token: " + trappedException.token + ", resync="
				+ getText() + ">";
		}
	else if (trappedException instanceof NoViableAltException)
		{
		return "<unexpected: " + trappedException.token + ", resync=" + getText()
				+ ">";
		}
	return "<error: " + getText() + ">";
	}

}