/* This file is part of the Joshua Machine Translation System.
 * 
 * Joshua is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */
package joshua.corpus.vocab;

import java.util.HashMap;


/**
 * Partial basic implementation of a symbol table.
 *
 * @author Lane Schwartz
 * @author Zhifei Li
 * @version $LastChangedDate: 2009-11-30 16:47:19 -0600 (Mon, 30 Nov 2009) $
 */
public abstract class AbstractSymbolTable implements SymbolTable {	
	/*a speed up trick*/
	HashMap<Integer, Integer> targetNonterminalIntexCache = new HashMap<Integer, Integer> ();
	
	/* See Javadoc for SymbolTable interface. */
	final public int[] addTerminals(String sentence){
		return addTerminals(sentence.split("\\s+"));
	}	
	
	/* See Javadoc for SymbolTable interface. */
    final public int[] addTerminals(String[] words){
		int[] res =new int[words.length];
		for(int t=0; t<words.length; t++)
			res[t]=addTerminal(words[t]);
		return res;
	}	
    
    /* See Javadoc for SymbolTable interface. */
	final public int getTargetNonterminalIndex(int id) {
		if (! isNonterminal(id)) {
			return -1;
		} else {
			Integer res = targetNonterminalIntexCache.get(id);
			if(res!=null)
				return res;
			else{
				res = getTargetNonterminalIndex( getWord(id) );//convert to string, and then get the index
				targetNonterminalIntexCache.put(id, res);
				return res;
			}
		}
	}
	
	/* See Javadoc for SymbolTable interface. */
	final public int getTargetNonterminalIndex(String wrd) {
		// Assumes the last character is a digit
		// and extracts it, starting from one.
		// Assumes the whole prefix is the
		// nonterminal-ID portion of the string
		
		//TODO: this function is called exponentially many times, we should speed it up further
		return Integer.parseInt( wrd.substring(wrd.length() - 2,	wrd.length() - 1) ) - 1;
		
		/*
		String nonterminalID = 
			wrd.substring(wrd.length() - 2,	wrd.length() - 1);

		if (FormatUtil.isNumber(nonterminalID)) {//!!!!!!!!!!!!!! this function causes the decoding 7 times slow, confirmed by zhifei
			return Integer.parseInt( nonterminalID ) - 1;
		} else {
			throw new MalformedNonterminalException(
					"Substring '" +nonterminalID+ "' " +
					"of string '" +wrd+ "' is not a number");
		}*/

	}

	/* See Javadoc for SymbolTable interface. */
	public String getUnknownWord() {
		return SymbolTable.UNKNOWN_WORD_STRING;
	}

	/* See Javadoc for SymbolTable interface. */
	public int getUnknownWordID() {
		return SymbolTable.UNKNOWN_WORD;
	}
	
	/* See Javadoc for SymbolTable interface. */
	public String getWords(int[] wordIDs, boolean ntIndexIncrements) {
		StringBuilder s = new StringBuilder();
		
		int nextNTIndex = 1;
		for (int t=0; t<wordIDs.length; t++) {
			if(t>0) {
				s.append(' ');
			}
			
			int wordID = wordIDs[t];
			
//			if (wordID >= vocabList.size()) { 
//				s.append(UNKNOWN_WORD_STRING);
//			} else 
			if (wordID < 0 && ntIndexIncrements) {
				s.append("[X,"); //XXX This should NOT be hardcoded here!
				if (ntIndexIncrements) {
					s.append(nextNTIndex++);
				} else {
					s.append(-1*wordID);
				}
				s.append(']');
			} else {
				String word = getWord(wordID);
				s.append(word);
			}

		}
		
		return s.toString();
	}
	
	/* See Javadoc for SymbolTable interface. */
	public boolean isNonterminal(int id) {
		return (id < 0);
	}

}