/*
    * Copyright 2010 James Pether Sörling
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   *	$Id$
   *  $HeadURL$
  */
  package com.hack23.cia.service.impl.action.user.wordcount;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.stereotype.Service;
  
  import com.hack23.cia.model.external.riksdagen.documentcontent.impl.DocumentContentData;
  
  import weka.core.Attribute;
  import weka.core.DenseInstance;
  import weka.core.Instance;
  import weka.core.Instances;
  import weka.core.stopwords.StopwordsHandler;
  import weka.core.tokenizers.NGramTokenizer;
  import weka.filters.Filter;
  import weka.filters.unsupervised.attribute.StringToWordVector;
  
  /**
   * The Class WordCounterImpl.
   */
  @Service
  final class WordCounterImpl implements WordCounter {
  
  	/** The Constant TOKEN_DELIMITERS. */
  	private static final String TOKEN_DELIMITERS = " \r\n\t.,;:'\"()?!'";
  
  	/** The Constant HTML. */
  	private static final String HTML = "html";
  	
  	/** The Constant LOGGER. */
  	private static final Logger LOGGER = LoggerFactory
  			.getLogger(WordCounterImpl.class);
  
  
  	/**
  	 * Instantiates a new word counter impl.
  	 */
  	public WordCounterImpl() {
  		super();
  	}
  
  	@Override
  	public Map<String, Integer> calculateWordCount(final DocumentContentData documentContentData, final int maxResult) {
  
  		final String html = documentContentData.getContent();
  
  		final Attribute input = new Attribute(HTML, (ArrayList<String>) null);
  
  		final ArrayList<Attribute> inputVec = new ArrayList<>();
  		inputVec.add(input);
  
  		final Instances htmlInst = new Instances(HTML, inputVec, 1);
  
  		htmlInst.add(new DenseInstance(1));
  		htmlInst.instance(0).setValue(0, html);
  
  
  		final StopwordsHandler stopwordsHandler = new StopwordsHandler() {
  
  			@Override
  			public boolean isStopword(final String word) {
  
  				return word.length() <5;
  			}
  		};
  
  		final NGramTokenizer tokenizer = new NGramTokenizer();
  		tokenizer.setNGramMinSize(1);
  		tokenizer.setNGramMaxSize(1);
  		tokenizer.setDelimiters(TOKEN_DELIMITERS);
  
  		final StringToWordVector filter = new StringToWordVector();
  		filter.setTokenizer(tokenizer);
  		filter.setStopwordsHandler(stopwordsHandler);
  		filter.setLowerCaseTokens(true);
  		filter.setOutputWordCounts(true);
  		filter.setWordsToKeep(maxResult);
 
 		final Map<String,Integer> result = new HashMap<>();
 
 		try {
 			filter.setInputFormat(htmlInst);
 			final Instances dataFiltered = Filter.useFilter(htmlInst, filter);
 
 			final Instance last = dataFiltered.lastInstance();
 
 			final int numAttributes = last.numAttributes();
 
 			for (int i = 0; i < numAttributes; i++) {
 				result.put(last.attribute(i).name(), Integer.valueOf(last.toString(i)));
 			}
 		} catch (final Exception e) {
 			LOGGER.warn("Problem calculating wordcount for : {} , exception:{}",documentContentData.getId() ,e);
 		}
 
 
 		return result;
 	}
 
 
 }