/**
 * 
 */
package de.fhswf.in.inf.java1.aufgabe09;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Collections;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;

/**
 * A class, that counts words in files.
 *
 * @author $Author: $
 * @version $Revision: $, $Date: $ UTC
 */
public class WordCount
{

   private TreeMap<String, Integer> wordMap = new TreeMap<>();

   /**
    * Empty constructor.
    *
    */
   public WordCount()
   {

   }

   /**
    * Reads a file and counts the words.
    *
    * @param file
    *           The file to be read.
    */
   public final void readFile(File file)
   {
      try (BufferedReader f = new BufferedReader(new FileReader(file)))
      {
         wordMap.clear();
         
         String line = null;

         while ((line = f.readLine()) != null)
         {
            String[] lineArray = line
                  .split("[^\\p{IsAlphabetic}\\p{Digit}]+");
            for (String word : lineArray)
            {
               // Split creates empty String, if first char is a split char.
               if (!word.isEmpty())
               {
                  word = word.toLowerCase();

                  Integer tmp = wordMap.get(word);
                  if (tmp != null)
                  {
                     wordMap.put(word, tmp + 1);
                  }
                  else
                  {
                     wordMap.put(word, new Integer(1));
                  }
               }
            }
         }
      }
      catch (IOException e)
      {
         e.printStackTrace(System.err);
      }
   }

   /*
    * (non-Javadoc)
    * 
    * @see java.lang.Object#toString()
    */
   @Override
   public final String toString()
   {
      StringBuilder ret = new StringBuilder();

      for (Entry<String, Integer> mapping : wordMap.entrySet())
      {
         ret.append(mapping.getKey() + " = " + mapping.getValue() + "\n");
      }

      return ret.toString();
   }

   /**
    * Returns all words from the file.
    *
    * @return An unmodifiable Set of the words from the file.
    */
   public final Set<String> getWords()
   {
      return Collections.unmodifiableSet(wordMap.keySet());
   }

   /**
    * Returns the count of a word in a file.
    *
    * @param word
    *           The file to be counted.
    * @return Returns the count of findings in the file.
    */
   public final int getCount(String word)
   {
      if (word == null)
      {
         throw new IllegalArgumentException("Word must be a valid referece.");
      }
      if (word.isEmpty())
      {
         throw new IllegalArgumentException("The word can't be empty.");
      }

      Integer tmp = wordMap.get(word);
      if (tmp == null)
      {
         return 0;
      }
      return tmp;
   }

}