/*
  A wrapper for some common sorting/searching/filtering methods etc, mostly using java.util.Collections
 */

public static class TransactionUtils
{
  public static final int ASCENDING = 1;
  public static final int DESCENDING = -1;
  
 
  //pass in a List of Transactions and it returns a List of Map.Entrys mapping the unique subject name --> num times found in Transactions
  public static ArrayList countUniqueSubjects(ArrayList transactions)
  {
    Map uniqueSubjectToCount = new HashMap(); // string to an integer: unique subject --> frequemncy of unique subject

    for (int i = 0; i < transactions.size(); i++)
    {
      Transaction t = (Transaction) transactions.get(i);

      /*for (int ii = 0; ii < t.subjects.length; ii++)
      {
        Integer cnt = (Integer) uniqueSubjectToCount.get(t.subjects[ii]);

        if (cnt == null)
        {
          uniqueSubjectToCount.put(t.subjects[ii], new Integer(1));
        }  
        else
        {
          uniqueSubjectToCount.put(t.subjects[ii], new Integer(cnt + 1));
        }
      }*/
    }

    return new ArrayList(uniqueSubjectToCount.entrySet());  
  }

  public static String getStringKeyForEntry(Object o)
  {
    Map.Entry me = (Map.Entry) o;
    return (String) me.getKey();
  }

  public static int getIntValueForEntry(Object o)
  {
    Map.Entry me = (Map.Entry) o;
    return ((Integer) me.getValue()).intValue();
  }
  
  //sort a list of Map.Entrys by their value. This assumes that the value is an Integer! 
  //order = 1 for Ascending, order = -1 for descending.  
  public static void sortUniqueSubjectsByCount(ArrayList entryList, final int order)
  {
    Collections.sort(entryList, new Comparator()
    {
      public int compare(Object o1, Object o2)
      {
        Map.Entry me1 = (Map.Entry) o1;
        Map.Entry me2 = (Map.Entry) o2;

        return (((Integer)me1.getValue()).intValue() - ((Integer)me2.getValue()).intValue()) * order;
      }
    }
    );
  }


  //sort a List of transactions by the title
  public static void sortTransactionsByTitle(ArrayList transactions)
  {
    Collections.sort(transactions, new Comparator()
    {
      public int compare(Object o1, Object o2)
      {
        Transaction t1 = (Transaction) o1;
        Transaction t2 = (Transaction) o2;

        return t1.title.compareToIgnoreCase(t2.title);
      }
    }
    );
  }

  //reverse order of List
  public static void reverse(ArrayList transactions)
  {
    Collections.reverse(transactions); 
  }

  public static void filterOutNonAlphabeticalTitles(ArrayList transactions)
  {
    for (int i = transactions.size() - 1; i >= 0; i--)  
    {
      Transaction t = (Transaction) transactions.get(i);
      if (t.title.length() < 1)
      {
        transactions.remove(t);
        continue;
      }
      char firstLetter = t.title.charAt(0); 
      if (! ((firstLetter >= 'a' && firstLetter <= 'z') || (firstLetter >= 'A' && firstLetter <= 'Z')) )
      {
        transactions.remove(t);
        continue;  
      }

    }
  }

}