package lrs.visitor;
import lrs.*;

/**
* Finds, removes, and returns the minimum Integer element in a LRStruct.
* NOTE: There is a bug in this code.  Find and fix it.
* @author D. X. Nguyen
*/
public class RemMinBuggy implements IAlgo
{
   public static final RemMinBuggy Singleton = new RemMinBuggy ();
   private RemMinBuggy ()
   {
   }

   public Object nullCase (LRStruct host, Object inputNotUsed)
   {
      throw new java.util.NoSuchElementException ("Empty host has no min element.");
   }

   public Object nonNullCase(LRStruct host, Object inputNotUsed)
   {
      // passes itself to the tail and asks the tail to "help" find, remove, and return the min.
      return host.getRest().execute (
         new IAlgo ()
         {
            public Object nullCase (LRStruct hostTail, Object tempMinLRS)
            {
               return ((LRStruct)tempMinLRS).removeFront();
            }

            public Object nonNullCase (LRStruct hostTail, Object tempMinLRS)
            {
               Integer tempMin = (Integer)((LRStruct)tempMinLRS).getFirst ();
               Integer dat = (Integer)hostTail.getFirst ();
               return tempMin.intValue () <= dat.intValue ()?
                        hostTail.getRest ().execute (this, tempMin):
                        hostTail.getRest ().execute (this, hostTail);
            }
         }
         , host);
   }

   public static void main (String[] args)
   {
      LRStruct L = new LRStruct ();
      System.out.println ("\nL = (" + L + ')');
      try
      {
         System.out.println ("RemMinBuggy L = " + L.execute (RemMinBuggy.Singleton, null));
      }
      catch (Exception e)
      {
         System.out.println ("Get Last L: " + e);
      }
      L.insertFront (new Integer (4));
      System.out.println ("\nL = ( " + L + ')');
      System.out.println ("RemMinBuggy L = " + L.execute (RemMinBuggy.Singleton, null));
      System.out.println ("L = ( " + L + ')');
      L.insertFront (new Integer (4));
      L.insertFront (new Integer (99));
      System.out.println ("\nL = ( " + L + ')');
      System.out.println ("RemMinBuggy L = " + L.execute (RemMinBuggy.Singleton, null));
      System.out.println ("L = ( " + L + ')');
      L.insertFront (new Integer (4));
      L.insertFront (new Integer (-7));
      L.insertFront (new Integer (99));
      System.out.println ("\nL = ( " + L + ')');
      System.out.println ("RemMinBuggy L = " + L.execute (RemMinBuggy.Singleton, null));
      System.out.println ("L = ( " + L + ')');
   }

}