package org.paneris.bibliomania.fti;
   
   import org.melati.util.BugException;
   import org.melati.poem.util.Order;
   import org.melati.poem.util.SortUtils;
   
   import com.sleepycat.db.DatabaseException;
   
   public class Score {
  
    public static class Hit {
      public double score;
      public long textID;
  
      public Hit(SearchResults results) {
        if ((textID = results.currentTextID()) == -1)
          throw new BugException("Tried to score an empty hit.");
  
        score = 1.;
        int i = results.currentWordIndex();
        for (;;) {
          results.skipToNextHit();
          int j = results.currentWordIndex();
          if (j == -1) break;
          score += 0.2 + Math.exp((i - j) * (j - i) / 100.);
          i = j;
        }
      }
    }
  
    private static final Order highScoreFirst =
        new Order() {
          public boolean lessOrEqual(Object a, Object b) {
            return ((Hit)a).score >= ((Hit)b).score;
          }
        };
  
    /**
     * FIXME should be implemented with "select the N smallest" rather than a
     * full "sort"
     */
    public static Hit[] scoredHits(
        SearchResults r, long startTextID, long limitTextID, int max)
            throws DatabaseException {
      Hit[] them = new Hit[512];
  
      int n = 0;
      for (r.gotoText(startTextID);
           n < max && r.currentTextID() != -1 && r.currentTextID() < limitTextID;
           r.gotoText(r.currentTextID() + 1)) {
        if (n >= them.length) {
          Hit[] old = them;
          them = new Hit[old.length * 2];
          System.arraycopy(old, 0, them, 0, old.length);
        }
  
        them[n++] = new Hit(r);
      }
  
      Hit[] sorted = new Hit[n];
      System.arraycopy(them, 0, sorted, 0, n);
      SortUtils.qsort(highScoreFirst, sorted);
      return sorted;
    }
  }