import java.util.Arrays;
import java.util.Random;

public class PlayList {
   private Song[] list;

   public PlayList() {
      list = new Song[1];
      list[0] = new Song();
   }

   public PlayList(int x) {
      list = new Song[x];
   }

   public void setList(int x) {
      list = new Song[x];
   }

   public Song[] getList() {
      return list;
   }

   public void addSong(int x, Song s) {
      int length = list.length;
      if (x < length) {
         list[x] = s;
      } else {
         Song[] newList = new Song[length + 1];
         for (int i = 0; i < length; i++) {
            newList[i] = list[i];
         }
         newList[length] = s;
         list = newList;
      }
   }

   public Song getSong(int x) {
      return list[x];
   }

   public int numSongs() {
      int n = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) { n++; }
      }
      return n;
   }

   public int totalLength() {
      int t = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) {
            t += list[i].getLength();
         }
      }
      return t;
   }

   public void removeArtist(String ar) {
      int ct = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) {
            if (list[i].getArtist().equals(ar)) {
               ct++;
            }
         }
      }
      Song[] newList = new Song[list.length - ct];
      int j = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) {
            if (!list[i].getArtist().equals(ar)) {
               newList[j] = list[i];
               j++;
            }
         }
      }
      list = newList;
   }

   public void removeLength(int length) {
      int ct = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) {
            if (list[i].getLength() > length) {
               ct++;
            }
         }
      }
      Song[] newList = new Song[list.length - ct];
      int j = 0;
      for (int i = 0; i < list.length; i++) {
         if (list[i] != null) {
            if (list[i].getLength() <= length) {
               newList[j] = list[i];
               j++;
            }
         }
      }
      list = newList;
   }

   public void shuffle() {
      Random rnd = new Random();
      for (int i = list.length - 1; i > 0; i--) {
         int index = rnd.nextInt(i+1);
         Song a = list[index];
         list[index] = list[i];
         list[i] = a;
      }
   }

   public boolean equals(Object obj) {
      PlayList pl = (PlayList)obj;
      return Arrays.equals(list, pl.getList());
   }

   public String toString() {
      return Arrays.toString(list);
   }

}