import java.util.Arrays;
import java.io.*;

public class PlayList {

    // Instance variables

    private Song[] songs;
    private int count;
    private int capacityIncrement;
  
    // Constructor
    // See below for a new usage of the reserved keyword this.

    public PlayList( int initialCapacity, int capacityIncrement ) {
    
        if ( initialCapacity < 1 )
            throw new IllegalArgumentException( "Illegal capacity: "+ initialCapacity );
    
        if ( capacityIncrement < 1 )
            throw new IllegalArgumentException( "Illegal increment: "+ capacityIncrement );
    
        songs = new Song[ initialCapacity ];
        this.capacityIncrement = capacityIncrement;
    }
  
    public PlayList( int initialCapacity ) {
        this( initialCapacity, 10 );
    }
  
    public PlayList() {
        this( 10, 10 );
    }

    // Returns the number of elements currently stored in the PlayList
  
    public int getSize() {
        return count;
    }
  
    public boolean addSong( Song song ) {

        if ( song == null )
            throw new IllegalArgumentException( "null is not a valid argument" );

        for ( int i=0; i<count; i++ )
            if ( songs[ i ].equals( song ) ) // songs[ i ] cannot be null
                return false;
        
        if ( count == songs.length ) {

            Song[] tmp = songs;
            songs = new Song[ tmp.length + capacityIncrement ];
            for ( int i=0; i< tmp.length; i++ )
                songs[ i ] = tmp[ i ];
        }

        songs[ count++ ] = song;
        return true;
    }
  
    public Song getSongAt( int index ) {

        if ( index < 0 || index >= count )
            throw new IndexOutOfBoundsException( "" + index );

        return songs[ index ];
    }
  
    // Arrays already has a sort method.

    public void sort2( java.util.Comparator c ) {
        Arrays.sort( songs, c );
    }

    // Implementing our own sort method.

    public void sort( java.util.Comparator c ) {
    
        for ( int i = 0; i < count; i++ ) {
      
            int min = i;
      
            // Find the smallest element in the unsorted region of the
            // array.
      
            for ( int j = i+1; j < count; j++ )
                if ( c.compare( songs[ j ], songs[ min ] ) < 0 )
                    min = j;
      
            // Swap the smallest unsorted element with the element
            // found a position i.
      
            Song tmp = songs[ min ];
            songs[ min ] = songs[ i ];
            songs[ i ] = tmp;
        }
    }

    public static PlayList getSongsFromFile( String fileName )
        throws IOException, FileNotFoundException {

        BufferedReader input;

        input = new BufferedReader( new InputStreamReader( new FileInputStream( fileName ) ) );
        
        PlayList result = new PlayList();

        int lineNumber = 0;
        String line;

        while ( ( line = input.readLine() ) != null ) {
            result.addSong( Song.parseSong( line ) );
        }

        input.close();

        return result;
    }

    public void writeSongsToFile( String fileName )
        throws IOException, FileNotFoundException {

        PrintWriter output;

        output = new PrintWriter(
                     new OutputStreamWriter( 
                         new FileOutputStream( fileName ) ) );
        
        for ( int i=0; i<count; i++ ) {
            output.println( songs[ i ] );
        }
        
        output.close();
    }

}