НП MP3

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class PatternTest {
    public static void main(String args[]) {
        List<Song> listSongs = new ArrayList<Song>();
        listSongs.add(new Song("first-title", "first-artist"));
        listSongs.add(new Song("second-title", "second-artist"));
        listSongs.add(new Song("third-title", "third-artist"));
        listSongs.add(new Song("fourth-title", "fourth-artist"));
        listSongs.add(new Song("fifth-title", "fifth-artist"));
        MP3Player player = new MP3Player(listSongs);


        System.out.println(player.toString());
        System.out.println("First test");


        player.pressPlay();
        player.printCurrentSong();
        player.pressPlay();
        player.printCurrentSong();

        player.pressPlay();
        player.printCurrentSong();
        player.pressStop();
        player.printCurrentSong();

        player.pressPlay();
        player.printCurrentSong();
        player.pressFWD();
        player.printCurrentSong();

        player.pressPlay();
        player.printCurrentSong();
        player.pressREW();
        player.printCurrentSong();


        System.out.println(player.toString());
        System.out.println("Second test");


        player.pressStop();
        player.printCurrentSong();
        player.pressStop();
        player.printCurrentSong();

        player.pressStop();
        player.printCurrentSong();
        player.pressPlay();
        player.printCurrentSong();

        player.pressStop();
        player.printCurrentSong();
        player.pressFWD();
        player.printCurrentSong();

        player.pressStop();
        player.printCurrentSong();
        player.pressREW();
        player.printCurrentSong();


        System.out.println(player.toString());
        System.out.println("Third test");


        player.pressFWD();
        player.printCurrentSong();
        player.pressFWD();
        player.printCurrentSong();

        player.pressFWD();
        player.printCurrentSong();
        player.pressPlay();
        player.printCurrentSong();

        player.pressFWD();
        player.printCurrentSong();
        player.pressStop();
        player.printCurrentSong();

        player.pressFWD();
        player.printCurrentSong();
        player.pressREW();
        player.printCurrentSong();


        System.out.println(player.toString());
    }
}

//Vasiot kod ovde

class Song{
	String title;
	String artist;

	public Song(String title, String artist) {
		super();
		this.title = title;
		this.artist = artist;
	}

	public String getTitle() {
		return title;
	}

	public String getArtist() {
		return artist;
	}

	@Override
	public String toString() {
		return String.format("Song{title=%s, artist=%s}", getTitle(),getArtist());
	}



}

class MP3Player{
	List<Song> list;
	int i=0;
	int pom=10;
	boolean stop=true;
	boolean play=false;
	public MP3Player(List<Song> list) {
		super();
		this.list = list;
	}

	public void pressPlay() {
		if(play) {
			System.out.println("Song is already playing");
			return;
		}else {
		System.out.println(String.format("Song %d is playing", i));
		play=true;
		stop=false;
		pom=10;
		}
	}

	public void pressStop() {
		if(stop&&i==0 && pom==-1) {
			System.out.println("Songs are already stopped");
			return ;
		}
		if(stop) {
			System.out.println("Songs are stopped");
			i=0;
			pom=-1;
		}else {
			stop=true;
			play=false;
			System.out.println(String.format("Song %d is paused", i));
		}
	}

	public void pressREW() {
		System.out.println("Reward...");
		if(i-1<0) {
			i=list.size()-1;
		}else {
			i--;
		}
		play=false;
		stop=true;
		pom=10;
	}
	public void pressFWD() {
		System.out.println("Forward...");
		if(i+1==list.size()) {
			i=0;
		}else {
			i++;
		}
		play=false;
		stop=true;
		pom=10;
	}

	public void printCurrentSong() {
		System.out.println(list.get(i).toString());
	}

	public String songsToString() {
        return list.stream().map(Song::toString).collect(Collectors.joining(", "));
    }

 @Override
    public String toString() {
        return "MP3Player{currentSong = " + i + ", songList = [" + songsToString() + "]}";
    }


}