Playlist

import random
import json


class MusicPiece(dict):
    def __init__(self, author, title, length):
        dict.__init__(self, author = author, title = title, length = length)
        self.author = author
        self.title = title
        self.length = length

    def __eq__(self, other):
        return self.title == other.title

    def __str__(self):
        return f'{self.author} - {self.title} - {self.length}sec'

    def toJson(self):
        return json.dumps(self.__dict__)


class Playlist(dict):
    musicPieces = None

    def __init__(self, title):
        self.musicPieces = []
        self.title = title

    def shuffle(self):
        random.shuffle(self.musicPieces)

    def addMusicPiece(self, musicPiece):
        if not isinstance(musicPiece, MusicPiece):
            raise "Can only add music pieces to a playlist"
        self.musicPieces.append(musicPiece)

    def deleteMusicPiece(self, title):
        toRemove = MusicPiece('_', title, 0)
        if(toRemove in self.musicPieces):
            self.musicPieces.remove(toRemove)
            return True
        return False

    def sortByTitle(self, desc=False):
        self.musicPieces.sort(key=lambda mp: mp.title, reverse=desc)

    def __str__(self):
        return "\n".join([piece.__str__() for piece in self.musicPieces])

    def toJson(self):
        dict.__init__(self, musicPieces = self.musicPieces, title=self.title)
        return json.dumps(self.__dict__)

def main():
    my_playlist = Playlist('Blues')
    my_playlist.addMusicPiece(MusicPiece('Blues Brothers', 'Sweet Home Chicago', 180))
    my_playlist.addMusicPiece(MusicPiece('Eric Clapton', 'Blues With Russel', 230))
    print(my_playlist)

    print("-" * 50)
    print(my_playlist.toJson())
    print("-" * 50)

    my_playlist.deleteMusicPiece('Blues With Russel')
    print(my_playlist)
    print("-" * 50)

    jsonDump = '{\
      "musicPieces":[\
          {\
            "author":"Blues Brothers",\
            "title":"Sweet Home Chicago",\
            "length":180\
          },\
          {\
            "author":"Eric Clapton",\
            "title":"Blues With Russel",\
            "length":230\
          }\
      ],\
      "title":"Blues"\
    }'
    newPlaylist = Playlist(json.loads(jsonDump))
    print(newPlaylist)

if __name__ == "__main__":
    main()