//1
class Media {
//2 common property not set to a value
  constructor(title){
//3 common properties
    this._title = title;
    this._isCheckedOut = false;
    this._ratings = [];
  }
//4 create getters
  get title(){
    return this._title;
  }
  get isCheckedOut(){
    return this._isCheckedOut;
  }
  get ratings(){
    return this._ratings;
  }

//5 create a method
  toggleCheckOutStatus(){
  this._isCheckedOut = !this._isCheckedOut;
   }
//6 calculate the ratings
   getAverageRating(){
    let ratingSum = this.ratings.reduce((total, currentValue) =>
    total + currentValue, 0);
    return ratings;

    }
//7
  addRating(nRatings){
    this.ratings.push(nRatings);
  }

}

//8 create book class
class Book extends Media {
  //9 cosntructor accepts 3 arguments
  constructor(title, author, pages){
  //10 argument that parent constructor uses
    super(title);
  this._author = author;
	this._pages = pages;


  }
//12
  get author(){
    return this._author;
  }
	get pages(){
    return this._pages;
  }
  addAuthor(newAuthor){
    this.author.push(newAuthor);
  }
  totalPages(nOfPages){
    this.pages.push(nOfPages);
  }
}
const historyOfEverything = new Book('A Short Histor of Nearly Everyting', 'Bill Bryson', 544, 90);
console.log(historyOfEverything.title);
console.log(historyOfEverything.author);
console.log(historyOfEverything.pages);
historyOfEverything.toggleCheckOutStatus();
console.log(historyOfEverything.isCheckedOut);
historyOfEverything.addRating(4);
historyOfEverything.addRating(4);
historyOfEverything.addRating(4);
console.log('These are the ratings: '+ historyOfEverything.ratings);

//13 movies class
class Movies extends Media {
  constructor(title, director, runTime){
  super(title);
  this._director = director;
	this._runTime = runTime;
}
}