class BookClub {
  constructor(library) {
    this.library = library;
    this.books = [];
    this.members = [];
  }

  addBook (title, author) {
    if(this.books.length > 0 && this.books.find(x => x.title === title && x.author === author)) {
        return(`The book "${title}" by ${author} is already in ${this.library} library.`)
    } else {
        this.books.push({title, author})
        return(`The book "${title}" by ${author} has been added to ${this.library} library.`)
    }
  }

  addMember (memberName) {
    if(this.members.length > 0 && this.members.find(x => x === memberName)) {
        return(`Member ${memberName} is already a part of the book club.`)
    } else {
        this.members.push(memberName)
        return(`Member ${memberName} has been joined to the book club.`)
    }
  }

  assignBookToMember (memberName, bookTitle)  {
        if(this.members.length > 0 && !this.members.find(x => x === memberName)) {
            throw new Error(`Member ${memberName} not found.`)
        } else if (this.books.length > 0 && !this.books.find(x => x.title === bookTitle)) {
            throw new Error(`Book "${bookTitle}" not found.`)
        } else {
            const foundBook = this.books.find(x => x.title === bookTitle);
            this.books = this.books.filter(x => x.title !== bookTitle);
            return(`Member ${memberName} has been assigned the book "${bookTitle}" by ${foundBook.author}.`)
        }

  }

  generateReadingReport () {
        if(this.members.length === 0) {
            return("No members in the book club.")
        } else if (this.books.length === 0) {
            return("No available books in the library.")
        } else {
            let string = "";
            string += (`Available Books in ${this.library} library:\n`)
            this.books.map((book, i) => {
                string += (`"${book.title}" by ${book.author}`)
                if(this.books.length - 1 !== i) {
                    string += '\n';
                }
            })

            return string;
        }

  }
}