class BookCollection{
    constructor(shelfGenre, room, shelfCapacity){
        if(room === 'livingRoom' || room === 'bedRoom' || room === 'closet'){
            this.shelfGenre = shelfGenre;
            this.room = room;
            this.shelfCapacity = shelfCapacity;
            this.shelf = [];
        } else {
            throw new Error(`Cannot have book shelf in ${room}`)
        }
    }

    addBook(bookName, bookAuthor, genre){
        let createBook = {name: bookName, author: bookAuthor, genre: genre};
        if(this.shelf.length < this.shelfCapacity) {
            if (genre !== undefined) {
                createBook.genre = genre;
            } else {
                createBook.genre = this.shelfGenre;
            }
            if (this.shelf.length < this.shelfCapacity) {
                this.shelf.push(createBook);
            } else {
                this.shelf.shift();
                this.shelf.push(createBook);
            }
        }

        this.shelf.sort((a, b) => a.author.localeCompare(b.author));
    }

    throwAwayBook(bookName){
        for (let i = 0; i < this.shelf.length; i++) {
            if(this.shelf[i].name === bookName){
                this.shelf.splice(i, 1);
            }
        }
    }

    showBooks(genre){
        let result = '';
        result += `Results for search "${genre}":\n`;
        for (let i = 0; i < this.shelf.length; i++) {
            if(this.shelf[i].genre === genre){
                result += ` \uD83D\uDCD6 ${this.shelf[i].author} - "${this.shelf[i].name}"\n`
            }
        }
        return result;
    }

    get shelfCondition(){
        let count = this.shelfCapacity - this.shelf.length;
        if(count > 0){
            return count;
        }
        return 0;
    }

    toString(){
        if(this.shelf.length === 0){
            return "It's an empty shelf";
        } else {
            let result = '';
            result += `"${this.shelfGenre}" shelf in ${this.room} contains: \n`;
            for (let obj of this.shelf) {
                result += ` \uD83D\uDCD6 "${obj.name}" - ${obj.author}\n`
            }
            return result;
        }
    }

}