JS- Advanced-Exam-Problem-03.Library

class Library {
    constructor(libraryName) {
        this.libraryName = libraryName;
        this.subscribers = [];
        this.subscriptionTypes = {
            normal: libraryName.length,
            special: libraryName.length * 2,
            vip: Number.MAX_SAFE_INTEGER
        }
    }

    subscribe(name, type) {
        if (this.subscriptionTypes.hasOwnProperty(type) === false) {
            throw new Error(`The type ${type} is invalid`);
        }

        let subscriber = {
            name,
            type,
            books: []
        }

        let person = this.subscribers.find(p => p.name === name);

        if (person === undefined) {
            this.subscribers.push(subscriber);
        } else {
            person.type = type;
        }

        return subscriber;
    }

    unsubscribe(name) {
        let person = this.subscribers.find(p => p.name === name);

        if (person) {
            let index = this.subscribers.indexOf(person);
            this.subscribers.splice(index, 1);
        } else {
            throw new Error(`There is no such subscriber as ${name}`);
        }

        return this.subscribers;
    }

    receiveBook(subscriberName, bookTitle, bookAuthor) {
        let person = this.subscribers.find(p => p.name === subscriberName);

        if (!person) {
            throw new Error(`There is no such subscriber as ${subscriberName}`);
        } else {
            let limit = this.subscriptionTypes[person.type];

            if (person.books.length < limit) {
                let book = { bookTitle, bookAuthor };
                person.books.push(book);
            } else {
                throw new Error(`You have reached your subscription limit ${limit}!`);
            }
        }

        return person;
    }

    showInfo() {
        let result = [];

        if (this.subscribers.length === 0) {
            return `${this.libraryName} has no information about any subscribers`;
        } else {
            for (let subscriber of this.subscribers) {
                result.push(`Subscriber: ${subscriber.name}, Type: ${subscriber.type}`);
                let bookPrint = '';
                subscriber.books.forEach(b => bookPrint += `${b.bookTitle} by ${b.bookAuthor}, `);
                result.push(`Recived Books: ${bookPrint.substring(0, bookPrint.length - 2)}`);
            }
        }

        return result.join('\n');
    }
}

let lib = new Library('Lib');

lib.subscribe('Peter', 'normal');
lib.subscribe('John', 'special');

lib.receiveBook('John', 'A Song of Ice and Fire', 'George R. R. Martin');
lib.receiveBook('Peter', 'Lord of the rings', 'J. R. R. Tolkien');
lib.receiveBook('John', 'Harry Potter', 'J. K. Rowling');

console.log(lib.showInfo());