class Article {
    constructor(title, creator) {
        this.title = title;
        this.creator = creator;
        this._comments = [];
        this._likes = [];
    }

    get likes() {
        if (this._likes.length === 0) {
            return `${this.title} has 0 likes`;
        } else if (this._likes.length === 1) {
            return `${this._likes[0]} likes this article!`;
        } else {
            return `${this._likes[0]} and ${this._likes.length - 1} others like this article!`;
        }
    }

    like(username) {
        if (this._likes.includes(username)) {
            throw new Error("You can't like the same article twice!");
        }

        if (this.creator === username) {
            throw new Error("You can't like your own articles!");
        }

        this._likes.push(username);
        return `${username} liked ${this.title}!`;
    }

    dislike (username) {
        if (!this._likes.includes(username)) {
            throw new Error("You can't dislike this article!");
        } else {
            let index = this._likes.indexOf(username);
            this._likes.splice(index, 1);
            return `${username} disliked ${this.title}`;
        }
    }

    comment (username, content, id) {

        let obj = {
            username: username,
            content: content,
            id: id,
            replies: []
        };

        let comment = this._comments.filter(x => x.id === id)[0];

        if (obj.id === undefined || comment === undefined) {
            obj.id = this._comments.length + 1;
            this._comments.push(obj);
            return `${username} commented on ${this.title}`;
        } else {
            let reply = {
                username: username,
                content: content,
                id: id += comment.replies.length * 0.1 + 0.1
            };

            comment.replies.push(reply);
            return `You replied successfully`;
        }
    }

    toString(sortingType) {
        if (sortingType === 'asc') {
            this._comments.sort((a, b) => a.id - b.id);

            for (let i = 0; i < this._comments.length; i++) {
                const replies = this._comments[i].replies;
                replies.sort((a, b) => a.id - b.id);
            }

        } else if (sortingType === 'desc') {
            this._comments.sort((a, b) => b.id - a.id);

            for (let i = 0; i < this._comments.length; i++) {
                const replies = this._comments[i].replies;
                replies.sort((a, b) => b.id - a.id);
            }
        } else if (sortingType === 'username') {
            this._comments.sort((a, b) => a.username.localeCompare(b.username));

            for (let i = 0; i < this._comments.length; i++) {
                const replies = this._comments[i].replies;
                replies.sort((a, b) => a.username.localeCompare(b.username));
            }
        }

        let output = '';
        output += `Title: ${this.title}\n`;
        output += `Creator: ${this.creator}\n`;
        output += `Likes: ${this._likes.length}\n`;
        output += 'Comments:\n';

        for (let i = 0; i < this._comments.length; i++) {
            const comment = this._comments[i];
            if (comment.replies.length > 0) {
                output += `-- ${comment.id}. ${comment.username}: ${comment.content}\n`;

                for (let j = 0; j < comment.replies.length; j++) {
                    const reply = comment.replies[j];

                    output += `--- ${reply.id}. ${reply.username}: ${reply.content}\n`;
                }
            } else {
                output += `-- ${comment.id}. ${comment.username}: ${comment.content}\n`;
            }
        }

        return output.trim();
    }
}