const _fetch = require("node-fetch");
const crypto = require("crypto");
const { decode } = require("./lib/b64arraybuffer");

const API_BASE = "https://cohost.org/api/v1";

/**
 * Fetches an API endpoint.
 * 
 * @private
 * @param {string} method HTTP method to use
 * @param {string} endpoint Relative endpoint to fetch
 * @param {string} [cookies] Cookies to send. Used for auth
 * @param {object} [data] Data to send. Query if method is GET, body if method is anything else
 * @param {boolean} [complex=false] Whether to return {headers, body}, or just the body
 * @returns Response, JSON parsed if parsable, string if not
 */
async function fetch(method, endpoint, cookies = "", data, complex = false) {
    let url = API_BASE + endpoint + (method == "GET" && data ? "?" + new URLSearchParams(data).toString() : "");

    let req = await _fetch(url, {
        method,
        headers: {
            "Content-Type": "application/json",
            "Cookie": cookies
        },
        body: (method != "GET" && data) ? JSON.stringify(data) : undefined
    });

    let res = await req.text();
    try {
        res = JSON.parse(res);
    } catch (_) {}

    if (req.status >= 400) {
        throw JSON.stringify(res);
    } else {
        if (complex) {
            return {
                headers: req.headers,
                body: res
            };
        } else {
            return res;
        }
    }
}

/**
 * Represents a cohost User (e.g. john.doe@gmail.com)
 */
class User {
    /**
     * Authenticates the User.
     * This should always be called before using this instance or its references.
     * 
     * @param {string} email E-mail address
     * @param {string} password Password
     */
    async login(email, password) {
        const { salt } = await fetch(
            "GET",
            "/login/salt",
            undefined,
            { email }
        );
        
        const hash = crypto.pbkdf2Sync(Buffer.from(password, "utf8"), decode(salt), 200000, 128, "sha384")
        const clientHash = Buffer.from(hash).toString("base64");

        const res = await fetch(
            "POST",
            "/login",
            undefined,
            { email, clientHash },
            true
        );

        this.sessionCookie = res.headers.get("set-cookie").split(";")[0];

        this.userId = res.body.userId;
        this.email = res.body.email;
    }

    /**
     * Get Projects the User has edit permissions on.
     * 
     * @returns {Project[]} User's projects
     */
    async getProjects() {
        return (await fetch(
            "GET",
            "/projects/edited",
            this.sessionCookie
        )).projects.map(x => new Project(this, x));
    }
}

/**
 * Represents a cohost Project (e.g. @mog)
 */
class Project {
    constructor(user, data) {
        this.user = user;
        this.populate(data);
    }

    /**
     * @private
     */
    populate(data) {
        this.id = data.projectId;
        this.handle = data.handle;
        this.displayName = data.displayName;
        this.dek = data.dek;
        this.description = data.description;
        this.avatarURL = data.avatarURL;
        this.headerURL = data.headerURL;
        this.privacy = data.privacy;
        this.pronouns = data.pronouns;
        this.url = data.url;
        this.flags = data.flags;
        this.avatarShape = data.avatarShape;
    }

    /**
     * @param {number} [page=0] Page of posts to get, 20 posts per page
     * @returns {object[]}
     */
    async getPosts(page = 0) {
        let res = await fetch(
            "GET",
            `/project/${encodeURIComponent(this.handle)}/posts?page=${encodeURIComponent(page.toString())}`,
            this.user.sessionCookie
        );

        return res.items.map(x => new Post(this.user, x));
    }
}

/**
 * Represents a cohost Post
 */
class Post {
    constructor(user, data) {
        this.user = user;
        this.populate(data);
    }

    /**
     * @typedef {Object} PostMarkdownBlock
     * @property {string} content
     */

    /**
     * @typedef {Object} PostAttachmentBlock
     * @property {string} fileURL
     * @property {string} attachmentId
     */

    /**
     * @typedef {Object} PostBlock
     * @property {string} type Type of block. Currently available: 'markdown' and 'attachment'
     * @property {PostMarkdownBlock} [markdown] Should only be present if type is 'markdown'
     * @property {PostAttachmentBlock} [attachment] Should only be present if type is 'attachment'
     */

    /**
     * @typedef {Object} PostCreate
     * @property {number} postState 1 for published, 0 for draft? or pending maybe?
     * @property {string} headline Headline
     * @property {boolean} adultContent Does the post contain adult content?
     * @property {PostBlock[]} blocks Blocks (docs TBD)
     * @property {string[]} cws Content Warnings
     * @property {string[]} tags Tags (docs TBD)
     */

    /**
     * 
     * @param {Project} project Project to post to
     * @param {PostCreate} data 
     * @returns 
     */
    static async create(project, data) {
        let { postId } = await fetch(
            "POST",
            `/project/${encodeURIComponent(project.handle)}/posts`,
            project.user.sessionCookie,
            data
        );

        // return await Post.getById(project, postId);
        return postId;
    }

    // Endpoint is disabled;
    // static async getById(project, id) {
    //     let data = await fetch(
    //         "GET",
    //         `/project_posts/${id}`,
    //         project.user.sessionCookie
    //     );

    //     return new Post(user, data);
    // }

    /**
     * @private
     */
    populate(data) {
        this.id = data.postId;
        this.headline = data.headline;
        this.publishedAt = new Date(data.publishedAt);
        this.filename = data.filename;
        this.transparentShareOfPostId = data.transparentShareOfPostId;
        this.state = data.state;
        this.numComments = data.numComments;
        this.numSharedComments = data.numSharedComments;
        this.cws = data.cws;
        this.tags = data.tags;
        this.blocks = data.blocks;
        this.plainTextBody = data.plainTextBody;
        this.project = new Project(this.user, data.postingProject);
        this.shareTree = data.shareTree;
        this.relatedProjects = data.relatedProjects;
        this.effectiveAdultContent = data.effectiveAdultContent;
        this.isEditor = data.isEditor;
        this.contributorBlockIncomingOrOutgoing = data.contributorBlockIncomingOrOutgoing;
        this.hasAnyContributorMuted = data.hasAnyContributorMuted;
        this.isLiked = data.isLiked;
        this.canShare = data.canShare;
        this.canPublish = data.canPublish;
        this.singlePostPageUrl = data.singlePostPageUrl;
        this.renderInIframe = data.renderInIframe;
        this.postPreviewIFrameUrl = data.postPreviewIFrameUrl;
        this.postEditUrl = data.postEditUrl;
    }
}

module.exports = {
    User,
    Project,
    Post,
};