'use strict';

const EventEmitter = require('events');
const puppeteer = require('puppeteer');
const moduleRaid = require('moduleraid/moduleraid');
const jsQR = require('jsqr');

const Util = require('./util/Util');
const { WhatsWebURL, UserAgent, DefaultOptions, Events, WAState } = require('./util/Constants');
const { ExposeStore, LoadUtils } = require('./util/Injected');
const ChatFactory = require('./factories/ChatFactory');
const ClientInfo = require('./structures/ClientInfo');
const Message = require('./structures/Message');

/**
 * Starting point for interacting with the WhatsApp Web API
 * @extends {EventEmitter}
 */
class Client extends EventEmitter {
    constructor(options = {}) {
        super();

        this.options = Util.mergeDefault(DefaultOptions, options);

        this.pupBrowser = null;
        this.pupPage = null;
    }

    /**
     * Sets up events and requirements, kicks off authentication request
     */
    async initialize() {
        const browser = await puppeteer.launch(this.options.puppeteer);
        const page = await browser.newPage();
        page.setUserAgent(UserAgent);

        if (this.options.session) {
            await page.evaluateOnNewDocument(
                session => {
                    localStorage.clear();
                    localStorage.setItem("WABrowserId", session.WABrowserId);
                    localStorage.setItem("WASecretBundle", session.WASecretBundle);
                    localStorage.setItem("WAToken1", session.WAToken1);
                    localStorage.setItem("WAToken2", session.WAToken2);
                }, this.options.session);
        }

        await page.goto(WhatsWebURL);

        const KEEP_PHONE_CONNECTED_IMG_SELECTOR = '[data-asset-intro-image="true"]';

        if (this.options.session) {
            // Check if session restore was successfull 
            try {
                await page.waitForSelector(KEEP_PHONE_CONNECTED_IMG_SELECTOR, { timeout: 15000 });
            } catch (err) {
                if (err.name === 'TimeoutError') {
                    this.emit(Events.AUTHENTICATION_FAILURE, 'Unable to log in. Are the session details valid?');
                    browser.close();

                    return;
                }

                throw err;
            }

        } else {
            // Wait for QR Code
            const QR_CANVAS_SELECTOR = 'canvas';
            await page.waitForSelector(QR_CANVAS_SELECTOR);
            const qrImgData = await page.$eval(QR_CANVAS_SELECTOR, canvas => [].slice.call(canvas.getContext('2d').getImageData(0,0,264,264).data));
            const qr = jsQR(qrImgData, 264, 264).data;
            
            this.emit(Events.QR_RECEIVED, qr);

            // Wait for code scan
            await page.waitForSelector(KEEP_PHONE_CONNECTED_IMG_SELECTOR, { timeout: 0 });
        }

        await page.evaluate(ExposeStore, moduleRaid.toString());

        // Get session tokens
        const localStorage = JSON.parse(await page.evaluate(() => {
            return JSON.stringify(window.localStorage);
        }));

        const session = {
            WABrowserId: localStorage.WABrowserId,
            WASecretBundle: localStorage.WASecretBundle,
            WAToken1: localStorage.WAToken1,
            WAToken2: localStorage.WAToken2
        }

        this.emit(Events.AUTHENTICATED, session);

        // Check Store Injection
        await page.waitForFunction('window.Store != undefined');

        //Load util functions (serializers, helper functions)
        await page.evaluate(LoadUtils);

        // Expose client info
        this.info = new ClientInfo(this, await page.evaluate(() => {
            return Store.Conn.serialize();
        }));

        // Register events
        await page.exposeFunction('onAddMessageEvent', msg => {
            if (!msg.isNewMsg) return;

            const message = new Message(this, msg);
            this.emit(Events.MESSAGE_CREATE, message);

            if (msg.id.fromMe) return;
            this.emit(Events.MESSAGE_RECEIVED, message);
        });

        await page.exposeFunction('onAppStateChangedEvent', (AppState, state) => {
            const ACCEPTED_STATES = [WAState.CONNECTED, WAState.OPENING, WAState.PAIRING];
            if (!ACCEPTED_STATES.includes(state)) {
                this.emit(Events.DISCONNECTED);
                this.destroy();
            }
        });

        await page.evaluate(() => {
            Store.Msg.on('add', onAddMessageEvent);
            Store.AppState.on('change:state', onAppStateChangedEvent);
        });

        this.pupBrowser = browser;
        this.pupPage = page;

        this.emit(Events.READY);
    }

    async destroy() {
        await this.pupBrowser.close();
    }

    /**
     * Send a message to a specific chatId
     * @param {string} chatId
     * @param {string} message 
     */
    async sendMessage(chatId, message) {
        const newMessage = await this.pupPage.evaluate(async (chatId, message) => {
            const msg = await WWebJS.sendMessage(Store.Chat.get(chatId), message);
            return msg.serialize();
        }, chatId, message);

        return new Message(this, newMessage);
    }

    /**
     * Get all current chat instances
     */
    async getChats() {
        let chats = await this.pupPage.evaluate(() => {
            return WWebJS.getChats();
        });

        return chats.map(chat => ChatFactory.create(this, chat));
    }

    /**
     * Get chat instance by ID
     * @param {string} chatId 
     */
    async getChatById(chatId) {
        let chat = await this.pupPage.evaluate(chatId => {
            return WWebJS.getChat(chatId);
        }, chatId);

        return ChatFactory.create(this, chat);
    }

    /**
     * Accepts an invite by code
     * @param {string} inviteCode
     */
    async acceptInvite(inviteCode) {
        const chat = await this.pupPage.evaluate(async inviteCode => {
            const chatId = await Store.Invite.sendJoinGroupViaInvite(inviteCode);
            return WWebJS.getChat(chatId._serialized);
        }, inviteCode);

        return ChatFactory.create(this.client, chat);
    }

}

module.exports = Client;