/*
 * chat.js
 * Copyright (c) 2019, Texx
 * License: MIT
 *     See https://github.com/texxme/Texx/blob/master/LICENSE
 */

// general imports
const $ = require('jquery');
const crypto = require('crypto');
const encryption = require('./encryption');
const wordList = require('./wordlist');
const pinInput = require('./input_pin');
const swal = require('sweetalert');
const xkcdPassword = require('xkcd-password');

// setup vars
const host = '127.0.0.1';
let peerId, call, passphrase, connectedPeer;
let connectedPeers = []; // TODO: Save new peers in array

// setup generator
const generator = new xkcdPassword();
generator.initWithWordList(wordList);

/**
 * Sets up encryption, user etc.
 */
(async () => {
    // generate peerId
    if (localStorage.getItem('peer_id') === null) {
        peerId = await generator.generate().then(words => words.join('-'));
        localStorage.setItem('peer_id', peerId);
    } else
        peerId = localStorage.getItem('peer_id');

    encryption.setup();
    await evaluateKeyGeneration();
})();

/**
 * Evaluates whether a key generation is needed and initializes regarding actions
 * @returns {Promise<void>}
 */
async function evaluateKeyGeneration() {
    if (localStorage.getItem('database') === 'success' && await encryption.check()) {
        pinInput.init(async (pin, tryCount) => {
            try {
                if (await encryption.getId(await encryption.getPublic()) !== peerId) throw "Not verified!";
                passphrase = new Buffer(crypto.createHmac('SHA256', pin).update(pin).digest('hex')).toString('base64');
                await encryption.decryptPrivate(await encryption.getPrivate(), passphrase);
                chat()
            } catch (e) { // decrypting failed
                if (tryCount === 3) {
                    encryption.reset();
                    console.error('Too many tries!');
                    pinInput.failure('This account got removed, the site will reload.');
                    setTimeout(() => location.reload(true), 1500)
                } else if (e === 'Not verified!') {
                    console.error(e);
                    pinInput.failure(e);
                } else {
                    console.error('Passphrase is wrong!');
                    pinInput.failure('Passphrase is wrong!');
                }
            }
        });
    } else {
        pinInput.init(pin => {
            console.log('[LOG] No existing keys found! Generating...');
            pinInput.generate();
            passphrase = new Buffer(crypto.createHmac('SHA256', pin).update(pin).digest('hex')).toString('base64');
            (async () => await encryption.generate(peerId, passphrase).then(() => chat()))()
        });
    }
}

/**
 * Initializes chat functions
 */
function chat() {
    // hide pin input and display chat
    $('#enter_pin').hide();
    $('#chat').fadeIn();

    // start the peer
    const peer = new Peer(peerId, {host: host, port: 8080, path: '/api', debug: 0});

    // Peer events
    peer.on('call', call => getMediaStream(stream => call.answer(stream))); // TODO: Ask for call accept
    peer.on('open', id => {
        console.log('[LOG] Your ID is', id);
        swal('Hello world!', 'Your ID is "' + id + '".\nYou can share this ID with your friends so they can chat with you!', 'success')
    });
    peer.on('error', err => {
        console.error(err);
        if (err.type === 'network') swal('Connection to server lost!', '', 'error');
        else if (err.type === 'browser-incompatible') swal('Your server is not compatible!', 'Please update or use another browser!', 'error');
        else if (err.type === 'peer-unavailable') swal('Peer could not be found!', '', 'error');
        else if (err.type === 'unavailable-id') swal('Ou snap! Your ID isn\'t available!', '', 'error');
        else swal('Unhandled Error!', 'You just threw up this error: ' + err.type, 'error');
    });
    peer.on('connection', async conn => {
        connectedPeer = conn;
        console.log('[LOG] Connected to', connectedPeer.peer);
        swal('New connection!', `You have successfully connected to the user ${connectedPeer.peer}!`, 'success');
        encryption.getMsgs(connectedPeer.peer, await encryption.get(connectedPeer.peer), await encryption.getPrivate(), passphrase).then(messages =>
            messages.forEach(async data => await receivedMessage(`${data.message} - ${data.time}`, true))
        );
        connectedPeer.on('open', async () => transferKey(await encryption.getPublic()));
        connectedPeer.on('data', async message => {
            console.log('[LOG] Received new message!');
            await receivedMessage(message);
        })
    });

    /**
     * Connects to a peer via his id
     * @param id
     * @returns {Promise<void>}
     */
    async function connect(id) {
        const connectionId = (await generator.generate()).join('-');
        console.log('[LOG] Connecting to', id);
        console.log('[LOG] Your connection ID is', connectionId);
        connectedPeer = peer.connect(id, {label: connectionId});
        console.log('[LOG] Connected with', connectedPeer.peer);
        encryption.getMsgs(connectedPeer.peer, await encryption.get(connectedPeer.peer), await encryption.getPrivate(), passphrase).then(messages =>
            messages.forEach(async data => await receivedMessage(`${data.message} - ${data.time}`, true))
        );
        connectedPeer.on('open', async () => {
            swal(`Successfully connected to "${connectedPeer.peer}"!`, '', 'success');
            transferKey(await encryption.getPublic())
        });
        connectedPeer.on('data', async message => {
            console.log('[LOG] Received new message!');
            await receivedMessage(message);
        });
    }

    /**
     * Sends a message to the peer with which you're currently connected
     * @param message
     * @returns {Promise<void>}
     */
    async function sendMessage(message) {
        console.log(`[LOG] Sending message '${message}' to ${connectedPeer.peer}`);
        connectedPeer.send({
            type: 'text',
            data: await encryption.encrypt(message, await encryption.get(connectedPeer.peer), await encryption.getPrivate(), passphrase)
        });
        await receivedMessage(message, true);
    }

    /**
     * Transfers the (public) key to the currently connected peer
     * @param key
     */
    function transferKey(key) {
        console.log(`[LOG] Transferring key to ${connectedPeer.peer}`);
        connectedPeer.send({type: 'key', data: key});
    }

    /**
     * Renders and processes the incoming messages
     * @param message
     * @param self
     */
    async function receivedMessage(message, self = false) {
        if (self) {
            $('#messages').append(`<span style="color: green">${message}</span><br>`);
        } else {
            if (message.type === 'text') {
                await encryption.storeMsg(connectedPeer.peer, message.data, passphrase);
                await encryption.decrypt(message.data, await encryption.get(connectedPeer.peer), await encryption.getPrivate(), passphrase)
                    .then(plaintext => $('#messages').append(`<span>${plaintext}</span><br>`));
            } else if (message.type === 'key') {
                await encryption.store(connectedPeer.peer, message.data)
            }
        }
    }

    /**
     * Sends a message of the text input field
     * @returns {Promise<void>}
     */
    async function sendMessageFromInput() {
        return await sendMessage($('#message').val()) & $('#message').val('')
    }

    /*+
     * Shows warning modal and deletes account
     */
    function deleteAccount() {
        swal({
            title: 'Are you sure?',
            text: 'Once deleted, you will not be able to recover any messages or connections!',
            icon: 'warning',
            buttons: true,
            dangerMode: true,
        }).then(willDelete => {
            if (willDelete) {
                encryption.reset();
                swal('Successfully deleted your data.', '', 'success').then(() => location.reload(true));
            }
        });
    }

    /**
     * Shows modal for adding a contact
     */
    function addContact() {
        swal('Add a contact', {
            buttons: true,
            content: 'input',
            attributes: {
                placeholder: 'Contact ID',
            },
        }).then(contactId => {
            if (contactId.match(/^([a-zA-Z]*-[a-zA-Z]*)+$/)) {
                connect(contactId).then(() => swal({
                    title: 'Connecting...',
                    icon: 'info',
                    text: ' ',
                    buttons: false,
                    closeOnClickOutside: false,
                    closeOnEsc: false
                }))
            } else
                swal('Invalid ID!', '', 'error')
        })
    }

    /**
     * Click events
     */
    $(document).ready(() => {
        $('#send_message').on('click', async () => await sendMessageFromInput());
        $('#message').on('keydown', async e => {
            if (e.key === 'Enter') await sendMessageFromInput()
        });

        // FABs
        $('#add_contact').on('click', () => addContact());
        $('#logout').on('click', () => location.reload(true));
        $('#delete').on('click', () => deleteAccount());
        $('#anonymize').on('click', () => {
            if (peer.disconnected) {
                swal('Reconnected to broker server!', 'You can now connect to new peers again.', 'success').then(() =>
                    peer.reconnect()
                )
            } else {
                peer.disconnect();
                swal('Disconnected from broker server!', 'You will still be able to send and receive messages.', 'success')
            }
        });
        $('#call').on('click', () => getMediaStream(stream => {
            call = peer.call(peerId, stream); // TODO: Encrypt call
            initCall(call)
        }));
    });
}

function getMediaStream(callback) {
    navigator.getUserMedia(
        {audio: true, video: {width: 1280, height: 720}},
        stream => callback(stream),
        err => console.error(err)
    )
}

function initCall(call) {
    call.on('stream', stream => {
        const video = document.querySelector('video');
        video.srcObject = stream;
        video.onloadedmetadata = () => {
            video.play();
        };
    })
}