client.js

const zlib = require("zlib-sync");
const WebSocket = require("ws");
const erlpack = require("erlpack");
const op = require("./op");
const {reportErr} = require("./gift")
const ZLIB_SUFFIX = 0x0000FFFF;

class discord_client {
    #handleEvent = null;

    #auth_data = null;
    #d_gateway = null;

    #zlib_inflate = null;

    #ws = null;
    #heartbeat_id = null;

    #got_heartbeat_ack = null;
    #last_sequence = null;
    last_heartbeat_timestamp = Date.now();

    constructor(token, gateway, eventHandler) {
        this.#d_gateway = gateway;
        this.#auth_data = erlpack.pack({"op":op.IDENTIFY,"d":{"token":token,"capabilities":61,"properties":{"os":"Windows","browser":"Discord Client","release_channel":"stable","client_version":"1.0.9001","os_version":"10.0.19041","os_arch":"x64","system_locale":"en-US","client_build_number":84941,"client_event_source":null},"presence":{"status":"invisible","since":0,"activities":[],"afk":true},"compress":false,"client_state":{"guild_hashes":{},"highest_last_message_id":"0","read_state_version":0,"user_guild_settings_version":-1}}})
        this.#handleEvent = eventHandler;
    }

    connect = function() {
        this.#ws = new WebSocket(this.#d_gateway);
        this.#ws.on("error", (e)=>{reportErr(e, 0x301800, "Caught ws error, things are hopefully fine")});

        this.#ws.on("open", ()=>{
            this.#zlib_inflate = new zlib.Inflate({chunkSize: 65535, flush: zlib.Z_SYNC_FLUSH});
            this.#got_heartbeat_ack = true;
            console.log("| WS | OPEN");
            this.#ws.send(this.#auth_data);
            console.log("| WS | SENT AUTH");
        })

        this.#ws.on('message', data => {
            if (data.readUInt32BE(data.length-4) ^ ZLIB_SUFFIX == 0) {
                this.#zlib_inflate.push(data, zlib.Z_SYNC_FLUSH);
                if (this.#zlib_inflate.result == undefined)
                    return;

                this.#handlePacket(erlpack.unpack(this.#zlib_inflate.result));
            } else {
                console.log(data.buffer.toString());
            }
        });

        this.#ws.on("close", async ()=>{
            console.log("on_disconect");
            await new Promise(res=>setTimeout(res, 1000));
            this.connect();
        });
    }

    disconnect = function() {
        this.#ws.close();
    }

    #handlePacket = function (packet) {
        if (packet.s != undefined)
            this.#last_sequence = packet.s;

        switch (packet.op) {
            case op.DISPATCH:
                this.#handleEvent(packet)
                break
            case op.HELLO:
                const heartbeat_interval = packet.d.heartbeat_interval;
                console.log("| OP | HELLO");
                console.log(`| SET | heartbeat_interval: ${heartbeat_interval}`);
                if (this.#heartbeat_id != null)
                    clearInterval(this.#heartbeat_id)
                    this.#heartbeat_id = setInterval(()=>{
                    if (!this.#got_heartbeat_ack) {
                        this.#ws.close();
                        return;
                    }
                    if (this.#ws != null && this.#ws.OPEN) {
                        this.#ws.send(erlpack.pack({op: op.HEARTBEAT, d: this.#last_sequence}));
                        console.log("| HEARTBEAT |");
                        this.#got_heartbeat_ack = false;
                    }
                }, heartbeat_interval);
                break
            case op.HEARBEAT_ACK:
                this.#got_heartbeat_ack = true;
                this.last_heartbeat_timestamp = Date.now();
                console.log("| OP | HEARBEAT_ACK");
                break
            case op.RECONNECT:
                console.log("| OP | RECONNECT");
                this.#ws.close();
                break;
            case op.INVALID_SESSION:
                console.log("| OP | INVALID_SESSION");
                this.#ws.close();
                break;
            default:
                console.log(`| OP | ${JSON.stringify(packet)}`);
        }
    }
}

module.exports = discord_client