/*
	Fosscord: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Fosscord and Fosscord Contributors
	
	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published
	by the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.
	
	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/* eslint-disable @typescript-eslint/ban-ts-comment */
import WS from "ws";
import { genSessionId, WebSocket } from "@fosscord/gateway";
import { Send } from "../util/Send";
import { CLOSECODES, OPCODES } from "../util/Constants";
import { setHeartbeat } from "../util/Heartbeat";
import { IncomingMessage } from "http";
import { Close } from "./Close";
import { Message } from "./Message";
import { Deflate, Inflate } from "fast-zlib";
import { URL } from "url";
import { Config, ErlpackType } from "@fosscord/util";

let erlpack: ErlpackType | null = null;
try {
	erlpack = require("erlpack") as ErlpackType;
} catch (e) {
	// empty
}

// TODO: check rate limit
// TODO: specify rate limit in config
// TODO: check msg max size

export async function Connection(
	this: WS.Server,
	socket: WebSocket,
	request: IncomingMessage,
) {
	const forwardedFor = Config.get().security.forwadedFor;
	const ipAddress = forwardedFor
		? (request.headers[forwardedFor] as string)
		: request.socket.remoteAddress;

	socket.ipAddress = ipAddress;

	//Create session ID when the connection is opened. This allows gateway dump to group the initial websocket messages with the rest of the conversation.
	const session_id = genSessionId();
	socket.session_id = session_id; //Set the session of the WebSocket object

	try {
		// @ts-ignore
		socket.on("close", Close);
		// @ts-ignore
		socket.on("message", Message);

		socket.on("error", (err) => console.error("[Gateway]", err));

		// console.log(
		// 	`[Gateway] New connection from ${socket.ipAddress}, total ${this.clients.size}`,
		// );

		if (process.env.WS_LOGEVENTS)
			[
				"close",
				"error",
				"upgrade",
				//"message",
				"open",
				"ping",
				"pong",
				"unexpected-response",
			].forEach((x) => {
				socket.on(x, (y) => console.log(x, y));
			});

		const { searchParams } = new URL(`http://localhost${request.url}`);
		// @ts-ignore
		socket.encoding = searchParams.get("encoding") || "json";
		if (!["json", "etf"].includes(socket.encoding))
			return socket.close(CLOSECODES.Decode_error);

		if (socket.encoding === "etf" && !erlpack)
			throw new Error("Erlpack is not installed: 'npm i erlpack'");

		socket.version = Number(searchParams.get("version")) || 8;
		if (socket.version != 8)
			return socket.close(CLOSECODES.Invalid_API_version);

		// @ts-ignore
		socket.compress = searchParams.get("compress") || "";
		if (socket.compress) {
			if (socket.compress !== "zlib-stream")
				return socket.close(CLOSECODES.Decode_error);
			socket.deflate = new Deflate();
			socket.inflate = new Inflate();
		}

		socket.events = {};
		socket.member_events = {};
		socket.permissions = {};
		socket.sequence = 0;

		setHeartbeat(socket);

		await Send(socket, {
			op: OPCODES.Hello,
			d: {
				heartbeat_interval: 1000 * 30,
			},
		});

		socket.readyTimeout = setTimeout(() => {
			return socket.close(CLOSECODES.Session_timed_out);
		}, 1000 * 30);
	} catch (error) {
		console.error(error);
		return socket.close(CLOSECODES.Unknown_error);
	}
}