/*
	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Spacebar and Spacebar 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/>.
*/

import { checkToken, Rights } from "@spacebar/util";
import { NextFunction, Request, Response } from "express";
import { HTTPError } from "lambert-server";

export const NO_AUTHORIZATION_ROUTES = [
	// Authentication routes
	"POST /auth/login",
	"POST /auth/register",
	"GET /auth/location-metadata",
	"POST /auth/mfa/",
	"POST /auth/verify",
	"POST /auth/forgot",
	"POST /auth/reset",
	"POST /auth/fingerprint",
	"GET /invites/",
	// Routes with a seperate auth system
	/^(POST|HEAD|GET|PATCH|DELETE) \/webhooks\/\d+\/\w+\/?/, // no token requires auth
	/^POST \/interactions\/\d+\/[A-Za-z0-9_-]+\/callback/,
	// Public information endpoints
	"GET /ping",
	"GET /gateway",
	"GET /experiments",
	"GET /updates",
	"GET /download",
	"GET /scheduled-maintenances/upcoming.json",
	// Public kubernetes integration
	"GET /-/readyz",
	"GET /-/healthz",
	// Client analytics
	"POST /science",
	"POST /track",
	// Public policy pages
	"GET /policies/instance/",
	// Oauth callback
	"/oauth2/callback",
	// Asset delivery
	/^(GET|HEAD) \/guilds\/\d+\/widget\.(json|png)/,
	// Connections
	/^(POST|HEAD) \/connections\/\w+\/callback/,
	// Image proxy
	/^(GET|HEAD) \/imageproxy\/[A-Za-z0-9+/]\/\d+x\d+\/.+/,
];

export const API_PREFIX = /^\/api(\/v\d+)?/;
export const API_PREFIX_TRAILING_SLASH = /^\/api(\/v\d+)?\//;

declare global {
	// eslint-disable-next-line @typescript-eslint/no-namespace
	namespace Express {
		interface Request {
			user_id: string;
			user_bot: boolean;
			token: { id: string; iat: number };
			rights: Rights;
			fingerprint?: string;
		}
	}
}

export async function Authentication(req: Request, res: Response, next: NextFunction) {
	if (req.method === "OPTIONS") return res.sendStatus(204);
	const url = req.url.replace(API_PREFIX, "");

	if (req.headers.cookie?.split("; ").find((x) => x.startsWith("__sb_sessid=")))
		req.fingerprint = req.headers.cookie
			.split("; ")
			.find((x) => x.startsWith("__sb_sessid="))!
			.split("=")[1];
	// for some reason we need to require here, else the openapi generator fails with "route is not a function"
	else res.setHeader("Set-Cookie", `__sb_sessid=${req.fingerprint = (await require("../util")).randomString(32)}; Secure; HttpOnly; SameSite=None`);

	if (
		NO_AUTHORIZATION_ROUTES.some((x) => {
			if (typeof x !== "string") {
				return x.test(req.method + " " + url);
			}

			const fullRoute = req.method + " " + url;

			if (req.method === "HEAD") {
				const urlPart = x.split(" ").slice(1).join(" ");
				if (urlPart.endsWith("/")) {
					return url.startsWith(urlPart);
				} else {
					return url === urlPart;
				}
			}

			if (x.endsWith("/")) {
				return fullRoute.startsWith(x);
			} else {
				return fullRoute === x;
			}
		})
	)
		return next();

	if (!req.headers.authorization) return next(new HTTPError("Missing Authorization Header", 401));

	try {
		const { decoded, user } = await checkToken(req.headers.authorization, {
			ipAddress: req.ip,
			fingerprint: req.fingerprint,
		});

		req.token = decoded;
		req.user_id = decoded.id;
		req.user_bot = user.bot;
		req.rights = new Rights(Number(user.rights));
		return next();
	} catch (error) {
		return next(new HTTPError(error!.toString(), 400));
	}
}