import {Request, RequestHandler} from 'express';
import {DefaultConfig, Logger, Resolvable, UserInfo} from '.';
import fetch from 'node-fetch';

const cachedUsers: {[token: string]: UserInfo} = {};

const router: RequestHandler = (req: Request, res, next) => {
	const resolvable = new Resolvable(async () => {
		if (!DefaultConfig.USERINFO_HEADER) {
			return undefined;
		}
		const token = req.header(DefaultConfig.USERINFO_HEADER);
		if (token && cachedUsers[token]) return cachedUsers[token];
		const url = DefaultConfig.AUTH_PROXY_USERINFO_URL;
		if (token === undefined || url === undefined) {
			return undefined;
		}
		try {
			const expireHeader = req.header(DefaultConfig.EXPIRE_HEADER);
			const expireSecDate = expireHeader && parseInt(expireHeader, 10) || undefined;
			const expiresIn = expireSecDate && expireSecDate * 1000 > Date.now() && expireSecDate * 1000 - Date.now();
			const res = await fetch(url, {headers: [[DefaultConfig.USERINFO_HEADER, token]]});
			const userinfo = await res.json() as UserInfo;
			if (expiresIn) {
				cachedUsers[token] = userinfo;
				setTimeout(() => delete cachedUsers[token], expiresIn);
			}
			return userinfo;
		} catch (e) {
			Logger.warn(e);
			return undefined;
		}
	});

	req.getUserInfo = () => resolvable.resolve();
	res.initLogout = function() {
		const url = DefaultConfig.AUTH_PROXY_INIT_LOGOUT_URL;
		if (url === undefined) {
			return false;
		}
		this.redirect(307, url);
		return true;
	};
	next();
};

export const AuthProxy = {
	router,
};