import crypto = require('crypto');
import jwt = require('jsonwebtoken');

export interface AuthMiddlewareConfig {
	serialize(user): any;
	deserialize(user): any;
}

export function authMiddleware(config: AuthMiddlewareConfig) {
	return function authMiddleware(req, res, next) {
		req.login = async function login(user) {
			const serial = await config.serialize(user);

			req.session.authToken = jwt.sign({ serial }, process.env.auth_secret, { expiresIn: '5m' });
			req.session.refreshToken = jwt.sign({ serial }, process.env.auth_secret, { expiresIn: '24m' });
		
			req.user = user;
		}

		req.logout = function logout() {
			delete req.session.authToken;
			delete req.session.refreshToken;
			delete req.user;
		}

		// Check if refresh token is valid
		if (req.session.refreshToken) {
			let refreshToken;
			try {
				refreshToken = jwt.verify(req.session.refreshToken, process.env.auth_secret);
			} catch (e) {
				// Refresh token is invalid, log out
				return req.logout().then(() => next());
			}

			// Refresh token is valid, check if auth token is valid
			try {
				jwt.verify(req.session.authToken, process.env.auth_secret);
			} catch (e) {
				// Auth token expired, regenerate
				const data = jwt.sign({ serial: refreshToken.serial }, process.env.auth_secret);
				req.session.authToken = data;
			}

			// Auth token is valid
			return config.deserialize(refreshToken.serial).then(user => {
				if (!user) {
					req.logout();
					return next();
				}
	
				req.user = user;
				next();
			}).catch(err => {
				req.logout();
				console.log(err);
				next();
			});
		}

		next();
	}
}