import { Request, Response } from 'express';
const crypto = require('crypto');

const START_DATE_TS = (new Date()).getTime();
const COOKIE_KEY = "sessId";
const SESSION_TIME = 36000; // 10 min, FIXME config

export class Session {
	constructor(req: Request) {
		this.mExpireTs = 0;
		this.mUsername = null;
		this.mHash = crypto.createHash('sha1').update(
			(new Date()).toISOString()
			+ "__salt__"
			+ req.connection.remoteAddress
			+ ""
			+ req.connection.remotePort
			+ ""
			+ START_DATE_TS
		).digest('hex');
		this.Ping();
	}

	public IsValid(): boolean {
		return ((new Date()).getTime() < this.mExpireTs) &&
			this.mUsername !== null;
	}

	public GetUsername(): string {
		return this.mUsername || "";
	}

	public Login(username: string) {
		this.mUsername = username;
	}

	public GetHash(): string {
		return this.mHash;
	}

	public Ping(): void {
		this.mExpireTs = (new Date()).getTime() + SESSION_TIME;
	}

	private mExpireTs: number;
	private mUsername: string | null;
	private mHash: string;
}

export var SessionManager = new class {
	public GetSession(req: Request): Session {
		const sessionId: string | undefined = req.mCookies.get(COOKIE_KEY);
		return (sessionId ? this.mStoredSessions.get(sessionId) : undefined) || new Session(req);
	}

	public Write(res: Response, sess: Session) {
		res.cookie(COOKIE_KEY, sess.GetHash());
		this.mStoredSessions.set(sess.GetHash(), sess);
	}

	private mStoredSessions: Map<string, Session> = new Map();
}();