def login():
    username = request.form['username']
    redirect_to_home = redirect("/")
    response = make_response(redirect_to_home)
    if username != "":
        params = {'key': STEAM_API_KEY, 'vanityurl': username}
        r = requests.get(
            "http://api.steampowered.com/ISteamUser/ResolveVanityURL/v0001/",
            params)
        success = int(r.json()['response']['success'])
        if success == 1:
            steamid = r.json()['response']['steamid']
            response.set_cookie("steam_ID", value=steamid)
            del params['vanityurl']
            params['steamids'] = steamid
            r3 = requests.get(
                "http://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/",
                params)
            if 200 <= r3.status_code < 300:
                response.set_cookie(
                    "username",
                    value=r3.json()['response']['players'][0]['personaname'])
                del params["steamids"]
                params["steamid"] = steamid
                params["format"] = "json"
                params["include_played_free_games"] = "1"
                r2 = requests.get(
                    "http://api.steampowered.com/IPlayerService/GetOwnedGames/v0001/",
                    params)
                if 'games' not in r2.json()['response']:
                    return render_template(
                        "search.html",
                        username=request.cookies.get("username"),
                        invalid_login=True)
                games = r2.json()['response']['games']
                game_list = [int(game['appid']) for game in games]
                hours_played = [
                    int(game['playtime_forever']) for game in games
                ]
                response.set_cookie("game_list", value=json.dumps(game_list))
                library_vector = Game.compute_library_vector(
                    game_list, hours_played)
                response.set_cookie("library_vector",
                                    value=json.dumps(library_vector.tolist()))
            else:
                pass  #???
        else:
            return render_template("search.html",
                                   username=request.cookies.get("username"),
                                   invalid_login=True)
    elif request.cookies.get('username'):
        del session["steam_ID"]
        del session["library_vector"]
        response.set_cookie("steam_id", "", max_age=0)
        response.set_cookie("library_vector", "", max_age=0)
    return response