/** @const @type {number} */
var POLL_INTERVAL = 5000;

function doGet(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function(e) {
        if (xhr.readyState === 4) {
            var resp = null;

            if (xhr.status === 200) {
                resp = xhr.response;
                try {
                    resp = JSON.parse(/** @type {string} */ (resp));
                } catch (e) {
                    resp = null;
                }
            }
            callback(xhr.status, resp);
        }
    };
    xhr.open('GET', url, true);
    xhr.send(null);
}

function initPolling() {
    lazyGetPseudonyme(function(pseudo) {
        if (pseudo) {
            doGet("/api/poll?grid=" +GRID_PUBLIC_ID +"&v=" +KNOWN_VERSION, function(status, resp) {
                if (resp) {
                    GRID = new Grid(resp);
                    updateOnPollResult(resp);
                    GRID.playerSelf = GRID.players[pseudo];
                    scheduleNextPoll();
                } // TODO else cannot init party
            });
        } // TODO else cannot init pseudo
    });
}

function pollNow() {
    if (pollNow.polling !== true) {
        if (pollNow.pollSchedule) {
            clearTimeout(pollNow.pollSchedule);
            pollNow.pollSchedule = 0;
        }
        pollNow.polling = true;
        doGet("/api/poll?grid=" +GRID_PUBLIC_ID +"&v=" +KNOWN_VERSION, function(status, resp) {
            pollNow.polling = false;
            if (resp) {
                updateOnPollResult(resp);
            }
            scheduleNextPoll();
        });
    }
}

function scheduleNextPoll() {
    if (!pollNow.pollSchedule)
        pollNow.pollSchedule = setInterval(pollNow, POLL_INTERVAL);
};