function initSelects() {
    var selectElements = document.querySelectorAll('select');
    var selectInstances = M.FormSelect.init(selectElements, {});

}

function initSidenav() {
    var sidenavElements = document.querySelectorAll('.sidenav');
    var sidenavInstances = M.Sidenav.init(sidenavElements, {});
};

function initModals() {
    var modalElements = document.querySelectorAll('.modal');
    var modalInstances = M.Modal.init(modalElements, {
        'onOpenEnd': initSelects
    });
};

function openEventModal(eventId) {
    openModal(`#event-modal-${eventId}`);
}

function openModal(modalId) {
    var modalElement = document.querySelector(modalId);
    if (modalElement === null) {
        return;
    }
    var modalInstance = M.Modal.getInstance(modalElement);
    modalInstance.open();
}

// What to do when the document is loaded.
document.addEventListener('DOMContentLoaded', function () {
    // init materialize elements
    initModals();
    initSidenav();
    initSelects();

    // opening event modal if given
    var eventId = parseInt(window.location.hash.substring(1));
    if (!isNaN(eventId)) {
        openEventModal(eventId);
    }
});