(function () {
    'use strict';

    function savePaperChoice(choice) {
        var ajaxUrl = window.wsGiftDropdownAjaxUrl || '';
        if (!ajaxUrl || !choice) {
            return;
        }
        var xhr = new XMLHttpRequest();
        xhr.open('POST', ajaxUrl, true);
        xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        xhr.send('gift_paper=' + encodeURIComponent(choice) + '&ajax=1');
    }

    function init() {
        var checked = document.querySelector('input[name="gift_paper"]:checked');
        if (checked) {
            savePaperChoice(checked.value);
        }

        document.addEventListener('change', function (e) {
            if (e.target && e.target.name === 'gift_paper') {
                savePaperChoice(e.target.value);
            }
        });
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
}());