define(['css!./loading'], function () {
    'use strict';

    var loadingElem;
    var layer1;
    var layer2;
    var layer3;
    var layer4;
    var circleLefts;
    var circleRights;

    return {
        show: function () {
            var elem = loadingElem;

            if (!elem) {
                elem = document.createElement('div');
                loadingElem = elem;

                elem.classList.add('docspinner');
                elem.classList.add('mdl-spinner');

                elem.innerHTML = '<div class="mdl-spinner__layer mdl-spinner__layer-1"><div class="mdl-spinner__circle-clipper mdl-spinner__left"><div class="mdl-spinner__circle mdl-spinner__circleLeft"></div></div><div class="mdl-spinner__circle-clipper mdl-spinner__right"><div class="mdl-spinner__circle mdl-spinner__circleRight"></div></div></div><div class="mdl-spinner__layer mdl-spinner__layer-2"><div class="mdl-spinner__circle-clipper mdl-spinner__left"><div class="mdl-spinner__circle mdl-spinner__circleLeft"></div></div><div class="mdl-spinner__circle-clipper mdl-spinner__right"><div class="mdl-spinner__circle mdl-spinner__circleRight"></div></div></div><div class="mdl-spinner__layer mdl-spinner__layer-3"><div class="mdl-spinner__circle-clipper mdl-spinner__left"><div class="mdl-spinner__circle mdl-spinner__circleLeft"></div></div><div class="mdl-spinner__circle-clipper mdl-spinner__right"><div class="mdl-spinner__circle mdl-spinner__circleRight"></div></div></div><div class="mdl-spinner__layer mdl-spinner__layer-4"><div class="mdl-spinner__circle-clipper mdl-spinner__left"><div class="mdl-spinner__circle mdl-spinner__circleLeft"></div></div><div class="mdl-spinner__circle-clipper mdl-spinner__right"><div class="mdl-spinner__circle mdl-spinner__circleRight"></div></div></div>';

                document.body.appendChild(elem);

                layer1 = elem.querySelector('.mdl-spinner__layer-1');
                layer2 = elem.querySelector('.mdl-spinner__layer-2');
                layer3 = elem.querySelector('.mdl-spinner__layer-3');
                layer4 = elem.querySelector('.mdl-spinner__layer-4');

                circleLefts = elem.querySelectorAll('.mdl-spinner__circleLeft');
                circleRights = elem.querySelectorAll('.mdl-spinner__circleRight');
            }

            elem.classList.add('mdlSpinnerActive');

            layer1.classList.add('mdl-spinner__layer-1-active');
            layer2.classList.add('mdl-spinner__layer-2-active');
            layer3.classList.add('mdl-spinner__layer-3-active');
            layer4.classList.add('mdl-spinner__layer-4-active');

            var i;
            var length;

            for (i = 0, length = circleLefts.length; i < length; i++) {
                circleLefts[i].classList.add('mdl-spinner__circleLeft-active');
            }

            for (i = 0, length = circleRights.length; i < length; i++) {
                circleRights[i].classList.add('mdl-spinner__circleRight-active');
            }
        },
        hide: function () {
            var elem = loadingElem;

            if (elem) {
                elem.classList.remove('mdlSpinnerActive');

                elem.classList.remove('mdl-spinner__layer-1-active');
                elem.classList.remove('mdl-spinner__layer-2-active');
                elem.classList.remove('mdl-spinner__layer-3-active');
                elem.classList.remove('mdl-spinner__layer-4-active');

                var i;
                var length;

                for (i = 0, length = circleLefts.length; i < length; i++) {
                    circleLefts[i].classList.remove('mdl-spinner__circleLeft-active');
                }

                for (i = 0, length = circleRights.length; i < length; i++) {
                    circleRights[i].classList.remove('mdl-spinner__circleRight-active');
                }
            }
        }
    };
});