/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/

define([
'jquery',
'jquery-ui-modules/widget'
], function ($) {
'use strict';

$.widget('mage.sticky', {
options: {
/**
* Element selector, who's height will be used to restrict the
* maximum offsetTop position of the stuck element.
* Default uses document body.
* @type {String}
*/
container: '',

/**
* Spacing in pixels above the stuck element
* @type {Number|Function} Number or Function that will return a Number
*/
spacingTop: 0,

/**
* Allows postponing sticking, until element will go out of the
* screen for the number of pixels.
* @type {Number|Function} Number or Function that will return a Number
*/
stickAfter: 0,

/**
* CSS class for active sticky state
* @type {String}
*/
stickyClass: '_sticky'
},

/**
* Retrieve option value
* @param {String} option
* @return {*}
* @private
*/
_getOptionValue: function (option) {
var value = this.options[option] || 0;

if (typeof value === 'function') {
value = this.options[option]();
}

return value;
},

/**
* Bind handlers to scroll event
* @private
*/
_create: function () {
$(window).on({
'scroll': $.proxy(this._stick, this),
'resize': $.proxy(this.reset, this)
});

this.element.on('dimensionsChanged', $.proxy(this.reset, this));

this.reset();

// Application of the workaround for IE11 and Edge
this.normalizeIE11AndEdgeScroll();
},

/**
* float Block on windowScroll
* @private
*/
_stick: function () {
var offset,
isStatic,
stuck,
stickAfter;

isStatic = this.element.css('position') === 'static';

if (!isStatic && this.element.is(':visible')) {
offset = $(document).scrollTop() -
this.parentOffset +
this._getOptionValue('spacingTop');

offset = Math.max(0, Math.min(offset, this.maxOffset));

stuck = this.element.hasClass(this.options.stickyClass);
stickAfter = this._getOptionValue('stickAfter');

if (offset && !stuck && offset < stickAfter) {
offset = 0;
}

this.element
.toggleClass(this.options.stickyClass, offset > 0)
.css('top', offset);
}
},

/**
* Defines maximum offset value of the element.
* @private
*/
_calculateDimens: function () {
var $parent = this.element.parent(),
topMargin = parseInt(this.element.css('margin-top'), 10),
parentHeight = $parent.height() - topMargin,
height = this.element.innerHeight(),
maxScroll = document.body.offsetHeight - window.innerHeight;

if (this.options.container.length > 0) {
maxScroll = $(this.options.container).height();
}

this.parentOffset = $parent.offset().top + topMargin;
this.maxOffset = maxScroll - this.parentOffset;

if (this.maxOffset + height >= parentHeight) {
this.maxOffset = parentHeight - height;
}

return this;
},

/**
* Facade method that places sticky element where it should be.
*/
reset: function () {
this._calculateDimens()
._stick();
},

/**
* Workaround for IE11 and Edge that solves the IE known rendering issue
* that prevents sticky element from jumpy movement on scrolling the page.
*
* Alternatively, undesired jumpy movement can be eliminated by changing the setting in IE:
* Settings > Internet options > Advanced tab > inside 'Browsing' item > set 'Use smooth scrolling' to False
*/
normalizeIE11AndEdgeScroll: function () {
if (navigator.userAgent.match(/Trident.*rv[ :]*11\.|Edge\//)) {
document.body.addEventListener('mousewheel', function () {
event.preventDefault();
window.scrollTo(0, window.pageYOffset - event.wheelDelta);
});
}
}
});

return $.mage.sticky;
});