describe("stick-at-top-when-scrolling", function(){
  var $stickyElement,
      $stickyWrapper;

  beforeEach(function(){
    $stickyElement = $('<div class="stick-at-top-when-scrolling"></div>');
    $stickyWrapper = $('<div>').append($stickyElement);

    $('body').append($stickyWrapper);
  });

  afterEach(function(){
    $stickyWrapper.remove();
  });

  describe('when stick is called', function(){

    it('should add fixed class on stick', function(){
      expect(!$stickyElement.hasClass('content-fixed')).toBe(true);
      GOVUK.stickAtTopWhenScrolling.stick($stickyElement);
      expect($stickyElement.hasClass('content-fixed')).toBe(true);
    });

    it('should insert shim when sticking the element', function(){
      expect($('.shim').length).toBe(0);
      GOVUK.stickAtTopWhenScrolling.stick($stickyElement);
      expect($('.shim').length).toBe(1);
    });

    it('should insert shim with minimum height', function(){
      GOVUK.stickAtTopWhenScrolling.stick($stickyElement);
      expect($('.shim').height()).toBe(1);
    });

  });

  describe('when release is called', function(){

    it('should remove fixed class', function(){
      $stickyElement.addClass('content-fixed');
      GOVUK.stickAtTopWhenScrolling.release($stickyElement);
      expect($stickyElement.hasClass('content-fixed')).toBe(false);
    });

    it('should remove the shim', function(){
      $stickyElement = $('<div class="stick-at-top-when-scrolling content-fixed"></div>');
      GOVUK.stickAtTopWhenScrolling.release($stickyElement);
      expect($('.shim').length).toBe(0);
    });

  });

  describe('for larger screens (>768px)', function(){

    beforeEach(function() {
      GOVUK.stickAtTopWhenScrolling.getWindowPositions = function(){
        return {
          scrollTop: 300
        };
      };
      GOVUK.stickAtTopWhenScrolling.getElementOffset = function(){
        return {
          top: 300
        };
      };
      GOVUK.stickAtTopWhenScrolling.getWindowDimensions = function(){
        return {
          height: 768,
          width: 769
        };
      };
      GOVUK.stickAtTopWhenScrolling.$els = $stickyElement;
      GOVUK.stickAtTopWhenScrolling._hasScrolled = true;
      GOVUK.stickAtTopWhenScrolling.checkScroll();
    });

    it('should stick, if the scroll position is past the element position', function(){
      expect($stickyElement.hasClass('content-fixed')).toBe(true);
    });

    it('should unstick, if the scroll position is less than the point at which scrolling started', function(){
      GOVUK.stickAtTopWhenScrolling.getWindowPositions = function() {
        return {
          scrollTop: 0
        };
      };
      GOVUK.stickAtTopWhenScrolling.$els = $stickyElement;
      GOVUK.stickAtTopWhenScrolling._hasScrolled = true;
      GOVUK.stickAtTopWhenScrolling.checkScroll();
      expect($stickyElement.hasClass('content-fixed')).toBe(false);
    });

  });

  describe('for smaller screens (<=768px)', function(){

    beforeEach(function() {
      GOVUK.stickAtTopWhenScrolling.getWindowDimensions = function() {
        return {
          height: 768,
          width: 767
        };
      };
      GOVUK.stickAtTopWhenScrolling.getElementOffset = function() {
        return {
          top: 300
        };
      };
      GOVUK.stickAtTopWhenScrolling.$els = $stickyElement;
      GOVUK.stickAtTopWhenScrolling._hasScrolled = true;
      GOVUK.stickAtTopWhenScrolling.checkScroll();
    });

    it('should unstick the element', function(){
      expect($stickyElement.hasClass('content-fixed')).toBe(false);
    });

  });

});