// lock scrollnav on scroll

var $scrollNav = $('.mcs-scrollnav');
var sTop = $scrollNav.offset().top + 84;

$(window).scroll(function (event) {
  var y2 = $(this).scrollTop();
  if (y2 >= sTop) {
    $scrollNav.addClass('mcs-scrollnav-lock');
    $body.addClass('add-padding-more');
  } else {
    $scrollNav.removeClass('mcs-scrollnav-lock');
    $body.removeClass('add-padding-more');
  }
});

// highlight active section when scrolling

function navHighlight() {
    var scrollTop = $(document).scrollTop();

    $('.mcs-feature').each(function () {
        var xPos = $(this).position();
        var sectionPos = xPos.top;
        var sectionHeight = $(this).height();
        var overall = scrollTop + sectionHeight;

        if ((scrollTop + 240) >= sectionPos && scrollTop < overall) {
            $(this).addClass('mcs-feature-active');
            $(this).prevAll().removeClass('mcs-feature-active');
        }

        else if (scrollTop <= overall) {
            $(this).removeClass('mcs-feature-active');
        }

    });
    
        var xIndex = $('.mcs-feature-active').children('.anchor').attr('id')

        $('.mcs-scrollnav--item[href="#'+ xIndex +'"]').addClass('mcs-scrollnav--item-active').siblings().removeClass('mcs-scrollnav--item-active');
    
}

// find out which elements are overflowing the left side of scrollnav container

    function whatsOverflowingLeft () {
    var scrollnavLeft = $('.mcs-scrollnav--list').offset().left;
    $('.mcs-scrollnav--list').find('.mcs-scrollnav--item').each(function(){
		var self = $(this);
        if(self.offset().left < scrollnavLeft) {
            self.addClass('overflowing-left');
        } else {
            self.removeClass('overflowing-left');
        }
    });
        
    }

// find out which elements are overflowing the right side of scrollnav container

    function whatsOverflowingRight () {
    var scrollnavRight = $('.mcs-scrollnav--list').offset().left + $('.mcs-scrollnav--list').width();
    $('.mcs-scrollnav--list').find('.mcs-scrollnav--item').each(function(){
		var self = $(this);
        if(self.offset().left + self.width() > scrollnavRight) {
            self.addClass('overflowing-right');
        } else {
            self.removeClass('overflowing-right');
        }
    });
        
    }

// mark scrollnav container to note left overflow

    function hasLeftOverflow () {

    if($('.mcs-scrollnav--list .overflowing-left').length > 0){
        $('.mcs-scrollnav').addClass('overflows-left');
    }
    else {
        $('.mcs-scrollnav').removeClass('overflows-left');
    }
        
    }

// mark scrollnav container to note right overflow

    function hasRightOverflow () {

    if($('.mcs-scrollnav--list .overflowing-right').length > 0){
        $('.mcs-scrollnav').addClass('overflows-right');
    }
    else {
        $('.mcs-scrollnav').removeClass('overflows-right');
    }
        
    }

// scroll list forward when clicking arrow

    function goForward () {

    if($('.mcs-scrollnav--list .overflowing-right').length > 0){
        $('.mcs-scrollnav--list').animate({
        scrollLeft: 2000
        },200);   
    }
    else {

    }    
        
    }

// scroll list backward when clicking arrow

    function goBack () {

    if($('.mcs-scrollnav--list .overflowing-left').length > 0){
        $('.mcs-scrollnav--list').animate({
        scrollLeft: 0
        },200);
    }
    else {

    }  
        
    }

// call functions on load

$(function() {
    navHighlight();
    whatsOverflowingLeft();
    whatsOverflowingRight();
    hasLeftOverflow();
    hasRightOverflow();
});

// call functions on scroll

$(window).scroll(function() {
    navHighlight();

    if($('.mcs-scrollnav--item-active.overflowing-left').length > 0){
    goBack();
    setTimeout(whatsOverflowingLeft,250);
    setTimeout(whatsOverflowingRight,250);
    setTimeout(hasLeftOverflow,300);
    setTimeout(hasRightOverflow,300);
            
    }
    else if($('.mcs-scrollnav--item-active.overflowing-right').length > 0){
    goForward();
    setTimeout(whatsOverflowingLeft,250);
    setTimeout(whatsOverflowingRight,250);
    setTimeout(hasLeftOverflow,300);
    setTimeout(hasRightOverflow,300);
    }
    else {

    }    
    
});

// call functions on click forward

  $(function(){
    $('.scrollnav-next, .overflowing-right').on('click',function() {
    goForward();
    setTimeout(whatsOverflowingLeft,250);
    setTimeout(whatsOverflowingRight,250);
    setTimeout(hasLeftOverflow,300);
    setTimeout(hasRightOverflow,300);
    });
  });


// call functions on click back

  $(function(){
    $('.scrollnav-back, .overflowing-left').on('click',function() {
    goBack();
    setTimeout(whatsOverflowingLeft,250);
    setTimeout(whatsOverflowingRight,250);
    setTimeout(hasLeftOverflow,300);
    setTimeout(hasRightOverflow,300);
    });
  });