define(['jquery', 'underscore'], function($, _) {

  var sticky = function(options) {
    this.selector = options.selector;
    this.offsets = options.offsets;
    this.totalOffset = 0;
    this.cachedLoc = 0;
    this.currScroll = 0;
    this.$mainEl = $(this.selector);
    this.$offsetEls = [];

    this.init = function() {
      var self = this;

      self.cacheLocation();

      $(window).scroll(function() {
        self.checkSticky();
      });
    }

    this.cacheLocation = function() {
      var self = this;

      _.each(self.offsets, function(selector) {
        self.totalOffset += $(selector).outerHeight();
      });

      self.cachedLoc = self.totalOffset + self.$mainEl.offset().top;
    }

    this.checkSticky = function() {
      var self = this;

      self.currScroll = $(window).scrollTop();

      if (self.currScroll >= self.cachedLoc) {
        self.$mainEl.css({
          position: 'fixed',
          top: self.totalOffset + 'px',
          bottom: 0
        });
      }
      else if (self.currScroll < self.cachedLoc) {
        self.$mainEl.removeAttr('style');
      }
    }

    this.init();
  }

  return sticky;

});