(function ($) {
  var countto = function (element, options) {
    this.$element = $(element);
    this.options  = $.extend({}, countto.defaults, this.dataoptions(), options);
    this.init();
  };

  countto.defaults = {
    from: 0,               // the number the element should start at
    to: 0,                 // the number the element should end at
    speed: 1000,           // how long it should take to count between the target numbers
    refreshinterval: 100,  // how often the element should be updated
    decimals: 0,           // the number of decimal places to show
    formatter: formatter,  // handler for formatting the value before rendering
    onupdate: null,        // callback method for every time the element is updated
    oncomplete: null       // callback method for when the element finishes updating
  };

  countto.prototype.init = function () {
    this.value     = this.options.from;
    this.loops     = math.ceil(this.options.speed / this.options.refreshinterval);
    this.loopcount = 0;
    this.increment = (this.options.to - this.options.from) / this.loops;
  };

  countto.prototype.dataoptions = function () {
    var options = {
      from:            this.$element.data('from'),
      to:              this.$element.data('to'),
      speed:           this.$element.data('speed'),
      refreshinterval: this.$element.data('refresh-interval'),
      decimals:        this.$element.data('decimals')
    };

    var keys = object.keys(options);

    for (var i in keys) {
      var key = keys[i];

      if (typeof(options[key]) === 'undefined') {
        delete options[key];
      }
    }

    return options;
  };

  countto.prototype.update = function () {
    this.value += this.increment;
    this.loopcount++;

    this.render();

    if (typeof(this.options.onupdate) == 'function') {
      this.options.onupdate.call(this.$element, this.value);
    }

    if (this.loopcount >= this.loops) {
      clearinterval(this.interval);
      this.value = this.options.to;

      if (typeof(this.options.oncomplete) == 'function') {
        this.options.oncomplete.call(this.$element, this.value);
      }
    }
  };

  countto.prototype.render = function () {
    var formattedvalue = this.options.formatter.call(this.$element, this.value, this.options);
    this.$element.text(formattedvalue);
  };

  countto.prototype.restart = function () {
    this.stop();
    this.init();
    this.start();
  };

  countto.prototype.start = function () {
    this.stop();
    this.render();
    this.interval = setinterval(this.update.bind(this), this.options.refreshinterval);
  };

  countto.prototype.stop = function () {
    if (this.interval) {
      clearinterval(this.interval);
    }
  };

  countto.prototype.toggle = function () {
    if (this.interval) {
      this.stop();
    } else {
      this.start();
    }
  };

  function formatter(value, options) {
    return value.tofixed(options.decimals);
  }

  $.fn.countto = function (option) {
    return this.each(function () {
      var $this   = $(this);
      var data    = $this.data('countto');
      var init    = !data || typeof(option) === 'object';
      var options = typeof(option) === 'object' ? option : {};
      var method  = typeof(option) === 'string' ? option : 'start';

      if (init) {
        if (data) data.stop();
        $this.data('countto', data = new countto(this, options));
      }

      data[method].call(data);
    });
  };
}(jquery));