;(function($, window, document, undefined) {
  'use strict';

  var output = function(msg) {
    window.console && console.log(msg);
  };

  var wanspinner = function(element, options) {
    this.defaults = {
      maxvalue: 9999,
      minvalue: 1,
      step: 1,
      start: 1,
      inputwidth: 40,
      plusclick: function(element, val) {
        return true;
      },
      minusclick: function(element, val) {
        return true;
      },
      exceptionfun: function(exp) {
        return true;
      },
      valuechanged: function(element, val) {
        return true;
      }
    };
    this.options = $.extend({}, this.defaults, options);
    this.options.steplength = ((+this.options.step).tostring().split('.')[1] || '').length;
    this.options.stepfloat = parseint(1 * math.pow(10, this.options.steplength) / this.options.step) || 1;
    this.element = $(element);

    this.element.each(function(index, dt) {
      var input = $(dt).children('input');
      var initvalue = input.val() || this.options.start;
      input.val(initvalue);
    });

    this.element.children('input').css('width', this.options.inputwidth);

    this.exception = {
      too_large: 1,
      normal: 0,
      too_small: -1
    };
  };

  wanspinner.prototype.bind = function() {
    var self = this;
    $(self.element).delegate('.minus', 'click', function() {
      var val;
      var input = $(this).siblings('input');
      if (self.options.stepfloat > 1) {
        val = (+input.val() || 0) * self.options.stepfloat - self.options.step  * self.options.stepfloat;
        val = math.round(val) / self.options.stepfloat;
      } else {
        val = (+input.val() || 0) - self.options.step;
      }
      val = val.tofixed(self.options.steplength);
      if (val < self.options.minvalue) {
        typeof(self.options.exceptionfun) === 'function' && self.options.exceptionfun(self.exception.too_small);
      } else {
        input.val(val);
        typeof(self.options.minusclick) === 'function' && self.options.minusclick($(this).parent(), val);
        typeof(self.options.valuechanged) === 'function' && self.options.valuechanged($(this).parent(), val);
      }
      return false;
    }).delegate('.plus', 'click', function() {
      var val;
      var input = $(this).siblings('input');
      if (self.options.stepfloat > 1) {
        val = (+input.val() || 0) * self.options.stepfloat + self.options.step * self.options.stepfloat;
        val = math.round(val) / self.options.stepfloat;
      } else {
        val = (+input.val() || 0) + self.options.step;
      }
      val = val.tofixed(self.options.steplength);
      if (val > self.options.maxvalue) {
        typeof(self.options.exceptionfun) === 'function' && self.options.exceptionfun(self.exception.too_large);
      } else {
        input.val(val);
        typeof(self.options.plusclick) === 'function' && self.options.plusclick($(this).parent(), val);
        typeof(self.options.valuechanged) === 'function' && self.options.valuechanged($(this).parent(), val);
      }
      return false;
    }).delegate('input', 'change', function() {
      var val = +$(this).val() || 0;
      if (val > self.options.maxvalue) {
        val = self.options.maxvalue;
        typeof(self.options.exceptionfun) === 'function' && self.options.exceptionfun(self.exception.too_large);
      } else if (val < self.options.minvalue) {
        val = self.options.minvalue;
        typeof(self.options.exceptionfun) === 'function' && self.options.exceptionfun(self.exception.too_small);
      }
      $(this).val(val);
      typeof(self.options.valuechanged) === 'function' && self.options.valuechanged($(this).parent(), val);
    });
  }


  $.fn.wanspinner = function(options) {
    var wanspinner = new wanspinner(this, options);
    wanspinner.bind();
    return this;
  };

})(jquery, window, document);