'use strict';
  
  var clear             = require('es5-ext/array/#/clear')
    , assign            = require('es5-ext/object/assign')
    , setPrototypeOf    = require('es5-ext/object/set-prototype-of')
    , contains          = require('es5-ext/string/#/contains')
    , d                 = require('d')
    , autoBind          = require('d/auto-bind')
    , Iterator          = require('es6-iterator')
    , toStringTagSymbol = require('es6-symbol').toStringTag
  
    , defineProperties = Object.defineProperties, keys = Object.keys
    , unBind = Iterator.prototype._unBind
    , PrimitiveSetIterator;
  
  PrimitiveSetIterator = module.exports = function (set, kind) {
  	if (!(this instanceof PrimitiveSetIterator)) {
  		return new PrimitiveSetIterator(set, kind);
  	}
  	Iterator.call(this, keys(set.__setData__), set);
  	kind = (!kind || !contains.call(kind, 'key+value')) ? 'value' : 'key+value';
  	defineProperties(this, {
  		__kind__: d('', kind),
  		__data__: d('w', set.__setData__)
  	});
  };
  if (setPrototypeOf) setPrototypeOf(PrimitiveSetIterator, Iterator);
  
  PrimitiveSetIterator.prototype = Object.create(Iterator.prototype, assign({
  	constructor: d(PrimitiveSetIterator),
  	_resolve: d(function (i) {
  		var value = this.__data__[this.__list__[i]];
  		return (this.__kind__ === 'value') ? value : [value, value];
  	}),
  	_unBind: d(function () {
  		this.__data__ = null;
  		unBind.call(this);
  	}),
  	toString: d(function () { return '[object Set Iterator]'; })
  }, autoBind({
  	_onAdd: d(function (key) { this.__list__.push(key); }),
  	_onDelete: d(function (key) {
  		var index = this.__list__.lastIndexOf(key);
  		if (index < this.__nextIndex__) return;
  		this.__list__.splice(index, 1);
  	}),
  	_onClear: d(function () {
  		clear.call(this.__list__);
  		this.__nextIndex__ = 0;
  	})
  })));
  Object.defineProperty(PrimitiveSetIterator.prototype, toStringTagSymbol,
  	d('c', 'Set Iterator'));