/* global define:false */
(function () {
  'use strict'
  
  var ctx = this
  var origMovingAverage = ctx.movingAverage

  function isNumber(obj) {
    if (isNaN(obj)) {
      return false
    }

    return Object.prototype.toString.call(obj) === '[object Number]'
  }

  function maybeCoerce(item) {
    if (! isNumber(item)) {
      item = parseFloat(item) || 0
    }

    return item
  }

  function reducer(memo, item, index, arr) {
    Object.defineProperty(memo, 'currentTotal', {
      value: (memo.currentTotal || 0) + item,
      enumerable: false,
      writable: true
    })

    memo.push(memo.currentTotal / (index + 1))
    return memo
  }

  function movingAverage(items) {
    if (! Array.isArray(items)) {
      items = []
    }

    return items.map(maybeCoerce).reduce(reducer, [])
  }

  movingAverage.noConflict = function () {
    ctx.movingAverage = origMovingAverage
    return movingAverage
  }


  // AMD
  if (typeof define !== 'undefined' && define.amd) {
    define([], function () {
      return movingAverage
    })
  }

  // Node.js
  else if (typeof module !== 'undefined' && module.exports) {
    module.exports = movingAverage;
  }

  // <script> tag
  else {
    this.movingAverage = movingAverage;
  }
}).call(this)