(function (factory, global) {

  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else {
    // Browser globals.
    factory(global.jQuery);
  }

}(function ($, undef) {

  var dataKey = 'plugin_hideShowPassword'
    , shorthandArgs = ['show', 'innerToggle']
    , SPACE = 32
    , ENTER = 13;

  var canSetInputAttribute = (function(){
    var body = document.body
      , input = document.createElement('input')
      , result = true;
    if (! body) {
      body = document.createElement('body');
    }
    input = body.appendChild(input);
    try {
      input.setAttribute('type', 'text');
    } catch (e) {
      result = false;
    }
    body.removeChild(input);
    return result;
  }());

  var defaults = {
    // Visibility of the password text. Can be true, false, 'toggle'
    // or 'infer'. If 'toggle', it will be the opposite of whatever
    // it currently is. If 'infer', it will be based on the input
    // type (false if 'password', otherwise true).
    show: 'infer',

    // Set to true to create an inner toggle for this input. Can
    // also be sent to an event name to delay visibility of toggle
    // until that event is triggered on the input element.
    innerToggle: false,

    // If false, the plugin will be disabled entirely. Set to
    // the outcome of a test to insure input attributes can be
    // set after input has been inserted into the DOM.
    enable: canSetInputAttribute,

    // Class to add to input element when the plugin is enabled.
    className: 'hideShowPassword-field',

    // Event to trigger when the plugin is initialized and enabled.
    initEvent: 'hideShowPasswordInit',

    // Event to trigger whenever the visibility changes.
    changeEvent: 'passwordVisibilityChange',

    // Properties to add to the input element.
    props: {
      autocapitalize: 'off',
      autocomplete: 'off',
      autocorrect: 'off',
      spellcheck: 'false'
    },

    // Options specific to the inner toggle.
    toggle: {
      // The element to create.
      element: '<button type="button">',
      // Class name of element.
      className: 'hideShowPassword-toggle',
      // Whether or not to support touch-specific enhancements.
      // Defaults to the value of Modernizr.touch if available,
      // otherwise false.
      touchSupport: (typeof Modernizr === 'undefined') ? false : Modernizr.touch,
      // Non-touch event to bind to.
      attachToEvent: 'click',
      // Event to bind to when touchSupport is true.
      attachToTouchEvent: 'touchstart mousedown',
      // Key event to bind to if attachToKeyCodes is an array
      // of at least one keycode.
      attachToKeyEvent: 'keyup',
      // Key codes to bind the toggle event to for accessibility.
      // If false, this feature is disabled entirely.
      // If true, the array of key codes will be determined based
      // on the value of the element option.
      attachToKeyCodes: true,
      // Styles to add to the toggle element. Does not include
      // positioning styles.
      styles: { position: 'absolute' },
      // Styles to add only when touchSupport is true.
      touchStyles: { pointerEvents: 'none' },
      // Where to position the inner toggle relative to the
      // input element. Can be 'right', 'left' or 'infer'. If
      // 'infer', it will be based on the text-direction of the
      // input element.
      position: 'infer',
      // Where to position the inner toggle on the y-axis
      // relative to the input element. Can be 'top', 'bottom'
      // or 'middle'.
      verticalAlign: 'middle',
      // Amount by which to "offset" the toggle from the edge
      // of the input element.
      offset: 0,
      // Attributes to add to the toggle element.
      attr: {
        role: 'button',
        'aria-label': 'Show Password',
        tabIndex: 0
      }
    },

    // Options specific to the wrapper element, created
    // when the innerToggle is initialized to help with
    // positioning of that element.
    wrapper: {
      // The element to create.
      element: '<div>',
      // Class name of element.
      className: 'hideShowPassword-wrapper',
      // If true, the width of the wrapper will be set
      // unless it is already the same width as the inner
      // element. If false, the width will never be set. Any
      // other value will be used as the width.
      enforceWidth: true,
      // Styles to add to the wrapper element. Does not
      // include inherited styles or width if enforceWidth
      // is not false.
      styles: { position: 'relative' },
      // Styles to "inherit" from the input element, allowing
      // the wrapper to avoid disrupting page styles.
      inheritStyles: [
        'display',
        'verticalAlign',
        'marginTop',
        'marginRight',
        'marginBottom',
        'marginLeft'
      ],
      // Styles for the input element when wrapped.
      innerElementStyles: {
        marginTop: 0,
        marginRight: 0,
        marginBottom: 0,
        marginLeft: 0
      }
    },

    // Options specific to the 'shown' or 'hidden'
    // states of the input element.
    states: {
      shown: {
        className: 'hideShowPassword-shown',
        changeEvent: 'passwordShown',
        props: { type: 'text' },
        toggle: {
          className: 'hideShowPassword-toggle-hide',
          content: 'HIDE',
          attr: { 'aria-pressed': 'true' }
        }
      },
      hidden: {
        className: 'hideShowPassword-hidden',
        changeEvent: 'passwordHidden',
        props: { type: 'password' },
        toggle: {
          className: 'hideShowPassword-toggle-show',
          content: 'SHOW',
          attr: { 'aria-pressed': 'false' }
        }
      }
    }

  };

  function HideShowPassword (element, options) {
    this.element = $(element);
    this.wrapperElement = $();
    this.toggleElement = $();
    this.init(options);
  }

  HideShowPassword.prototype = {

    init: function (options) {
      if (this.update(options, defaults)) {
        this.element.addClass(this.options.className);
        if (this.options.innerToggle) {
          this.wrapElement(this.options.wrapper);
          this.initToggle(this.options.toggle);
          if (typeof this.options.innerToggle === 'string') {
            this.toggleElement.hide();
            this.element.one(this.options.innerToggle, $.proxy(function(){
              this.toggleElement.show();
            }, this));
          }
        }
        this.element.trigger(this.options.initEvent, [ this ]);
      }
    },

    update: function (options, base) {
      this.options = this.prepareOptions(options, base);
      if (this.updateElement()) {
        this.element
          .trigger(this.options.changeEvent, [ this ])
          .trigger(this.state().changeEvent, [ this ]);
      }
      return this.options.enable;
    },

    toggle: function (showVal) {
      showVal = showVal || 'toggle';
      return this.update({ show: showVal });
    },

    prepareOptions: function (options, base) {
      var keyCodes = []
        , testElement;
      base = base || this.options;
      options = $.extend(true, {}, base, options);
      if (options.enable) {
        if (options.show === 'toggle') {
          options.show = this.isType('hidden', options.states);
        } else if (options.show === 'infer') {
          options.show = this.isType('shown', options.states);
        }
        if (options.toggle.position === 'infer') {
          options.toggle.position = (this.element.css('text-direction') === 'rtl') ? 'left' : 'right';
        }
        if (! $.isArray(options.toggle.attachToKeyCodes)) {
          if (options.toggle.attachToKeyCodes === true) {
            testElement = $(options.toggle.element);
            switch(testElement.prop('tagName').toLowerCase()) {
              case 'button':
              case 'input':
                break;
              case 'a':
                if (testElement.filter('[href]').length) {
                  keyCodes.push(SPACE);
                  break;
                }
              default:
                keyCodes.push(SPACE, ENTER);
                break;
            }
          }
          options.toggle.attachToKeyCodes = keyCodes;
        }
      }
      return options;
    },

    updateElement: function () {
      if (! this.options.enable || this.isType()) return false;
      this.element
        .prop($.extend({}, this.options.props, this.state().props))
        .addClass(this.state().className)
        .removeClass(this.otherState().className);
      this.updateToggle();
      return true;
    },

    isType: function (comparison, states) {
      states = states || this.options.states;
      comparison = comparison || this.state(undef, undef, states).props.type;
      if (states[comparison]) {
        comparison = states[comparison].props.type;
      }
      return this.element.prop('type') === comparison;
    },

    state: function (key, invert, states) {
      states = states || this.options.states;
      if (key === undef) {
        key = this.options.show;
      }
      if (typeof key === 'boolean') {
        key = key ? 'shown' : 'hidden';
      }
      if (invert) {
        key = (key === 'shown') ? 'hidden' : 'shown';
      }
      return states[key];
    },

    otherState: function (key) {
      return this.state(key, true);
    },

    wrapElement: function (options) {
      var enforceWidth = options.enforceWidth
        , targetWidth;
      if (! this.wrapperElement.length) {
        targetWidth = this.element.outerWidth();
        $.each(options.inheritStyles, $.proxy(function (index, prop) {
          options.styles[prop] = this.element.css(prop);
        }, this));
        this.element.css(options.innerElementStyles).wrap(
          $(options.element).addClass(options.className).css(options.styles)
        );
        this.wrapperElement = this.element.parent();
        if (enforceWidth === true) {
          enforceWidth = (this.wrapperElement.outerWidth() === targetWidth) ? false : targetWidth;
        }
        if (enforceWidth !== false) {
          this.wrapperElement.css('width', enforceWidth);
        }
      }
      return this.wrapperElement;
    },

    initToggle: function (options) {
      if (! this.toggleElement.length) {
        // Create element
        this.toggleElement = $(options.element)
          .attr(options.attr)
          .addClass(options.className)
          .css(options.styles)
          .appendTo(this.wrapperElement);
        // Update content/attributes
        this.updateToggle();
        // Position
        this.positionToggle(options.position, options.verticalAlign, options.offset);
        // Events
        if (options.touchSupport) {
          this.toggleElement.css(options.touchStyles);
          this.element.on(options.attachToTouchEvent, $.proxy(this.toggleTouchEvent, this));
        } else {
          this.toggleElement.on(options.attachToEvent, $.proxy(this.toggleEvent, this));
        }
        if (options.attachToKeyCodes.length) {
          this.toggleElement.on(options.attachToKeyEvent, $.proxy(this.toggleKeyEvent, this));
        }
      }
      return this.toggleElement;
    },

    positionToggle: function (position, verticalAlign, offset) {
      var styles = {};
      styles[position] = offset;
      switch (verticalAlign) {
        case 'top':
        case 'bottom':
          styles[verticalAlign] = offset;
          break;
        case 'middle':
          styles['top'] = '50%';
          styles['marginTop'] = this.toggleElement.outerHeight() / -2;
          break;
      }
      return this.toggleElement.css(styles);
    },

    updateToggle: function (state, otherState) {
      var paddingProp
        , targetPadding;
      if (this.toggleElement.length) {
        paddingProp = 'padding-' + this.options.toggle.position;
        state = state || this.state().toggle;
        otherState = otherState || this.otherState().toggle;
        this.toggleElement
          .attr(state.attr)
          .addClass(state.className)
          .removeClass(otherState.className)
          .html(state.content);
        targetPadding = this.toggleElement.outerWidth() + (this.options.toggle.offset * 2);
        if (this.element.css(paddingProp) !== targetPadding) {
          this.element.css(paddingProp, targetPadding);
        }
      }
      return this.toggleElement;
    },

    toggleEvent: function (event) {
      event.preventDefault();
      this.toggle();
    },

    toggleKeyEvent: function (event) {
      $.each(this.options.toggle.attachToKeyCodes, $.proxy(function(index, keyCode) {
        if (event.which === keyCode) {
          this.toggleEvent(event);
          return false;
        }
      }, this));
    },

    toggleTouchEvent: function (event) {
      var toggleX = this.toggleElement.offset().left
        , eventX
        , lesser
        , greater;
      if (toggleX) {
        eventX = event.pageX || event.originalEvent.pageX;
        if (this.options.toggle.position === 'left') {
          toggleX+= this.toggleElement.outerWidth();
          lesser = eventX;
          greater = toggleX;
        } else {
          lesser = toggleX;
          greater = eventX;
        }
        if (greater >= lesser) {
          this.toggleEvent(event);
        }
      }
    }

  };

  $.fn.hideShowPassword = function () {
    var options = {};
    $.each(arguments, function (index, value) {
      var newOptions = {};
      if (typeof value === 'object') {
        newOptions = value;
      } else if (shorthandArgs[index]) {
        newOptions[shorthandArgs[index]] = value;
      } else {
        return false;
      }
      $.extend(true, options, newOptions);
    });
    return this.each(function(){
      var $this = $(this)
        , data = $this.data(dataKey);
      if (data) {
        data.update(options);
      } else {
        $this.data(dataKey, new HideShowPassword(this, options));
      }
    });
  };

  $.each({ 'show':true, 'hide':false, 'toggle':'toggle' }, function (verb, showVal) {
    $.fn[verb + 'Password'] = function (innerToggle, options) {
      return this.hideShowPassword(showVal, innerToggle, options);
    };
  });

}, this));