define([
  'require',
  'jquery',
  './defaults',
  './utils'
], function (require, $, Defaults, Utils) {
  function Options (options, $element) {
    this.options = options;

    if ($element != null) {
      this.fromElement($element);
    }

    this.options = Defaults.apply(this.options);

    if ($element && $element.is('input')) {
      var InputCompat = require(this.get('amdBase') + 'compat/inputData');

      this.options.dataAdapter = Utils.Decorate(
        this.options.dataAdapter,
        InputCompat
      );
    }
  }

  Options.prototype.fromElement = function ($e) {
    var excludedData = ['select2'];

    if (this.options.multiple == null) {
      this.options.multiple = $e.prop('multiple');
    }

    if (this.options.disabled == null) {
      this.options.disabled = $e.prop('disabled');
    }

    if (this.options.language == null) {
      if ($e.prop('lang')) {
        this.options.language = $e.prop('lang').toLowerCase();
      } else if ($e.closest('[lang]').prop('lang')) {
        this.options.language = $e.closest('[lang]').prop('lang');
      }
    }

    if (this.options.dir == null) {
      if ($e.prop('dir')) {
        this.options.dir = $e.prop('dir');
      } else if ($e.closest('[dir]').prop('dir')) {
        this.options.dir = $e.closest('[dir]').prop('dir');
      } else {
        this.options.dir = 'ltr';
      }
    }

    $e.prop('disabled', this.options.disabled);
    $e.prop('multiple', this.options.multiple);

    if (Utils.GetData($e[0], 'select2Tags')) {
      if (this.options.debug && window.console && console.warn) {
        console.warn(
          'Select2: The `data-select2-tags` attribute has been changed to ' +
          'use the `data-data` and `data-tags="true"` attributes and will be ' +
          'removed in future versions of Select2.'
        );
      }

      Utils.StoreData($e[0], 'data', Utils.GetData($e[0], 'select2Tags'));
      Utils.StoreData($e[0], 'tags', true);
    }

    if (Utils.GetData($e[0], 'ajaxUrl')) {
      if (this.options.debug && window.console && console.warn) {
        console.warn(
          'Select2: The `data-ajax-url` attribute has been changed to ' +
          '`data-ajax--url` and support for the old attribute will be removed' +
          ' in future versions of Select2.'
        );
      }

      $e.attr('ajax--url', Utils.GetData($e[0], 'ajaxUrl'));
      Utils.StoreData($e[0], 'ajax-Url', Utils.GetData($e[0], 'ajaxUrl'));
    }

    var dataset = {};

    function upperCaseLetter(_, letter) {
      return letter.toUpperCase();
    }

    // Pre-load all of the attributes which are prefixed with `data-`
    for (var attr = 0; attr < $e[0].attributes.length; attr++) {
      var attributeName = $e[0].attributes[attr].name;
      var prefix = 'data-';

      if (attributeName.substr(0, prefix.length) == prefix) {
        // Get the contents of the attribute after `data-`
        var dataName = attributeName.substring(prefix.length);

        // Get the data contents from the consistent source
        // This is more than likely the jQuery data helper
        var dataValue = Utils.GetData($e[0], dataName);

        // camelCase the attribute name to match the spec
        var camelDataName = dataName.replace(/-([a-z])/g, upperCaseLetter);

        // Store the data attribute contents into the dataset since
        dataset[camelDataName] = dataValue;
      }
    }

    // Prefer the element's `dataset` attribute if it exists
    // jQuery 1.x does not correctly handle data attributes with multiple dashes
    if ($.fn.jquery && $.fn.jquery.substr(0, 2) == '1.' && $e[0].dataset) {
      dataset = $.extend(true, {}, $e[0].dataset, dataset);
    }

    // Prefer our internal data cache if it exists
    var data = $.extend(true, {}, Utils.GetData($e[0]), dataset);

    data = Utils._convertData(data);

    for (var key in data) {
      if ($.inArray(key, excludedData) > -1) {
        continue;
      }

      if ($.isPlainObject(this.options[key])) {
        $.extend(this.options[key], data[key]);
      } else {
        this.options[key] = data[key];
      }
    }

    return this;
  };

  Options.prototype.get = function (key) {
    return this.options[key];
  };

  Options.prototype.set = function (key, val) {
    this.options[key] = val;
  };

  return Options;
});
