define([
  'jquery',

  './results',

  './selection/single',
  './selection/multiple',
  './selection/placeholder',
  './selection/allowClear',
  './selection/search',
  './selection/selectionCss',
  './selection/eventRelay',

  './utils',
  './translation',
  './diacritics',

  './data/select',
  './data/array',
  './data/ajax',
  './data/tags',
  './data/tokenizer',
  './data/minimumInputLength',
  './data/maximumInputLength',
  './data/maximumSelectionLength',

  './dropdown',
  './dropdown/search',
  './dropdown/hidePlaceholder',
  './dropdown/infiniteScroll',
  './dropdown/attachBody',
  './dropdown/minimumResultsForSearch',
  './dropdown/selectOnClose',
  './dropdown/closeOnSelect',
  './dropdown/dropdownCss',
  './dropdown/tagsSearchHighlight',

  './i18n/en'
], function ($,

             ResultsList,

             SingleSelection, MultipleSelection, Placeholder, AllowClear,
             SelectionSearch, SelectionCSS, EventRelay,

             Utils, Translation, DIACRITICS,

             SelectData, ArrayData, AjaxData, Tags, Tokenizer,
             MinimumInputLength, MaximumInputLength, MaximumSelectionLength,

             Dropdown, DropdownSearch, HidePlaceholder, InfiniteScroll,
             AttachBody, MinimumResultsForSearch, SelectOnClose, CloseOnSelect,
             DropdownCSS, TagsSearchHighlight,

             EnglishTranslation) {
  function Defaults () {
    this.reset();
  }

  Defaults.prototype.apply = function (options) {
    options = $.extend(true, {}, this.defaults, options);

    if (options.dataAdapter == null) {
      if (options.ajax != null) {
        options.dataAdapter = AjaxData;
      } else if (options.data != null) {
        options.dataAdapter = ArrayData;
      } else {
        options.dataAdapter = SelectData;
      }

      if (options.minimumInputLength > 0) {
        options.dataAdapter = Utils.Decorate(
          options.dataAdapter,
          MinimumInputLength
        );
      }

      if (options.maximumInputLength > 0) {
        options.dataAdapter = Utils.Decorate(
          options.dataAdapter,
          MaximumInputLength
        );
      }

      if (options.maximumSelectionLength > 0) {
        options.dataAdapter = Utils.Decorate(
          options.dataAdapter,
          MaximumSelectionLength
        );
      }

      if (options.tags) {
        options.dataAdapter = Utils.Decorate(options.dataAdapter, Tags);
      }

      if (options.tokenSeparators != null || options.tokenizer != null) {
        options.dataAdapter = Utils.Decorate(
          options.dataAdapter,
          Tokenizer
        );
      }
    }

    if (options.resultsAdapter == null) {
      options.resultsAdapter = ResultsList;

      if (options.ajax != null) {
        options.resultsAdapter = Utils.Decorate(
          options.resultsAdapter,
          InfiniteScroll
        );
      }

      if (options.placeholder != null) {
        options.resultsAdapter = Utils.Decorate(
          options.resultsAdapter,
          HidePlaceholder
        );
      }

      if (options.selectOnClose) {
        options.resultsAdapter = Utils.Decorate(
          options.resultsAdapter,
          SelectOnClose
        );
      }

      if (options.tags) {
        options.resultsAdapter = Utils.Decorate(
          options.resultsAdapter,
          TagsSearchHighlight
        );
      }
    }

    if (options.dropdownAdapter == null) {
      if (options.multiple) {
        options.dropdownAdapter = Dropdown;
      } else {
        var SearchableDropdown = Utils.Decorate(Dropdown, DropdownSearch);

        options.dropdownAdapter = SearchableDropdown;
      }

      if (options.minimumResultsForSearch !== 0) {
        options.dropdownAdapter = Utils.Decorate(
          options.dropdownAdapter,
          MinimumResultsForSearch
        );
      }

      if (options.closeOnSelect) {
        options.dropdownAdapter = Utils.Decorate(
          options.dropdownAdapter,
          CloseOnSelect
        );
      }

      if (options.dropdownCssClass != null) {
        options.dropdownAdapter = Utils.Decorate(
          options.dropdownAdapter,
          DropdownCSS
        );
      }

      options.dropdownAdapter = Utils.Decorate(
        options.dropdownAdapter,
        AttachBody
      );
    }

    if (options.selectionAdapter == null) {
      if (options.multiple) {
        options.selectionAdapter = MultipleSelection;
      } else {
        options.selectionAdapter = SingleSelection;
      }

      // Add the placeholder mixin if a placeholder was specified
      if (options.placeholder != null) {
        options.selectionAdapter = Utils.Decorate(
          options.selectionAdapter,
          Placeholder
        );
      }

      if (options.allowClear) {
        options.selectionAdapter = Utils.Decorate(
          options.selectionAdapter,
          AllowClear
        );
      }

      if (options.multiple) {
        options.selectionAdapter = Utils.Decorate(
          options.selectionAdapter,
          SelectionSearch
        );
      }

      if (options.selectionCssClass != null) {
        options.selectionAdapter = Utils.Decorate(
          options.selectionAdapter,
          SelectionCSS
        );
      }

      options.selectionAdapter = Utils.Decorate(
        options.selectionAdapter,
        EventRelay
      );
    }

    // If the defaults were not previously applied from an element, it is
    // possible for the language option to have not been resolved
    options.language = this._resolveLanguage(options.language);

    // Always fall back to English since it will always be complete
    options.language.push('en');

    var uniqueLanguages = [];

    for (var l = 0; l < options.language.length; l++) {
      var language = options.language[l];

      if (uniqueLanguages.indexOf(language) === -1) {
        uniqueLanguages.push(language);
      }
    }

    options.language = uniqueLanguages;

    options.translations = this._processTranslations(
      options.language,
      options.debug
    );

    return options;
  };

  Defaults.prototype.reset = function () {
    function stripDiacritics (text) {
      // Used 'uni range + named function' from http://jsperf.com/diacritics/18
      function match(a) {
        return DIACRITICS[a] || a;
      }

      return text.replace(/[^\u0000-\u007E]/g, match);
    }

    function matcher (params, data) {
      // Always return the object if there is nothing to compare
      if (params.term == null || params.term.trim() === '') {
        return data;
      }

      // Do a recursive check for options with children
      if (data.children && data.children.length > 0) {
        // Clone the data object if there are children
        // This is required as we modify the object to remove any non-matches
        var match = $.extend(true, {}, data);

        // Check each child of the option
        for (var c = data.children.length - 1; c >= 0; c--) {
          var child = data.children[c];

          var matches = matcher(params, child);

          // If there wasn't a match, remove the object in the array
          if (matches == null) {
            match.children.splice(c, 1);
          }
        }

        // If any children matched, return the new object
        if (match.children.length > 0) {
          return match;
        }

        // If there were no matching children, check just the plain object
        return matcher(params, match);
      }

      var original = stripDiacritics(data.text).toUpperCase();
      var term = stripDiacritics(params.term).toUpperCase();

      // Check if the text contains the term
      if (original.indexOf(term) > -1) {
        return data;
      }

      // If it doesn't contain the term, don't return anything
      return null;
    }

    this.defaults = {
      amdLanguageBase: './i18n/',
      autocomplete: 'off',
      closeOnSelect: true,
      debug: false,
      dropdownAutoWidth: false,
      escapeMarkup: Utils.escapeMarkup,
      language: {},
      matcher: matcher,
      minimumInputLength: 0,
      maximumInputLength: 0,
      maximumSelectionLength: 0,
      minimumResultsForSearch: 0,
      selectOnClose: false,
      scrollAfterSelect: false,
      sorter: function (data) {
        return data;
      },
      templateResult: function (result) {
        return result.text;
      },
      templateSelection: function (selection) {
        return selection.text;
      },
      theme: 'default',
      width: 'resolve'
    };
  };

  Defaults.prototype.applyFromElement = function (options, $element) {
    var optionLanguage = options.language;
    var defaultLanguage = this.defaults.language;
    var elementLanguage = $element.prop('lang');
    var parentLanguage = $element.closest('[lang]').prop('lang');

    var languages = Array.prototype.concat.call(
      this._resolveLanguage(elementLanguage),
      this._resolveLanguage(optionLanguage),
      this._resolveLanguage(defaultLanguage),
      this._resolveLanguage(parentLanguage)
    );

    options.language = languages;

    return options;
  };

  Defaults.prototype._resolveLanguage = function (language) {
    if (!language) {
      return [];
    }

    if ($.isEmptyObject(language)) {
      return [];
    }

    if ($.isPlainObject(language)) {
      return [language];
    }

    var languages;

    if (!Array.isArray(language)) {
      languages = [language];
    } else {
      languages = language;
    }

    var resolvedLanguages = [];

    for (var l = 0; l < languages.length; l++) {
      resolvedLanguages.push(languages[l]);

      if (typeof languages[l] === 'string' && languages[l].indexOf('-') > 0) {
        // Extract the region information if it is included
        var languageParts = languages[l].split('-');
        var baseLanguage = languageParts[0];

        resolvedLanguages.push(baseLanguage);
      }
    }

    return resolvedLanguages;
  };

  Defaults.prototype._processTranslations = function (languages, debug) {
    var translations = new Translation();

    for (var l = 0; l < languages.length; l++) {
      var languageData = new Translation();

      var language = languages[l];

      if (typeof language === 'string') {
        try {
          // Try to load it with the original name
          languageData = Translation.loadPath(language);
        } catch (e) {
          try {
            // If we couldn't load it, check if it wasn't the full path
            language = this.defaults.amdLanguageBase + language;
            languageData = Translation.loadPath(language);
          } catch (ex) {
            // The translation could not be loaded at all. Sometimes this is
            // because of a configuration problem, other times this can be
            // because of how Select2 helps load all possible translation files
            if (debug && window.console && console.warn) {
              console.warn(
                'Select2: The language file for "' + language + '" could ' +
                'not be automatically loaded. A fallback will be used instead.'
              );
            }
          }
        }
      } else if ($.isPlainObject(language)) {
        languageData = new Translation(language);
      } else {
        languageData = language;
      }

      translations.extend(languageData);
    }

    return translations;
  };

  Defaults.prototype.set = function (key, value) {
    function upperCaseLetter(_, letter) {
      return letter.toUpperCase();
    }
    var camelKey = key.replace(/-([a-z])/g, upperCaseLetter);

    var data = {};
    data[camelKey] = value;

    var convertedData = Utils._convertData(data);

    $.extend(true, this.defaults, convertedData);
  };

  var defaults = new Defaults();

  return defaults;
});
