(function (factory) {
  /* global define */
  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else {
    // Browser globals: jQuery
    factory(window.jQuery);
  }
}(function ($) {
  var range = $.summernote.core.range;
  var list = $.summernote.core.list;

  var KEY = {
    UP: 38,
    DOWN: 40,
    ENTER: 13
  };

  var DROPDOWN_KEYCODES = [38, 40, 13];

  /**
   * @class plugin.hint
   * 
   * Hello Plugin  
   */
  $.summernote.addPlugin({
    /** @property {String} name name of plugin */
    name: 'hint',

    /**
     * @param {jQuery} $node
     */
    scrollTo: function ($node) {
      var $parent = $node.parent();
      $parent[0].scrollTop = $node[0].offsetTop - ($parent.innerHeight() / 2);
    },

    /**
     * @param {jQuery} $popover
     */
    moveDown: function ($popover) {
      var index = $popover.find('.active').index();
      this.activate($popover, (index === -1) ? 0 : (index + 1) % $popover.children().length);
    },

    /**
     * @param {jQuery} $popover
     */
    moveUp: function ($popover) {
      var index = $popover.find('.active').index();
      this.activate($popover, (index === -1) ? 0 : (index - 1) % $popover.children().length);
    },

    /**
     * @param {jQuery} $popover
     * @param {Number} i
     */
    activate: function ($popover, idx) {
      idx = idx || 0;

      if (idx < 0) {
        idx = $popover.children().length - 1;
      }

      $popover.children().removeClass('active');
      var $activeItem = $popover.children().eq(idx);
      $activeItem.addClass('active');

      this.scrollTo($activeItem);
    },

    /**
     * @param {jQuery} $popover
     */
    replace: function ($popover) {
      var wordRange = $popover.data('wordRange');
      var $activeItem = $popover.find('.active');
      var content = this.content($activeItem.html(), $activeItem.data('keyword'));

      if (typeof content === 'string') {
        content = document.createTextNode(content);
      }

      $popover.removeData('wordRange');

      wordRange.insertNode(content);
      range.createFromNode(content).collapse().select();
    },

    /**
     * @param {String} keyword
     * @return {Object|null}
     */
    searchKeyword: function (keyword) {
      var triggerChar = keyword.charAt(0);

      if (triggerChar === ':' && keyword.length > 1) {
        var trigger = keyword.toLowerCase().replace(':', '');
        return {
          type: 'emoji',
          list: $.grep(this.emojiKeys, function (item) {
            return item.indexOf(trigger) === 0;
          })
        };
      }

      return null;
    },

    /**
     * create items
     *
     * @param {Object} searchResult
     * @param {String} searchResult.type
     * @param {String[]} searchResult.list
     * @return {jQuery[]}
     */
    createItems: function (searchResult) {
      var items = [];
      var list = searchResult.list;

      for (var i = 0, len = list.length; i < len; i++) {
        var $item = $('<a class="list-group-item"></a>');
        $item.append(this.createItem(list[i]));
        $item.data('keyword', list[i]);
        items.push($item);
      }

      if (items.length) {
        items[0].addClass('active');
      }

      return items;
    },

    /**
     * create list item template
     *
     * @param {Object} item
     * @returns {String}
     */
    createItem: function (item) {
      var content = this.emojiInfo[item];
      return '<img src="' + content + '" width="20" /> :' + item + ':';
    },

    /**
     * create inserted content to add in summernote
     *
     * @param {String} html
     * @param {String} keyword
     * @return {Node|String}
     */
    content: function (html, item) {
      var url = this.emojiInfo[item];

      if (url) {
        var $img = $('<img />').attr('src', url).css({
          width : 20
        });
        return $img[0];
      }

      return html;
    },

    /**
     * @return {Promise}
     */
    loadEmojis: function () {
      var self = this;
      return $.getJSON('https://api.github.com/emojis').then(function (data) {
        self.emojiKeys = Object.keys(data);
        self.emojiInfo = data;
      });
    },

    init: function (layoutInfo) {
      var self = this;

      var $note = layoutInfo.holder();
      var $popover = $('<div class="list-group" />').css({
        position: 'absolute',
        'max-height': 300,
        'overflow-y': 'scroll',
        'display': 'none'
      });

      // FIXME We need a handler for unload resources.
      $popover.on('click', '.list-group-item', function () {
        self.replace($popover);

        $popover.hide();
        $note.summernote('focus');
      });

      $(document).on('click', function () {
        $popover.hide();
      });

      $note.on('summernote.keydown', function (customEvent, nativeEvent) {
        if ($popover.css('display') !== 'block') {
          return;
        }

        if (nativeEvent.keyCode === KEY.DOWN) {
          nativeEvent.preventDefault();
          self.moveDown($popover);
        } else if (nativeEvent.keyCode === KEY.UP) {
          nativeEvent.preventDefault();
          self.moveUp($popover);
        } else if (nativeEvent.keyCode === KEY.ENTER) {
          nativeEvent.preventDefault();
          self.replace($popover);

          $popover.hide();
          $note.summernote('focus');
        }
      });

      $note.on('summernote.keyup', function (customEvent, nativeEvent) {
        if (DROPDOWN_KEYCODES.indexOf(nativeEvent.keyCode) === -1) {
          var wordRange = $(this).summernote('createRange').getWordRange();
          var result = self.searchKeyword(wordRange.toString());
          if (!result || !result.list.length) {
            $popover.hide();
            return;
          }

          layoutInfo.popover().append($popover);

          var rect = list.last(wordRange.getClientRects());
          $popover.html(self.createItems(result)).css({
            left: rect.left,
            top: rect.top + rect.height
          }).data('wordRange', wordRange).show();
        }
      });

      this.loadEmojis();
    },

    // FIXME Summernote doesn't support event pipeline yet.
    //  - Plugin -> Base Code
    events: {
      ENTER: function () {
        // prevent ENTER key
        return false;
      }
    }
  });
}));