text: (function (factory) {
    /* global define */
    if (typeof define === 'function' && define.amd) {
      // AMD. Register as an anonymous module.
      define(['jquery'], factory);
    } else if (typeof module === 'object' && module.exports) {
      // Node/CommonJS
      module.exports = factory(require('jquery'));
    } else {
      // Browser globals
      factory(window.jQuery);
    }
  }(function ($) {
    $.extend($.summernote.plugins, {
      'specialchars': function (context) {
        var self = this;
        var ui = $.summernote.ui;
  
        var $editor = context.layoutInfo.editor;
        var options = context.options;
        var lang = options.langInfo;
  
        var KEY = {
          UP: 38,
          DOWN: 40,
          LEFT: 37,
          RIGHT: 39,
          ENTER: 13
        };
        var COLUMN_LENGTH = 15;
        var COLUMN_WIDTH = 35;
  
        var currentColumn, currentRow, totalColumn, totalRow = 0;
  
        // special characters data set
        var specialCharDataSet = [
          '&quot;', '&amp;', '&lt;', '&gt;', '&iexcl;', '&cent;',
          '&pound;', '&curren;', '&yen;', '&brvbar;', '&sect;',
          '&uml;', '&copy;', '&ordf;', '&laquo;', '&not;',
          '&reg;', '&macr;', '&deg;', '&plusmn;', '&sup2;',
          '&sup3;', '&acute;', '&micro;', '&para;', '&middot;',
          '&cedil;', '&sup1;', '&ordm;', '&raquo;', '&frac14;',
          '&frac12;', '&frac34;', '&iquest;', '&times;', '&divide;',
          '&fnof;', '&circ;', '&tilde;', '&ndash;', '&mdash;',
          '&lsquo;', '&rsquo;', '&sbquo;', '&ldquo;', '&rdquo;',
          '&bdquo;', '&dagger;', '&Dagger;', '&bull;', '&hellip;',
          '&permil;', '&prime;', '&Prime;', '&lsaquo;', '&rsaquo;',
          '&oline;', '&frasl;', '&euro;', '&image;', '&weierp;',
          '&real;', '&trade;', '&alefsym;', '&larr;', '&uarr;',
          '&rarr;', '&darr;', '&harr;', '&crarr;', '&lArr;',
          '&uArr;', '&rArr;', '&dArr;', '&hArr;', '&forall;',
          '&part;', '&exist;', '&empty;', '&nabla;', '&isin;',
          '&notin;', '&ni;', '&prod;', '&sum;', '&minus;',
          '&lowast;', '&radic;', '&prop;', '&infin;', '&ang;',
          '&and;', '&or;', '&cap;', '&cup;', '&int;',
          '&there4;', '&sim;', '&cong;', '&asymp;', '&ne;',
          '&equiv;', '&le;', '&ge;', '&sub;', '&sup;',
          '&nsub;', '&sube;', '&supe;', '&oplus;', '&otimes;',
          '&perp;', '&sdot;', '&lceil;', '&rceil;', '&lfloor;',
          '&rfloor;', '&loz;', '&spades;', '&clubs;', '&hearts;',
          '&diams;'
        ];
  
        context.memo('button.specialCharacter', function () {
          return ui.button({
            contents: '<i class="fa fa-font fa-flip-vertical">',
            tooltip: lang.specialChar.specialChar,
            click: function () {
              self.show();
            }
          }).render();
        });
  
        /**
         * Make Special Characters Table
         *
         * @member plugin.specialChar
         * @private
         * @return {jQuery}
         */
        this.makeSpecialCharSetTable = function () {
          var $table = $('<table/>');
          $.each(specialCharDataSet, function (idx, text) {
            var $td = $('<td/>').addClass('note-specialchar-node');
            var $tr = (idx % COLUMN_LENGTH === 0) ? $('<tr/>') : $table.find('tr').last();
  
            var $button = ui.button({
              callback : function ($node) {
                $node.html(text);
                $node.attr('title', text);
                $node.attr('data-value', encodeURIComponent(text));
                $node.css({
                  width: COLUMN_WIDTH,
                  'margin-right' : '2px',
                  'margin-bottom' : '2px'
                });
              }
            }).render();
  
            $td.append($button);
  
            $tr.append($td);
            if (idx % COLUMN_LENGTH === 0) {
              $table.append($tr);
            }
          });
  
          totalRow = $table.find('tr').length;
          totalColumn = COLUMN_LENGTH;
  
          return $table;
        };
  
        this.initialize = function () {
          var $container = options.dialogsInBody ? $(document.body) : $editor;
  
          var body = '<div class="form-group row-fluid">' + this.makeSpecialCharSetTable()[0].outerHTML + '</div>';
  
          this.$dialog = ui.dialog({
            title: lang.specialChar.select,
            body: body
          }).render().appendTo($container);
        };
  
        this.show = function () {
          var text = context.invoke('editor.getSelectedText');
          context.invoke('editor.saveRange');
          this.showSpecialCharDialog(text).then(function (selectChar) {
            context.invoke('editor.restoreRange');
  
            // build node
            var $node = $('<span></span>').html(selectChar)[0];
  
            if ($node) {
              // insert video node
              context.invoke('editor.insertNode', $node);
            }
          }).fail(function () {
            context.invoke('editor.restoreRange');
          });
        };
  
        /**
         * show image dialog
         *
         * @param {jQuery} $dialog
         * @return {Promise}
         */
        this.showSpecialCharDialog = function (text) {
          return $.Deferred(function (deferred) {
            var $specialCharDialog = self.$dialog;
            var $specialCharNode = $specialCharDialog.find('.note-specialchar-node');
            var $selectedNode = null;
            var ARROW_KEYS = [KEY.UP, KEY.DOWN, KEY.LEFT, KEY.RIGHT];
            var ENTER_KEY = KEY.ENTER;
  
            function addActiveClass($target) {
              if (!$target) {
                return;
              }
              $target.find('button').addClass('active');
              $selectedNode = $target;
            }
  
            function removeActiveClass($target) {
              $target.find('button').removeClass('active');
              $selectedNode = null;
            }
  
            // find next node
            function findNextNode(row, column) {
              var findNode = null;
              $.each($specialCharNode, function (idx, $node) {
                var findRow = Math.ceil((idx + 1) / COLUMN_LENGTH);
                var findColumn = ((idx + 1) % COLUMN_LENGTH === 0) ? COLUMN_LENGTH : (idx + 1) % COLUMN_LENGTH;
                if (findRow === row && findColumn === column) {
                  findNode = $node;
                  return false;
                }
              });
              return $(findNode);
            }
  
            function arrowKeyHandler(keyCode) {
              // left, right, up, down key
              var $nextNode;
              var lastRowColumnLength = $specialCharNode.length % totalColumn;
  
              if (KEY.LEFT === keyCode) {
  
                if (currentColumn > 1) {
                  currentColumn = currentColumn - 1;
                } else if (currentRow === 1 && currentColumn === 1) {
                  currentColumn = lastRowColumnLength;
                  currentRow = totalRow;
                } else {
                  currentColumn = totalColumn;
                  currentRow = currentRow - 1;
                }
  
              } else if (KEY.RIGHT === keyCode) {
  
                if (currentRow === totalRow && lastRowColumnLength === currentColumn) {
                  currentColumn = 1;
                  currentRow = 1;
                } else if (currentColumn < totalColumn) {
                  currentColumn = currentColumn + 1;
                } else {
                  currentColumn = 1;
                  currentRow = currentRow + 1;
                }
  
              } else if (KEY.UP === keyCode) {
                if (currentRow === 1 && lastRowColumnLength < currentColumn) {
                  currentRow = totalRow - 1;
                } else {
                  currentRow = currentRow - 1;
                }
              } else if (KEY.DOWN === keyCode) {
                currentRow = currentRow + 1;
              }
  
              if (currentRow === totalRow && currentColumn > lastRowColumnLength) {
                currentRow = 1;
              } else if (currentRow > totalRow) {
                currentRow = 1;
              } else if (currentRow < 1) {
                currentRow = totalRow;
              }
  
              $nextNode = findNextNode(currentRow, currentColumn);
  
              if ($nextNode) {
                removeActiveClass($selectedNode);
                addActiveClass($nextNode);
              }
            }
  
            function enterKeyHandler() {
              if (!$selectedNode) {
                return;
              }
  
              deferred.resolve(decodeURIComponent($selectedNode.find('button').data('value')));
              $specialCharDialog.modal('hide');
            }
  
            function keyDownEventHandler(event) {
              event.preventDefault();
              var keyCode = event.keyCode;
              if (keyCode === undefined || keyCode === null) {
                return;
              }
              // check arrowKeys match
              if (ARROW_KEYS.indexOf(keyCode) > -1) {
                if ($selectedNode === null) {
                  addActiveClass($specialCharNode.eq(0));
                  currentColumn = 1;
                  currentRow = 1;
                  return;
                }
                arrowKeyHandler(keyCode);
              } else if (keyCode === ENTER_KEY) {
                enterKeyHandler();
              }
              return false;
            }
  
            // remove class
            removeActiveClass($specialCharNode);
  
            // find selected node
            if (text) {
              for (var i = 0; i < $specialCharNode.length; i++) {
                var $checkNode = $($specialCharNode[i]);
                if ($checkNode.text() === text) {
                  addActiveClass($checkNode);
                  currentRow = Math.ceil((i + 1) / COLUMN_LENGTH);
                  currentColumn = (i + 1) % COLUMN_LENGTH;
                }
              }
            }
  
            ui.onDialogShown(self.$dialog, function () {
  
              $(document).on('keydown', keyDownEventHandler);
  
              self.$dialog.find('button').tooltip();
  
              $specialCharNode.on('click', function (event) {
                event.preventDefault();
                deferred.resolve(decodeURIComponent($(event.currentTarget).find('button').data('value')));
                ui.hideDialog(self.$dialog);
              });
  
  
            });
  
            ui.onDialogHidden(self.$dialog, function () {
              $specialCharNode.off('click');
  
              self.$dialog.find('button').tooltip('destroy');
  
              $(document).off('keydown', keyDownEventHandler);
  
              if (deferred.state() === 'pending') {
                deferred.reject();
              }
            });
  
            ui.showDialog(self.$dialog);
          });
        };
      }
    });
  }));
  