module.exports.register = function(backgrid) {
    backgrid.SonarrHeaderCell = backgrid.HeaderCell.extend({
        events                  : {
            'click' : 'onClick'
        },
        _originalInit           : backgrid.HeaderCell.prototype.initialize,
        initialize              : function(options){
            this._originalInit.call(this, options);
            this.listenTo(this.collection, 'drone:sort', this.render);
        },
        render                  : function(){
            this.$el.empty();
            this.$el.append(this.column.get('label'));
            var column = this.column;
            var sortable = backgrid.callByNeed(column.sortable(), column, this.collection);
            if(sortable) {
                this.$el.addClass('sortable');
                this.$el.append(' <i class="pull-right"></i>');
            }
            this.$el.addClass(column.get('name'));
            if(column.has('className')) {
                this.$el.addClass(column.get('className'));
            }
            this.delegateEvents();
            this.direction(column.get('direction'));
            if(this.collection.state) {
                var name = this._getSortMapping().name;
                var order = this.collection.state.order;
                if(name === column.get('name')) {
                    this._setSortIcon(order);
                }
                else {
                    this._removeSortIcon();
                }
            }
            return this;
        },
        direction               : function(dir){
            this.$el.children('i').removeClass('icon-sort-up icon-sort-down');
            if(arguments.length) {
                if(dir) {
                    this._setSortIcon(dir);
                }
                this.column.set('direction', dir);
            }
            var columnDirection = this.column.get('direction');
            if(!columnDirection && this.collection.state) {
                var name = this._getSortMapping().name;
                var order = this.collection.state.order;
                if(name === this.column.get('name')) {
                    columnDirection = order;
                }
            }
            return columnDirection;
        },
        _getSortMapping         : function(){
            var sortKey = this.collection.state.sortKey;
            if(this.collection._getSortMapping) {
                return this.collection._getSortMapping(sortKey);
            }
            return {
                name    : sortKey,
                sortKey : sortKey
            };
        },
        onClick                 : function(e){
            e.preventDefault();
            var collection = this.collection;
            var event = 'backgrid:sort';
            var column = this.column;
            var sortable = backgrid.callByNeed(column.sortable(), column, collection);
            if(sortable) {
                var direction = collection.state.order;
                if(direction === 'ascending' || direction === -1) {
                    direction = 'descending';
                }
                else {
                    direction = 'ascending';
                }
                if(collection.setSorting) {
                    collection.setSorting(column.get('name'), direction);
                }
                else {
                    collection.state.sortKey = column.get('name');
                    collection.state.order = direction;
                }
                collection.trigger(event, column, direction);
            }
        },
        _resetCellDirection     : function(columnToSort, direction){
            if(columnToSort !== this.column) {
                this.direction(null);
            }
            else {
                this.direction(direction);
            }
        },
        _convertDirectionToIcon : function(dir){
            if(dir === 'ascending' || dir === -1) {
                return 'icon-sort-up';
            }
            return 'icon-sort-down';
        },
        _setSortIcon            : function(dir){
            this._removeSortIcon();
            this.$el.children('i').addClass(this._convertDirectionToIcon(dir));
        },
        _removeSortIcon         : function(){
            this.$el.children('i').removeClass('icon-sort-up icon-sort-down');
        }
    });
};