ng.module('smart-table')
  .directive('stPagination', ['stConfig', function (stConfig) {
    return {
      restrict: 'EA',
      require: '^stTable',
      scope: {
        stItemsByPage: '=?',
        stDisplayedPages: '=?',
        stPageChange: '&'
      },
      templateUrl: function (element, attrs) {
        if (attrs.stTemplate) {
          return attrs.stTemplate;
        }
        return stConfig.pagination.template;
      },
      link: function (scope, element, attrs, ctrl) {

        scope.stItemsByPage = scope.stItemsByPage ? +(scope.stItemsByPage) : stConfig.pagination.itemsByPage;
        scope.stDisplayedPages = scope.stDisplayedPages ? +(scope.stDisplayedPages) : stConfig.pagination.displayedPages;

        scope.currentPage = 1;
        scope.pages = [];

        function redraw () {
          var paginationState = ctrl.tableState().pagination;
          var start = 1;
          var end;
          var i;
          var prevPage = scope.currentPage;
          scope.totalItemCount = paginationState.totalItemCount;
          scope.currentPage = Math.floor(paginationState.start / paginationState.number) + 1;

          start = Math.max(start, scope.currentPage - Math.abs(Math.floor(scope.stDisplayedPages / 2)));
          end = start + scope.stDisplayedPages;

          if (end > paginationState.numberOfPages) {
            end = paginationState.numberOfPages + 1;
            start = Math.max(1, end - scope.stDisplayedPages);
          }

          scope.pages = [];
          scope.numPages = paginationState.numberOfPages;

          for (i = start; i < end; i++) {
            scope.pages.push(i);
          }

          if (prevPage !== scope.currentPage) {
            scope.stPageChange({newPage: scope.currentPage});
          }
        }

        //table state --> view
        scope.$watch(function () {
          return ctrl.tableState().pagination;
        }, redraw, true);

        //scope --> table state  (--> view)
        scope.$watch('stItemsByPage', function (newValue, oldValue) {
          if (newValue !== oldValue) {
            scope.selectPage(1);
          }
        });

        scope.$watch('stDisplayedPages', redraw);

        //view -> table state
        scope.selectPage = function (page) {
          if (page > 0 && page <= scope.numPages) {
            ctrl.slice((page - 1) * scope.stItemsByPage, scope.stItemsByPage);
          }
        };

        if (!ctrl.tableState().pagination.number) {
          ctrl.slice(0, scope.stItemsByPage);
        }
      }
    };
  }]);