(function () {
  "use strict";

  var name = 'adPagination';

  angular.module('app.directive')
    .constant(name + 'Config', {
      maxSize: 10,
      boundaryLinks: true,
      directionLinks: true,
      firstText: '«',
      prevText: '‹',
      nextText: '›',
      lastText: '»',
      rotate: true
    })

    .directive('adPagination', ['$parse', name + 'Config', function ($parse, config) {
      return {
        restrict: 'EA',
        scope: {
          /** @type {PaginationInfo} */
          pagination: '=' + name
        },
        templateUrl: 'directive/' + name + '/' + name + '.html',
        replace: true,
        link: function (scope, element, attributes) {
          var limit = angular.isDefined(attributes.limit) ? parseInt(attributes.limit) : config.maxSize,
            boundaryLinks = config.boundaryLinks,
            directionLinks = config.directionLinks,
            firstText = config.firstText,
            prevText = config.prevText,
            nextText = config.nextText,
            lastText = config.lastText,
            rotate = config.rotate;

          var onPaginationChange = $parse(attributes[name + 'Change']);

          var noPrev = function () {
            return scope.pagination.currentPageIndex === 0;
          };
          var noNext = function () {
            return scope.pagination.currentPageIndex === scope.pagination.pageCount - 1;
          };
          var isActive = function (index) {
            return scope.pagination.currentPageIndex === index;
          };
          var render = function () {
            if (scope.pagination.currentPageIndex >= 0 && scope.pagination.currentPageIndex < scope.pagination.pageCount) {
              scope.pages = getPages();
            } else {
              scope.pages = [];
            }
          };
          var makePage = function (index, text, isActive, isDisabled) {
            return {
              index: index,
              text: text,
              active: isActive,
              disabled: isDisabled
            };
          };

          var getPages = function () {
            var pageIndex = scope.pagination.currentPageIndex;
            var pageCount = scope.pagination.pageCount;
            var pages = [];

            // Default page limits
            var startIdx = 0, endIdx = pageCount - 1;
            var isMaxSized = ( angular.isDefined(limit) && limit < pageCount );

            // recompute if limit
            if (isMaxSized) {
              if (rotate) {
                // Current page is displayed in the middle of the visible ones
                startIdx = Math.max(pageIndex - Math.floor(limit / 2), 0);
                endIdx = startIdx + limit - 1;

                // Adjust if limit is exceeded
                if (endIdx >= pageCount) {
                  endIdx = pageCount - 1;
                  startIdx = endIdx - limit;
                }
              } else {
                // Visible pages are paginated with limit
                startIdx = ((Math.ceil(pageIndex / limit) - 1) * limit) + 1;

                // Adjust last page if limit is exceeded
                endIdx = Math.min(startIdx + limit - 1, pageCount);
              }
            }

            // Add page index links
            for (var index = startIdx; index <= endIdx; index++) {
              var page = makePage(index, index + 1, isActive(index), false);
              pages.push(page);
            }

            // Add links to move between page sets
            if (isMaxSized && !rotate) {
              if (startIdx > 0) {
                var previousPageSet = makePage(startIdx - 1, '...', false, false);
                pages.unshift(previousPageSet);
              }

              if (endIdx < pageCount - 2) {
                var nextPageSet = makePage(endIdx + 1, '...', false, false);
                pages.push(nextPageSet);
              }
            }

            // Add previous & next links
            if (directionLinks) {
              // prev page
              pages.unshift(makePage(pageIndex - 1, prevText, false, noPrev()));

              // next page
              pages.push(makePage(pageIndex + 1, nextText, false, noNext()));
            }

            // Add first & last links
            if (boundaryLinks) {
              // first page
              pages.unshift(makePage(0, firstText, false, noPrev()));

              // last page
              pages.push(makePage(pageCount - 1, lastText, false, noNext()));
            }

            return pages;
          };

          scope.selectPage = function (index) {
            if (!isActive(index) && index >= 0 && index < scope.pagination.pageCount) {
              scope.pagination.currentPageIndex = index;
              onPaginationChange(scope.$parent, {index: index});
              render();
            }
          };

          scope.$watch('pagination', function () {
            render();
          });

        }
      };
    }]);

})();