app.constant('paginationConfig', {
  boundaryLinks: false,
  directionLinks: true,
  firstText: 'First',
  previousText: 'Previous',
  nextText: 'Next',
  lastText: 'Last'
})

.directive('pagination', ['paginationConfig', function(paginationConfig) {
  return {
    restrict: 'EA',
    scope: {
      numPages: '=',
      currentPage: '=',
      maxSize: '=',
      onSelectPage: '&'
    },
    templateUrl: 'js/directives/pagination.html',
    replace: true,
    link: function(scope, element, attrs) {

      // Setup configuration parameters
      var boundaryLinks = angular.isDefined(attrs.boundaryLinks) ? scope.$eval(attrs.boundaryLinks) : paginationConfig.boundaryLinks;
      var directionLinks = angular.isDefined(attrs.directionLinks) ? scope.$eval(attrs.directionLinks) : paginationConfig.directionLinks;
      var firstText = angular.isDefined(attrs.firstText) ? attrs.firstText : paginationConfig.firstText;
      var previousText = angular.isDefined(attrs.previousText) ? attrs.previousText : paginationConfig.previousText;
      var nextText = angular.isDefined(attrs.nextText) ? attrs.nextText : paginationConfig.nextText;
      var lastText = angular.isDefined(attrs.lastText) ? attrs.lastText : paginationConfig.lastText;

      // Create page object used in template
      function makePage(number, text, isActive, isDisabled) {
        return {
          number: number,
          text: text,
          active: isActive,
          disabled: isDisabled
        };
      }

      scope.$watch('numPages + currentPage + maxSize', function() {
        scope.pages = [];
        
        //set the default maxSize to numPages
        var maxSize = ( scope.maxSize && scope.maxSize < scope.numPages ) ? scope.maxSize : scope.numPages;
        var startPage = scope.currentPage - Math.floor(maxSize/2);
        
        //adjust the startPage within boundary
        if(startPage < 1) {
            startPage = 1;
        }
        if ((startPage + maxSize - 1) > scope.numPages) {
            startPage = startPage - ((startPage + maxSize - 1) - scope.numPages );
        }

        // Add page number links
        for (var number = startPage, max = startPage + maxSize; number < max; number++) {
          var page = makePage(number, number, scope.isActive(number), false);
          scope.pages.push(page);
        }

        // Add previous & next links
        if (directionLinks) {
          var previousPage = makePage(scope.currentPage - 1, previousText, false, scope.noPrevious());
          scope.pages.unshift(previousPage);

          var nextPage = makePage(scope.currentPage + 1, nextText, false, scope.noNext());
          scope.pages.push(nextPage);
        }

        // Add first & last links
        if (boundaryLinks) {
          var firstPage = makePage(1, firstText, false, scope.noPrevious());
          scope.pages.unshift(firstPage);

          var lastPage = makePage(scope.numPages, lastText, false, scope.noNext());
          scope.pages.push(lastPage);
        }


        if ( scope.currentPage > scope.numPages ) {
          scope.selectPage(scope.numPages);
        }
      });
      scope.noPrevious = function() {
        return scope.currentPage === 1;
      };
      scope.noNext = function() {
        return scope.currentPage === scope.numPages;
      };
      scope.isActive = function(page) {
        return scope.currentPage === page;
      };

      scope.selectPage = function(page) {
        if ( ! scope.isActive(page) && page > 0 && page <= scope.numPages) {
          scope.currentPage = page;
          scope.onSelectPage({ page: page });
        }
      };
    }
  };
}]);