TD-4893 Delegate activities - view course delegates resulted in 500 error when course admin field applied filters got deleted

DigitalLearningSolutions.Data/DataServices/CourseDataService.cs

@@ -139,7 +139,7 @@ int EnrolOnActivitySelfAssessment(int selfAssessmentId, int candidateId, int sup
         public IEnumerable<DelegateAssessmentStatistics> GetDelegateAssessmentStatisticsAtCentre(string searchString, int centreId, string categoryName, string isActive, int? categoryId);
 
         bool IsSelfEnrollmentAllowed(int customisationId);
-        Customisation? GetCourse(int customisationId);
+        Customisation? GetCourse(int? customisationId);
     }
 
     public class CourseDataService : ICourseDataService
@@ -2024,7 +2024,7 @@ public bool IsSelfEnrollmentAllowed(int customisationId)
             return selfRegister > 0;
         }
 
-        public Customisation? GetCourse(int customisationId)
+        public Customisation? GetCourse(int? customisationId)
         {
             return connection.Query<Customisation>(
                 @"SELECT CustomisationID

DigitalLearningSolutions.Data/Helpers/FilteringHelper.cs

@@ -66,8 +66,7 @@ public static string BuildFilterValueString(string group, string propertyName, s
                 ? defaultFilterValue
                 : AddNewFilterToFilterString(existingFilterString, newFilterToAdd);
         }
-
-        public static string? GetCategoryAndTopicFilterString(
+       public static string? GetCategoryAndTopicFilterString(
             string? categoryFilterString,
             string? topicFilterString
         )
@@ -168,7 +167,33 @@ public static string GetFilterValueForRegistrationPrompt(int promptNumber, strin
                 : answer;
             return BuildFilterValueString(group, group.Split('(')[0], propertyValue);
         }
+        public  static  string? CheckIfFilterisValid(bool clearFilters, string existingFilterString, string newFilterToAdd, IEnumerable<FilterModel> availableFilters, HttpRequest request,
+       string cookieName, HttpResponse response)
+        {
+            var cookieValue = request.Cookies[cookieName];
+            if (string.IsNullOrEmpty(cookieValue) || cookieValue == EmptyFiltersCookieValue)
+            {
+                return existingFilterString;
+            }
+            var existingFilters = cookieValue.Split('╡');
+            var validFilterValues = availableFilters
+                .SelectMany(filter => filter.FilterOptions)
+                .Select(option => option.FilterValue)
+                .ToHashSet();
+
+            var filteredResults = existingFilters
+        .Where(entry => IsFilterInvalid(entry, validFilterValues))
+        .ToList();
+            var newCookieValue = string.Join("╡", filteredResults);
+            if (string.IsNullOrEmpty(newCookieValue)) return null;
+            return AddNewFilterToFilterString(newCookieValue, newFilterToAdd);  
+        }
 
+        private static  bool IsFilterInvalid(string filterEntry, HashSet<string> validFilterValues)
+        {
+            if (validFilterValues.Contains(filterEntry)) return true;
+            return false;
+        }
         private static IEnumerable<FilterOptionModel> GetFilterOptionsForPromptWithOptions(Prompt prompt)
         {
             var group = GetFilterGroupForPrompt(prompt);

DigitalLearningSolutions.Web/Controllers/TrackingSystem/Delegates/ActivityDelegatesController.cs

@@ -95,8 +95,7 @@ public IActionResult Index(
 
             sortBy ??= DefaultSortByOptions.Name.PropertyName;
             sortDirection ??= GenericSortingHelper.Ascending;
-
-            existingFilterString = FilteringHelper.GetFilterString(
+                existingFilterString = FilteringHelper.GetFilterString(
                 existingFilterString,
                 newFilterToAdd,
                 clearFilters,
@@ -276,7 +275,10 @@ public IActionResult Index(
                 var activityName = isCourseDelegate
                     ? courseService.GetCourseNameAndApplication((int)customisationId).CourseName
                     : selfAssessmentService.GetSelfAssessmentNameById((int)selfAssessmentId);
-
+                if (!string.IsNullOrEmpty(existingFilterString))
+                {
+                    existingFilterString = FilteringHelper.CheckIfFilterisValid(clearFilters, existingFilterString, newFilterToAdd, availableFilters, Request, filterCookieName, Response);
+                }
                 if (isCourseDelegate)
                 {
                     var result = paginateService.Paginate(

DigitalLearningSolutions.Web/Services/CourseService.cs

@@ -134,7 +134,7 @@ int diagCompletionThreshold
         int GetNumberOfActiveCoursesAtCentreFilteredByCategory(int centreId, int? categoryId);
         public IEnumerable<Course> GetApplicationsAvailableToCentre(int centreId);
         bool IsSelfEnrollmentAllowed(int customisationId);
-        Customisation? GetCourse(int customisationId);
+        Customisation? GetCourse(int? customisationId);
     }
 
     public class CourseService : ICourseService
@@ -632,7 +632,7 @@ public bool IsSelfEnrollmentAllowed(int customisationId)
             return courseDataService.IsSelfEnrollmentAllowed(customisationId);
         }
 
-        public Customisation? GetCourse(int customisationId)
+        public Customisation? GetCourse(int? customisationId)
         {
             return courseDataService.GetCourse(customisationId);
         }