Merge pull request #54 from PandaTechAM/development

ColumnDistinctValue null handling extended

Author: HaikAsatryan

src/GridifyExtensions/Extensions/QueryableExtensions.cs

@@ -105,7 +105,7 @@ public static async Task<PagedResponse<TDto>> FilterOrderAndGetPagedAsync<TEntit
                        .Select(selectExpression)
                        .ApplyPaging(model.Page, model.PageSize)
                        .ToListAsync(cancellationToken);
-      
+
       return new PagedResponse<TDto>(data, model.Page, model.PageSize, totalCount);
    }
 
@@ -184,7 +184,8 @@ public static async Task<PagedResponse<object>> ColumnDistinctValuesAsync<TEntit
       return new PagedResponse<object>([decrypted], 1, 1, 1);
    }
 
-   public static async Task<CursoredResponse<object>> ColumnDistinctValuesAsync<TEntity>(this IQueryable<TEntity> query,
+   public static async Task<CursoredResponse<object?>> ColumnDistinctValuesAsync<TEntity>(
+      this IQueryable<TEntity> query,
       ColumnDistinctValueCursoredQueryModel model,
       Func<byte[], string>? decryptor = default,
       CancellationToken cancellationToken = default)
@@ -195,32 +196,79 @@ public static async Task<CursoredResponse<object>> ColumnDistinctValuesAsync<TEn
 
       if (!mapper.IsEncrypted(model.PropertyName))
       {
-         var result = await query
-                            .ApplyFiltering(gridifyModel, mapper)
-                            .ApplySelect(model.PropertyName, mapper)
+         var baseQuery = query
+                         .ApplyFiltering(gridifyModel, mapper)
+                         .ApplySelect(model.PropertyName, mapper);
+
+         var filterEmpty = string.IsNullOrWhiteSpace(gridifyModel.Filter);
+         var hasNull = false;
+         var take = model.PageSize;
+
+         if (filterEmpty)
+         {
+            // ReSharper disable once ConditionIsAlwaysTrueOrFalseAccordingToNullableAPIContract
+            hasNull = await baseQuery.AnyAsync(x => x == null, cancellationToken);
+            if (hasNull && take > 0)
+            {
+               take -= 1;
+            }
+         }
+
+         var result = await baseQuery
                             .Distinct()
                             .OrderBy(x => x)
-                            .Take(model.PageSize)
+                            .Take(take)
                             .ToListAsync(cancellationToken);
 
-         return new CursoredResponse<object>(result, model.PageSize);
+         if (!filterEmpty || !hasNull)
+         {
+            return new CursoredResponse<object?>(result!, model.PageSize);
+         }
+
+         if (result.Count > 0 && ReferenceEquals(result[^1], null))
+         {
+            result.RemoveAt(result.Count - 1);
+         }
+
+         result.Insert(0, null!);
+         return new CursoredResponse<object?>(result!, model.PageSize);
       }
 
-      var item = await query
-                       .ApplyFiltering(gridifyModel, mapper)
-                       .Select(CreateSelector<TEntity>(model.PropertyName))
-                       .FirstOrDefaultAsync(cancellationToken);
+      // Encrypted (byte[]) path:
+      var encryptedQuery = query
+                           .ApplyFiltering(gridifyModel, mapper)
+                           .Select(CreateSelector<TEntity>(model.PropertyName));
 
-      if (item is null || string.IsNullOrEmpty(model.Filter))
-         return new CursoredResponse<object>([], model.PageSize);
+      if (string.IsNullOrWhiteSpace(model.Filter))
+      {
+         // ReSharper disable once ConditionIsAlwaysTrueOrFalseAccordingToNullableAPIContract
+         var hasNull = await encryptedQuery.AnyAsync(x => x == null, cancellationToken);
+
+         if (hasNull)
+            return new CursoredResponse<object?>([null],
+               model.PageSize);
+
+         return new CursoredResponse<object?>([], model.PageSize);
+      }
+
+      var item = await encryptedQuery.FirstOrDefaultAsync(cancellationToken);
+      if (item is null)
+      {
+         return new CursoredResponse<object?>([], model.PageSize);
+      }
 
       if (decryptor is null)
       {
          throw new KeyNotFoundException("Decryptor is required for encrypted properties.");
       }
 
-      var decrypted = decryptor((byte[])item);
-      return new CursoredResponse<object>([decrypted], model.PageSize);
+      if (item is not byte[] bytes)
+      {
+         throw new InvalidCastException("Encrypted selector did not return a byte[] value.");
+      }
+
+      var decrypted = decryptor(bytes);
+      return new CursoredResponse<object?>([decrypted], model.PageSize);
    }
 
    // ---------- Aggregation ----------

src/GridifyExtensions/GridifyExtensions.csproj

@@ -8,13 +8,13 @@
         <PackageReadmeFile>Readme.md</PackageReadmeFile>
         <Authors>Pandatech</Authors>
         <Copyright>MIT</Copyright>
-        <Version>2.1.1</Version>
+        <Version>2.1.2</Version>
         <PackageId>Pandatech.GridifyExtensions</PackageId>
         <Title>Pandatech.Gridify.Extensions</Title>
         <PackageTags>Pandatech, library, Gridify, Pagination, Filters</PackageTags>
         <Description>Pandatech.Gridify.Extensions simplifies and extends the functionality of the Gridify NuGet package. It provides additional extension methods and functionality to streamline data filtering and pagination, making it more intuitive and powerful to use in .NET applications. Our enhancements ensure more flexibility, reduce boilerplate code, and improve overall developer productivity when working with Gridify.</Description>
         <RepositoryUrl>https://github.com/PandaTechAM/be-lib-gridify-extensions</RepositoryUrl>
-        <PackageReleaseNotes>TotalCount bug fix on edge cases</PackageReleaseNotes>
+        <PackageReleaseNotes>ColumnDistinctValue null handling extended</PackageReleaseNotes>
     </PropertyGroup>
 
     <ItemGroup>