Add Facet Paging

Author: ductran95

src/JustCSharp.Database.MongoDB/Extensions/AggregateFluentExtensions.cs

@@ -4,6 +4,7 @@
 using System.Linq.Expressions;
 using JustCSharp.Data.Linq;
 using JustCSharp.Data.Requests;
+using JustCSharp.Database.MongoDB.Model;
 using MongoDB.Driver;
 
 namespace JustCSharp.Database.MongoDB.Extensions;
@@ -82,4 +83,26 @@ public static IAggregateFluent<T> PagingBy<T>(this IAggregateFluent<T> query, in
 
         return query.Skip(skip).Limit(pageSize);
     }
+    
+    public static IAggregateFluent<MongoFacetPagingResult<T>> FacetPagingBy<T>(
+        this IAggregateFluent<T> query, int page, int pageSize)
+    {
+        var skip = (page - 1) * pageSize;
+        var countPipeline = PipelineStageDefinitionBuilder.Count<T>();
+        var skipPipeline = PipelineStageDefinitionBuilder.Skip<T>(skip);
+        var limitPipeline = PipelineStageDefinitionBuilder.Limit<T>(pageSize);
+        
+        var countFacet = new AggregateFacet<T, AggregateCountResult>(
+            nameof(MongoFacetPagingResult<T>.CountResult),
+            PipelineDefinition<T, AggregateCountResult>.Create(
+                new List<IPipelineStageDefinition>{countPipeline}));
+        
+        var pagingFacet = new AggregateFacet<T, T>(
+            nameof(MongoFacetPagingResult<T>.Data),
+            PipelineDefinition<T, T>.Create(
+                new List<IPipelineStageDefinition>{skipPipeline, limitPipeline}));
+
+        return query
+            .Facet<T, MongoFacetPagingResult<T>>(countFacet, pagingFacet);
+    }
 }

src/JustCSharp.Database.MongoDB/Model/MongoFacetPagingResult.cs

@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+using System.Linq;
+using MongoDB.Bson.Serialization.Attributes;
+
+namespace JustCSharp.Database.MongoDB.Model;
+
+public class MongoFacetPagingResult<TData>
+{
+    public long Count => CountResult.FirstOrDefault()?.Count ?? 0;
+    public MongoFacetCountResult[] CountResult { get; set; }
+    public List<TData> Data { get; set; }
+}
+
+public class MongoFacetCountResult
+{
+    [BsonElement("count")]
+    public long Count { get; set; }
+}

src/JustCSharp.Database.MongoDB/Trace.cs

@@ -3,9 +3,9 @@
 
 namespace JustCSharp.Database.MongoDB;
 
-internal class Trace
+public class Trace
 {
-    private static readonly string TraceName = typeof(Trace).Namespace ?? "JustCSharp.Database.MongoDB";
+    public static readonly string TraceName = typeof(Trace).Namespace ?? "JustCSharp.Database.MongoDB";
 
     internal static ActivitySource ActivitySource { get; } =
         new(TraceName, AssemblyHelper.GetAssemblyVersion(typeof(Trace)));