Adding CommentsFilter

--HG--
branch : 1.x

src/Orchard.Web/Modules/Orchard.Comments/Projections/CommentsFilter.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Linq;
+using Orchard.ContentManagement;
+using Orchard.Events;
+using Orchard.Localization;
+using Orchard.Comments.Models;
+
+namespace Orchard.Comments.Projections {
+    public interface IFilterProvider : IEventHandler {
+        void Describe(dynamic describe);
+    }
+
+    public class CommentsFilter : IFilterProvider {
+
+        public CommentsFilter() {
+            T = NullLocalizer.Instance;
+        }
+
+        public Localizer T { get; set; }
+
+        public void Describe(dynamic describe) {
+            describe.For("Comments", T("Comments"), T("Comments"))
+                .Element("HasComments", T("Has Comments"), T("Commented content items"),
+                    (Action<dynamic>)ApplyFilter,
+                    (Func<dynamic, LocalizedString>)DisplayFilter,
+                    null
+                );
+        }
+
+        public void ApplyFilter(dynamic context) {
+            var query = (IContentQuery<ContentItem>)context.Query;
+            context.Query = query.Where<CommentsPartRecord>(x => x.CommentPartRecords.Any());
+        }
+
+        public LocalizedString DisplayFilter(dynamic context) {
+            return T("Has comments");
+        }
+    }
+}