Merge branch 'bugfix/import-deletions' into develop

Author: JeremyCaney

OnTopic.Editor.AspNetCore/Controllers/EditorController.cs

@@ -4,6 +4,7 @@
 | Project       Topics Library
 \=============================================================================================================================*/
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
@@ -23,6 +24,7 @@
 using OnTopic.Internal.Diagnostics;
 using OnTopic.Mapping;
 using OnTopic.Metadata;
+using OnTopic.Querying;
 using OnTopic.Repositories;
 
 namespace OnTopic.Editor.AspNetCore.Controllers {
@@ -694,6 +696,11 @@ public async Task<IActionResult> Import(IFormFile jsonFile, [Bind(Prefix = "Impo
         return View(editorViewModel);
       }
 
+      /*------------------------------------------------------------------------------------------------------------------------
+      | INDEX TOPICS IN SCOPE
+      \-----------------------------------------------------------------------------------------------------------------------*/
+      var topics                = target.FindAll(t => t.Id >= 0).ToList();
+
       /*------------------------------------------------------------------------------------------------------------------------
       | IMPORT INTO TOPIC GRAPH
       >-------------------------------------------------------------------------------------------------------------------------
@@ -704,6 +711,20 @@ public async Task<IActionResult> Import(IFormFile jsonFile, [Bind(Prefix = "Impo
       target.Import(topicData, options);
       target.Import(topicData, options);
 
+      /*------------------------------------------------------------------------------------------------------------------------
+      | DELETE UNMATCHED TOPICS
+      >-------------------------------------------------------------------------------------------------------------------------
+      | ### HACK JJC20200327: The Data Transfer library doesnt have access to the ITopicRepository, so it can't delete topics.
+      | Instead, it removes them from the topic graph. But the ITopicRepository implementations don't have a means of detecting
+      | removed topics during a recursive save and, therefore, the deletions aren't persited to the database. To mitigate this,
+      | we evaluate the topic graph after the save, and then delete any orphans.
+      \-----------------------------------------------------------------------------------------------------------------------*/
+      var unmatchedTopics       = topics.Except(target.FindAll(t => t.Id >= 0));
+
+      foreach (var unmatchedTopic in unmatchedTopics) {
+        TopicRepository.Delete(unmatchedTopic);
+      }
+
       /*------------------------------------------------------------------------------------------------------------------------
       | SAVE
       >-------------------------------------------------------------------------------------------------------------------------