CombinedEnumAndIndex

Shared/Models/FilePath.cs

@@ -1,3 +1,4 @@
+using System.Collections.ObjectModel;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using View_by_Distance.Shared.Models.Stateless.Methods;
@@ -83,6 +84,33 @@ public record FilePath(long CreationTicks,
         return result;
     }
 
+    public static ReadOnlyDictionary<int, ReadOnlyCollection<FilePath>> GetKeyValuePairs(ReadOnlyCollection<ReadOnlyCollection<FilePath>> filePathsCollection)
+    {
+        Dictionary<int, ReadOnlyCollection<FilePath>> results = [];
+        List<FilePath>? collection;
+        Dictionary<int, List<FilePath>> keyValuePairs = [];
+        foreach (ReadOnlyCollection<FilePath> filePaths in filePathsCollection)
+        {
+            if (filePaths.Count == 0)
+                continue;
+            foreach (FilePath filePath in filePaths)
+            {
+                if (filePath.Id is null)
+                    continue;
+                if (!keyValuePairs.TryGetValue(filePath.Id.Value, out collection))
+                {
+                    keyValuePairs.Add(filePath.Id.Value, []);
+                    if (!keyValuePairs.TryGetValue(filePath.Id.Value, out collection))
+                        throw new Exception();
+                }
+                collection.Add(filePath);
+            }
+        }
+        foreach (KeyValuePair<int, List<FilePath>> keyValuePair in keyValuePairs)
+            results.Add(keyValuePair.Key, new(keyValuePair.Value));
+        return results.AsReadOnly();
+    }
+
 }
 
 [JsonSourceGenerationOptions(WriteIndented = true)]