Preserve space-saved data on same-size upserts

Protect encoded savings calculations by preserving the current size when an existing video already has original_size and an incoming upsert reports the same file size. This keeps sync and webhook upserts from disturbing actual space-saved metrics unless the file size really changes.

Also add regression coverage for encoded videos and same-size updates.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mjc

lib/reencodarr/media/video_upsert.ex

@@ -216,13 +216,34 @@ defmodule Reencodarr.Media.VideoUpsert do
     # These are set by the encoding pipeline and must never be reset by sync.
     base = [:id, :inserted_at, :state, :failed, :chosen_vmaf_id, :original_size]
 
+    base =
+      if preserve_saved_space_size?(attrs) do
+        [:size | base]
+      else
+        base
+      end
+
     if Map.has_key?(attrs, "bitrate") do
       base
     else
       [:bitrate | base]
     end
   end
 
+  defp preserve_saved_space_size?(%{"path" => path, "size" => new_size})
+       when is_binary(path) and is_integer(new_size) do
+    case Repo.one(
+           from v in Video,
+             where: v.path == ^path and not is_nil(v.original_size),
+             select: %{size: v.size}
+         ) do
+      %{size: ^new_size} -> true
+      _ -> false
+    end
+  end
+
+  defp preserve_saved_space_size?(_), do: false
+
   @spec build_on_conflict_query(%{String.t() => any()}, [atom()]) ::
           {:replace_all_except, [atom()]} | Ecto.Query.t()
   defp build_on_conflict_query(attrs, conflict_except) do

test/reencodarr/media/video_upsert_test.exs

@@ -497,11 +497,49 @@ defmodule Reencodarr.Media.VideoUpsertTest do
       {:ok, video} = VideoUpsert.upsert(attrs)
       assert video.state == :encoded
 
+      video =
+        video
+        |> Ecto.Changeset.change(%{original_size: 1_500_000})
+        |> Repo.update!()
+
       # Should not query for metadata comparison when encoded
       updated_attrs = Map.merge(attrs, %{"size" => 2_000_000})
       {:ok, updated_video} = VideoUpsert.upsert(updated_attrs)
 
       assert updated_video.id == video.id
+      assert updated_video.size == 2_000_000
+      assert updated_video.original_size == 1_500_000
+    end
+
+    test "preserves encoded size data on same-size upserts", %{library: library} do
+      attrs = %{
+        "path" => "/mnt/test/show/episode.mkv",
+        "size" => 1_000_000,
+        "duration" => 3600.0,
+        "bitrate" => 8_000_000,
+        "width" => 1920,
+        "height" => 1080,
+        "video_codecs" => ["av1"],
+        "audio_codecs" => ["opus"],
+        "library_id" => library.id,
+        "state" => "encoded",
+        "service_id" => "file-1"
+      }
+
+      {:ok, video} = VideoUpsert.upsert(attrs)
+
+      video =
+        video
+        |> Ecto.Changeset.change(%{original_size: 1_500_000})
+        |> Repo.update!()
+
+      updated_attrs = Map.merge(attrs, %{"service_id" => "file-2"})
+      {:ok, updated_video} = VideoUpsert.upsert(updated_attrs)
+
+      assert updated_video.id == video.id
+      assert updated_video.size == 1_000_000
+      assert updated_video.original_size == 1_500_000
+      assert updated_video.service_id == "file-2"
     end
 
     test "handles update when video is in failed state", %{library: library} do