Improved the way playlist_indexes are rejected on update

lib/pinchflat/media/media.ex

@@ -142,12 +142,17 @@ defmodule Pinchflat.Media do
   """
   def create_media_item_from_backend_attrs(source, media_attrs_struct) do
     attrs = Map.merge(%{source_id: source.id}, Map.from_struct(media_attrs_struct))
+    # Some fields should only be set on insert and not on update.
+    fields_to_drop_on_update = [:playlist_index]
 
     %MediaItem{}
     |> MediaItem.changeset(attrs)
     |> Repo.insert(
       on_conflict: [
-        set: Map.to_list(attrs)
+        set:
+          attrs
+          |> Map.drop(fields_to_drop_on_update)
+          |> Map.to_list()
       ],
       conflict_target: [:source_id, :media_id]
     )

lib/pinchflat/yt_dlp/media.ex

@@ -11,8 +11,7 @@ defmodule Pinchflat.YtDlp.Media do
     :livestream,
     :short_form_content,
     :uploaded_at,
-    :duration_seconds,
-    :playlist_index
+    :duration_seconds
   ]
 
   defstruct [
@@ -109,7 +108,7 @@ defmodule Pinchflat.YtDlp.Media do
       duration_seconds: response["duration"] && round(response["duration"]),
       short_form_content: response["webpage_url"] && short_form_content?(response),
       uploaded_at: response["upload_date"] && parse_uploaded_at(response),
-      playlist_index: response["playlist_index"]
+      playlist_index: response["playlist_index"] || 0
     }
   end
 

test/pinchflat/media_test.exs

@@ -689,7 +689,24 @@ defmodule Pinchflat.MediaTest do
       assert {:ok, %MediaItem{} = media_item_2} = Media.create_media_item_from_backend_attrs(source, different_attrs)
 
       assert media_item_1.id == media_item_2.id
-      assert media_item_2.title == different_attrs.title
+      assert Repo.reload(media_item_2).title == different_attrs.title
+    end
+
+    test "doesn't update fields like playlist_index" do
+      source = source_fixture()
+
+      media_attrs =
+        media_attributes_return_fixture()
+        |> Phoenix.json_library().decode!()
+        |> Map.put("playlist_index", 1)
+        |> YtDlpMedia.response_to_struct()
+
+      different_attrs = %YtDlpMedia{media_attrs | playlist_index: 9999}
+
+      assert {:ok, %MediaItem{} = _media_item_1} = Media.create_media_item_from_backend_attrs(source, media_attrs)
+      assert {:ok, %MediaItem{} = media_item_2} = Media.create_media_item_from_backend_attrs(source, different_attrs)
+
+      assert Repo.reload(media_item_2).playlist_index == media_attrs.playlist_index
     end
   end