From 227365b0765a6cc704ea6f1ecadb633fe4b63240 Mon Sep 17 00:00:00 2001
From: Luca Zaninotto <luca.zaninotto@secomind.com>
Date: Fri, 10 Jan 2025 11:04:07 +0100
Subject: [PATCH] feat!(pagination): paginate `existing_device_tags`

Part of #779
Paginates the `existing_device_tags` query with relay

Signed-off-by: Luca Zaninotto <luca.zaninotto@secomind.com>
---
 backend/lib/edgehog/labeling/labeling.ex      |  6 ++--
 backend/lib/edgehog/labeling/tag.ex           | 11 ++++++-
 .../query/existing_device_tags_test.exs       | 33 +++++++++++++++----
 3 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/backend/lib/edgehog/labeling/labeling.ex b/backend/lib/edgehog/labeling/labeling.ex
index 6c867e8ce..99e6f7578 100644
--- a/backend/lib/edgehog/labeling/labeling.ex
+++ b/backend/lib/edgehog/labeling/labeling.ex
@@ -1,7 +1,7 @@
 #
 # This file is part of Edgehog.
 #
-# Copyright 2022-2024 SECO Mind Srl
+# Copyright 2022 - 2025 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -32,7 +32,9 @@ defmodule Edgehog.Labeling do
 
     queries do
       list Tag, :existing_device_tags, :read_assigned_to_devices do
-        paginate_with nil
+        description "Returns the list of device tags associated to some device group."
+        relay? true
+        paginate_with :keyset
       end
     end
   end
diff --git a/backend/lib/edgehog/labeling/tag.ex b/backend/lib/edgehog/labeling/tag.ex
index f18cb8b8c..cb3ce542c 100644
--- a/backend/lib/edgehog/labeling/tag.ex
+++ b/backend/lib/edgehog/labeling/tag.ex
@@ -1,7 +1,7 @@
 #
 # This file is part of Edgehog.
 #
-# Copyright 2022 SECO Mind Srl
+# Copyright 2022 - 2025 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -36,6 +36,8 @@ defmodule Edgehog.Labeling.Tag do
 
   graphql do
     type :tag
+
+    paginate_relationship_with device_tags: :relay
   end
 
   actions do
@@ -52,6 +54,13 @@ defmodule Edgehog.Labeling.Tag do
     read :read_assigned_to_devices do
       description "Returns Tags currently assigned to some device."
       prepare build(filter: expr(exists(device_tags, true)))
+
+      pagination do
+        required? false
+        offset? true
+        keyset? true
+        countable true
+      end
     end
   end
 
diff --git a/backend/test/edgehog_web/schema/query/existing_device_tags_test.exs b/backend/test/edgehog_web/schema/query/existing_device_tags_test.exs
index e4f8a4ecc..0c82e4a58 100644
--- a/backend/test/edgehog_web/schema/query/existing_device_tags_test.exs
+++ b/backend/test/edgehog_web/schema/query/existing_device_tags_test.exs
@@ -1,7 +1,7 @@
 #
 # This file is part of Edgehog.
 #
-# Copyright 2022 SECO Mind Srl
+# Copyright 2022 - 2025 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -34,7 +34,12 @@ defmodule EdgehogWeb.Schema.Query.ExistingDeviceTagsTest do
       |> Ash.Changeset.for_update(:add_tags, tags: ["foo", "bar"])
       |> Ash.update!()
 
-      assert tags = [tenant: tenant] |> existing_device_tags_query() |> extract_result!()
+      assert tags =
+               [tenant: tenant]
+               |> existing_device_tags_query()
+               |> extract_result!()
+               |> extract_nodes!()
+
       assert length(tags) == 2
       tag_names = Enum.map(tags, &Map.fetch!(&1, "name"))
       assert "foo" in tag_names
@@ -50,7 +55,10 @@ defmodule EdgehogWeb.Schema.Query.ExistingDeviceTagsTest do
       |> Ash.update!()
 
       assert [%{"name" => "bar"}] ==
-               [tenant: tenant] |> existing_device_tags_query() |> extract_result!()
+               [tenant: tenant]
+               |> existing_device_tags_query()
+               |> extract_result!()
+               |> extract_nodes!()
     end
 
     test "does not return duplicates if a tag is assigned multiple times", %{tenant: tenant} do
@@ -64,7 +72,12 @@ defmodule EdgehogWeb.Schema.Query.ExistingDeviceTagsTest do
       |> Ash.Changeset.for_update(:add_tags, tags: ["foo", "baz"])
       |> Ash.update!()
 
-      assert tags = [tenant: tenant] |> existing_device_tags_query() |> extract_result!()
+      assert tags =
+               [tenant: tenant]
+               |> existing_device_tags_query()
+               |> extract_result!()
+               |> extract_nodes!()
+
       assert length(tags) == 3
       tag_names = Enum.map(tags, &Map.fetch!(&1, "name"))
       assert "foo" in tag_names
@@ -77,7 +90,11 @@ defmodule EdgehogWeb.Schema.Query.ExistingDeviceTagsTest do
     document = """
     query {
       existingDeviceTags {
-        name
+        edges {
+          node {
+            name
+          }
+        }
       }
     }
     """
@@ -89,9 +106,13 @@ defmodule EdgehogWeb.Schema.Query.ExistingDeviceTagsTest do
 
   defp extract_result!(result) do
     refute :errors in Map.keys(result)
-    assert %{data: %{"existingDeviceTags" => tags}} = result
+    assert %{data: %{"existingDeviceTags" => %{"edges" => tags}}} = result
     assert tags != nil
 
     tags
   end
+
+  defp extract_nodes!(result) do
+    Enum.map(result, &Map.fetch!(&1, "node"))
+  end
 end