Merge branch 'develop' into 'develop'

Draft: feat: replies collection views for object

See merge request pleroma/pleroma!4322

lib/pleroma/web/activity_pub/views/object_view.ex

@@ -37,4 +37,52 @@ defmodule Pleroma.Web.ActivityPub.ObjectView do
 
     Map.merge(base, additional)
   end
+
+  def render("replies.json", %{object: object, page: page} = opts) do
+    query = Object.replies(object)
+    query = from(object in query, select: [:ap_id])
+    replies = Repo.all(query)
+
+    total = length(replies)
+
+    collection(replies, "#{object.ap_id}/replies", page, true, total)
+    |> Map.merge(Utils.make_json_ld_header())
+  end
+
+  def render("replies.json", %{object: object} = opts) do
+    query = Object.replies(object)
+    query = from(object in query, select: [:ap_id])
+    replies = Repo.all(query)
+
+    total = length(replies)
+
+    %{
+      "id" => "#{object.ap_id}/replies",
+      "type" => "OrderedCollection",
+      "totalItems" => total,
+      "first" => collection(replies, "#{object.ap_id}/replies", 1, true)
+    }
+    |> Map.merge(Utils.make_json_ld_header())
+  end
+
+  def collection(collection, iri, page, show_items \\ true, total \\ nil) do
+    offset = (page - 1) * 10
+    items = Enum.slice(collection, offset, 10)
+    items = Enum.map(items, fn item -> item.ap_id end)
+    total = total || length(collection)
+
+    map = %{
+      "id" => "#{iri}?page=#{page}",
+      "type" => "OrderedCollectionPage",
+      "partOf" => iri,
+      "totalItems" => total,
+      "orderedItems" => if(show_items, do: items, else: [])
+    }
+
+    if offset < total do
+      Map.put(map, "next", "#{iri}?page=#{page + 1}")
+    else
+      map
+    end
+  end
 end