Adds API to return a random record from the collection

lib/music_library/collection.ex

@@ -50,6 +50,17 @@ defmodule MusicLibrary.Collection do
     Repo.one!(q)
   end
 
+  def get_random_record! do
+    q =
+      from r in Record,
+        where: not is_nil(r.purchased_at),
+        order_by: fragment("RANDOM()"),
+        limit: 1,
+        select: ^Records.essential_fields()
+
+    Repo.one!(q)
+  end
+
   def collected_releases(release_ids) do
     q =
       from r in fragment("records, json_each(records.release_ids)"),

lib/music_library_web/controllers/collection_controller.ex

@@ -8,4 +8,10 @@ defmodule MusicLibraryWeb.CollectionController do
 
     render(conn, :show, record: latest_record)
   end
+
+  def random(conn, _params) do
+    random_record = Collection.get_random_record!()
+
+    render(conn, :show, record: random_record)
+  end
 end

lib/music_library_web/router.ex

@@ -58,6 +58,7 @@ defmodule MusicLibraryWeb.Router do
     pipe_through :api
 
     get "/collection/latest", CollectionController, :latest
+    get "/collection/random", CollectionController, :random
     get "/covers/:record_id", CoverController, :show
   end