Refactor to support case when on first page and only one total pages

lib/scrivener/html/seo.ex

@@ -43,18 +43,21 @@ defmodule Scrivener.HTML.SEO do
       iex> Phoenix.HTML.safe_to_string(Scrivener.HTML.SEO.header_links(%Scrivener.Page{total_pages: 10, page_number: 3}))
       "<link href=\"?page=2\" rel=\"prev\"></link>\n<link href=\"?page=4\" rel=\"next\"></link>"
   """
-  def header_links(conn, %Page{page_number: 1} = paginator, args, opts) do
-    next_header_link(conn, paginator, args, opts)
-  end
-
-  def header_links(conn, %Page{total_pages: page, page_number: page} = paginator, args, opts) do
-    prev_header_link(conn, paginator, args, opts)
-  end
-
-  def header_links(conn, paginator, args, opts) do
-    {:safe, prev} = prev_header_link(conn, paginator, args, opts)
-    {:safe, next} = next_header_link(conn, paginator, args, opts)
-    {:safe, [prev, "\n", next]}
+  def header_links(
+        conn,
+        %Page{total_pages: total_pages, page_number: page_number} = paginator,
+        args,
+        opts
+      ) do
+    prev = if page_number > 1, do: prev_header_link(conn, paginator, args, opts)
+    next = if total_pages > page_number, do: next_header_link(conn, paginator, args, opts)
+
+    if prev && next do
+      [{:safe, prev}, {:safe, next}] = [prev, next]
+      {:safe, [prev, "\n", next]}
+    else
+      prev || next
+    end
   end
 
   def header_links(%Scrivener.Page{} = paginator), do: header_links(nil, paginator, [], [])

test/scrivener/html/seo_test.exs

@@ -27,7 +27,11 @@ defmodule Scrivener.HTML.SEOTest do
   end
 
   describe "#header_links" do
-    test "on the first page" do
+    test "on the first page with only one total pages" do
+      refute header_links(%Page{total_pages: 1, page_number: 1})
+    end
+
+    test "on the first page with more than one total pages" do
       assert header_links(%Page{total_pages: 10, page_number: 1}) ==
                {:safe,
                 [