From ace33f3d06b2712e9782fae5ae048eebc2e4672b Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sat, 25 Apr 2020 15:47:22 -0400
Subject: [PATCH] Timeline pagination

---
 assets/css/clacks.scss                        |  4 +++
 .../templates/frontend/_timeline.html.eex     | 15 +++++++++++
 lib/clacks_web/views/frontend_view.ex         | 27 ++++++++++++++++---
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/assets/css/clacks.scss b/assets/css/clacks.scss
index b05774a..7756eb2 100644
--- a/assets/css/clacks.scss
+++ b/assets/css/clacks.scss
@@ -84,6 +84,10 @@ ul.status-list {
 	}
 }
 
+.pagination-link {
+	text-align: center;
+}
+
 .status {
 	padding: 0.5rem;
 	border: 1px solid #ddd;
diff --git a/lib/clacks_web/templates/frontend/_timeline.html.eex b/lib/clacks_web/templates/frontend/_timeline.html.eex
index 2ee54a8..3c38c4a 100644
--- a/lib/clacks_web/templates/frontend/_timeline.html.eex
+++ b/lib/clacks_web/templates/frontend/_timeline.html.eex
@@ -1,3 +1,10 @@
+<% newer = prev_page_path(@conn, @statuses_with_authors) %>
+<%= if newer do %>
+  <p class="pagination-link">
+    <a href="<%= newer %>">Newer</a>
+  </p>
+<% end %>
+
 <ul class="status-list">
   <%= for {status, author} <- @statuses_with_authors do %>
     <li>
@@ -5,3 +12,11 @@
     </li>
   <% end %>
 </ul>
+
+<% older = next_page_path(@conn, @statuses_with_authors) %>
+<%= if older do %>
+  <p class="pagination-link">
+    <a href="<%= older %>">Older</a>
+  </p>
+<% end %>
+
diff --git a/lib/clacks_web/views/frontend_view.ex b/lib/clacks_web/views/frontend_view.ex
index 1d5d57c..53a98af 100644
--- a/lib/clacks_web/views/frontend_view.ex
+++ b/lib/clacks_web/views/frontend_view.ex
@@ -1,6 +1,6 @@
 defmodule ClacksWeb.FrontendView do
   use ClacksWeb, :view
-  alias Clacks.Actor
+  alias Clacks.{Actor, Activity}
 
   @spec display_username(actor :: Actor.t()) :: String.t()
 
@@ -13,8 +13,6 @@ defmodule ClacksWeb.FrontendView do
     "@" <> name <> "@" <> host
   end
 
-  @absolute_timestamp_threshold 24 * 60 * 60
-
   def display_timestamp(str) when is_binary(str) do
     display_timestamp(Timex.parse!(str, "{ISO:Extended}"))
   end
@@ -43,4 +41,27 @@ defmodule ClacksWeb.FrontendView do
         Timex.format!(datetime, "%FT%T%:z", :strftime)
     end
   end
+
+  def prev_page_path(conn, activities) do
+    if Map.has_key?(conn.query_params, "max_id") do
+      Phoenix.Controller.current_path(conn, %{
+        since_id: activities |> List.first() |> activity_id()
+      })
+    else
+      nil
+    end
+  end
+
+  def next_page_path(conn, activities) do
+    if length(activities) < 20 do
+      nil
+    else
+      Phoenix.Controller.current_path(conn, %{
+        max_id: activities |> List.last() |> activity_id()
+      })
+    end
+  end
+
+  defp activity_id(%Activity{id: id}), do: id
+  defp activity_id({%Activity{id: id}, _}), do: id
 end