feat: Show basic statistics in subreddit date view

lib/bdfr_browser/http/plug.ex

@@ -44,7 +44,8 @@ defmodule BdfrBrowser.HTTP.Plug do
 
     tpl_args = [
       subreddit: subreddit,
-      dates: subreddit_record |> Post.date_listing() |> Repo.all()
+      dates: subreddit_record |> Post.date_listing() |> Repo.all(),
+      statistics: subreddit |> Subreddit.statistics() |> Repo.all()
     ]
 
     content = render_template("subreddit", tpl_args)
@@ -94,7 +95,8 @@ defmodule BdfrBrowser.HTTP.Plug do
 
     tpl_args = [
       subreddit: subreddit_names,
-      dates: subreddit_records |> Post.date_listing() |> Repo.all()
+      dates: subreddit_records |> Post.date_listing() |> Repo.all(),
+      statistics: subreddit_names |> Subreddit.statistics() |> Repo.all()
     ]
 
     content = render_template("subreddit", tpl_args)

lib/bdfr_browser/subreddit.ex

@@ -22,4 +22,16 @@ defmodule BdfrBrowser.Subreddit do
   def names_without(hidden) do
     from(s in __MODULE__, select: s.name, where: s.name not in ^hidden, order_by: [asc: fragment("lower(?)", s.name)])
   end
+
+  def statistics(subreddit) when is_binary(subreddit), do: statistics([subreddit])
+
+  def statistics(subreddits) when is_list(subreddits) do
+    from(s in __MODULE__,
+      join: p in assoc(s, :posts),
+      left_join: c in assoc(p, :comments),
+      select: {s.name, count(p.id), count(c.id)},
+      where: s.name in ^subreddits,
+      group_by: [s.name]
+    )
+  end
 end

priv/templates/http/subreddit.eex

@@ -49,4 +49,12 @@
       <% end %>
     <% end %>
   </div>
+
+  <div class="d-grid gap-2 col-12 mx-auto">
+    <p class="text-secondary">
+      <%= for {name, post_count, comment_count} <- statistics do %>
+        <%= name %>: <%= post_count %> Posts; <%= comment_count %> Comments<br />
+      <% end %>
+    </p>
+  </div>
 </div>