Use group by for grouping tweets

lib/plausible/stats/stats.ex

@@ -253,10 +253,7 @@ defmodule Plausible.Stats do
       tweets = Repo.all(
         from t in Plausible.Twitter.Tweet,
         where: t.link in ^urls
-      ) |> Enum.reduce(%{}, fn tweet, acc ->
-        Map.update(acc, tweet.link, [tweet], &([tweet | &1]))
-      end)
-      |> IO.inspect
+      ) |> Enum.group_by(&(&1.link))
 
       Enum.map(referring_urls, fn url ->
         Map.put(url, :tweets, tweets[url[:name]])

test/plausible_web/controllers/api/stats_controller/referrers_test.exs

@@ -133,5 +133,21 @@ defmodule PlausibleWeb.Api.StatsController.ReferrersTest do
         "search_terms" => terms
       }
     end
+
+    test "enriches twitter referrers with tweets if available", %{conn: conn, site: site} do
+      insert(:pageview, hostname: site.domain, referrer: "t.co/some-link", referrer_source: "Twitter", timestamp: ~N[2019-01-01 01:00:00])
+      insert(:pageview, hostname: site.domain, referrer: "t.co/some-link", referrer_source: "Twitter", timestamp: ~N[2019-01-01 01:00:00])
+      insert(:pageview, hostname: site.domain, referrer: "t.co/nonexistent-link", referrer_source: "Twitter", timestamp: ~N[2019-01-01 02:00:00])
+
+      insert(:tweet, link: "t.co/some-link", text: "important tweet")
+
+      conn = get(conn, "/api/stats/#{site.domain}/referrers/Twitter?period=day&date=2019-01-01")
+
+      res = json_response(conn, 200)
+      assert res["total_visitors"] == 3
+      assert [tweet1, tweet2] = res["referrers"]
+      assert %{"name" => "t.co/some-link", "count" => 2, "tweets" => [%{"text" => "important tweet"}]} = tweet1
+      assert %{"name" => "t.co/nonexistent-link", "count" => 1, "tweets" => nil} = tweet2
+    end
   end
 end

test/support/factory.ex

@@ -79,4 +79,15 @@ defmodule Plausible.Factory do
       expires: Timex.now() |> Timex.shift(days: 1)
     }
   end
+
+  def tweet_factory do
+    %Plausible.Twitter.Tweet{
+      tweet_id: UUID.uuid4(),
+      author_handle: "author-handle",
+      author_name: "author-name",
+      author_image: "pic.twitter.com/author.png",
+      text: "tweet-text",
+      created: Timex.now()
+    }
+  end
 end