From 3dc8f4a33651e7c1b4d00a0eb17198a60dbd9cd0 Mon Sep 17 00:00:00 2001
From: Jerod Santo <jerod@changelog.com>
Date: Wed, 10 Jan 2024 08:56:37 -0600
Subject: [PATCH] Remove recommendation engine

---
 lib/changelog/application.ex                  |  6 --
 lib/changelog/schema/news/news_item.ex        | 65 ----------------
 test/changelog/schema/news/news_item_test.exs | 76 -------------------
 3 files changed, 147 deletions(-)

diff --git a/lib/changelog/application.ex b/lib/changelog/application.ex
index b22163ee78..9c2f12b3f9 100644
--- a/lib/changelog/application.ex
+++ b/lib/changelog/application.ex
@@ -17,12 +17,6 @@ defmodule Changelog.Application do
         ttl_check_interval: :timer.seconds(1),
         global_ttl: :timer.seconds(60)
       ),
-      con_cache_child_spec(
-        :news_item_recommendations,
-        ttl_check_interval: :timer.seconds(30),
-        global_ttl: :timer.minutes(5),
-        touch_on_read: false
-      ),
       Changelog.EpisodeTracker,
       Changelog.Metacasts.Filterer.Cache,
       {Oban, oban_config()}
diff --git a/lib/changelog/schema/news/news_item.ex b/lib/changelog/schema/news/news_item.ex
index 495e7bab5d..147410b96e 100644
--- a/lib/changelog/schema/news/news_item.ex
+++ b/lib/changelog/schema/news/news_item.ex
@@ -387,69 +387,4 @@ defmodule Changelog.NewsItem do
     |> Repo.all()
     |> Enum.map(&load_object/1)
   end
-
-  def recommend_podcasts(episode = %Episode{}, num_recommendations) do
-    recommendation_query = "SELECT * FROM query_related_podcast($1::integer, $2::integer)"
-    query_args = [episode.id, num_recommendations]
-
-    ConCache.fetch_or_store(
-      :news_item_recommendations,
-      {:podcast, episode.id, num_recommendations},
-      fn ->
-        query_recommendations(recommendation_query, query_args)
-      end
-    )
-  end
-
-  def recommend_news_items(news_item = %__MODULE__{}, num_recommendations) do
-    recommendation_query = "SELECT * FROM query_related_news_item($1::integer, $2::integer)"
-    query_args = [news_item.id, num_recommendations]
-
-    ConCache.fetch_or_store(
-      :news_item_recommendations,
-      {:news_item, news_item.id, num_recommendations},
-      fn ->
-        query_recommendations(recommendation_query, query_args)
-      end
-    )
-  end
-
-  def recommend_posts(news_item = %__MODULE__{}, num_recommendations) do
-    recommendation_query = "SELECT * FROM query_related_post($1::integer, $2::integer)"
-    query_args = [news_item.id, num_recommendations]
-
-    ConCache.fetch_or_store(
-      :news_item_recommendations,
-      {:post, news_item.id, num_recommendations},
-      fn ->
-        query_recommendations(recommendation_query, query_args)
-      end
-    )
-  end
-
-  defp query_recommendations(query, args) do
-    try do
-      query
-      |> Changelog.Repo.query(args)
-      |> case do
-        {:ok, %Postgrex.Result{columns: columns, rows: rows}} ->
-          results =
-            Enum.map(rows, fn row ->
-              columns
-              |> Enum.zip(row)
-              |> Map.new()
-            end)
-
-          {:ok, results}
-
-        error ->
-          Logger.warn("Failed to fetch recommended items: #{inspect(error)}")
-          {:error, error}
-      end
-    rescue
-      error ->
-        Logger.warn("Failed to fetch recommended items: #{inspect(error)}")
-        {:error, error}
-    end
-  end
 end
diff --git a/test/changelog/schema/news/news_item_test.exs b/test/changelog/schema/news/news_item_test.exs
index 8a7c6670be..2a6a338728 100644
--- a/test/changelog/schema/news/news_item_test.exs
+++ b/test/changelog/schema/news/news_item_test.exs
@@ -88,80 +88,4 @@ defmodule Changelog.NewsItemTest do
       refute Enum.member?(subscribed_ids, wilma.id)
     end
   end
-
-  describe "recommend_podcasts/2" do
-    test "should return a list of similar podcasts" do
-      podcast = insert(:podcast)
-
-      author = insert(:person, twitter_handle: "ohai")
-      t1 = insert(:topic, name: "iOS", slug: "ios", twitter_handle: "OfficialiOS")
-      t2 = insert(:topic, name: "Machine Learning", slug: "machine-learning")
-
-      e1 = insert(:episode, podcast: podcast, slug: "114", audio_bytes: 26_238_621)
-
-      i1 =
-        insert(:news_item,
-          author: author,
-          object_id: "#{podcast.id}:#{e1.id}",
-          type: :audio,
-          status: :published,
-          published_at: NaiveDateTime.utc_now()
-        )
-
-      e2 = insert(:episode, podcast: podcast, slug: "181", audio_bytes: 59_310_792)
-
-      i2 =
-        insert(:news_item,
-          author: author,
-          click_count: 10,
-          object_id: "#{podcast.id}:#{e2.id}",
-          type: :audio,
-          status: :published,
-          published_at: NaiveDateTime.utc_now()
-        )
-
-      e3 =
-        insert(:episode,
-          podcast: podcast,
-          slug: "182",
-          audio_bytes: 56_304_828,
-          reach_count: 10_000
-        )
-
-      i3 =
-        insert(:news_item,
-          author: author,
-          click_count: 50,
-          object_id: "#{podcast.id}:#{e3.id}",
-          type: :audio,
-          status: :published,
-          published_at: NaiveDateTime.utc_now()
-        )
-
-      e4 = insert(:episode, podcast: podcast, slug: "183", audio_bytes: 63_723_737)
-
-      i4 =
-        insert(:news_item,
-          author: author,
-          click_count: 100,
-          object_id: "#{podcast.id}:#{e4.id}",
-          type: :audio,
-          status: :published,
-          published_at: NaiveDateTime.utc_now()
-        )
-
-      insert(:news_item_topic, news_item: i1, topic: t1)
-      insert(:news_item_topic, news_item: i2, topic: t1)
-      insert(:news_item_topic, news_item: i3, topic: t2)
-      insert(:news_item_topic, news_item: i4, topic: t2)
-
-      i1
-      |> NewsItem.load_object()
-      |> Repo.preload([:news_item_topics, :topics])
-
-      assert {:ok, [rec1, rec2, rec3]} = NewsItem.recommend_podcasts(e1, 3)
-      assert rec1["ranking"] > rec2["ranking"]
-      assert rec2["ranking"] > rec3["ranking"]
-    end
-  end
 end