refactoring: improved readability

lib/podcast_feed/provider/archive/parser.ex

@@ -2,56 +2,66 @@ defmodule PodcastFeed.Provider.Archive.Parser do
   alias PodcastFeed.Utility.Format
 
   @extra_metadata_url "https://archive.org/download/{identifier}/metadata.json"
-  @metadata_url "http://archive.org/metadata/{identifier}"
+  @archive_metadata_url "http://archive.org/metadata/{identifier}"
   @download_url "https://archive.org/download/{identifier}/{filename}"
 
+  @extra_metadata_defaults %{
+    "link" => "",
+    "image" => %{
+      "url" => "",
+      "title" => "",
+      "link" => "",
+    },
+    "category" => "",
+    "explicit" => "",
+  }
+
   def by_identifier(identifier) do
     extra_metadata_json = fetch_extra_metadata(identifier)
-    metadata_json = fetch_metadata(identifier)
+    metadata_json = fetch_archive_metadata(identifier)
     parse(identifier, metadata_json, extra_metadata_json)
   end
 
   defp fetch_extra_metadata(identifier) do
     extra_metadata_url = Format.compile(@extra_metadata_url, identifier: identifier)
-    case :hackney.get(extra_metadata_url, [], "", [follow_redirect: true]) do
-      {:ok, 200, _headers, client_ref} ->
-        {:ok, extra_metadata_json} = :hackney.body(client_ref)
-        extra_metadata_json |> String.split("\n") |> Enum.join() |> Poison.decode!()
-    _ -> %{
-          "link" => "",
-          "image" => %{
-            "url" => "",
-            "title" => "",
-            "link" => "",
-          },
-          "category" => "",
-          "explicit" => "",
-        }
-    end
+    parse_extra_metadata_response(:hackney.get(extra_metadata_url, [], "", [follow_redirect: true]))
   end
 
-  defp fetch_metadata(identifier) do
-    metadata_url = Format.compile(@metadata_url, identifier: identifier)
+  defp parse_extra_metadata_response({:ok, 200, _headers, client_ref}) do
+    {:ok, extra_metadata_json} = :hackney.body(client_ref)
+    extra_metadata_json
+    |> String.split("\n")
+    |> Enum.join()
+    |> Poison.decode!()
+  end
+  defp parse_extra_metadata_response(_), do: @extra_metadata_defaults
+
+  defp fetch_archive_metadata(identifier) do
+    metadata_url = Format.compile(@archive_metadata_url, identifier: identifier)
     {:ok, 200, _headers, client_ref} = :hackney.get(metadata_url, [], "", [follow_redirect: true, connect_timeout: 30000, recv_timeout: 30000])
     {:ok, metadata_json} = :hackney.body(client_ref)
     metadata_json |> Poison.decode!()
   end
 
   def parse(identifier, %{"metadata" => metadata, "files" => files}, extra) do
-    # cover = files |> fetch_cover(identifier)
+    extra = files
+    |> fetch_cover(identifier)
+    |> enrich_extra_metadata_with_cover(extra)
+
     %{podcast: podcast_data(metadata, extra), items: items_data(files, identifier)}
   end
 
-  defp fetch_cover(files, identifier) do
-    filename = files
-    |> Enum.filter(fn f -> f["source"] == "original" end)
-    |> Enum.filter(fn f -> f["format"] == "JPEG" end) #FIXME:! jpg, png, gif
-    |> List.first()
-    |> Map.get("name")
+  # cover is nil
+  defp enrich_extra_metadata_with_cover(nil, extra), do: extra
 
-    Format.compile(@download_url, identifier: identifier, filename: filename) |> URI.encode()
+  # cover is found and image is missing in the extra_metadata
+  defp enrich_extra_metadata_with_cover(cover, extra = %{"image" => %{"url" => ""}}) do
+    put_in(extra, ["image", "url"], cover)
   end
 
+  # image is already set in the extra_metadata
+  defp enrich_extra_metadata_with_cover(_cover, extra), do: extra
+
   defp podcast_data(metadata, extra) do
     %{
       title: metadata["title"],
@@ -104,6 +114,19 @@ defmodule PodcastFeed.Provider.Archive.Parser do
     }
   end
 
+  defp fetch_cover(files, identifier) do
+    filename = files
+    |> Enum.filter(fn f -> f["source"] == "original" end)
+    |> Enum.filter(fn f -> f["format"] == "JPEG" end) #FIXME:! jpg, png, gif
+    |> List.first()
+    |> case do
+      nil -> nil
+      file -> Map.get(file, "name")
+    end
+
+    download_url(identifier, filename)
+  end
+
   defp fetch_image_of_audio(audio_file, files) do
     files
     |> Enum.filter(fn