1 files changed, 98 insertions, 70 deletions

diff --git a/lib/plugins/link/html.ex b/lib/plugins/link/html.ex
index a941aac..5899ed5 100644
--- a/lib/plugins/link/html.ex
+++ b/lib/plugins/link/html.ex
@@ -5,102 +5,130 @@ defmodule Nola.Plugins.Link.HTML do
   def match(_, _), do: false
 
   @impl true
-  def post_match(_url, "text/html"<>_, _header, _opts) do
-    {:body, nil}
-  end
+  def post_match(_url, "text/html" <> _, _header, _opts), do: {:body, nil}
   def post_match(_, _, _, _), do: false
 
   @impl true
   def post_expand(url, body, _params, _opts) do
     html = Floki.parse(body)
-    title = collect_title(html)
     opengraph = collect_open_graph(html)
-    itemprops = collect_itemprops(html)
-    text = if Map.has_key?(opengraph, "title") && Map.has_key?(opengraph, "description") do
-      sitename = if sn = Map.get(opengraph, "site_name") do
-        "#{sn}"
-      else
-        ""
-      end
-      paywall? = if Map.get(opengraph, "article:content_tier", Map.get(itemprops, "article:content_tier", "free")) == "free" do
-        ""
-      else
-        "[paywall] "
-      end
-      section = if section = Map.get(opengraph, "article:section", Map.get(itemprops, "article:section", nil)) do
-        ": #{section}"
-      else
-        ""
-      end
-      date = case DateTime.from_iso8601(Map.get(opengraph, "article:published_time", Map.get(itemprops, "article:published_time", ""))) do
-        {:ok, date, _} ->
-          "#{Timex.format!(date, "%d/%m/%y", :strftime)}. "
-        _ ->
-          ""
-      end
-      uri = URI.parse(url)
-
-      prefix = "#{paywall?}#{Map.get(opengraph, "site_name", uri.host)}#{section}"
-      prefix = unless prefix == "" do
-        "#{prefix} — "
-      else
-          ""
-      end
-      [clean_text("#{prefix}#{Map.get(opengraph, "title")}")] ++ Nola.Irc.Message.splitlong(clean_text("#{date}#{Map.get(opengraph, "description")}"))
+
+    text = if has_sufficient_opengraph_data?(opengraph) do
+      generate_text_from_opengraph(url, html, opengraph)
     else
-      clean_text(title)
+      clean_text(collect_title(html))
     end
+
     {:ok, text}
   end
 
+  defp has_sufficient_opengraph_data?(opengraph) do
+    Map.has_key?(opengraph, "title") && Map.has_key?(opengraph, "description")
+  end
+
+  defp generate_text_from_opengraph(url, html, opengraph) do
+    itemprops = collect_itemprops(html)
+    prefix = collect_prefix_and_site_name(url, opengraph, itemprops)
+    description = collect_description(opengraph, itemprops, 500)
+
+    [clean_text("#{prefix}#{Map.get(opengraph, "title")}")] ++ description
+  end
+
   defp collect_title(html) do
     case Floki.find(html, "title") do
-    [{"title", [], [title]} | _] ->
-      String.trim(title)
-    _ ->
-      nil
+      [{"title", [], [title]} | _] -> String.trim(title)
+      _ -> ""
     end
   end
 
   defp collect_open_graph(html) do
-    Enum.reduce(Floki.find(html, "head meta"), %{}, fn(tag, acc) ->
-      case tag do
-        {"meta", values, []} ->
-          name = List.keyfind(values, "property", 0, {nil, nil}) |> elem(1)
-          content = List.keyfind(values, "content", 0, {nil, nil}) |> elem(1)
-          case name do
-           "og:" <> key ->
-              Map.put(acc, key, content)
-            "article:"<>_ ->
-              Map.put(acc, name, content)
-            _other -> acc
-          end
-        _other -> acc
-      end
-    end)
+    Floki.find(html, "head meta")
+    |> Enum.reduce(%{}, &extract_meta_tag/2)
   end
 
+  defp extract_meta_tag({"meta", values, []}, acc) do
+    with {_, name} <- List.keyfind(values, "property", 0, {nil, nil}),
+         {_, content} <- List.keyfind(values, "content", 0, {nil, nil}),
+         true <- is_valid_meta_tag?(name) do
+      Map.put(acc, strip_prefix(name), content)
+    else
+      _ -> acc
+    end
+  end
+  defp extract_meta_tag(_, acc), do: acc
+
+  defp is_valid_meta_tag?(name) do
+    String.starts_with?(name, "og:") || String.starts_with?(name, "article:")
+  end
+
+  defp is_valid_meta_tag?(nil) do
+    false
+  end
+
+  defp strip_prefix("og:" <> key), do: key
+  defp strip_prefix(other), do: other
+
   defp collect_itemprops(html) do
-    Enum.reduce(Floki.find(html, "[itemprop]"), %{}, fn(tag, acc) ->
-      case tag do
-        {"meta", values, []} ->
-          name = List.keyfind(values, "itemprop", 0, {nil, nil}) |> elem(1)
-          content = List.keyfind(values, "content", 0, {nil, nil}) |> elem(1)
-          case name do
-           "article:" <> key ->
-              Map.put(acc, name, content)
-            _other -> acc
-          end
-        _other -> acc
-      end
-    end)
+    Floki.find(html, "[itemprop]")
+    |> Enum.reduce(%{}, &extract_itemprop/2)
   end
 
+  defp extract_itemprop({"meta", values, []}, acc) do
+    with {_, name} <- List.keyfind(values, "itemprop", 0, {nil, nil}),
+         {_, content} <- List.keyfind(values, "content", 0, {nil, nil}),
+         true <- String.starts_with?(name, "article:") do
+      Map.put(acc, name, content)
+    else
+      _ -> acc
+    end
+  end
+  defp extract_itemprop(_, acc), do: acc
+
+  defp collect_prefix_and_site_name(url, opengraph, itemprops) do
+    uri = URI.parse(url)
+    site_name = Map.get(opengraph, "site_name", uri.host)
+    paywall_status = get_paywall_status(opengraph, itemprops)
+    section = get_section(opengraph, itemprops)
+
+    prefix = "#{paywall_status}#{site_name}#{section}"
+    if prefix == "", do: "", else: "#{prefix} — "
+  end
+
+  defp get_paywall_status(opengraph, itemprops) do
+    content_tier = Map.get(opengraph, "article:content_tier", Map.get(itemprops, "article:content_tier", "free"))
+    if content_tier == "free", do: "", else: "[paywall] "
+  end
+
+  defp get_section(opengraph, itemprops) do
+    section = Map.get(opengraph, "article:section", Map.get(itemprops, "article:section"))
+    if section, do: ": #{section}", else: ""
+  end
+
+  defp collect_description(opengraph, itemprops, max_length) do
+    date = get_formatted_date(opengraph, itemprops)
+    description = transform_description(Map.get(opengraph, "description"), max_length)
+
+    Nola.Irc.Message.splitlong(clean_text("#{date}#{description}"))
+  end
+
+  defp get_formatted_date(opengraph, itemprops) do
+    published_time = Map.get(opengraph, "article:published_time", Map.get(itemprops, "article:published_time", ""))
+    case DateTime.from_iso8601(published_time) do
+      {:ok, date, _} -> "#{Timex.format!(date, "%d/%m/%y", :strftime)}. "
+      _ -> ""
+    end
+  end
+
+  # TODO: Swap with AI description instead of truncating.
+  defp transform_description(string, length) when is_binary(string) do
+    if String.length(string) >= length, do: String.truncate(string, length), else: string
+  end
+  defp transform_description(nil, _), do: nil
+
   defp clean_text(text) do
     text
     |> String.replace("\n", " ")
     |> HtmlEntities.decode()
   end
 
-
 end