[Metadata] Fix actors not sanitizing their description and refactor

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/metadata/utils.ex

@@ -9,28 +9,63 @@ defmodule Mobilizon.Service.Metadata.Utils do
 
   @slice_limit 200
 
-  @spec stringify_tags(Enum.t()) :: String.t()
+  @doc """
+  Converts list of tags, containing either `t:Phoenix.HTML.safe/0` or strings, to a concatenated string listing the tags
+  """
+  @spec stringify_tags(list(Phoenix.HTML.safe() | String.t())) :: String.t()
   def stringify_tags(tags), do: Enum.reduce(tags, "", &stringify_tag/2)
 
-  defp stringify_tag(tag, acc) when is_tuple(tag), do: acc <> HTML.safe_to_string(tag)
-  defp stringify_tag(tag, acc) when is_binary(tag), do: acc <> tag
-
+  @doc """
+  Removes the HTML tags from a text
+  """
   @spec strip_tags(String.t()) :: String.t()
-  def strip_tags(text), do: HTMLFormatter.strip_tags(text)
+  def strip_tags(text), do: HTMLFormatter.strip_tags_and_insert_spaces(text)
 
+  @doc """
+  Processes a text and limits it.
+
+  * Removes the HTML tags from a text
+  * Slices it to a limit and add an ellipsis character
+  * Returns a default description if text is empty
+  """
   @spec process_description(String.t(), String.t(), integer()) :: String.t()
   def process_description(description, locale \\ "en", limit \\ @slice_limit)
   def process_description(nil, locale, limit), do: process_description("", locale, limit)
 
   def process_description("", locale, _limit) do
-    Gettext.put_locale(locale)
-    gettext("The event organizer didn't add any description.")
+    default_description(locale)
   end
 
   def process_description(description, _locale, limit) do
     description
-    |> HTMLFormatter.strip_tags()
-    |> String.slice(0..limit)
-    |> (&"#{&1}…").()
+    |> HTMLFormatter.strip_tags_and_insert_spaces()
+    |> String.trim()
+    |> maybe_slice(limit)
   end
+
+  @doc """
+  Returns the default description for a text
+  """
+  @spec default_description(String.t()) :: String.t()
+  def default_description(locale \\ "en") do
+    Gettext.put_locale(locale)
+    gettext("The event organizer didn't add any description.")
+  end
+
+  defp maybe_slice(description, limit) do
+    if String.length(description) > limit do
+      description
+      |> String.slice(0..limit)
+      |> String.trim()
+      |> (&"#{&1}…").()
+    else
+      description
+    end
+  end
+
+  @spec stringify_tag(Phoenix.HTML.safe(), String.t()) :: String.t()
+  defp stringify_tag(tag, acc) when is_tuple(tag), do: acc <> HTML.safe_to_string(tag)
+
+  @spec stringify_tag(String.t(), String.t()) :: String.t()
+  defp stringify_tag(tag, acc) when is_binary(tag), do: acc <> tag
 end