chore: refactorings of big modules

Co-authored-by: Copilot <copilot@github.com>

lib/bds/generation/pagefind.ex

@@ -0,0 +1,70 @@
+defmodule BDS.Generation.Pagefind do
+  @moduledoc false
+
+  @typedoc "An (relative_path, content) HTML output tuple."
+  @type html_output :: {String.t(), String.t()}
+
+  @typedoc "A (relative_path, content) generated file tuple."
+  @type generated_file :: {String.t(), String.t()}
+
+  @doc """
+  Build the per-language Pagefind index outputs (`pagefind/index.json`,
+  `pagefind/pagefind-ui.js`, `pagefind/pagefind-ui.css`) for every blog
+  language declared on the plan.
+  """
+  @spec build_outputs(map(), [html_output()]) :: [generated_file()]
+  def build_outputs(plan, html_outputs) do
+    plan.blog_languages
+    |> Enum.uniq()
+    |> Enum.flat_map(fn language ->
+      route_language = route_language(plan.language, language)
+      pages = pages_for_language(html_outputs, route_language)
+      prefix = if route_language in [nil, ""], do: ["pagefind"], else: [route_language, "pagefind"]
+
+      [
+        {Path.join(prefix ++ ["index.json"]), Jason.encode!(%{"language" => language, "pages" => pages})},
+        {Path.join(prefix ++ ["pagefind-ui.js"]), ui_js(language)},
+        {Path.join(prefix ++ ["pagefind-ui.css"]), ui_css()}
+      ]
+    end)
+  end
+
+  defp pages_for_language(html_outputs, route_language) do
+    html_outputs
+    |> Enum.filter(fn {relative_path, _content} ->
+      String.ends_with?(relative_path, ".html") and language_match?(relative_path, route_language)
+    end)
+    |> Enum.map(fn {relative_path, content} ->
+      %{
+        "url" => "/" <> relative_path,
+        "text" => text(content)
+      }
+    end)
+  end
+
+  defp language_match?(relative_path, nil),
+    do: not String.starts_with?(relative_path, ["de/", "fr/", "it/", "es/"])
+
+  defp language_match?(relative_path, ""), do: language_match?(relative_path, nil)
+
+  defp language_match?(relative_path, route_language),
+    do: String.starts_with?(relative_path, route_language <> "/")
+
+  defp text(content) do
+    content
+    |> String.replace(~r/<[^>]+>/, " ")
+    |> String.replace(~r/\s+/u, " ")
+    |> String.trim()
+  end
+
+  defp ui_js(language) do
+    "window.bDSPagefind = { language: #{Jason.encode!(language)} };\n"
+  end
+
+  defp ui_css do
+    ".pagefind-ui{display:block;}\n"
+  end
+
+  defp route_language(main_language, language) when main_language == language, do: nil
+  defp route_language(_main_language, language), do: language
+end