defmodule Merger do
  def child_spec(opts) do
    %{
      id: __MODULE__,
      start: {__MODULE__, :start_link, [opts]},
      type: :supervisor,
      restart: :temporary,
      shutdown: 500
    }
  end
  def start_link(opts) do
    Supervisor.start_link(__MODULE__, :ok, opts)
  end
  def init(:ok) do
    File.cd(Application.fetch_env!(:webgen, :root))
    [merg | file] = String.split(File.read!("./gen-conf"), "\n")
    Enum.each(file, fn i ->
      if String.at(i, 0) != "#" do
        docomp(i, merg)
      end
    end)
    Supervisor.init([], [strategy: :one_for_one])
  end
  def docomp(file, merg) do
    [title, content] = String.split(File.read!(file), "\n", parts: 2)
    first = String.replace(String.replace(content, ~r/\n.*/s, "", global: false), ~r/<.*?>/, "")
    file = String.replace(file, ~r/blogindex$/, "")
    url = String.replace(String.replace(file, ~r/^index\//, ""), ~r/^inde?x$/, "");
    File.write([file, ".html"], String.replace(
      String.replace(
        String.replace(
          String.replace(merg, "$file", url),
          "$first", first),
        "$title", title),
      "$content", String.replace(
        String.replace(content, "\n\n", "</p><p>"), "\n", "<br/>"
      )
    ))
  end
end