defmodule Mix.Tasks.GenerateOpenNebulaRecords do
  use Mix.Task

  @moduledoc """
  Generate erlang records from OpenNebula's XSD templates. Inspired from
  http://codesinger.blogspot.com/2015/12/elixir-erlang-records-and-erlsom-xml.html
  """

  @opennebula_release "5.12"

  @shortdoc "Generate erlang records from OpenNebula's XSD templates"
  def run(_) do
    priv_dir = to_string(:code.priv_dir(:meta))
    xsd_dir = Path.join([priv_dir, "opennebula", @opennebula_release, "xsd-src"])
    hrl_dir = Path.join([priv_dir, "opennebula", @opennebula_release, "xsd-records"])

    files = xsd_dir
            |> File.ls!()
            |> Enum.filter(fn filename -> String.ends_with?(filename, ".xsd") end)
            |> Enum.sort()

    # Delete existing hrl headers.
    if File.exists?(hrl_dir) do
      File.rm_rf!(hrl_dir)
    end
    File.mkdir_p(hrl_dir)

    for xsd_filename <- files do
      hrl_filename = String.replace_trailing(xsd_filename, ".xsd", ".hrl")

      xsd_file = Path.join([xsd_dir, xsd_filename]) |> String.to_charlist
      hrl_file = Path.join([hrl_dir, hrl_filename]) |> String.to_charlist

      IO.write "> Processing #{xsd_filename}... "
      try do
        :erlsom.write_xsd_hrl_file(xsd_file, hrl_file, [])
        IO.puts "OK"
      catch
        e -> IO.puts "Error: #{inspect(e)}"
      end
    end
  end
end