.ex

defmodule Mix.Tasks.Release do
  @shortdoc "Build and release using reltool"

  use Mix.Task

  def run([]) do
    Mix.Project.get!()

    Mix.Task.run("compile")

    target_dir = "rel"
    File.rm_rf!(target_dir)
    File.mkdir_p!(target_dir)

    {:ok, spec} = :reltool.get_target_spec(confs)
    :ok = :reltool.eval_target_spec(spec, :code.root_dir, '#{target_dir}')
  end

  defp confs do
    props = base_props ++ rels ++ boot_rels
    [{:sys, props}]
  end

  defp base_props do
    [
      {:lib_dirs, ['_build/#{Mix.env}/lib', '/usr/lib/elixir/lib']},
      {:relocatable, true},
      {:profile, :standalone},
    ]
  end

  defp rels do
    Mix.Project.config()
    |> Dict.get(:releases, [])
    |> Enum.map(fn({name, version, apps}) ->
      {:rel, '#{name}', '#{version}', apps}
    end)
  end

  defp boot_rels do
    case Mix.Project.config()[:boot_release] do
      nil -> []
      boot_release -> [{:boot_rel, '#{boot_release}'}]
    end
  end
end