defmodule ReleaseManager.Plugin.Conform do
  @name "conform"
  @shortdoc "Generates a .conf for your release"
  @moduledoc """
  Generates a .conf for your release

  This plugin ensures that your application has a .schema.exs
  and .conf file for setting up configuration via the `conform`
  library. This .conf file then offers a simplified interface
  for sysadmins and other deployment staff for easily configuring
  your release in production.
  """

  use   ReleaseManager.Plugin
  alias ReleaseManager.Config
  alias ReleaseManager.Utils

  def before_release(%Config{name: app, version: version}) do
    relx_conf_path = Utils.rel_file_dest_path("relx.config")
    conf_src       = Path.join([File.cwd!, "config", "#{app}.conf"])

    debug "Conform: Loading schema..."
    schema_src = Conform.Schema.schema_path(app)
    if File.exists?(schema_src) do
      # Define overlays for relx.config
      overlays = [{:copy, '#{schema_src}', 'releases/#{version}/#{app}.schema.exs'}]
      # generate archive
      result = Mix.Task.run("conform.archive", ["#{schema_src}"])
      # add archive to the overlays
      overlays = case result do
        {_, _, []} ->
          {:ok, cwd} = File.cwd
          arch = "#{cwd}/rel/releases/#{version}/#{app}.schema.ez"
          case File.exists?(arch) do
            true  -> File.rm(arch)
            false -> :ok
          end
          overlays
        {_, zip_path, _} ->
          [{:copy, '#{zip_path}', 'releases/#{version}/#{app}.schema.ez'}|overlays]
      end

      overlays = case File.exists?(conf_src) do
        true ->
          [{:copy, '#{conf_src}', 'releases/#{version}/#{app}.conf'}|overlays]
        false ->
          overlays
      end

      # Generate escript for release
      debug "Conform: Generating escript.."
      escript_path = Mix.Task.run("conform.release")
      overlays = [{:copy, '#{escript_path}', 'releases/#{version}/conform'}|overlays]

      # Add .conf, .schema.exs, and escript to relx.config as overlays
      debug "Conform: Adding overlays to relx.config..."
      relx_config = relx_conf_path |> Utils.read_terms
      updated = Utils.merge(relx_config, [overlay: overlays])

      # Persist relx.config
      Utils.write_terms(relx_conf_path, updated)

      debug "Conform: Done!"
    end
  end

  def after_release(_), do: nil
  def after_package(_), do: nil
  def after_cleanup(_), do: nil

end