defmodule Mix.Tasks.Deployment.CanDeploy do
  use Mix.Task

  @shortdoc "Indicates if the latest relase can be deployed"

  @moduledoc "
If the local release's `relup` (generated by relx)
correctly transtions from the remote version to the local version,
prints 'yes' and exits normally,
otherwise prints 'no' and exits with a non-zero exit code.
"

  def run([stage]) do
    {:ok, remote_version} = Exdm.Remote.get_version(String.to_atom(stage))
    handle_can_transition_from(Exdm.Local.can_transition_from(remote_version))
  end

  defp handle_can_transition_from({:ok}) do
    IO.puts "yes"
  end
  defp handle_can_transition_from({:error, reason}) do
    IO.puts "no"
    raise reason
  end
end