defmodule Mix.Tasks.Exfmt do
  @moduledoc """
  Formats Elixir source code.

      mix exfmt path/to/file.ex

  ## Command line options

    * `--stdin` - Read from STDIN instead of a file
    * `--unsafe` - Disable the semantics check that verifies
      that `exmft` has not altered the semantic meaning of
      the input file.

  """

  @shortdoc  "Format Elixir source code"
  @usage """
  USAGE:
      mix exfmt path/to/file.ex
  """

  use Mix.Task
  alias Exfmt.Cli

  @doc false
  @spec run(OptionParser.argv) :: any
  def run([]) do
    Mix.Shell.IO.error @usage
  end

  def run(argv) do
    argv
    |> Cli.run()
    |> execute_output()
  end


  def execute_output(output) do
    if output.stdout do
      IO.write output.stdout
    end
    if output.stderr do
      Mix.Shell.IO.error output.stderr
    end
    if output.exit_code && output.exit_code != 0 do
      System.halt output.exit_code
    end
  end
end