defmodule Rapport.PageNumbering do
  defstruct add_page_numbers: nil, page_number_position: nil, page_number_formatter: nil

  alias Rapport.Report

  @doc """
  Adds page numbers to the pages

  It expects the page position to be an atom and must be `:bottom_right`, `:bottom_left`, `:top_right` or `:top_left`,
  otherwise `ArgumentError` will be raised.

  ## Options

    * `report` - The `Rapport.Report` that you want set the padding for
    * `page_number_position` - Where the page number will be positioned.
  """
  def add_page_numbers(%Report{} = report, page_number_position \\ :bottom_right, formatter \\ fn(cnt_page, _) -> "#{cnt_page}" end)
  when is_atom(page_number_position) do
    Rapport.validate_list(page_number_position, [:bottom_right, :bottom_left, :top_right, :top_left], "Invalid page number position")

    opts =
      report.page_number_opts
      |> Map.put(:add_page_numbers, true)
      |> Map.put(:page_number_position, page_number_position)
      |> Map.put(:page_number_formatter, formatter)

    Map.put(report, :page_number_opts, opts)
  end

end