defmodule Phoenix.HTML.SimplifiedHelpers.Truncate do

  def truncate(text, options \\ []) do
    len = options[:length] || 30
    omi = options[:omission] || "..."

    case String.length(text) do
      x when x < len ->
        text

      _ ->
        len_with_omi = len - String.length(omi)
        stop =
          if options[:separator] do
            rindex(text, options[:separator]) || len_with_omi
          else
            len_with_omi
          end

        "#{String.slice(text, 0, stop)}#{omi}"
    end
  end

  defp rindex(text, str) do
    {index, _} =
      text
      |> String.reverse
      |> :binary.match(str)

    String.length(text) - index - 1
  end

end