exml

defmodule Exml do

  require Record
  Record.defrecord :xmlElement, Record.extract(:xmlElement, from_lib: "xmerl/include/xmerl.hrl")
  Record.defrecord :xmlAttribute, Record.extract(:xmlAttribute, from_lib: "xmerl/include/xmerl.hrl")
  Record.defrecord :xmlText, Record.extract(:xmlText, from_lib: "xmerl/include/xmerl.hrl")

  def parse(xml_string, options \\ [quiet: true, ]) when is_binary(xml_string) do
    {doc, []} = xml_string
                |> :binary.bin_to_list
                |> :xmerl_scan.string(options)
    doc
  end

  def get(node, path) do
    xpath(node,path) |> text
  end

  defp xpath(nil, _), do: nil
  defp xpath(node, path) do
    :xmerl_xpath.string(to_char_list(path), node)
  end

  defp text([]), do: nil
  defp text([item]), do: text(item)
  defp text(xmlElement(content: content)), do: text(content)
  defp text(xmlAttribute(value: value)), do: List.to_string(value)
  defp text(xmlText(value: value)), do: List.to_string(value)
  defp text(list) when is_list(list) do
    cond do
      Enum.all?(list, &parsable/1 ) -> Enum.map(list, &(text &1))
      true -> fatal(list)
    end
  end
  defp text(term), do: fatal(term)

  defp parsable(term) do
    Record.is_record(term,:xmlText) or
    Record.is_record(term,:xmlElement) or
    Record.is_record(term,:xmlAttribute)
  end

  defp fatal(term) do
    raise "Could not extract text value for xmerl node #{ inspect term }"
  end

end