httparrot

defmodule HTTParrot.GeneralRequestInfo do
  def retrieve(req) do
    args = :cowboy_req.parse_qs(req)
    headers = :cowboy_req.headers(req)
    url = IO.iodata_to_binary(:cowboy_req.uri(req))
    {ip, _port} = :cowboy_req.peer(req)

    ip =
      case ip do
        {127, 0, 0, 1} -> ""
        :local -> ""
        _ -> :inet_parse.ntoa(ip) |> to_string
      end

    args = group_by_keys(args)

    {[args: args, headers: headers, url: url, origin: ip], req}
  end

  @doc """
  Group by keys and if duplicated keys, aggregate them as a list

  iex> group_by_keys([{"a", "v1"}, {"a", "v2"}, {"b", "v3"}, {"a", "v4"}])
  %{"a" => ["v1", "v2", "v4"], "b" => "v3"}
  """
  @spec group_by_keys(list) :: map
  def group_by_keys([]), do: %{}

  def group_by_keys(args) do
    args
    |> Enum.map(fn {k, v} -> %{k => v} end)
    |> Enum.reduce(fn m, acc ->
      Map.merge(m, acc, fn _k, v1, v2 ->
        List.wrap(v2) ++ List.wrap(v1)
      end)
    end)
  end
end