defmodule ScrapyCloudEx.HttpAdapter.Helpers do
  @moduledoc false

  @doc """
  Returns an atom representing the content type found in a response header.
  """
  @spec get_format([{String.t(), String.t()}]) :: ScrapyCloudEx.Decoder.format()
  def get_format([]), do: :text
  def get_format([{"Content-Type", "application/json" <> _} | _]), do: :json
  def get_format([{"Content-Type", "application/x-jsonlines" <> _} | _]), do: :jl
  def get_format([{"Content-Type", "application/xml" <> _} | _]), do: :xml
  def get_format([{"Content-Type", "text/csv" <> _} | _]), do: :csv
  def get_format([{"Content-Type", "text/html" <> _} | _]), do: :html
  def get_format([{"Content-Type", "text/plain" <> _} | _]), do: :text
  def get_format([_ | t]), do: get_format(t)

  @doc """
  Extracts the decoder function.
  """
  @spec get_decoder_fun(function | atom) :: ScrapyCloudEx.Decoder.decoder_function()

  def get_decoder_fun(decoder_fun) when is_function(decoder_fun), do: decoder_fun

  def get_decoder_fun(decoder_module) when is_atom(decoder_module),
    do: &decoder_module.decode(&1, &2)
end