@spec validate(action :: :token | :authorize | :introspect | :revoke, params :: map()) ::
  {:ok, params :: map()} | {:error, message :: String.t()}

Validates given OAuth parameters.

Examples

iex> validate(:token, %{
  "grant_type" => "client_credentials",
  "client_id" => "client_id",
  "client_secret" => "client_secret"
})
{:ok, %{
  "grant_type" => "client_credentials",
  "client_id" => "client_id",
  "client_secret" => "client_secret"
}}

iex> validate(:authorize, %{})
{:error, "Request is not a valid OAuth request. Need a response_type param."}