use std::io::Result;
use serde;
#[macro_use] extern crate serde_derive;

#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
#[serde(untagged)]
pub enum Aud {
    One(String),
    Many(Vec<String>),
}

fn aud_from_json(data: &Aud) -> Result<String> {
    match data {
        Aud::One(audience) => Ok(audience.clone()),
        Aud::Many(audiences) => audiences
          .last()
          .ok_or(std::io::Error::new(std::io::ErrorKind::NotFound, "No audience found"))
          .map(|r| r.clone())
    }
}

#[test]
fn works() {
    let aud = Aud::One("CBr3zBlrKBbwmxOAM1avZQ==".to_string());
    let serialized = aud_from_json(&aud).unwrap();
    assert_eq!(aud_from_json(&aud).unwrap(), "CBr3zBlrKBbwmxOAM1avZQ==".to_string());
}