use super::Error;
use nanoid::nanoid;
use nanoid_dictionary::NOLOOKALIKES;
use std::fmt::{Display, Formatter};
use std::str::FromStr;

const LENGTH: usize = 15;

#[derive(Debug, Clone, PartialEq)]
pub struct UserID(pub String);

impl Display for UserID {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

impl Default for UserID {
    fn default() -> Self {
        Self(nanoid!(LENGTH, NOLOOKALIKES))
    }
}

impl FromStr for UserID {
    type Err = Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s.len() == LENGTH && s.chars().all(|c| NOLOOKALIKES.contains(&c)) {
            Ok(Self(s.to_string()))
        } else {
            Err(Error::Invalid("User"))
        }
    }
}

#[cfg(test)]
mod tests {
    use super::{UserID, LENGTH};
    use std::str::FromStr;

    #[test]
    fn invalid_length() {
        assert!(UserID::from_str("test").is_err());
    }

    #[test]
    fn invalid_characters() {
        let value = "11lI0Oouv5Ss2ZZ";
        assert_eq!(value.len(), LENGTH);

        assert!(UserID::from_str(value).is_err());
    }

    #[test]
    fn valid() {
        let value = "nqWxagcdTGGXUgn";
        let id = UserID::from_str(value);
        assert!(id.is_ok());

        let id = id.unwrap();
        assert_eq!(id.0, value);
    }
}