use std::borrow::Cow;
use std::error::Error;

use crate::error::GroupError;

pub trait LogError {
    fn log_error<S: AsRef<str>>(self, msg: S);
}

impl<V, E: Error> LogError for Result<V, E> {
    fn log_error<S: AsRef<str>>(self, msg: S) {
        match self {
            Ok(_) => {}
            Err(e) => {
                error!("{}: {}", msg.as_ref(), e);
            }
        }
    }
}

pub(crate) fn acct_to_server(acct: &str) -> Option<&str> {
    acct.trim_start_matches('@').split('@').nth(1)
}

pub(crate) fn normalize_acct<'a, 'g>(acct: &'a str, group: &'g str) -> Result<Cow<'a, str>, GroupError> {
    let acct = acct.trim_start_matches('@');
    if acct_to_server(acct).is_some() {
        // already has server
        Ok(Cow::Borrowed(acct))
    } else if let Some(gs) = acct_to_server(group) {
        // attach server from the group actor
        Ok(Cow::Owned(format!("{}@{}", acct, gs)))
    } else {
        Err(GroupError::BadConfig(
            format!("Group acct {} is missing server!", group).into(),
        ))
    }
}

#[cfg(test)]
mod test {
    use crate::error::GroupError;
    use crate::utils::{acct_to_server, normalize_acct};

    #[test]
    fn test_acct_to_server() {
        assert_eq!(Some("novak"), acct_to_server("pepa@novak"));
        assert_eq!(Some("banana.co.uk"), acct_to_server("@pepa@banana.co.uk"));
        assert_eq!(None, acct_to_server("probably_local"));
    }

    #[test]
    fn test_normalize_acct() {
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("piggo", "betty@piggo.space")
        );
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("@piggo", "betty@piggo.space")
        );
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("@piggo@piggo.space", "betty@piggo.space")
        );
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("@piggo@piggo.space", "oggip@mastodon.social")
        );
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("piggo@piggo.space", "oggip@mastodon.social")
        );
        assert_eq!(
            Ok("piggo@mastodon.social".into()),
            normalize_acct("@piggo", "oggip@mastodon.social")
        );
        assert_eq!(
            Ok("piggo@piggo.space".into()),
            normalize_acct("piggo@piggo.space", "uhh")
        );
        assert_eq!(Err(GroupError::BadConfig("_".into())), normalize_acct("piggo", "uhh"));
    }
}