use serde::de::DeserializeOwned;
use actix_session::Session;

pub trait SessionExt {
    /// Get a `value` from the session.
    fn take<T: DeserializeOwned>(&self, key: &str) -> Result<Option<T>, actix_web::error::Error>;

    fn render_flash(&self, context : &mut tera::Context);

    fn flash_error(&self, msg : impl AsRef<str>);

    fn flash_success(&self, msg : impl AsRef<str>);
}

impl SessionExt for Session {
    fn take<T: DeserializeOwned>(&self, key: &str) -> Result<Option<T>, actix_web::error::Error> {
        let val = self.get(key);
        self.remove(key); // Always remove, even if parsing failed
        Ok(val?)
    }

    fn render_flash(&self, context : &mut tera::Context) {
        if let Ok(Some(msg)) = self.take::<String>("flash_error") {
            context.insert("flash_error", &msg);
        }

        if let Ok(Some(msg)) = self.take::<String>("flash_success") {
            context.insert("flash_success", &msg);
        }
    }

    fn flash_error(&self, msg : impl AsRef<str>) {
        self.set("flash_error", msg.as_ref()).unwrap();
    }

    fn flash_success(&self, msg : impl AsRef<str>) {
        self.set("flash_success", msg.as_ref()).unwrap();
    }
}