use std::future::{ready, Ready};

use actix_web::dev::Payload;
use actix_web::{error::ErrorUnauthorized, Error, FromRequest, HttpMessage, HttpRequest};

/// The user id of the caller, as established by the auth middleware after
/// verifying the `user-token` header. Extracting this (instead of trusting a
/// client-supplied `user_id` in the path/body) is the source of truth for
/// "who is making this request".
#[derive(Clone, Copy)]
pub struct AuthUser(pub i32);

impl FromRequest for AuthUser {
    type Error = Error;
    type Future = Ready<Result<Self, Self::Error>>;

    fn from_request(req: &HttpRequest, _payload: &mut Payload) -> Self::Future {
        match req.extensions().get::<AuthUser>() {
            Some(auth_user) => ready(Ok(*auth_user)),
            None => ready(Err(ErrorUnauthorized("missing authenticated user"))),
        }
    }
}