use actix_service::{Service, Transform};
use actix_web::dev::{ServiceRequest, ServiceResponse};
use actix_web::{http, HttpResponse};
use futures::future::{ok, Either, FutureResult};
use futures::Poll;

pub struct CheckLogin;

impl<S, P, B> Transform<S> for CheckLogin
where
    S: Service<Request = ServiceRequest<P>, Response = ServiceResponse<B>>,
    S::Future: 'static,
{
    type Request = ServiceRequest<P>;
    type Response = ServiceResponse<B>;
    type Error = S::Error;
    type InitError = ();
    type Transform = CheckLoginMiddleware<S>;
    type Future = FutureResult<Self::Transform, Self::InitError>;

    fn new_transform(&self, service: S) -> Self::Future {
        ok(CheckLoginMiddleware { service })
    }
}
pub struct CheckLoginMiddleware<S> {
    service: S,
}

impl<S, P, B> Service for CheckLoginMiddleware<S>
where
    S: Service<Request = ServiceRequest<P>, Response = ServiceResponse<B>>,
    S::Future: 'static,
{
    type Request = ServiceRequest<P>;
    type Response = ServiceResponse<B>;
    type Error = S::Error;
    type Future = Either<S::Future, FutureResult<Self::Response, Self::Error>>;

    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
        self.service.poll_ready()
    }

    fn call(&mut self, req: ServiceRequest<P>) -> Self::Future {
        // We only need to hook into the `start` for this middleware.

        let is_logged_in = false; // Change this to see the change in outcome in the browser

        if is_logged_in {
            Either::A(self.service.call(req))
        } else {
            // Don't forward to /login if we are already on /login
            if req.path() == "/login" {
                Either::A(self.service.call(req))
            } else {
                Either::B(ok(req.into_response(
                    HttpResponse::Found()
                        .header(http::header::LOCATION, "/login")
                        .finish()
                        .into_body(),
                )))
            }
        }
    }
}