use rocket::{
    http::Status,
    request::{FromRequest, Outcome, Request},
};
use std::net::IpAddr;

use crate::types::MacAddr;

pub struct ClientEUI64 {
    pub mac_address: MacAddr,
}

#[derive(Debug)]
pub enum EUI64Error {
    NotIPV6,
    NotEUI64,
    InvalidMACAddr,
}

#[rocket::async_trait]
impl<'r> FromRequest<'r> for ClientEUI64 {
    type Error = EUI64Error;

    async fn from_request(request: &'r Request<'_>) -> Outcome<ClientEUI64, EUI64Error> {
        let client_ip = match request.client_ip() {
            Some(IpAddr::V6(ip)) => ip,
            _ => return Outcome::Failure((Status::Forbidden, EUI64Error::NotIPV6)),
        };
        if client_ip.segments()[0] == 0xfe80 {
            let octets = client_ip.octets();
            let mut mac = [&octets[8..11], &octets[13..]].concat();
            mac[0] ^= 0x2;
            let mac: [u8; 6] = match mac.try_into() {
                Ok(t) => t,
                Err(_) => {
                    return Outcome::Failure((
                        Status::InternalServerError,
                        EUI64Error::InvalidMACAddr,
                    ))
                }
            };
            return Outcome::Success(ClientEUI64 {
                mac_address: MacAddr(mac),
            });
        } else {
            return Outcome::Failure((Status::Forbidden, EUI64Error::NotEUI64));
        }
    }
}