//! RFC2274 - User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)

use crate::parse_ber_octetstring_as_str;

use asn1_rs::{Error, FromBer, Sequence};

use nom::IResult;

#[derive(Debug, PartialEq)]

pub struct UsmSecurityParameters<'a> {

    pub msg_authoritative_engine_id: &'a [u8],

    pub msg_authoritative_engine_boots: u32,

    pub msg_authoritative_engine_time: u32,

    pub msg_user_name: String,

    pub msg_authentication_parameters: &'a [u8],

    pub msg_privacy_parameters: &'a [u8],

}

pub fn parse_usm_security_parameters(bytes: &[u8]) -> IResult<&[u8], UsmSecurityParameters, Error> {

    Sequence::from_der_and_then(bytes, |i| {

        let (i, msg_authoritative_engine_id) = <&[u8]>::from_ber(i)?;

        let (i, msg_authoritative_engine_boots) = u32::from_ber(i)?;

        let (i, msg_authoritative_engine_time) = u32::from_ber(i)?;

        let (i, msg_user_name) = parse_ber_octetstring_as_str(i)?;

        let (i, msg_authentication_parameters) = <&[u8]>::from_ber(i)?;

        let (i, msg_privacy_parameters) = <&[u8]>::from_ber(i)?;

        let usm = UsmSecurityParameters {

            msg_authoritative_engine_id,

            msg_authoritative_engine_boots,

            msg_authoritative_engine_time,

            msg_user_name: msg_user_name.to_string(),

            msg_authentication_parameters,

            msg_privacy_parameters,

        };

        Ok((i, usm))

    })

}