use std::time::SystemTime;

use crate::util::HttpDate;

/// `Expires` header, defined in [RFC7234](https://datatracker.ietf.org/doc/html/rfc7234#section-5.3)

///

/// The `Expires` header field gives the date/time after which the

/// response is considered stale.

///

/// The presence of an Expires field does not imply that the original

/// resource will change or cease to exist at, before, or after that

/// time.

///

/// # ABNF

///

/// ```text

/// Expires = HTTP-date

/// ```

///

/// # Example values

/// * `Thu, 01 Dec 1994 16:00:00 GMT`

///

/// # Example

///

/// ```

/// use headers::Expires;

/// use std::time::{SystemTime, Duration};

///

/// let time = SystemTime::now() + Duration::from_secs(60 * 60 * 24);

/// let expires = Expires::from(time);

/// ```

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]

pub struct Expires(HttpDate);

derive_header! {

    Expires(_),

    name: EXPIRES

}

impl From<SystemTime> for Expires {

    fn from(time: SystemTime) -> Expires {

        Expires(time.into())

    }

}

impl From<Expires> for SystemTime {

    fn from(date: Expires) -> SystemTime {

        date.0.into()

    }

}