use http::{HeaderName, HeaderValue};

use crate::util::FlatCsv;

/// `Vary` header, defined in [RFC7231](https://tools.ietf.org/html/rfc7231#section-7.1.4)

///

/// The "Vary" header field in a response describes what parts of a

/// request message, aside from the method, Host header field, and

/// request target, might influence the origin server's process for

/// selecting and representing this response.  The value consists of

/// either a single asterisk ("*") or a list of header field names

/// (case-insensitive).

///

/// # ABNF

///

/// ```text

/// Vary = "*" / 1#field-name

/// ```

///

/// # Example values

///

/// * `accept-encoding, accept-language`

///

/// # Example

///

/// ```

/// use headers::Vary;

///

/// let vary = Vary::any();

/// ```

#[derive(Debug, Clone, PartialEq)]

pub struct Vary(FlatCsv);

derive_header! {

    Vary(_),

    name: VARY

}

impl Vary {

    /// Create a new `Very: *` header.

    pub fn any() -> Vary {

        Vary(HeaderValue::from_static("*").into())

    }

    /// Check if this includes `*`.

    pub fn is_any(&self) -> bool {

        self.0.iter().any(|val| val == "*")

    }

    /// Iterate the header names of this `Vary`.

    pub fn iter_strs(&self) -> impl Iterator<Item = &str> {

        self.0.iter()

    }

}

impl From<HeaderName> for Vary {

    fn from(name: HeaderName) -> Self {

        Vary(HeaderValue::from(name).into())

    }

}

/*

test_vary {

    test_header!(test1, vec![b"accept-encoding, accept-language"]);

    #[test]

    fn test2() {

        let mut vary: ::Result<Vary>;

        vary = Header::parse_header(&"*".into());

        assert_eq!(vary.ok(), Some(Vary::Any));

        vary = Header::parse_header(&"etag,cookie,allow".into());

        assert_eq!(vary.ok(), Some(Vary::Items(vec!["eTag".parse().unwrap(),

                                                    "cookIE".parse().unwrap(),

                                                    "AlLOw".parse().unwrap(),])));

    }

}

*/

#[cfg(test)]

mod tests {

    use super::*;

    #[test]

    fn any_is_any() {

        assert!(Vary::any().is_any());

    }

}