use std::convert::TryFrom;

use std::fmt;

use http::uri::Authority;

use http::{HeaderName, HeaderValue};

use crate::{Error, Header};

/// The `Host` header.

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

pub struct Host(Authority);

impl Host {

    /// Get the hostname, such as example.domain.

    pub fn hostname(&self) -> &str {

        self.0.host()

    }

    /// Get the optional port number.

    pub fn port(&self) -> Option<u16> {

        self.0.port_u16()

    }

}

impl Header for Host {

    fn name() -> &'static HeaderName {

        &::http::header::HOST

    }

    fn decode<'i, I: Iterator<Item = &'i HeaderValue>>(values: &mut I) -> Result<Self, Error> {

        values

            .next()

            .cloned()

            .and_then(|val| Authority::try_from(val.as_bytes()).ok())

            .map(Host)

            .ok_or_else(Error::invalid)

    }

    fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {

        let bytes = self.0.as_str().as_bytes();

        let val = HeaderValue::from_bytes(bytes).expect("Authority is a valid HeaderValue");

        values.extend(::std::iter::once(val));

    }

}

impl From<Authority> for Host {

    fn from(auth: Authority) -> Host {

        Host(auth)

    }

}

impl fmt::Display for Host {

    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

        fmt::Display::fmt(&self.0, f)

    }

}