use std::{
    net::{
	IpAddr,
	AddrParseError,
    },
    str,
    error,
    fmt,
};

#[derive(Debug)]
pub struct XFormatError;

impl error::Error for XFormatError{}

impl fmt::Display for XFormatError
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	write!(f, "X-Forwarded-For was not in the correct format")
    }
}

#[derive(Debug, Clone, PartialOrd, PartialEq, Eq, Default)]
pub struct XForwardedFor(Vec<IpAddr>);

impl XForwardedFor
{
    pub fn new() -> Self
    {
	Self(Vec::new())
    }
    pub fn single(ip: impl Into<IpAddr>) -> Self
    {
	Self(vec![ip.into()])
    }
    pub fn addrs(&self) -> &[IpAddr]
    {
	&self.0[..]
    }

    pub fn into_first(self) -> Option<IpAddr>
    {
	self.0.into_iter().next()
    }

    pub fn into_addrs(self) -> Vec<IpAddr>
    {
	self.0
    }
}

impl str::FromStr for XForwardedFor
{
    type Err = XFormatError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
	let mut output = Vec::new();
	for next in s.split(',')
	{
	    output.push(next.trim().parse()?)
	}
	Ok(Self(output))
    }
}

impl From<AddrParseError> for XFormatError
{
    #[inline(always)] fn from(_: AddrParseError) -> Self
    {
	Self
    }
}