use std::fmt;

use http::HeaderValue;

use crate::Error;

/// Reads a comma-delimited raw header into a Vec.

pub(crate) fn from_comma_delimited<'i, I, T, E>(values: &mut I) -> Result<E, Error>

where

    I: Iterator<Item = &'i HeaderValue>,

    T: ::std::str::FromStr,

    E: ::std::iter::FromIterator<T>,

{

    values

        .flat_map(|value| {

            value.to_str().into_iter().flat_map(|string| {

                string

                    .split(',')

                    .filter_map(|x| match x.trim() {

                        "" => None,

                        y => Some(y),

                    })

                    .map(|x| x.parse().map_err(|_| Error::invalid()))

            })

        })

        .collect()

}

/// Format an array into a comma-delimited string.

pub(crate) fn fmt_comma_delimited<T: fmt::Display>(

    f: &mut fmt::Formatter,

    mut iter: impl Iterator<Item = T>,

) -> fmt::Result {

    if let Some(part) = iter.next() {

        fmt::Display::fmt(&part, f)?;

    }

    for part in iter {

        f.write_str(", ")?;

        fmt::Display::fmt(&part, f)?;

    }

    Ok(())

}