email-parser 0.5.0

use crate::prelude::Res;

use crate::prelude::*;
use std::borrow::Cow;

use super::{base64, quoted_printables};

#[inline]
fn especials(c: u8) -> bool {
    c == b'('
        || c == b')'
        || c == b'<'
        || c == b'>'
        || c == b'@'
        || c == b','
        || c == b';'
        || c == b':'
        || c == b'\\'
        || c == b'"'
        || c == b'/'
        || c == b'['
        || c == b']'
        || c == b'?'
        || c == b'.'
        || c == b'='
}

fn charset(input: &[u8]) -> Res<Cow<str>> {
    let (input, charset) = take_while1(input, |c| {
        c > 0x20 && c < 0x7F && !especials(c) && c != b'*'
    })?;
    let charset = lowercase(Cow::Borrowed(charset));
    Ok((input, charset))
}

fn encoding(input: &[u8]) -> Res<Cow<str>> {
    let (input, encoding) = take_while1(input, |c| c > 0x20 && c < 0x7F && !especials(c))?;
    let encoding = lowercase(Cow::Borrowed(encoding));
    Ok((input, encoding))
}

fn encoded_text(input: &[u8]) -> Res<&str> {
    take_while1(input, |c| c > 0x20 && c <= 0x7E && c != b'?')
}

pub fn encoded_word(input: &[u8]) -> Res<Cow<str>> {
    let (input, _) = tag(input, b"=?")?;
    let (input, charset) = charset(input)?;
    let (input, _language) = match optional(input, |input| {
        pair(input, |input| tag(input, b"*"), encoding)
    }) {
        (input, Some(((), language))) => (input, Some(language)),
        (input, None) => (input, None),
    };
    let (input, _) = tag(input, b"?")?;
    let (input, encoding) = encoding(input)?;
    let (input, _) = tag(input, b"?")?;
    let (input, data) = encoded_text(input)?;
    let (input, _) = tag(input, b"?=")?;

    let value = match encoding.as_ref() {
        "b" => base64::decode_base64(data.to_owned().into_bytes())?,
        "q" => quoted_printables::decode_header_qp(data.to_owned().into_bytes()),
        _ => return Err(Error::Unknown("Unknown encoding")),
    };

    use textcode::*;
    let text: Cow<str> = match charset.as_ref() {
        "utf-8" | "us-ascii" => Cow::Owned(
            String::from_utf8(value).map_err(|_| Error::Unknown("Invalid text encoding"))?,
        ),
        "iso-8859-1" => Cow::Owned(iso8859_1::decode_to_string(&value)),
        "iso-8859-2" => Cow::Owned(iso8859_2::decode_to_string(&value)),
        "iso-8859-3" => Cow::Owned(iso8859_3::decode_to_string(&value)),
        "iso-8859-4" => Cow::Owned(iso8859_4::decode_to_string(&value)),
        "iso-8859-5" => Cow::Owned(iso8859_5::decode_to_string(&value)),
        "iso-8859-6" => Cow::Owned(iso8859_6::decode_to_string(&value)),
        "iso-8859-7" => Cow::Owned(iso8859_7::decode_to_string(&value)),
        "iso-8859-8" => Cow::Owned(iso8859_8::decode_to_string(&value)),
        "iso-8859-9" => Cow::Owned(iso8859_9::decode_to_string(&value)),
        "iso-8859-10" => Cow::Owned(iso8859_10::decode_to_string(&value)),
        "iso-8859-11" => Cow::Owned(iso8859_11::decode_to_string(&value)),
        "iso-8859-13" => Cow::Owned(iso8859_13::decode_to_string(&value)),
        "iso-8859-14" => Cow::Owned(iso8859_14::decode_to_string(&value)),
        "iso-8859-15" => Cow::Owned(iso8859_15::decode_to_string(&value)),
        "iso-8859-16" => Cow::Owned(iso8859_16::decode_to_string(&value)),
        "iso-6937" => Cow::Owned(iso6937::decode_to_string(&value)),
        "gb2312" => Cow::Owned(gb2312::decode_to_string(&value)),
        _ => return Err(Error::Unknown("Unknown charset")),
    };

    Ok((input, text))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn encoded_with_language() {
        assert_eq!(
            "this is some text",
            encoded_word(b"=?iso-8859-1*en?q?this=20is=20some=20text?=")
                .unwrap()
                .1
        );
        assert_eq!(
            "voici un peu de texte",
            encoded_word(b"=?utf-8*en?q?voici=20un=20peu=20de=20texte?=")
                .unwrap()
                .1
        );
    }

    #[test]
    fn encoded_word_test() {
        assert_eq!(
            "this is some text",
            encoded_word(b"=?iso-8859-1?q?this=20is=20some=20text?=")
                .unwrap()
                .1
        );
        assert_eq!(
            "Don't forget! Claim your $5 today 💸",
            encoded_word(b"=?utf-8?q?Don=27t_forget!_Claim_your_=245_today_=F0=9F=92=B8?=")
                .unwrap()
                .1
        );
        assert_eq!(
            "Chloé Helloco",
            encoded_word(b"=?UTF-8?Q?Chlo=C3=A9_Helloco?=").unwrap().1
        );

        assert_eq!(
            "If you can read this yo",
            encoded_word(b"=?ISO-8859-1?B?SWYgeW91IGNhbiByZWFkIHRoaXMgeW8=?=")
                .unwrap()
                .1
        );
        assert_eq!(
            "u understand the example.",
            encoded_word(b"=?ISO-8859-2?B?dSB1bmRlcnN0YW5kIHRoZSBleGFtcGxlLg==?=")
                .unwrap()
                .1
        );
    }
}