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//! Convenience methods and types to sanitize text messages.
/// Remove the [rich reply] fallback of the given plain text string.
///
/// [rich reply]: https://spec.matrix.org/v1.18/client-server-api/#rich-replies
pub fn remove_plain_reply_fallback(mut s: &str) -> &str {
// A reply fallback must begin with a mention of the original sender between `<` and `>`, and
// emotes add `*` as a prefix. If there is no newline, removing the detected fallback would
// result in an empty string.
if (!s.starts_with("> <") && !s.starts_with("> * <")) || !s.contains('\n') {
return s;
}
while s.starts_with("> ") {
if let Some((_line, rest)) = s.split_once('\n') {
s = rest;
} else {
return "";
}
}
// Strip the first line after the fallback if it is empty.
if let Some(rest) = s.strip_prefix('\n') { rest } else { s }
}
#[cfg(test)]
mod tests {
use super::remove_plain_reply_fallback;
#[test]
fn remove_plain_reply() {
assert_eq!(
remove_plain_reply_fallback("No reply here\nJust a simple message"),
"No reply here\nJust a simple message"
);
assert_eq!(
remove_plain_reply_fallback(
"> <@user:notareal.hs> Replied to on\n\
> two lines\n\
\n\
\n\
This is my reply"
),
"\nThis is my reply"
);
assert_eq!(remove_plain_reply_fallback("\n> Not on first line"), "\n> Not on first line");
assert_eq!(
remove_plain_reply_fallback("> <@user:notareal.hs> Previous message\n\n> New quote"),
"> New quote"
);
}
}