Add HTML classes to mention (#5475)

crates/utils/src/utils/markdown/link_rule.rs

@@ -1,4 +1,12 @@
-use markdown_it::{generics::inline::full_link, MarkdownIt, Node, NodeValue, Renderer};
+use crate::utils::mention::MENTIONS_REGEX;
+use markdown_it::{
+  generics::inline::full_link,
+  parser::inline::Text,
+  MarkdownIt,
+  Node,
+  NodeValue,
+  Renderer,
+};
 
 /// Renders markdown links. Copied directly from markdown-it source, unlike original code it also
 /// sets `rel=nofollow` attribute.
@@ -22,6 +30,14 @@ impl NodeValue for Link {
       attrs.push(("title", title.clone()));
     }
 
+    let text = node.children.first().and_then(|n| n.cast::<Text>());
+    if let Some(text) = text {
+      if MENTIONS_REGEX.is_match(&text.content) {
+        attrs.push(("class", "u-url".to_string()));
+        attrs.push(("class", "mention".to_string()));
+      }
+    }
+
     fmt.open("a", &attrs);
     fmt.contents(&node.children);
     fmt.close("a");

crates/utils/src/utils/markdown/mod.rs

@@ -133,6 +133,11 @@ mod tests {
 	 <li id=\"fn1\" class=\"footnote-item\">\n\
 	 <p>example.com <a href=\"#fnref1\" class=\"footnote-backref\">↩︎</a></p>\n\
 	 </li>\n</ol>\n</section>\n"
+      ),
+      (
+        "mention links",
+        "[@example@example.com](https://example.com/u/example)",
+        "<p><a href=\"https://example.com/u/example\" rel=\"nofollow\" class=\"u-url mention\">@example@example.com</a></p>\n"
       )
     ];
 

crates/utils/src/utils/mention.rs

@@ -3,7 +3,7 @@ use regex::Regex;
 use std::sync::LazyLock;
 
 #[allow(clippy::expect_used)]
-static MENTIONS_REGEX: LazyLock<Regex> = LazyLock::new(|| {
+pub(crate) static MENTIONS_REGEX: LazyLock<Regex> = LazyLock::new(|| {
   Regex::new(r"@(?P<name>[\w.]+)@(?P<domain>[a-zA-Z0-9._:-]+)").expect("compile regex")
 });
 // TODO nothing is done with community / group webfingers yet, so just ignore those for now