fix(comments): include replies to replies in the comment summary (#820) (#840)

The comment summary gathered a comment's direct replies only, matching /IRT against the comment itself. A reply to a reply points at the direct reply, so its text never reached the generated summary even though the stored discussion kept it.

Replies are now walked to any depth, with a bound, and indented one level per reply. The existing output for direct replies is unchanged.

The new test builds a rectangle, a reply and a reply to that reply, then checks the summary carries both texts with the nested one indented under its parent. It omitted the nested reply before the fix.

Co-authored-by: Big Pickle <[email protected]>

crates/engine/src/lib.rs

@@ -3190,9 +3190,25 @@ pub fn comment_kind(a: &pdfcraft_render::Annotation) -> &str {
 pub fn comment_summary(name: &str, all: &[pdfcraft_render::Annotation], sort: SummarySort) -> String {
     use std::fmt::Write;
     let top: Vec<&pdfcraft_render::Annotation> = all.iter().filter(|a| a.in_reply_to.is_none() && a.state.is_none()).collect();
-    let replies_of = |a: &pdfcraft_render::Annotation| -> Vec<&pdfcraft_render::Annotation> {
-        all.iter().filter(|r| r.state.is_none() && r.in_reply_to.is_some() && r.in_reply_to == a.name && a.name.is_some()).collect()
-    };
+    // Write a comment's replies, indenting each level. A reply to a reply keeps its `/IRT` on the
+    // direct parent, so following one level would leave the deeper replies out of the summary.
+    fn write_replies(out: &mut String, all: &[pdfcraft_render::Annotation], parent: &str, depth: usize) {
+        use std::fmt::Write;
+        if depth > 64 {
+            return;
+        }
+        for r in all.iter().filter(|r| r.state.is_none() && r.in_reply_to.as_deref() == Some(parent)) {
+            let indent = "    ".repeat(depth + 1);
+            let _ =
+                writeln!(out, "{indent}Author: {}  Subject: Reply  Date: {}", r.author.as_deref().unwrap_or(""), r.modified.as_deref().unwrap_or(""));
+            for line in r.contents.as_deref().unwrap_or("").lines() {
+                let _ = writeln!(out, "{indent}{line}");
+            }
+            if let Some(nm) = r.name.as_deref() {
+                write_replies(out, all, nm, depth + 1);
+            }
+        }
+    }
     let mut numbered: Vec<(usize, &pdfcraft_render::Annotation)> = Vec::new();
     let mut last = usize::MAX;
     let mut n = 0;
@@ -3229,11 +3245,8 @@ pub fn comment_summary(name: &str, all: &[pdfcraft_render::Annotation], sort: Su
         if let Some(c) = a.contents.as_deref().filter(|c| !c.is_empty()) {
             let _ = writeln!(out, "{c}");
         }
-        for r in replies_of(a) {
-            let _ = writeln!(out, "    Author: {}  Subject: Reply  Date: {}", r.author.as_deref().unwrap_or(""), r.modified.as_deref().unwrap_or(""));
-            for line in r.contents.as_deref().unwrap_or("").lines() {
-                let _ = writeln!(out, "    {line}");
-            }
+        if let Some(nm) = a.name.as_deref() {
+            write_replies(&mut out, all, nm, 0);
         }
         out.push('\n');
     }

crates/engine/src/tests.rs

@@ -1553,6 +1553,19 @@ fn comments_lock_take_checkmarks_hide_and_summarize() {
     assert_eq!(comment_summary("x", &[], SummarySort::Page), "Summary of Comments on x\n\nThis document has no comments.\n");
 }
 
+/// #820: the generated summary includes replies to replies, indented one level deeper.
+#[test]
+fn comment_summary_includes_replies_to_replies() {
+    let (mut s, id) = session_with(1);
+    s.apply(id, rect_comment(0, [40.0, 40.0, 90.0, 90.0])).unwrap();
+    s.apply(id, Edit::ReplyToAnnotation { page: 0, index: 0, text: "FIRST_REPLY".into(), author: "A".into() }).unwrap();
+    s.apply(id, Edit::ReplyToAnnotation { page: 0, index: 1, text: "NESTED_REPLY".into(), author: "B".into() }).unwrap();
+    let text = comment_summary("doc.pdf", &s.get(id).unwrap().info.annotations, SummarySort::Page);
+    assert!(text.contains("FIRST_REPLY"), "{text}");
+    assert!(text.contains("NESTED_REPLY"), "replies to replies are summarized: {text}");
+    assert!(text.contains("        NESTED_REPLY"), "the nested reply is indented under its parent: {text}");
+}
+
 #[test]
 fn signing_saving_trusting_and_commenting_afterwards() {
     let p12 = std::fs::read(concat!(env!("CARGO_MANIFEST_DIR"), "/../sign/tests/data/ec-p256.p12")).unwrap();