From 48535be9700485df128c8a568fc9f85b5b097a32 Mon Sep 17 00:00:00 2001
From: Zach Berry <1112351+zberry@users.noreply.github.com>
Date: Sun, 18 Oct 2026 23:58:58 -0500
Subject: [PATCH] [JJ1] review.compare says which side each change is on

Each change now carries number (the editor's slide number beside the 0-based
slide) and onlyIn (deck or file; absent for a change in both). Shape details
say (only in the deck) / (only in the file). The docs say review.accept takes
the file's side.

PowerPoint: Compare marks the other file's differences as revisions that
Accept applies and Reject discards, so accepting takes the file's side; kept.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 crates/engine/src/cmd/review.rs | 14 +++++++---
 crates/engine/src/compare.rs    | 48 +++++++++++++++++++++++++++++----
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/crates/engine/src/cmd/review.rs b/crates/engine/src/cmd/review.rs
index 82bb3ac6..e9801232 100644
--- a/crates/engine/src/cmd/review.rs
+++ b/crates/engine/src/cmd/review.rs
@@ -58,9 +58,17 @@ pub fn specs() -> Vec<CommandSpec> {
             has_text,
             insert_synonym
         ),
-        cmd!(noundo "review.compare", "Compare", ["Review", "Compare"], None, "{path} | {name, data: base64} — compare with a revised copy → {name, changes}", has_doc, compare),
-        cmd!(query "review.revisions", "Revisions", [], None, "{} → {name, changes: [{kind: inserted|deleted|changed, slide, revised, details}]}", has_doc, revisions),
-        cmd!("review.accept", "Accept Revision", ["Review", "Compare"], None, "{index} | {all: true}", comparing, accept),
+        cmd!(noundo "review.compare", "Compare", ["Review", "Compare"], None, "{path} | {name, data: base64} — compare the open deck with another file → {name, changes: [{kind, slide, number, onlyIn?, revised, details}]}; each change is described from the open deck: `onlyIn: \"deck\"` is in the deck and not in the file, `onlyIn: \"file\"` is in the file and not in the deck, `changed` is in both and differs; `slide` is 0-based, `number` the editor's slide number; review.accept takes the FILE's side, so it deletes what is only in the deck (Accept All keeps the deck's last remaining slide rather than deleting it)", has_doc, compare),
+        cmd!(query "review.revisions", "Revisions", [], None, "{} → {name, changes: [{kind: inserted|deleted|changed, slide (0-based), number (editor's), onlyIn?: deck|file, revised, details}]}; `onlyIn: deck` = only in the open deck, `file` = only in the compared file; accepting takes the file's side", has_doc, revisions),
+        cmd!(
+            "review.accept",
+            "Accept Revision",
+            ["Review", "Compare"],
+            None,
+            "{index} | {all: true} — accept the compared file's side of a change (or all): what is only in the file is added, what is only in the open deck is deleted (all: true leaves the deck's last remaining slide in place), a changed slide becomes the file's",
+            comparing,
+            accept
+        ),
         cmd!(
             noundo "review.reject",
             "Reject Revision",
diff --git a/crates/engine/src/compare.rs b/crates/engine/src/compare.rs
index fa71dc1a..ecdcea78 100644
--- a/crates/engine/src/compare.rs
+++ b/crates/engine/src/compare.rs
@@ -92,6 +92,12 @@ pub struct Change {
     pub kind: ChangeKind,
     /// Index in the open deck (for inserted: where it would go).
     pub slide: usize,
+    /// The editor's number of that slide (`slide` + 1).
+    pub number: usize,
+    /// Which side has it alone: `deck` (the open presentation; accepting deletes it) or `file`
+    /// (the compared file; accepting adds it). Absent when both have it and differ.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub only_in: Option<&'static str>,
     /// Index in the revised deck (none for deleted).
     pub revised: Option<usize>,
     /// What differs, readable: `Title 1: text`, `Picture 3 inserted`, `notes`…
@@ -118,19 +124,33 @@ pub fn diff(cur: &Presentation, rev: &Presentation, by_position: bool) -> Vec<Ch
         let (Some(a), Some(b)) = (cur.slides.get(*i), rev.slides.get(*j)) else { continue };
         let details = slide_details(cur, a, rev, b);
         if !details.is_empty() {
-            out.push(Change { kind: ChangeKind::Changed, slide: *i, revised: Some(*j), details });
+            out.push(Change { kind: ChangeKind::Changed, slide: *i, number: i.saturating_add(1), only_in: None, revised: Some(*j), details });
         }
     }
     for (i, s) in cur.slides.iter().enumerate() {
         if !cur_matched.contains(&i) {
-            out.push(Change { kind: ChangeKind::Deleted, slide: i, revised: None, details: vec![slide_title(s)] });
+            out.push(Change {
+                kind: ChangeKind::Deleted,
+                slide: i,
+                number: i.saturating_add(1),
+                only_in: Some("deck"),
+                revised: None,
+                details: vec![slide_title(s)],
+            });
         }
     }
     for (j, s) in rev.slides.iter().enumerate() {
         if !rev_matched.contains(&j) {
             // After the open slide that matches the revised slide before it.
             let at = (0..j).rev().find_map(|k| pairs.iter().find(|p| p.1 == k).map(|p| p.0 + 1)).unwrap_or(0);
-            out.push(Change { kind: ChangeKind::Inserted, slide: at, revised: Some(j), details: vec![slide_title(s)] });
+            out.push(Change {
+                kind: ChangeKind::Inserted,
+                slide: at,
+                number: at.saturating_add(1),
+                only_in: Some("file"),
+                revised: Some(j),
+                details: vec![slide_title(s)],
+            });
         }
     }
     out.sort_by_key(|c| (c.slide, c.revised.unwrap_or(0)));
@@ -230,12 +250,12 @@ fn slide_details(cp: &Presentation, a: &Slide, rp: &Presentation, b: &Slide) ->
                     shape_details(cp, sa, rp, sb, &mut out);
                 }
             }
-            _ => out.push(format!("{} deleted", shape_label(sa))),
+            _ => out.push(format!("{} deleted (only in the deck)", shape_label(sa))),
         }
     }
     for (k, sb) in b.shapes.iter().enumerate() {
         if !used.contains(&k) {
-            out.push(format!("{} inserted", shape_label(sb)));
+            out.push(format!("{} inserted (only in the file)", shape_label(sb)));
         }
     }
     let order = |s: &Slide| s.shapes.iter().map(|x| x.name.clone()).collect::<Vec<_>>();
@@ -494,6 +514,24 @@ mod tests {
         assert_eq!(bytes(back.media), b"open background");
     }
 
+    #[test]
+    fn each_change_says_which_side_it_is_on() {
+        let (mut s, rev, _) = decks();
+        let v = s.execute("review.compare", &json!({"name": "rev.deckcraft", "data": rev})).unwrap();
+        for c in v["changes"].as_array().unwrap() {
+            assert_eq!(c["number"].as_u64().unwrap(), c["slide"].as_u64().unwrap() + 1, "{c}");
+            match c["kind"].as_str().unwrap() {
+                "deleted" => assert_eq!(c["onlyIn"], "deck", "{c}"),
+                "inserted" => assert_eq!(c["onlyIn"], "file", "{c}"),
+                _ => assert!(c.get("onlyIn").is_none(), "{c}"),
+            }
+        }
+        // A shape only in the open deck reads as only in the deck.
+        s.execute("shape.insert", &json!({"preset": "ellipse", "rect": [10.0, 10.0, 40.0, 40.0]})).unwrap();
+        let v = s.execute("review.revisions", &json!({})).unwrap();
+        assert!(v.to_string().contains("deleted (only in the deck)"), "{v}");
+    }
+
     #[test]
     fn accept_one_then_all_makes_the_decks_equal_and_undoes() {
         let (mut s, rev, n) = decks();