From ca3f6181d7ef20ff5b35c9778ac51efc6c764e45 Mon Sep 17 00:00:00 2001
From: Junegunn Choi <junegunn.c@gmail.com>
Date: Sat, 9 Nov 2024 11:54:41 +0900
Subject: [PATCH] page-up/down: undo last up/down if items are skipped

Fix #4069
---
 src/terminal.go | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/terminal.go b/src/terminal.go
index dd3590c..2bd12f7 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -4468,13 +4468,16 @@ func (t *Terminal) Loop() error {
 					}
 				}
 
-				for ; linesToMove > 0; linesToMove-- {
-					cy := t.cy
+				for i := 0; i < linesToMove; i++ {
+					cy, offset := t.cy, t.offset
 					t.vset(cy + direction)
 					t.constrain()
-					if cy == t.cy ||
-						direction > 0 && t.offset >= maxOffset ||
-						direction < 0 && t.offset <= minOffset {
+					if cy == t.cy {
+						break
+					}
+					if i > 0 && (direction > 0 && t.offset > maxOffset ||
+						direction < 0 && t.offset < minOffset) {
+						t.cy, t.offset = cy, offset
 						break
 					}
 				}