From e08cd3e4d64837879b3857996c116464b0e09578 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sat, 3 Jan 2026 21:45:22 +0000
Subject: [PATCH] fix: undo wrong move instead of resetting puzzle to start
 position

When a user makes an incorrect move in a puzzle, now only that move
is undone (like chess.com) instead of resetting the entire puzzle.
This improves usability by letting users retry from the same position
rather than having to redo all previous correct moves.
---
 src/app/learning/tactics/[pattern]/page.tsx | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/app/learning/tactics/[pattern]/page.tsx b/src/app/learning/tactics/[pattern]/page.tsx
index 855529a..0ce650f 100644
--- a/src/app/learning/tactics/[pattern]/page.tsx
+++ b/src/app/learning/tactics/[pattern]/page.tsx
@@ -276,7 +276,10 @@ export default function TacticalPracticePage() {
                 } else {
                     errorSound.current?.play().catch(e => console.error("Audio play failed", e));
                     setFeedback('incorrect');
-                    gameRef.current = new Chess(exercise.startPosition.fen);
+                    // Undo the wrong move instead of resetting to start position
+                    // This allows the user to try again from the same position (like chess.com)
+                    gameRef.current.undo();
+                    setFen(gameRef.current.fen());
 
                     // Update stats for incorrect answer
                     setStats(prev => ({
@@ -313,10 +316,11 @@ export default function TacticalPracticePage() {
             if (!isCorrect) {
                 errorSound.current?.play().catch(e => console.error("Audio play failed", e));
                 setFeedback('incorrect');
-                // Reset the board to starting position
-                gameRef.current = new Chess(exercise.startPosition.fen);
-                setFen(exercise.startPosition.fen);
-                setCurrentMoveIndex(0);
+                // Undo the wrong move instead of resetting to start position
+                // This allows the user to try again from the same position (like chess.com)
+                // The currentMoveIndex stays the same since we're still waiting for the same move
+                gameRef.current.undo();
+                setFen(gameRef.current.fen());
 
                 // Update stats for incorrect answer
                 setStats(prev => ({
@@ -382,10 +386,10 @@ export default function TacticalPracticePage() {
     };
 
     const handleTryAgain = () => {
-        gameRef.current = new Chess(exercise.startPosition.fen);
-        setFen(exercise.startPosition.fen);
+        // Since we now undo the wrong move immediately when it's made,
+        // the board is already in the correct position (before the error).
+        // We just need to reset the feedback state to allow the user to try again.
         setFeedback('none');
-        setCurrentMoveIndex(0);  // Reset move sequence progress
         // Don't reset userMove - keep the chat context
         // The Tutor will know the user tried again because feedback changed to 'none'
     };