fix: comprehensive chess multiplayer sync overhaul

- Eliminate double polling: removed game.js own poller, use match-session's
  single 2s poll via handleLivePollData callback (halves network requests)
- Send last_move (from/to/san/promotion) in game_state so opponent gets
  exact move data — fixes castling, en passant, promotion animations
- Opponent moves now animate (piece slides) instead of board snap
- Capture particles now fire on opponent's captures too
- Castling sound+haptic plays for opponent's castles
- Draw flow: sender sees "sent" confirmation, receiver sees accept/deny
  dialog (30s timeout), both sides see result via game_state merge
- Emote dedup: timestamp tracking prevents repeated display on same emote
- Emotes use correct emoji lookup (getEmojiForKey) instead of 3 hardcoded
- Polling runs even during player's turn (emotes + draws must arrive anytime)
- Game end detection covers draw result ('draw' + 'aborted')
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/modules/chess/scenes/game.js

@@ -273,15 +273,13 @@ export function mountGame(el, params) {
   if (mode === 'live' && matchId) {
     matchLive.start(matchId, 'chess', {
       onMove: (data) => {
-        // Handled by existing polling — this is backup via match-live
-        mp.updateConnectionStatus(true);
+        // match-session polls every 2s — process all game events here
+        handleLivePollData(el, data);
       },
       onGameEnd: (data) => {
         if (!gameState.gameOver) endGame('loss', 'abandon');
       }
     });
-
-    startLivePolling(el);
     if (playerColor === 'b') {
       gameState.isPlayerTurn = false;
       clock.start('w');
@@ -581,12 +579,12 @@ function getEndReason() {
 }
 
 // ===== LIVE MULTIPLAYER =====
-let livePoller = null;
 let lastKnownMoveCount = 0;
 
 async function sendLiveMove(el) {
   if (!gameState.matchId) return;
   lastKnownMoveCount = gameState.moveCount;
+  const lastMove = gameState.moveHistory[gameState.moveHistory.length - 1];
   try {
     await net.post('game.php', {
       action: 'move',
@@ -595,124 +593,148 @@ async function sendLiveMove(el) {
       move: JSON.stringify(gameState.moveHistory),
       move_count: gameState.moveCount,
       white_time_remaining_ms: clock.white,
-      black_time_remaining_ms: clock.black
+      black_time_remaining_ms: clock.black,
+      game_state: JSON.stringify({
+        last_move: lastMove ? { from: lastMove.from, to: lastMove.to, san: lastMove.san, promotion: lastMove.promotion || null } : null
+      })
     });
   } catch (e) {}
 }
 
-function startLivePolling(el) {
-  if (lastKnownMoveCount === 0) lastKnownMoveCount = gameState.moveCount || 0;
-  livePoller = setInterval(async () => {
-    if (gameState.gameOver) { clearInterval(livePoller); return; }
-    if (gameState._recovering) return;
+function handleLivePollData(el, data) {
+  if (!data || data.error) return;
+  if (gameState.gameOver) return;
+  if (gameState._recovering) return;
 
-    try {
-      const data = await net.post('game.php', { action: 'get', match_id: gameState.matchId });
-      if (!data || data.error) return;
+  mp.updateConnectionStatus(true);
 
-      mp.updateConnectionStatus(true);
+  // Emotes — always check regardless of whose turn
+  const myId = store.get('auth.userId');
+  const emoteData = mp.checkForEmote(data.game_state, myId);
+  if (emoteData) {
+    const boardContainer = el.querySelector('#board-container');
+    const oppBar = el.querySelector('.chess-bar');
+    emoteSystem.showReceived(boardContainer, emoteSystem.getEmojiForKey(emoteData.key), oppBar);
+    audio.play('notification');
+  }
 
-      // Emotes — always check regardless of whose turn
-      const myId = store.get('auth.userId');
-      const emoteData = mp.checkForEmote(data.game_state, myId);
-      if (emoteData) {
-        const boardContainer = el.querySelector('#board-container');
-        const oppBar = el.querySelector('.chess-bar');
-        emoteSystem.showReceived(boardContainer, emoteSystem.getEmojiForKey(emoteData.key), oppBar);
-        audio.play('notification');
+  // Draw offer/response — always check
+  checkDrawOffer(el, data.game_state, myId);
+  checkDrawResponse(el, data.game_state, myId);
+
+  // New move arrived — only process when waiting for opponent
+  if (!gameState.isPlayerTurn && data.move_count > lastKnownMoveCount) {
+    lastKnownMoveCount = data.move_count;
+    const newFen = data.current_fen;
+    if (newFen && newFen !== engine.fen()) {
+      const oldFen = engine.fen();
+
+      // Get move info from game_state (reliable) or fall back to FEN diff
+      const gs = data.game_state ? (typeof data.game_state === 'string' ? JSON.parse(data.game_state) : data.game_state) : {};
+      const serverMove = gs.last_move;
+      let moveFrom = serverMove?.from;
+      let moveTo = serverMove?.to;
+      let moveSan = serverMove?.san;
+
+      // Fall back to FEN diff if game_state doesn't have the move
+      if (!moveFrom || !moveTo) {
+        const detected = detectLastMoveSquares(oldFen, newFen);
+        if (detected) { moveFrom = detected.from; moveTo = detected.to; }
+      }
+      if (!moveSan) {
+        moveSan = detectLastMoveSan(data, oldFen, newFen);
       }
 
-      // Draw offer/response — always check
-      checkDrawOffer(el, data.game_state, myId);
-      checkDrawResponse(el, data.game_state, myId);
-
-      // New move arrived — only process when waiting for opponent
-      if (!gameState.isPlayerTurn && data.move_count > lastKnownMoveCount) {
-        lastKnownMoveCount = data.move_count;
-        const newFen = data.current_fen;
-        if (newFen && newFen !== engine.fen()) {
-          const oldFen = engine.fen();
-          engine.load(newFen);
-
-          // Determine what kind of move it was for SFX + highlights
-          const lastMoveSan = detectLastMoveSan(data, oldFen, newFen);
-          const moveSquares = detectLastMoveSquares(oldFen, newFen);
+      engine.load(newFen);
 
+      // Animate the opponent's piece
+      if (moveFrom && moveTo) {
+        board.animateMove(moveFrom, moveTo, () => {
           board.setPosition(newFen);
-          if (moveSquares) {
-            board.setLastMove(moveSquares.from, moveSquares.to);
-          }
+          board.setLastMove(moveFrom, moveTo);
+        });
+      } else {
+        board.setPosition(newFen);
+      }
 
-          // Play appropriate sound
-          if (lastMoveSan && lastMoveSan.includes('#')) {
-            audio.play('gameOver', 'game');
-            juice.shake(el, 6, 400);
-            juice.hapticHeavy();
-          } else if (lastMoveSan && lastMoveSan.includes('+')) {
-            audio.play('check', 'game');
-            juice.shake(el, 3, 200);
-            juice.hapticMedium();
-          } else if (isCapture(oldFen, newFen)) {
-            audio.play('capture', 'game');
-            juice.shake(el, 2, 150);
-            juice.hapticLight();
-          } else if (lastMoveSan && (lastMoveSan === 'O-O' || lastMoveSan === 'O-O-O')) {
-            audio.play('castle', 'game');
-          } else {
-            audio.play('move', 'game');
+      // Play appropriate sound + juice
+      if (moveSan && moveSan.includes('#')) {
+        audio.play('gameOver', 'game');
+        juice.shake(el, 6, 400);
+        juice.hapticHeavy();
+      } else if (moveSan && moveSan.includes('+')) {
+        audio.play('check', 'game');
+        juice.shake(el, 3, 200);
+        juice.hapticMedium();
+      } else if (isCapture(oldFen, newFen)) {
+        audio.play('capture', 'game');
+        juice.shake(el, 2, 150);
+        juice.hapticLight();
+        if (moveTo) {
+          const captureXY = board.squareToXY(moveTo);
+          if (captureXY) {
+            const boardRect = board.canvas.getBoundingClientRect();
+            juice.burst(boardRect.left + captureXY.x + board.squareSize/2, boardRect.top + captureXY.y + board.squareSize/2,
+              { count: 8, colors: ['#EF4444', '#F97316', '#FBBF24'], size: 6, spread: 60, duration: 500 });
           }
+        }
+      } else if (moveSan && (moveSan === 'O-O' || moveSan === 'O-O-O')) {
+        audio.play('castle', 'game');
+        juice.hapticLight();
+      } else {
+        audio.play('move', 'game');
+      }
 
-          // Check highlight
-          if (engine.isCheck()) {
-            board.setCheck(findKing(engine.turn()));
-          } else {
-            board.highlights.check = null;
-            board.draw();
-          }
+      // Check highlight
+      if (engine.isCheck()) {
+        board.setCheck(findKing(engine.turn()));
+      } else {
+        board.highlights.check = null;
+        board.draw();
+      }
 
-          // Sync clocks from server
-          if (data.white_time_remaining_ms) clock.white = data.white_time_remaining_ms;
-          if (data.black_time_remaining_ms) clock.black = data.black_time_remaining_ms;
-          clock.switch();
-
-          gameState.isPlayerTurn = true;
-          gameState.moveCount = data.move_count;
-
-          // Update move list + captured pieces from server history
-          if (data.moves) {
-            try {
-              const moveHistory = typeof data.moves === 'string' ? JSON.parse(data.moves) : data.moves;
-              if (Array.isArray(moveHistory) && moveHistory.length > gameState.moveHistory.length) {
-                const newMove = moveHistory[moveHistory.length - 1];
-                if (newMove) {
-                  gameState.moveHistory.push(newMove);
-                  updateMoveList(el, newMove);
-                  if (newMove.captured) {
-                    gameState.capturedByOpponent.push(newMove.captured);
-                    updateCapturedDisplay(el);
-                  }
-                }
+      // Sync clocks from server
+      if (data.white_time_remaining_ms) clock.white = data.white_time_remaining_ms;
+      if (data.black_time_remaining_ms) clock.black = data.black_time_remaining_ms;
+      clock.switch();
+
+      gameState.isPlayerTurn = true;
+      gameState.moveCount = data.move_count;
+
+      // Update move list + captured pieces from server history
+      if (data.moves) {
+        try {
+          const moveHistory = typeof data.moves === 'string' ? JSON.parse(data.moves) : data.moves;
+          if (Array.isArray(moveHistory) && moveHistory.length > gameState.moveHistory.length) {
+            const newMove = moveHistory[moveHistory.length - 1];
+            if (newMove) {
+              gameState.moveHistory.push(newMove);
+              updateMoveList(el, newMove);
+              if (newMove.captured) {
+                gameState.capturedByOpponent.push(newMove.captured);
+                updateCapturedDisplay(el);
               }
-            } catch (e) {}
+            }
           }
-
-          if (engine.isGameOver()) {
-            endGame(engine.getResult(gameState.playerColor), getEndReason());
-          }
-        }
+        } catch (e) {}
       }
 
-      // Game ended (resign, abandon)
-      if (data.status === 'completed' && !gameState.gameOver) {
-        const result = data.result;
-        if (result) {
-          const isWin = (result === 'white_wins' && gameState.playerColor === 'w') ||
-                        (result === 'black_wins' && gameState.playerColor === 'b');
-          endGame(isWin ? 'win' : result === 'aborted' ? 'draw' : 'loss', 'resign');
-        }
+      if (engine.isGameOver()) {
+        endGame(engine.getResult(gameState.playerColor), getEndReason());
       }
-    } catch (e) {}
-  }, 2000);
+    }
+  }
+
+  // Game ended (resign, abandon, draw accepted by opponent)
+  if (data.status === 'completed' && !gameState.gameOver) {
+    const result = data.result;
+    if (result) {
+      const isWin = (result === 'white_wins' && gameState.playerColor === 'w') ||
+                    (result === 'black_wins' && gameState.playerColor === 'b');
+      const isDraw = result === 'draw' || result === 'aborted';
+      endGame(isWin ? 'win' : isDraw ? 'draw' : 'loss', result === 'aborted' ? 'abandon' : 'resign');
+    }
+  }
 }
 
 function detectLastMoveSan(data, oldFen, newFen) {
@@ -766,10 +788,6 @@ function isCapture(oldFen, newFen) {
   return newCount < oldCount;
 }
 
-function stopLivePolling() {
-  if (livePoller) { clearInterval(livePoller); livePoller = null; }
-}
-
 let lastDrawOfferHandled = 0;
 
 function checkDrawOffer(el, rawGameState, myId) {
@@ -866,7 +884,6 @@ function fetchAndRenderOpponent(el, oppId) {
 
 function endGame(result, reason) {
   if (gameState.gameOver) return;
-  stopLivePolling();
   mp.cleanup();
   matchLive.session.destroy(); // Clear recovery so homepage doesn't try to rejoin
   gameState.gameOver = true;