From 5db71bbc5e089c6653d9b7c8e260f515cbb6e9dd Mon Sep 17 00:00:00 2001
From: tiennm99 <tiennm99@outlook.com>
Date: Tue, 7 Apr 2026 21:33:04 +0700
Subject: [PATCH] fix: address code review issues (listener leak, pause,
 shuffle, board validation)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/game/board.ts              | 16 ++++++++++++++++
 src/game/emoji.ts              |  6 +++++-
 src/phaser/scenes/GameScene.ts | 24 ++++++++++++++----------
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/src/game/board.ts b/src/game/board.ts
index d05fc24..a59ddc6 100644
--- a/src/game/board.ts
+++ b/src/game/board.ts
@@ -1,6 +1,7 @@
 import { Board, Difficulty, TileData, Point } from "../types";
 import { DIFFICULTY_CONFIGS } from "./constants";
 import { getEmojisForDifficulty } from "./emoji";
+import { hasAnyValidMove } from "./pathfinder";
 
 let nextTileId = 0;
 
@@ -34,6 +35,21 @@ export function createBoard(difficulty: Difficulty): Board {
     board.push(row);
   }
 
+  // Validate at least one valid move exists; reshuffle if not
+  while (!hasAnyValidMove(board)) {
+    const allTiles = board.flat().filter((t): t is TileData => t !== null);
+    for (let i = allTiles.length - 1; i > 0; i--) {
+      const j = Math.floor(Math.random() * (i + 1));
+      [allTiles[i], allTiles[j]] = [allTiles[j], allTiles[i]];
+    }
+    let idx2 = 0;
+    for (let r = 0; r < rows; r++) {
+      for (let c = 0; c < cols; c++) {
+        board[r][c] = allTiles[idx2++];
+      }
+    }
+  }
+
   return board;
 }
 
diff --git a/src/game/emoji.ts b/src/game/emoji.ts
index f465639..007b84f 100644
--- a/src/game/emoji.ts
+++ b/src/game/emoji.ts
@@ -12,6 +12,10 @@ export const EMOJI_POOL: string[] = [
 
 export function getEmojisForDifficulty(difficulty: Difficulty): string[] {
   const count = DIFFICULTY_CONFIGS[difficulty].pairCount;
-  const shuffled = [...EMOJI_POOL].sort(() => Math.random() - 0.5);
+  const shuffled = [...EMOJI_POOL];
+  for (let i = shuffled.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
+  }
   return shuffled.slice(0, count);
 }
diff --git a/src/phaser/scenes/GameScene.ts b/src/phaser/scenes/GameScene.ts
index 4c788a5..09fd878 100644
--- a/src/phaser/scenes/GameScene.ts
+++ b/src/phaser/scenes/GameScene.ts
@@ -19,6 +19,8 @@ export class GameScene extends Phaser.Scene {
   private lineGraphics!: Phaser.GameObjects.Graphics;
   private isProcessing = false;
   private timerEvent: Phaser.Time.TimerEvent | null = null;
+  private hintHandler!: () => void;
+  private shuffleHandler!: () => void;
 
   constructor() {
     super({ key: "GameScene" });
@@ -35,8 +37,10 @@ export class GameScene extends Phaser.Scene {
     this.startTimer();
 
     // Listen for external actions (hint, shuffle)
-    this.stateManager.on("hint", () => this.handleHint());
-    this.stateManager.on("shuffle", () => this.handleShuffle());
+    this.hintHandler = () => this.handleHint();
+    this.shuffleHandler = () => this.handleShuffle();
+    this.stateManager.on("hint", this.hintHandler);
+    this.stateManager.on("shuffle", this.shuffleHandler);
   }
 
   private renderBoard(): void {
@@ -106,6 +110,7 @@ export class GameScene extends Phaser.Scene {
   }
 
   private onTileClick(pos: Point): void {
+    if (this.stateManager.getState().status !== "playing") return;
     const tile = this.board[pos.row][pos.col];
     if (!tile) return;
 
@@ -302,20 +307,19 @@ export class GameScene extends Phaser.Scene {
 
   private performShuffle(): void {
     this.clearSelection();
-    this.board = shuffleBoard(this.board);
+    do {
+      this.board = shuffleBoard(this.board);
+    } while (getRemainingTiles(this.board).length > 0 && !hasAnyValidMove(this.board));
     this.renderBoard();
-
-    if (
-      getRemainingTiles(this.board).length > 0 &&
-      !hasAnyValidMove(this.board)
-    ) {
-      this.performShuffle();
-    }
   }
 
   destroy(): void {
     if (this.timerEvent) {
       this.timerEvent.destroy();
     }
+    if (this.stateManager) {
+      this.stateManager.off("hint", this.hintHandler);
+      this.stateManager.off("shuffle", this.shuffleHandler);
+    }
   }
 }