From b6a409c5f47da22fcdd33417c5cb0f4a9a86297d Mon Sep 17 00:00:00 2001
From: RAJ <143867566+TheRaj71@users.noreply.github.com>
Date: Fri, 4 Oct 2024 22:18:41 +0530
Subject: [PATCH] AI Opponent added

---
 js/script.js | 189 ++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 136 insertions(+), 53 deletions(-)

diff --git a/js/script.js b/js/script.js
index 9a045c2..b5300ac 100644
--- a/js/script.js
+++ b/js/script.js
@@ -1,12 +1,16 @@
+// DOM Elements
 const gameBoard = document.getElementById("gameBoard");
 const resultElement = document.getElementById("result");
 const currentPlayerDisplay = document.getElementById("currentPlayer");
 const soundButton = document.getElementById("soundButton");
+const resetButton = document.getElementById("resetButton");
 
+// Game state
 let currentPlayer = "X";
 let gameIsOver = false;
+let isAIMode = false;
 
-//sound-effects"
+// Sound effects
 const backgroundSound = new Audio("sounds/background.wav");
 const clickSound = new Audio("sounds/click.wav");
 const winSound = new Audio("sounds/win.wav");
@@ -15,7 +19,26 @@ backgroundSound.loop = true;
 backgroundSound.volume = 0.1;
 backgroundSound.play();
 
-soundButton.addEventListener("click", () => {
+// Event Listeners
+soundButton.addEventListener("click", toggleSound);
+resetButton.addEventListener("click", resetGame);
+
+// Add mode selection
+const modeSelect = document.createElement("select");
+modeSelect.id = "modeSelect";
+const multiplayerOption = document.createElement("option");
+multiplayerOption.value = "multiplayer";
+multiplayerOption.textContent = "Multiplayer";
+const aiOption = document.createElement("option");
+aiOption.value = "ai";
+aiOption.textContent = "Play against AI";
+modeSelect.appendChild(multiplayerOption);
+modeSelect.appendChild(aiOption);
+document.body.insertBefore(modeSelect, gameBoard);
+
+modeSelect.addEventListener("change", changeGameMode);
+
+function toggleSound() {
   if (backgroundSound.paused) {
     backgroundSound.play();
     soundButton.textContent = "Sound: On";
@@ -23,96 +46,156 @@ soundButton.addEventListener("click", () => {
     backgroundSound.pause();
     soundButton.textContent = "Sound: Off";
   }
-});
+}
+
+function changeGameMode() {
+  isAIMode = modeSelect.value === "ai";
+  resetGame();
+}
 
 function createBoard() {
+  gameBoard.innerHTML = '';
   for (let i = 0; i < 9; i++) {
     const cell = document.createElement("div");
     cell.classList.add("cell");
     cell.addEventListener("click", handleCellClick);
     gameBoard.appendChild(cell);
   }
-  updateCurrentPlayerDisplay(); // Show the initial player
+  updateCurrentPlayerDisplay();
 }
 
 function handleCellClick(event) {
-  clickSound.play();
+  if (gameIsOver || (isAIMode && currentPlayer === "O")) return;
+  
   const cell = event.target;
-  if (!cell.textContent && !gameIsOver) {
-    cell.textContent = currentPlayer;
-
-    // Add class for styling based on current player
-    cell.classList.add(currentPlayer.toLowerCase());
-
-    if (checkWinner()) {
-      resultElement.textContent = `${currentPlayer} wins!`;
-      gameIsOver = true;
-    } else if (isBoardFull()) {
-      resultElement.textContent = "It's a draw!";
-      gameIsOver = true;
-    } else {
-      currentPlayer = currentPlayer === "X" ? "O" : "X";
-      updateCurrentPlayerDisplay(); // Update display after each turn
+  if (cell.textContent) return;
+
+  clickSound.play();
+  makeMove(cell, currentPlayer);
+
+  if (checkWinner()) {
+    endGame(`${currentPlayer} wins!`);
+  } else if (isBoardFull()) {
+    endGame("It's a draw!");
+  } else {
+    currentPlayer = currentPlayer === "X" ? "O" : "X";
+    updateCurrentPlayerDisplay();
+    
+    if (isAIMode && currentPlayer === "O") {
+      setTimeout(makeAIMove, 500);
+    }
+  }
+}
+
+function makeMove(cell, player) {
+  cell.textContent = player;
+  cell.classList.add(player.toLowerCase());
+}
+
+function makeAIMove() {
+  const bestMove = findBestMove();
+  const cell = gameBoard.children[bestMove];
+  makeMove(cell, currentPlayer);
+  
+  if (checkWinner()) {
+    endGame(`${currentPlayer} wins!`);
+  } else if (isBoardFull()) {
+    endGame("It's a draw!");
+  } else {
+    currentPlayer = "X";
+    updateCurrentPlayerDisplay();
+  }
+}
+
+function findBestMove() {
+  let bestScore = -Infinity;
+  let bestMove;
+  for (let i = 0; i < 9; i++) {
+    if (gameBoard.children[i].textContent === "") {
+      gameBoard.children[i].textContent = "O";
+      let score = minimax(gameBoard, 0, false);
+      gameBoard.children[i].textContent = "";
+      if (score > bestScore) {
+        bestScore = score;
+        bestMove = i;
+      }
     }
   }
+  return bestMove;
+}
+
+function minimax(board, depth, isMaximizing) {
+  if (checkWinner()) {
+    return isMaximizing ? -1 : 1;
+  } else if (isBoardFull()) {
+    return 0;
+  }
+
+  if (isMaximizing) {
+    let bestScore = -Infinity;
+    for (let i = 0; i < 9; i++) {
+      if (board.children[i].textContent === "") {
+        board.children[i].textContent = "O";
+        let score = minimax(board, depth + 1, false);
+        board.children[i].textContent = "";
+        bestScore = Math.max(score, bestScore);
+      }
+    }
+    return bestScore;
+  } else {
+    let bestScore = Infinity;
+    for (let i = 0; i < 9; i++) {
+      if (board.children[i].textContent === "") {
+        board.children[i].textContent = "X";
+        let score = minimax(board, depth + 1, true);
+        board.children[i].textContent = "";
+        bestScore = Math.min(score, bestScore);
+      }
+    }
+    return bestScore;
+  }
 }
 
 function updateCurrentPlayerDisplay() {
   currentPlayerDisplay.textContent = `Current Player: ${currentPlayer}`;
-  console.log("Current player:", currentPlayer);
 }
 
 function checkWinner() {
   const winningCombinations = [
-    [0, 1, 2],
-    [3, 4, 5],
-    [6, 7, 8],
-    [0, 3, 6],
-    [1, 4, 7],
-    [2, 5, 8],
-    [0, 4, 8],
-    [2, 4, 6],
+    [0, 1, 2], [3, 4, 5], [6, 7, 8], // Rows
+    [0, 3, 6], [1, 4, 7], [2, 5, 8], // Columns
+    [0, 4, 8], [2, 4, 6] // Diagonals
   ];
 
   for (let combination of winningCombinations) {
+    const [a, b, c] = combination;
     if (
-      gameBoard.children[combination[0]].textContent ===
-        gameBoard.children[combination[1]].textContent &&
-      gameBoard.children[combination[1]].textContent ===
-        gameBoard.children[combination[2]].textContent &&
-      gameBoard.children[combination[0]].textContent !== ""
+      gameBoard.children[a].textContent &&
+      gameBoard.children[a].textContent === gameBoard.children[b].textContent &&
+      gameBoard.children[a].textContent === gameBoard.children[c].textContent
     ) {
-      winSound.play();
       return true;
     }
   }
-
   return false;
 }
 
 function isBoardFull() {
-  for (let i = 0; i < gameBoard.children.length; i++) {
-    if (gameBoard.children[i].textContent === "") {
-      return false;
-    }
-  }
-  return true;
+  return [...gameBoard.children].every(cell => cell.textContent !== "");
+}
+
+function endGame(message) {
+  resultElement.textContent = message;
+  gameIsOver = true;
+  winSound.play();
 }
 
 function resetGame() {
   currentPlayer = "X";
   gameIsOver = false;
   resultElement.textContent = "";
-  updateCurrentPlayerDisplay(); // Reset display on game reset
-
-  for (let i = 0; i < gameBoard.children.length; i++) {
-    gameBoard.children[i].textContent = "";
-    gameBoard.children[i].classList.remove("x", "o"); // Remove the classes
-  }
+  updateCurrentPlayerDisplay();
+  createBoard();
 }
 
-// Set up the reset button
-const resetButton = document.getElementById("resetButton");
-resetButton.addEventListener("click", resetGame);
-
-createBoard();
+createBoard();
\ No newline at end of file