app.py

import streamlit as st
import math
import random

class TicTacToe:
    def __init__(self):
        """Initialize the game board"""
        self.board = [[' ' for _ in range(3)] for _ in range(3)]
        self.current_winner = None

    def make_move(self, row, col, player):
        """Make a move on the board"""
        if self.board[row][col] == ' ':
            self.board[row][col] = player
            return True
        return False

    def check_winner(self):
        """Check for a winner"""
        # Check rows
        for row in self.board:
            if row[0] == row[1] == row[2] != ' ':
                return row[0]
        
        # Check columns
        for col in range(3):
            if self.board[0][col] == self.board[1][col] == self.board[2][col] != ' ':
                return self.board[0][col]
        
        # Check diagonals
        if self.board[0][0] == self.board[1][1] == self.board[2][2] != ' ':
            return self.board[0][0]
        if self.board[0][2] == self.board[1][1] == self.board[2][0] != ' ':
            return self.board[0][2]
        
        return None

    def is_board_full(self):
        """Check if the board is full"""
        return all(cell != ' ' for row in self.board for cell in row)

    def minimax(self, depth, is_maximizing, alpha, beta):
        """Minimax algorithm with Alpha-Beta pruning"""
        winner = self.check_winner()
        
        # Terminal states
        if winner == 'X':
            return 1
        elif winner == 'O':
            return -1
        elif self.is_board_full():
            return 0

        if is_maximizing:
            max_eval = -math.inf
            for i in range(3):
                for j in range(3):
                    if self.board[i][j] == ' ':
                        self.board[i][j] = 'X'
                        eval = self.minimax(depth + 1, False, alpha, beta)
                        self.board[i][j] = ' '
                        max_eval = max(max_eval, eval)
                        alpha = max(alpha, eval)
                        if beta <= alpha:
                            break
            return max_eval
        else:
            min_eval = math.inf
            for i in range(3):
                for j in range(3):
                    if self.board[i][j] == ' ':
                        self.board[i][j] = 'O'
                        eval = self.minimax(depth + 1, True, alpha, beta)
                        self.board[i][j] = ' '
                        min_eval = min(min_eval, eval)
                        beta = min(beta, eval)
                        if beta <= alpha:
                            break
            return min_eval

    def find_best_move(self):
        """Find the best move for the AI"""
        best_val = -math.inf
        best_move = None
        
        for i in range(3):
            for j in range(3):
                if self.board[i][j] == ' ':
                    self.board[i][j] = 'X'
                    move_val = self.minimax(0, False, -math.inf, math.inf)
                    self.board[i][j] = ' '
                    
                    if move_val > best_val:
                        best_move = (i, j)
                        best_val = move_val
        
        return best_move

def main():
    # Set page configuration
    st.set_page_config(
        page_title="Tic-Tac-Toe AI",
        page_icon=":game_die:",
        layout="centered"
    )

    # Custom CSS for styling
    st.markdown("""
    <style>
    .stButton>button {
        width: 100px;
        height: 100px;
        font-size: 48px;
        margin: 5px;
    }
    .title {
        text-align: center;
        color: #4a4a4a;
    }
    .subtitle {
        text-align: center;
        color: #6a6a6a;
    }
    </style>
    """, unsafe_allow_html=True)

    # Title and introduction
    st.markdown("<h1 class='title'>🎲 Tic-Tac-Toe AI 🤖</h1>", unsafe_allow_html=True)
    st.markdown("<h3 class='subtitle'>Can you beat the AI?</h3>", unsafe_allow_html=True)

    # Initialize game state
    if 'game' not in st.session_state:
        st.session_state.game = TicTacToe()
        st.session_state.game_over = False
        st.session_state.winner = None

    # Function to handle button clicks
    def button_click(row, col):
        # Check if game is not over and the cell is empty
        if not st.session_state.game_over and st.session_state.game.board[row][col] == ' ':
            # Player's move
            st.session_state.game.make_move(row, col, 'O')
            
            # Check for player win
            winner = st.session_state.game.check_winner()
            if winner:
                st.session_state.game_over = True
                st.session_state.winner = winner
                return
            
            # Check for draw
            if st.session_state.game.is_board_full():
                st.session_state.game_over = True
                return
            
            # AI's move
            ai_move = st.session_state.game.find_best_move()
            if ai_move:
                st.session_state.game.make_move(ai_move[0], ai_move[1], 'X')
            
            # Check for AI win
            winner = st.session_state.game.check_winner()
            if winner:
                st.session_state.game_over = True
                st.session_state.winner = winner

    # Render the game board
    game_board = st.columns(3)
    for row in range(3):
        with game_board[row % 3]:
            for col in range(3):
                # Create a button for each cell
                button_label = st.session_state.game.board[row][col]
                button_key = f"button_{row}_{col}"
                
                # Style buttons based on their content
                if button_label == 'O':
                    button_style = "background-color: #FF6B6B; color: white;"
                elif button_label == 'X':
                    button_style = "background-color: #4ECDC4; color: white;"
                else:
                    button_style = ""
                
                # Create the button
                if st.button(button_label, key=button_key, 
                             on_click=button_click, 
                             args=(row, col),
                             disabled=st.session_state.game_over or button_label != ' ',
                             help="Click to make your move"):
                    pass

    # Display game result
    if st.session_state.game_over:
        if st.session_state.winner == 'O':
            st.success("🎉 Congratulations! You won!")
        elif st.session_state.winner == 'X':
            st.error("🤖 AI wins! Better luck next time.")
        else:
            st.warning("🤝 It's a draw!")

    # Restart game button
    if st.button("New Game", help="Start a new game"):
        st.session_state.game = TicTacToe()
        st.session_state.game_over = False
        st.session_state.winner = None
        st.rerun()

if __name__ == "__main__":
    main()