import gradio as gr
import numpy as np

# Game constants
PLAYER = "X"
AI = "O"
EMPTY = ""

def check_winner(board):
    # Standard Tic-Tac-Toe win conditions
    win_states = [
        [0, 1, 2], [3, 4, 5], [6, 7, 8], # Rows
        [0, 3, 6], [1, 4, 7], [2, 5, 8], # Cols
        [0, 4, 8], [2, 4, 6]             # Diagonals
    ]
    for line in win_states:
        if board[line[0]] == board[line[1]] == board[line[2]] != EMPTY:
            return board[line[0]]
    if EMPTY not in board:
        return "Tie"
    return None

def minimax(board, depth, is_maximizing):
    res = check_winner(board)
    if res == AI: return 10 - depth
    if res == PLAYER: return depth - 10
    if res == "Tie": return 0

    if is_maximizing:
        best_score = -float('inf')
        for i in range(9):
            if board[i] == EMPTY:
                board[i] = AI
                score = minimax(board, depth + 1, False)
                board[i] = EMPTY
                best_score = max(score, best_score)
        return best_score
    else:
        best_score = float('inf')
        for i in range(9):
            if board[i] == EMPTY:
                board[i] = PLAYER
                score = minimax(board, depth + 1, True)
                board[i] = EMPTY
                best_score = min(score, best_score)
        return best_score

def ai_move(board):
    best_score = -float('inf')
    move = -1
    for i in range(9):
        if board[i] == EMPTY:
            board[i] = AI
            score = minimax(board, 0, False)
            board[i] = EMPTY
            if score > best_score:
                best_score = score
                move = i
    return move

def play_game(board, idx):
    # Convert state to list
    board = list(board)
    
    # Player Move
    if board[idx] == EMPTY:
        board[idx] = PLAYER
    else:
        return board, "Cell already taken!"

    # Check if Player won
    status = check_winner(board)
    if status:
        return board, f"Game Over: {status} wins!" if status != "Tie" else "It's a Tie!"

    # AI Move
    ai_idx = ai_move(board)
    if ai_idx != -1:
        board[ai_idx] = AI

    # Check if AI won
    status = check_winner(board)
    if status:
        return board, f"Game Over: {status} wins!" if status != "Tie" else "It's a Tie!"

    return board, "Your turn, Player X"

def reset_game():
    return [EMPTY] * 9, "New Game! You are X."

# UI Construction
with gr.Blocks(css=".square {height: 100px !important; font-size: 2rem !important;}") as demo:
    gr.Markdown("# 🤖 AI Tic-Tac-Toe")
    gr.Markdown("Try to beat the unbeatable Minimax AI!")
    
    board_state = gr.State([EMPTY] * 9)
    status_msg = gr.Textbox(value="Your turn, Player X", label="Status")
    
    with gr.Column(elem_id="board"):
        buttons = []
        for i in range(3):
            with gr.Row():
                for j in range(3):
                    idx = i * 3 + j
                    btn = gr.Button(value=EMPTY, elem_classes="square")
                    buttons.append(btn)
    
    reset_btn = gr.Button("Reset Game", variant="primary")

    # Click Logic
    for i, btn in enumerate(buttons):
        btn.click(
            play_game, 
            inputs=[board_state, gr.Number(i, visible=False)], 
            outputs=[board_state, status_msg]
        )

    # Update UI buttons when state changes
    board_state.change(
        lambda b: [gr.update(value=val) for val in b], 
        inputs=board_state, 
        outputs=buttons
    )
    
    reset_btn.click(reset_game, outputs=[board_state, status_msg])

if __name__ == "__main__":
    demo.launch()