【PHP】WPで動作可能なブラックジャックの作成

add_action('init', function () {
    if (!session_id()) session_start();
});

add_action('wp_enqueue_scripts', function () {
    wp_enqueue_script(
        'blackjack-js',
        get_template_directory_uri() . '/js/blackjack.js',
        ['jquery'],
        null,
        true
    );
    wp_localize_script('blackjack-js', 'blackjackAjax', [
        'ajaxurl' => admin_url('admin-ajax.php')
    ]);
});

add_action('wp_ajax_ps_blackjack_play', 'ps_blackjack_play');

function ps_blackjack_play()
{
    if (!is_user_logged_in()) {
        wp_send_json(['status' => 'error', 'message' => 'Authentication required.']);
    }

    $user_id = get_current_user_id();
    $mycred = mycred();

    $bank_user_login = getenv('BLACKJACK_BANK_USER') ?: 'bank_account_placeholder';
    $bank_user = get_user_by('login', $bank_user_login);

    if (!$bank_user) {
        wp_send_json(['status' => 'error', 'message' => 'Service unavailable.']);
    }

    $bank_user_id = $bank_user->ID;

    $player_stand  = sanitize_text_field($_POST['player_stand'] ?? '');
    $bet_amount    = intval($_POST['bet_amount'] ?? 0);
    $deck          = json_decode(stripslashes($_POST['deck'] ?? ''), true) ?? [];
    $player_cards  = json_decode(stripslashes($_POST['player_cards'] ?? ''), true) ?? [];
    $dealer_cards  = json_decode(stripslashes($_POST['dealer_cards'] ?? ''), true) ?? [];

    $current_balance  = $mycred->get_users_balance($user_id);
    $previous_balance = $_SESSION['blackjack_previous_balance'] ?? $current_balance;
    $initial_balance  = $_SESSION['blackjack_initial_balance'] ?? $current_balance;

    if ($player_stand === "start") {
        $deck = generate_blackjack_deck();
        shuffle($deck);

        $player_cards = [array_pop($deck), array_pop($deck)];
        $dealer_cards = [array_pop($deck), array_pop($deck)];

        if ($current_balance < $bet_amount) {
            wp_send_json(['status' => 'error', 'message' => 'Insufficient balance.']);
        }

        $mycred->add_creds('bj_bet', $user_id, -$bet_amount, 'Bet placed');
        $mycred->add_creds('bj_bank_in', $bank_user_id, $bet_amount, 'Bank receive');

        $_SESSION['blackjack_previous_balance'] = $mycred->get_users_balance($user_id);
        if (!isset($_SESSION['blackjack_initial_balance'])) {
            $_SESSION['blackjack_initial_balance'] = $previous_balance;
        }

        $player_blackjack = is_blackjack($player_cards);
        $dealer_blackjack = is_blackjack($dealer_cards);

        if ($player_blackjack || $dealer_blackjack) {
            if ($player_blackjack && $dealer_blackjack) {
                $mycred->add_creds('bj_push', $user_id, $bet_amount, 'Push refund');
                $mycred->add_creds('bj_bank_out', $bank_user_id, -$bet_amount, 'Push bank return');
                return finish_response("Push.", $mycred, $user_id, $player_cards, $dealer_cards);
            } elseif ($player_blackjack) {
                $payout = intval($bet_amount * 2.5);
                $mycred->add_creds('bj_blackjack_win', $user_id, $payout, 'Blackjack win');
                $mycred->add_creds('bj_bank_out', $bank_user_id, -$payout, 'Blackjack payout');
                return finish_response("Blackjack! You win.", $mycred, $user_id, $player_cards, $dealer_cards);
            } else {
                return finish_response("Dealer blackjack. You lose.", $mycred, $user_id, $player_cards, $dealer_cards);
            }
        }

        wp_send_json([
            'status' => 'success',
            'deck' => $deck,
            'player_cards' => $player_cards,
            'dealer_cards' => $dealer_cards,
            'balance' => $mycred->get_users_balance($user_id)
        ]);
    }

    if ($player_stand === "hit") {
        $player_cards[] = array_pop($deck);
        $score = blackjack_calc_score($player_cards);

        if ($score > 21) {
            if (empty($dealer_cards)) {
                $dealer_cards = [array_pop($deck), array_pop($deck)];
            }
            return finish_response("Bust. You lose.", $mycred, $user_id, $player_cards, $dealer_cards);
        }

        wp_send_json([
            'status' => 'continue',
            'deck' => $deck,
            'player_cards' => $player_cards
        ]);
    }

    if ($player_stand === "stand") {
        while (blackjack_calc_score($dealer_cards) < 17) {
            $dealer_cards[] = array_pop($deck);
        }

        $player_score = blackjack_calc_score($player_cards);
        $dealer_score = blackjack_calc_score($dealer_cards);
        $result = "";

        if ($player_score > 21) {
            $result = "Bust. You lose.";
        } elseif ($dealer_score > 21 || $player_score > $dealer_score) {
            $result = "You win!";
            $payout = $bet_amount * 2;
            $mycred->add_creds('bj_win', $user_id, $payout, 'Win payout');
            $mycred->add_creds('bj_bank_out', $bank_user_id, -$payout, 'Payout from bank');
        } elseif ($player_score < $dealer_score) {
            $result = "You lose.";
        } else {
            $result = "Push.";
            $mycred->add_creds('bj_push', $user_id, $bet_amount, 'Push refund');
            $mycred->add_creds('bj_bank_out', $bank_user_id, -$bet_amount, 'Push return');
        }

        return finish_response($result, $mycred, $user_id, $player_cards, $dealer_cards);
    }

    wp_send_json(['status' => 'error', 'message' => 'Invalid request.']);
}

function finish_response($message, $mycred, $user_id, $player_cards, $dealer_cards)
{
    $current_balance  = $mycred->get_users_balance($user_id);
    $_SESSION['blackjack_previous_balance'] = $current_balance;

    wp_send_json([
        'status' => 'finish',
        'message' => $message,
        'balance' => $current_balance,
        'player_cards' => $player_cards,
        'dealer_cards' => $dealer_cards
    ]);
}

function generate_blackjack_deck()
{
    $suits = ['♠', '♥', '♦', '♣'];
    $deck = [];
    foreach ($suits as $suit) {
        for ($i = 1; $i <= 13; $i++) {
            $value = ($i > 10) ? 10 : ($i === 1 ? 1 : $i);
            $rank = ($i === 1) ? 'A' : (($i > 10) ? ['J', 'Q', 'K'][$i - 11] : strval($i));
            $deck[] = ['card' => "{$suit}{$rank}", 'value' => $value];
        }
    }
    return $deck;
}

function blackjack_calc_score($cards)
{
    $total = 0;
    $aces = 0;
    foreach ($cards as $c) {
        $total += $c['value'];
        if ($c['value'] == 1) $aces++;
    }
    while ($total <= 11 && $aces > 0) {
        $total += 10;
        $aces--;
    }
    return $total;
}

function is_blackjack($cards)
{
    if (count($cards) != 2) return false;
    $ranks = array_column($cards, 'value');
    return (in_array(1, $ranks) && in_array(10, $ranks));
}