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require_once __DIR__ . '/../includes/functions.php';
header('Content-Type: application/json');

$action = $_POST['action'] ?? $_GET['action'] ?? '';

switch ($action) {
    case 'add':
        $product_id = intval($_POST['product_id']);
        $quantity = intval($_POST['quantity']) ?: 1;
        $variation = $_POST['variation'] ?? '';
        
        $stmt = $db->prepare("SELECT id FROM products WHERE id = ? AND status = 1");
        $stmt->execute([$product_id]);
        if (!$stmt->fetch()) {
            echo json_encode(['success' => false, 'message' => 'Product not found']);
            exit;
        }
        
        add_to_cart($product_id, $quantity, $variation);
        echo json_encode([
            'success' => true, 
            'message' => 'Product added to cart successfully',
            'cart_count' => get_cart_count(),
            'cart_total' => format_currency(get_cart_total())
        ]);
        break;
        
    case 'update':
        $product_id = intval($_POST['product_id']);
        $quantity = intval($_POST['quantity']);
        update_cart($product_id, $quantity);
        echo json_encode([
            'success' => true,
            'message' => 'Cart updated',
            'cart_count' => get_cart_count(),
            'cart_total' => format_currency(get_cart_total())
        ]);
        break;
        
    case 'remove':
        $product_id = intval($_POST['product_id']);
        remove_from_cart($product_id);
        echo json_encode([
            'success' => true,
            'message' => 'Item removed from cart',
            'cart_count' => get_cart_count(),
            'cart_total' => format_currency(get_cart_total())
        ]);
        break;
        
    case 'apply_coupon':
        $code = sanitize($_POST['code']);
        $cart_total = get_cart_total();
        $coupon = validate_coupon($code, $cart_total);
        if ($coupon) {
            $_SESSION['coupon'] = $coupon;
            echo json_encode([
                'success' => true,
                'message' => 'Coupon applied successfully!',
                'discount' => $coupon['value']
            ]);
        } else {
            echo json_encode(['success' => false, 'message' => 'Invalid or expired coupon']);
        }
        break;
        
    default:
        echo json_encode(['success' => false, 'message' => 'Invalid action']);
}

function sanitize($input) {
    return htmlspecialchars(trim($input), ENT_QUOTES, 'UTF-8');
}