`<?php
namespace Opencart\Catalog\Controller\Account;
/**

• Class Wish List

• @Package Opencart\Catalog\Controller\Account
  /
  class WishList extends \Opencart\System\Engine\Controller {
  /*

  • @return void
    */
    public function index(): void {
    $this->load->language('account/wishlist');

    if (!$this->customer->isLogged() || (!isset($this->request->get['customer_token']) || !isset($this->session->data['customer_token']) || ($this->request->get['customer_token'] != $this->session->data['customer_token']))) {
    $this->session->data['redirect'] = $this->url->link('account/wishlist', 'language=' . $this->config->get('config_language'));

     $this->response->redirect($this->url->link('account/login', 'language=' . $this->config->get('config_language')));
    

    }

    $this->document->setTitle($this->language->get('heading_title'));

    $data['breadcrumbs'] = [];

    $data['breadcrumbs'][] = [
    'text' => $this->language->get('text_home'),
    'href' => $this->url->link('common/home', 'language=' . $this->config->get('config_language'))
    ];

    $data['breadcrumbs'][] = [
    'text' => $this->language->get('text_account'),
    'href' => $this->url->link('account/account', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : ''))
    ];

    $data['breadcrumbs'][] = [
    'text' => $this->language->get('heading_title'),
    'href' => $this->url->link('account/wishlist', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : ''))
    ];

    if (isset($this->session->data['success'])) {
    $data['success'] = $this->session->data['success'];

     unset($this->session->data['success']);
    

    } else {
    $data['success'] = '';
    }

    $data['list'] = $this->load->controller('account/wishlist.getList');

    $data['continue'] = $this->url->link('account/account', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : ''));

    $data['column_left'] = $this->load->controller('common/column_left');
    $data['column_right'] = $this->load->controller('common/column_right');
    $data['content_top'] = $this->load->controller('common/content_top');
    $data['content_bottom'] = $this->load->controller('common/content_bottom');
    $data['footer'] = $this->load->controller('common/footer');
    $data['header'] = $this->load->controller('common/header');

    $this->response->setOutput($this->load->view('account/wishlist', $data));
    }

  /**

  • @return void
    */
    public function list(): void {
    $this->load->language('account/wishlist');

    $this->response->setOutput($this->getList());
    }

  /**

  • @return string
    */
    public function getList(): string {
    $data['wishlist'] = $this->url->link('account/wishlist.list', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : ''));
    $data['add_to_cart'] = $this->url->link('checkout/cart.add', 'language=' . $this->config->get('config_language'));
    $data['remove'] = $this->url->link('account/wishlist.remove', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : ''));

    $data['products'] = [];

    $this->load->model('account/wishlist');
    $this->load->model('catalog/product');
    $this->load->model('tool/image');

    $results = $this->model_account_wishlist->getWishlist();

    foreach ($results as $result) {
    $product_info = $this->model_catalog_product->getProduct($result['product_id']);

     if ($product_info) {
     	if ($product_info['image']) {
     		$image = $this->model_tool_image->resize(html_entity_decode($product_info['image'], ENT_QUOTES, 'UTF-8'), $this->config->get('config_image_wishlist_width'), $this->config->get('config_image_wishlist_height'));
     	} else {
     		$image = false;
     	}
    

// Perubahan 2024
if ($product_info['quantity'] <= 0) {
$this->load->model('localisation/stock_status');

				$stock_status_info = $this->model_localisation_stock_status->getStockStatus($product_info['stock_status_id']);

				if ($stock_status_info) {
					$data['stock'] = $stock_status_info['name'];
				} else {
					$data['stock'] = '';
				}
			} elseif ($this->config->get('config_stock_display')) {
				$data['stock'] = $product_info['quantity'];
			} else {
				$data['stock'] = $this->language->get('text_instock');
			}

// Akhir Perubahan Jangan Lupa baris 130
if ($this->customer->isLogged() || !$this->config->get('config_customer_price')) {
$price = $this->currency->format($this->tax->calculate($product_info['price'], $product_info['tax_class_id'], $this->config->get('config_tax')), $this->session->data['currency']);
} else {
$price = false;
}

			if ((float)$product_info['special']) {
				$special = $this->currency->format($this->tax->calculate($product_info['special'], $product_info['tax_class_id'], $this->config->get('config_tax')), $this->session->data['currency']);
			} else {
				$special = false;
			}

			$data['products'][] = [
				'product_id' => $product_info['product_id'],
				'thumb'      => $image,
				'name'       => $product_info['name'],
				'model'      => $product_info['model'],
				// 'stock'      => $stock,
				'stock'      => $data['stock'],					
				'price'      => $price,
				'special'    => $special,
				'minimum'    => $product_info['minimum'] > 0 ? $product_info['minimum'] : 1,
				'href'       => $this->url->link('product/product', 'language=' . $this->config->get('config_language') . '&product_id=' . $product_info['product_id'])
			];
		} else {
			$this->model_account_wishlist->deleteWishlist($result['product_id']);
		}
	}

	return $this->load->view('account/wishlist_list', $data);
}

/**
 * @return void
 */
public function add(): void {
	$this->load->language('account/wishlist');

	$json = [];

	if (isset($this->request->post['product_id'])) {
		$product_id = (int)$this->request->post['product_id'];
	} else {
		$product_id = 0;
	}

	$this->load->model('catalog/product');

	$product_info = $this->model_catalog_product->getProduct($product_id);

	if (!$product_info) {
		$json['error'] = $this->language->get('error_product');
	}

	if (!$json) {
		if (!isset($this->session->data['wishlist'])) {
			$this->session->data['wishlist'] = [];
		}

		$this->session->data['wishlist'][] = $product_id;

		$this->session->data['wishlist'] = array_unique($this->session->data['wishlist']);

		// Logged in. We store the product ID into the wishlist
		if ($this->customer->isLogged()) {
			// Edit the customer's cart
			$this->load->model('account/wishlist');

			$this->model_account_wishlist->addWishlist($product_id);

			$json['success'] = sprintf($this->language->get('text_success'), $this->url->link('product/product', 'language=' . $this->config->get('config_language') . '&product_id=' . $product_id), $product_info['name'], $this->url->link('account/wishlist', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : '')));

			$json['total'] = sprintf($this->language->get('text_wishlist'), $this->model_account_wishlist->getTotalWishlist());
		} else {
			$json['success'] = sprintf($this->language->get('text_login'), $this->url->link('account/login', 'language=' . $this->config->get('config_language')), $this->url->link('account/register', 'language=' . $this->config->get('config_language')), $this->url->link('product/product', 'language=' . $this->config->get('config_language') . '&product_id=' . (int)$product_id), $product_info['name'], $this->url->link('account/wishlist', 'language=' . $this->config->get('config_language') . (isset($this->session->data['customer_token']) ? '&customer_token=' . $this->session->data['customer_token'] : '')));

			$json['total'] = sprintf($this->language->get('text_wishlist'), (isset($this->session->data['wishlist']) ? count($this->session->data['wishlist']) : 0));
		}
	}

	$this->response->addHeader('Content-Type: application/json');
	$this->response->setOutput(json_encode($json));
}

/**
 * @return void
 */
public function remove(): void {
	$this->load->language('account/wishlist');

	$json = [];

	if (isset($this->request->post['product_id'])) {
		$product_id = (int)$this->request->post['product_id'];
	} else {
		$product_id = 0;
	}

	if (!$json) {
		if ($this->customer->isLogged()) {
			$this->load->model('account/wishlist');

			$this->model_account_wishlist->deleteWishlist($product_id);

			$json['success'] = $this->language->get('text_remove');
		}
	}

	$this->response->addHeader('Content-Type: application/json');
	$this->response->setOutput(json_encode($json));
}

}`

That's the modification I made in the wishlist to prevent any errors when adding out-of-stock or 0 (pre-order) items to the wishlist. Is there any issue with this approach? @danielkerr @TheCartpenter
Thanks!