I found a bug where some of the text was not detected with the find() method properly as the method is case-sensitive. I tried using the following function:

//    To lower case
//    Source: https://stackoverflow.com/questions/313970/how-to-convert-an-instance-of-stdstring-to-lower-case
std::transform(keyword.begin(), keyword.end(), keyword.begin(),
               [](char c){return std::tolower(c);});

Unfortunately, it didn't work as I wanted it to because the lowercase() function cannot just simply convert non-English characters. I tried using std::locale and converting the keyword string to a wide string but to do that I needed to use the deprecated header file codecvt. I decided to avoid codecvt because it wasn't working as intended. The idea is to simply start using wstrings instead of strings as it will make the application support multiple languages properly.

I also changed the ParseContent method to accept only a string that contains the HTML content of the website and find all the anchor links.

std::vector<std::string> Scraper::ParseContent(std::string content) {
    lxb_status_t status;
    lxb_dom_element_t* body = nullptr;
    lxb_dom_element_t* gather_collection = nullptr;
    lxb_html_document_t* document = nullptr;
    lxb_dom_collection_t* collection = nullptr;
    lxb_html_parser_t* parser = nullptr;
    std::vector<std::string> output;
    // Initialize parser
    parser = lxb_html_parser_create();
    status = lxb_html_parser_init(parser);

    if (status != LXB_STATUS_OK)
    {
        exit(EXIT_FAILURE);
    }

    // Create an empty array of lxb_char_t
    // memset and then iterate through the content and
    // assign to the html variable
    lxb_char_t *html = new lxb_char_t[content.size() + 1];
//    std::memset(html, 0, content.size() + 1);

    std::transform(content.begin(), content.end(), content.begin(),
                   [](unsigned char c){return std::tolower(c);});

    for (int i = 0; i < content.length(); i++) {
        html[i] = content[i];
    }

    size_t html_len = content.length() + 1;
    document = lxb_html_parse(parser, html, html_len);

    if (document == nullptr) {
        exit(EXIT_FAILURE);
    }

    // Destroy parser now that the process has finished
    lxb_html_parser_destroy(parser);

    body = lxb_dom_interface_element(document->body);
    collection = lxb_dom_collection_make(&document->dom_document, 128);

    if (collection == nullptr)
    {
        exit(EXIT_FAILURE);
    }

    status = lxb_dom_elements_by_tag_name(lxb_dom_interface_element(document->body), collection,
                                          (const lxb_char_t *) "a", 1);

    if (status != LXB_STATUS_OK)
    {
        exit(EXIT_FAILURE);
    }

    size_t get_collection_length = lxb_dom_collection_length(collection);

    // Print out results
    for (size_t i = 0; i < get_collection_length; i++)
    {
        gather_collection = lxb_dom_collection_element(collection, i);
        serialize_node(lxb_dom_interface_node(gather_collection));
    }

    output.reserve(urls.size());
    for (std::string& item : urls)
    {
        output.push_back(item);
    }

    // Destroy objects to avoid memory leaks
    lxb_dom_collection_destroy(collection, true);
    lxb_html_document_destroy(document);
    delete [] html;

    return output;
}