How to set video thumbnail as featured image of wordpress post?

I’m trying to implement it on a video site that I’m building on WordPress.

I’m using two plugins: videopack and AccessPress Pro

What I would like to do is the following: When the user sends the video to the frontend, through the AccessPress form, three thumbnail options would be generated for them to choose which one will be used. At this point, it would be defined as the featured image of the post.

You can do this in the WordPress administrative area, in the videopack options. But I would like to bring this videopack functionality to the front-end, where any user can upload their videos and select the thumbnail.

Could someone help me?

I’ve already tried, through GPT Chat, but the option to select thumbnails doesn’t appear. Below are the options he suggested to me:

1. Edit the Form Template First, let’s modify the AccessPress form template to include the video upload field and the area where thumbnails will be displayed.

Locate the Template File:

Access your theme folder on the server via FTP or the WordPress admin panel. Navigate to wp-content/plugins/accesspress-anonymous-post-pro/templates. Find the file that contains the form. Generally, the file is form.php. Edit the form.php File:

Open the form.php file for editing. Add the Video Upload Field and Thumbnail Area:

Add the video upload field and thumbnail display area. Here is an example of how this can be done:

<?php
/**
 * Template para o formulário de post an?nimo do AccessPress.
 */

// Incluir o nonce de seguran?a
wp_nonce_field('post_nonce', 'post_nonce');

// Incluir o campo de upload de vídeo
?>
<p>
    <label for="post_video">Upload de Vídeo</label>
    <input type="file" id="post_video" name="post_video" accept="video/*">
</p>

<!-- área para exibir miniaturas -->
<div id="thumbnail-preview"></div>

<?php
// Restante do formulário...
?>

Now, let’s add the JavaScript code that will handle the video upload process, thumbnail generation, and user interaction.

Create a JavaScript File:

Create a new file called custom-thumbnail-selector.js inside your theme’s js directory. If the js directory does not exist, create one. Add JavaScript Code:

Add the following code to the custom-thumbnail-selector.js file:

jQuery(document).ready(function($) {
    $('#post_video').on('change', function() {
        var file_data = $('#post_video').prop('files')[0];
        var form_data = new FormData();
        form_data.append('post_video', file_data);
        form_data.append('action', 'generate_video_thumbnails');
        form_data.append('post_nonce', $('#post_nonce').val());

        // Limpar área de miniaturas
        $('#thumbnail-preview').html('');

        $.ajax({
            url: ajax_object.ajax_url,
            type: 'POST',
            data: form_data,
            processData: false,
            contentType: false,
            success: function(response) {
                if (response.success) {
                    // Exibir miniaturas geradas
                    $.each(response.data, function(index, value) {
                        $('#thumbnail-preview').append('<label><input type="radio" name="thumbnail_choice" value="' + value + '" required><img src="' + value + '" /></label>');
                    });
                } else {
                    alert('Erro: ' + response.data);
                }
            },
            error: function() {
                alert('Erro ao processar a requisi??o.');
            }
        });
    });
});

3. Add PHP Code to Process the Request Now, let’s add the PHP code needed to process the AJAX request and generate the video thumbnails.

Add PHP Code to functions.php or a Custom Plugin:

// Fun??o para gerar miniaturas de vídeo
function generate_video_thumbnails_ajax() {
    // Verificar nonce para seguran?a
    check_ajax_referer('post_nonce', 'post_nonce');

    // Verificar se o vídeo foi enviado
    if (isset($_FILES['post_video'])) {
        $file = $_FILES['post_video'];

        // Carregar o vídeo na biblioteca de mídia
        $attachment_id = media_handle_upload('post_video', 0);
        
        if (is_wp_error($attachment_id)) {
            wp_send_json_error('Erro ao carregar o vídeo.');
        }

        // Verificar se a fun??o do Videopack está disponível
        if (function_exists('vp_create_video_thumbnails')) {
            $thumbnails = vp_create_video_thumbnails($attachment_id);
            wp_send_json_success($thumbnails);
        } else {
            wp_send_json_error('Fun??o do Videopack n?o encontrada.');
        }
    } else {
        wp_send_json_error('Nenhum vídeo enviado.');
    }
}

// Adicionar a??o para processar a requisi??o AJAX
add_action('wp_ajax_generate_video_thumbnails', 'generate_video_thumbnails_ajax');
add_action('wp_ajax_nopriv_generate_video_thumbnails', 'generate_video_thumbnails_ajax');

// Adicionar script para manejar o AJAX no front-end
function enqueue_custom_scripts() {
    wp_enqueue_script('custom-thumbnail-selector'