<?php
class AltoLetras{    
    public function creacionImagen(){
        require_once 'wp-load.php';
        /**
        * @snippet       WordPress Snippet: Crear post con código
        * @author        Fabian Horta
        * @author_url    
        * @snippet_url 
        * Descripcion    Esta clase se crea con el objetivo de compartir la imagen de alto de letras.
        */
        
       $post_id = trim($_POST['post_id']);
       
        // Add Featured Image to Post
       $image_url        = $_POST['image']; // Define the image URL here
       $image_name       = 'diploma_'.$_POST['name'].'.jpg';
       $upload_dir       = wp_upload_dir("img"); // Set upload folder
       $image_data       = file_get_contents($image_url); // Get image data
       $unique_file_name = wp_unique_filename( $upload_dir['path'], $image_name ); // Generate unique name
       $filename         = time().'file.png'; // Create image file name
       
       // Check folder permission and define file location
       if( wp_mkdir_p( $upload_dir['path'] ) ) {
           $file = $upload_dir['path'] .  $filename;
       } else {
           $file = $upload_dir['basedir'] . $filename;
       }
       
       // Create the image  file on the server
       file_put_contents( $file, $image_data );
       
       
       // Check image file type
       $wp_filetype = wp_check_filetype( $filename, null );
       
       // Set attachment data
       $attachment = array(
           'post_mime_type' => $wp_filetype['type'],
           'post_title'     => sanitize_file_name( $filename ),
           'post_content'   => 'test_fav',
           'post_status'    => 'inherit'
       );
  
       
       // Create the attachment
       $attach_id = wp_insert_attachment( $attachment, $file, $post_id );

       
       if ( ! is_wp_error( $attach_id ) ) {
        // Include image.php
        require_once(ABSPATH . 'wp-admin/includes/image.php');
        
        // Define attachment metadata
        $attach_data = wp_generate_attachment_metadata( $attach_id, $file );
                
        // Assign metadata to attachment
        wp_update_attachment_metadata( $attach_id, $attach_data );
        
        // And finally assign featured image to post
        set_post_thumbnail($post_id, $attach_id);

         $return_arr[] = array("true" => true);      

        echo json_encode($return_arr);
        }
    }
}

$altoLetras = new AltoLetras();
$altoLetras->creacionImagen();

?>