PHP OOP practice | PHP OOP practice

class ShopProduct {
    private $title;
    private $producerMainName;
    private $producerFirstName;
    protected $price;
    private $discount = 0;
    
    public function __construct( string $title, string $firstName, string $mainName, float $price ) {
        $this->title = $title;
        $this->producerFirstName = $firstName;
        $this->producerMainName = $mainName;
        $this->price = $price;
    }

    public function getProducerFirstName() {
        return $this->producerFirstName;
    }
    
    public function getProducerMainName() { 
        return $this->producerMainName; 
    }
    
    public function setDiscount($num) {
        $this->discount = $num;
    }
    
    public function getDiscount() {
        return $this->discount;
    }
    
    public function getTitle() {
        return $this->title;
    }
    
    public function getPrice() {
        return ($this->price - $this->discount);
    }
    
    public function getProducer() {
        return $this->producerFirstName .
        . $this->producerMainName;
    }
    
    public function getSummaryLine() {
        $base = "{$this->title} ( {$this->producerMainName}, ";
        $base .= "{$this->producerFirstName} )";
        return $base;
    }
}

class CdProduct extends ShopProduct {
    private $playLength;
    
    public function __construct(string $title, string $firstName, string $mainName, float $price, int $playLength) {
        parent::__construct($title, $firstName, $mainName, $price) {
        $this->playLength = $playLength;
        }
    }
    
     public  function getPlayLength(){
        return $this->playLength;
    }
    
    public function getSummaryLine() {
        $base = "{$this->title} ( {$this->productMainName}, ";
        $base .= "{$this->productFirstName} )";
        $base .= ": Время звучания - {$this->playLength}";
        return $base;
    }   
}

class BookProduct extends ShopProduct {
    private $numPages;
    
    public function __construct(string $title, string $firstName, string $mainName, float $price, int $numPages) {
        parent:: __construct($title, $firstName, $mainName, $price) {
        $this->numPages = $numPages;
        }
    }
    
    public function getNumberOfPages() {
        return $this->numPages;
    }
    
    public function getSummaryLine() {
        $base = parent::getSummaryLine();
        $base .= ": {$this->numPages} стр.";
        return $base;
    }
    
    public function getPrice() {
    return $this->price;
    }
}

/**
 * Save Gravity Forms event registration file to media library.
 */
class WDSP_Event_Form {
    /**
     * Instance of class.
     *
     * @var class
     */
    protected static $instance = null;

    /*
     * Get an instance of the class.
     *
     * @return object $instance Instance of class.
     */
    public static function get_instance() {
        if ( null === self::$instance ) {
            self::$instance = new self;
        }

        return self::$instance;
    }

    /**
     * Constructor.
     *
     * @param  object $plugin Main plugin object.
     */
    public function __construct() {
        $this->hooks();
    }

    /**
     * Initiate our hooks.
     */
    public function hooks() {
        add_filter( 'gform_after_submission', array( $this, 'save_gravity_form_event_registration_file_to_media_library' ), 10, 2 );
    }

    /**
     * Insert event registration file in the media library and attach it to the post.
     * Delete the copy of it that was originally saved to the GF uploads directory.
     *
     * @param  array $entry The entry data.
     * @param  array $form  The form data.
     */
    public function save_gravity_form_event_registration_file_to_media_library( $entry, $form ) {

        // If the ID of the form being saved isn't the one we're looking for, bail.
        if ( 1234 !== $form['id'] ) {
            return;
        }

        // If we don't have the ID of the Post that was created, bail.
        if ( ! isset( $entry['post_id'] ) ) {
            return;
        }

        $gf_field_id        = 38;
        $acf_field_id       = 'field_57bb39fca15a9b';
        $post               = get_post( $entry['post_id'] );
        $file_url           = $entry[ $gf_field_id ];
        $relative_file_path = parse_url( $file_url, PHP_URL_PATH );
        $absolute_file_path = untrailingslashit( ABSPATH ) . $relative_file_path;
        $file_type          = wp_check_filetype( $absolute_file_path )['type'];
        $timeout_seconds    = 5;

        // Sideload media file.
        $sideload_result = $this->sideload_media_file( $file_url, $file_type, $timeout_seconds );

        // If an error occurred while trying to sideload the media file; continue to next blog.
        if ( ! $sideload_result || ! empty( $sideload_result['error'] ) ) {
            return;
        }

        $new_file_path = $sideload_result['file'];
        $new_file_type = $sideload_result['type'];

        // Insert file into the media library.
        $attachment_id = $this->insert_media_file( $new_file_path, $new_file_type );

        if ( $attachment_id ) {
            // Update the ACF field to reference the newly uploaded file.
            update_field( $acf_field_id, $attachment_id, $post->ID );
        }

        // Delete the original file from the Gravity Forms upload directory.
        unlink( $absolute_file_path );
    }

    /**
     * Sideload Media File.
     *
     * @param  string      $file_url        The URL of the file to sideload.
     * @param  string      $file_type       The file type of the file to sideload.
     * @param  int         $timeout_seconds The number of seconds to allow before sideloading times out.
     * @return array|false                  Returns an associative array of file attributes. On failure, returns false or
     *                                      $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
     */
    private function sideload_media_file( $file_url, $file_type, $timeout_seconds ) {

        // Gives us access to the download_url() and wp_handle_sideload() functions.
        require_once( ABSPATH . 'wp-admin/includes/file.php' );

        // Download file to temp dir.
        $temp_file = download_url( $file_url, $timeout_seconds );

        if ( is_wp_error( $temp_file ) ) {
            return false;
        }

        // Array based on $_FILE as seen in PHP file uploads.
        $file = array(
            'name'     => basename( $file_url ),
            'type'     => $file_type,
            'tmp_name' => $temp_file,
            'error'    => 0,
            'size'     => filesize( $temp_file ),
        );

        $overrides = array(
            // Tells WordPress to not look for the POST form
            // fields that would normally be present, default is true,
            // we downloaded the file from a remote server, so there
            // will be no form fields.
            'test_form'   => false,

            // Setting this to false lets WordPress allow empty files – not recommended.
            'test_size'   => true,

            // A properly uploaded file will pass this test.
            // There should be no reason to override this one.
            'test_upload' => true,
        );

        // Move the temporary file into the uploads directory.
        return wp_handle_sideload( $file, $overrides );
    }

    /**
     * Insert media file into the current site.
     *
     * @param  string $file_path              The path to the media file.
     * @param  string $file_type             The mime type of the media file.
     * @return int    $inserted_attachment_id The inserted attachment ID, or 0 on failure.
     */
    private function insert_media_file( $file_path = '', $file_type = '' ) {

        if ( ! $file_path || ! $file_type ) {
            return false;
        }

        // Get the path to the uploads directory.
        $wp_upload_dir = wp_upload_dir();

        // Prepare an array of post data for the attachment.
        $attachment_data = array(
            'guid'           => $wp_upload_dir['url'] . '/' . basename( $file_path ),
            'post_mime_type' => $file_type,
            'post_title'     => preg_replace( '/\.[^.]+$/', '', basename( $file_path ) ),
            'post_content'   => '',
            'post_status'    => 'inherit',
        );

        // Insert the attachment.
        $inserted_attachment_id   = wp_insert_attachment( $attachment_data, $file_path );
        $inserted_attachment_path = get_attached_file( $inserted_attachment_id );

        // Update the attachment metadata.
        $this->update_inserted_attachment_metadata( $inserted_attachment_id, $inserted_attachment_path );

        return $inserted_attachment_id;
    }

    /**
     * Update inserted attachment metadata.
     *
     * @param  int    $inserted_attachment_id The inserted attachment ID.
     * @param  string $file_path              The path to the media file.
     */
    private function update_inserted_attachment_metadata( $inserted_attachment_id, $file_path ) {

        // Make sure that this file is included, as wp_generate_attachment_metadata() depends on it.
        require_once( ABSPATH . 'wp-admin/includes/image.php' );

        // Generate metadata for the attachment and update the database record.
        $attach_data = wp_generate_attachment_metadata( $inserted_attachment_id, $file_path );
        wp_update_attachment_metadata( $inserted_attachment_id, $attach_data );
    }

}

// Instantiate class.
$wdsp_event_form = WDSP_Event_Form::get_instance();