app/bundles/CoreBundle/Twig/Helper/ThemeHelper.php

<?php

namespace Mautic\CoreBundle\Twig\Helper;

use Mautic\CoreBundle\Exception\BadConfigurationException;
use Mautic\CoreBundle\Exception\FileNotFoundException;
use Mautic\CoreBundle\Helper\PathsHelper;

/**
 * final class ThemeHelper.
 */
final class ThemeHelper
{
    private string $themeDir;

    private string $themePath;

    /**
     * @var mixed
     */
    private $config;

    /**
     * @param string $theme
     *
     * @throws BadConfigurationException
     * @throws FileNotFoundException
     */
    public function __construct(
        PathsHelper $pathsHelper,
        private $theme
    ) {
        $this->themeDir  = $pathsHelper->getSystemPath('themes').'/'.$this->theme;
        $this->themePath = $pathsHelper->getSystemPath('themes_root').'/'.$this->themeDir;

        // check to make sure the theme exists
        if (!file_exists($this->themePath)) {
            throw new FileNotFoundException($this->theme.' not found!');
        }

        // get the config
        if (file_exists($this->themePath.'/config.json')) {
            $this->config = json_decode(file_get_contents($this->themePath.'/config.json'), true);
        } else {
            throw new BadConfigurationException($this->theme.' is missing a required config file');
        }

        if (!isset($this->config['name'])) {
            throw new BadConfigurationException($this->theme.' does not have a valid config file');
        }
    }

    /**
     * Return  name of the template.
     *
     * @return mixed
     */
    public function getName()
    {
        return $this->config['name'];
    }

    /**
     * Returns the theme folder name.
     *
     * @return string
     */
    public function getTheme()
    {
        return $this->theme;
    }

    /**
     * Get the theme's config.
     *
     * @return mixed
     */
    public function getConfig()
    {
        return $this->config;
    }

    /**
     * Get the theme's slots.
     *
     * @param string $type
     *
     * @return array<string, mixed>
     */
    public function getSlots($type)
    {
        return $this->config['slots'][$type] ?? [];
    }

    /**
     * Returns path to this theme.
     *
     * @param bool $relative
     */
    public function getThemePath($relative = false): string
    {
        return ($relative) ? $this->themeDir : $this->themePath;
    }

    /**
     * Returns template.
     *
     * @param string $code
     *
     * @return bool|string
     */
    public function getErrorPageTemplate($code)
    {
        $errorPage = $this->getThemePath()."/error_{$code}.html.twig";
        if (file_exists($errorPage)) {
            return "@themes/{$this->theme}/error_{$code}.html.twig";
        } else {
            return false;
        }
    }
}