createFromThemeJson example

            /** @var array<string, mixed> $data */
            $data = json_decode($fileContent, true);
            if (json_last_error() !== \JSON_ERROR_NONE) {
                throw new ThemeCompileException(
                    $name,
                    'Unable to parse theme.json. Message: ' . json_last_error_msg()
                );
            }

            $config = $this->createFromThemeJson($name, $data, $path);
        } catch (ThemeCompileException $e) {
            throw $e;
        } catch (\Exception $e) {
            throw new ThemeCompileException(
                $name,
                sprintf(
                    'Got exception while parsing theme config. Exception message "%s"',
                    $e->getMessage()
                ),
                $e
            );
        }

private function updateMediaInConfiguration(
        ?ThemeEntity $theme,
        StorefrontPluginConfiguration $pluginConfiguration,
        Context $context
    ): array {
        $media = [];
        $themeData = [];
        $themeFolderId = $this->getMediaDefaultFolderId($context);

        $installedConfiguration = null;
        if ($theme && \is_array($theme->getThemeJson()) && $this->pluginConfigurationFactory) {
            $installedConfiguration = $this->pluginConfigurationFactory->createFromThemeJson(
                $theme->getTechnicalName() ?? 'childTheme',
                $theme->getThemeJson(),
                $pluginConfiguration->getBasePath(),
                false
            );
        }

        if (
            $pluginConfiguration->getPreviewMedia()
            && $pluginConfiguration->getPreviewMedia() !== $installedConfiguration?->getPreviewMedia()
            && (