How to get logo url using a store id in the backend?

Question

I'm trying to get url of the front-end logo inside a custom helper method in the backend, but I get stuck on getting a file using theme model. All I have is: store id, theme id, theme model and a filename:

/**
 * Retrieve default store logo image URL from design config or theme
 *
 * @param null $storeId
 * @return string
 */
protected function getDefaultStoreLogoUrl($storeId = null)
{
    $folderName = \Magento\Config\Model\Config\Backend\Image\Logo::UPLOAD_DIR;
    $storeLogoPath = $this->scopeConfig->getValue(
        'design/header/logo_src',
        ScopeInterface::SCOPE_STORE,
        $storeId
    );

    $path = $folderName . '/' . $storeLogoPath;
    $logoUrl = $this->_urlBuilder
            ->getBaseUrl(['_type' => UrlInterface::URL_TYPE_MEDIA]) . $path;

    if ($storeLogoPath !== null && $this->isFile($path)) {
        $url = $logoUrl;
    } else {
        $themeId = (int)$this->scopeConfig->getValue(
            'design/theme/theme_id',
            ScopeInterface::SCOPE_STORE,
            $storeId
        );
        /** @var \Magento\Theme\Model\ResourceModel\Theme\Collection $themeCollection */
        $themeCollection = $this->themeFactory->create();
        /** @var \Magento\Theme\Model\Theme $theme */
        $theme = $themeCollection->getItemById($themeId);

        // ..... I'm stuck here
    }

    return $url;
}

I need asset for the theme frontend, but I don't know how to access it. It's should be something similar to the Block/Logo's code:

$url = $this->assetRepository->getUrlWithParams(
    'images/logo.svg',
    [
        '_secure' => $this->_request->isSecure()
    ]
);

But inside the backend $this->assetRepository returns a backend asset :( and result url looks like:

http://baseurl.com/pub/static/adminhtml/Magento/backend/en_US/images/logo.svg

when I expect to get url like:

http://baseurl.com/pub/static/frontend/Magento/luma/en_US/images/logo.svg

The question is: how to get the frontend asset for specific theme in the backend?

Answer 1

Add to custom helper this dependency

\Magento\Store\Model\App\Emulation $emulation,
...
$this->emulation = $emulation;

and then in code before fetching logo run this

$this->emulation->startEnvironmentEmulation($storeId, \Magento\Framework\App\Area::AREA_FRONTEND, true);

Once you finish what you wanted just restore original environment

$this->emulation->stopEnvironmentEmulation();