<?php
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/

namespace Magento\Framework\Css\PreProcessor\Instruction;

use Magento\Framework\View\Asset\LocalInterface;
use Magento\Framework\View\Asset\NotationResolver;
use Magento\Framework\View\Asset\PreProcessorInterface;
use Magento\Framework\Css\PreProcessor\FileGenerator\RelatedGenerator;
use Magento\Framework\View\Asset\PreProcessor\Chain;

/**
* 'import' instruction preprocessor
*/
class Import implements PreProcessorInterface
{
/**
* Pattern of 'import' instruction
*/
const REPLACE_PATTERN =
'#@import[\s]*'
.'(?P<start>[\(\),\w\s]*?[\'\"][\s]*)'
.'(?P<path>[^\)\'\"]*?)'
.'(?P<end>[\s]*[\'\"][\s\w]*[\)]?)[\s]*;#';

/**
* @var \Magento\Framework\View\Asset\NotationResolver\Module
*/
private $notationResolver;

/**
* @var array
*/
protected $relatedFiles = [];

/**
* @var RelatedGenerator
*/
private $relatedFileGenerator;

/**
* Constructor
*
* @param NotationResolver\Module $notationResolver
* @param RelatedGenerator $relatedFileGenerator
*/
public function __construct(
NotationResolver\Module $notationResolver,
RelatedGenerator $relatedFileGenerator
) {
$this->notationResolver = $notationResolver;
$this->relatedFileGenerator = $relatedFileGenerator;
}

/**
* {@inheritdoc}
*/
public function process(Chain $chain)
{
$asset = $chain->getAsset();
$contentType = $chain->getContentType();
$replaceCallback = function ($matchContent) use ($asset, $contentType) {
return $this->replace($matchContent, $asset, $contentType);
};
$content = $this->removeComments($chain->getContent());

$processedContent = preg_replace_callback(self::REPLACE_PATTERN, $replaceCallback, $content);
$this->relatedFileGenerator->generate($this);
if ($processedContent !== $content) {
$chain->setContent($processedContent);
}
}

/**
* Returns the content without commented lines
*
* @param string $content
* @return string
*/
private function removeComments($content)
{
return preg_replace("#(^\s*//.*$)|((^\s*/\*(?s).*?(\*/)(?!\*/))$)#m", '', $content);
}

/**
* Retrieve information on all related files, processed so far
*
* BUG: this information about related files is not supposed to be in the state of this object.
* This class is meant to be a service (shareable instance) without such a transient state.
* The list of related files needs to be accumulated for the preprocessor,
* because it uses a 3rd-party library, which requires the files to physically reside in the base same directory.
*
* @return array
*/
public function getRelatedFiles()
{
return $this->relatedFiles;
}

/**
* Clear the record of related files, processed so far
*
* @return void
*/
public function resetRelatedFiles()
{
$this->relatedFiles = [];
}

/**
* Add related file to the record of processed files
*
* @param string $matchedFileId
* @param LocalInterface $asset
* @return void
*/
protected function recordRelatedFile($matchedFileId, LocalInterface $asset)
{
$this->relatedFiles[] = [$matchedFileId, $asset];
}

/**
* Return replacement of an original @import directive
*
* @param array $matchedContent
* @param LocalInterface $asset
* @param string $contentType
* @return string
*/
protected function replace(array $matchedContent, LocalInterface $asset, $contentType)
{
$matchedFileId = $this->fixFileExtension($matchedContent['path'], $contentType);

$start = $matchedContent['start'];
$end = $matchedContent['end'];
if (strpos(trim($start), 'url') !== 0) {
$this->recordRelatedFile($matchedFileId, $asset);
}

$resolvedPath = $this->notationResolver->convertModuleNotationToPath($asset, $matchedFileId);

return "@import {$start}{$resolvedPath}{$end};";
}

/**
* Resolve extension of imported asset according to exact format
*
* @param string $fileId
* @param string $contentType
* @return string
* @link http://lesscss.org/features/#import-directives-feature-file-extensions
*/
protected function fixFileExtension($fileId, $contentType)
{
if (!pathinfo($fileId, PATHINFO_EXTENSION)) {
$fileId .= '.' . $contentType;
}
return $fileId;
}
}