<?php
/**
 * Class Minify_ImportProcessor
 * @package Minify
 */

/**
 * Linearize a CSS/JS file by including content specified by CSS import
 * declarations. In CSS files, relative URIs are fixed.
 *
 * @imports will be processed regardless of where they appear in the source
 * files; i.e. @imports commented out or in string content will still be
 * processed!
 *
 * This has a unit test but should be considered "experimental".
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 * @author Simon Schick <simonsimcity@gmail.com>
 */
class Minify_ImportProcessor {

 public static $filesIncluded = array();

 public static function process($file)
 {
 self::$filesIncluded = array();
 self::$_isCss = (strtolower(substr($file, -4)) === '.css');
 $obj = new Minify_ImportProcessor(dirname($file));
 return $obj->_getContent($file);
 }

 // allows callback funcs to know the current directory
 private $_currentDir = null;

 // allows callback funcs to know the directory of the file that inherits this one
 private $_previewsDir = null;

 // allows _importCB to write the fetched content back to the obj
 private $_importedContent = '';

 private static $_isCss = null;

 /**
 * @param String $currentDir
 * @param String $previewsDir Is only used internally
 */
 private function __construct($currentDir, $previewsDir = "")
 {
 $this->_currentDir = $currentDir;
 $this->_previewsDir = $previewsDir;
 }

 private function _getContent($file, $is_imported = false)
 {
 $file = realpath($file);
 if (! $file
 || in_array($file, self::$filesIncluded)
 || false === ($content = @file_get_contents($file))
 ) {
 // file missing, already included, or failed read
 return '';
 }
 self::$filesIncluded[] = realpath($file);
 $this->_currentDir = dirname($file);

 // remove UTF-8 BOM if present
 if (pack("CCC",0xef,0xbb,0xbf) === substr($content, 0, 3)) {
 $content = substr($content, 3);
 }
 // ensure uniform EOLs
 $content = str_replace("\r\n", "\n", $content);

 // process @imports
 $content = preg_replace_callback(
 '/
 @import\\s+
 (?:url\\(\\s*)? # maybe url(
 [\'"]? # maybe quote
 (.*?) # 1 = URI
 [\'"]? # maybe end quote
 (?:\\s*\\))? # maybe )
 ([a-zA-Z,\\s]*)? # 2 = media list
 ; # end token
 /x'
 ,array($this, '_importCB')
 ,$content
 );

 // You only need to rework the import-path if the script is imported
 if (self::$_isCss && $is_imported) {
 // rewrite remaining relative URIs
 $content = preg_replace_callback(
 '/url\\(\\s*([^\\)\\s]+)\\s*\\)/'
 ,array($this, '_urlCB')
 ,$content
 );
 }

 return $this->_importedContent . $content;
 }

 private function _importCB($m)
 {
 $url = $m[1];
 $mediaList = preg_replace('/\\s+/', '', $m[2]);

 if (strpos($url, '://') > 0) {
 // protocol, leave in place for CSS, comment for JS
 return self::$_isCss
 ? $m[0]
 : "/* Minify_ImportProcessor will not include remote content */";
 }
 if ('/' === $url[0]) {
 // protocol-relative or root path
 $url = ltrim($url, '/');
 $file = realpath($_SERVER['DOCUMENT_ROOT']) . DIRECTORY_SEPARATOR
 . strtr($url, '/', DIRECTORY_SEPARATOR);
 } else {
 // relative to current path
 $file = $this->_currentDir . DIRECTORY_SEPARATOR
 . strtr($url, '/', DIRECTORY_SEPARATOR);
 }
 $obj = new Minify_ImportProcessor(dirname($file), $this->_currentDir);
 $content = $obj->_getContent($file, true);
 if ('' === $content) {
 // failed. leave in place for CSS, comment for JS
 return self::$_isCss
 ? $m[0]
 : "/* Minify_ImportProcessor could not fetch '{$file}' */";
 }
 return (!self::$_isCss || preg_match('@(?:^$|\\ball\\b)@', $mediaList))
 ? $content
 : "@media {$mediaList}{\n{$content}\n}\n";
 }

 private function _urlCB($m)
 {
 // $m[1] is either quoted or not
 $quote = ($m[1][0] === "'" || $m[1][0] === '"')
 ? $m[1][0]
 : '';
 $url = ($quote === '')
 ? $m[1]
 : substr($m[1], 1, strlen($m[1]) - 2);
 if ('/' !== $url[0]) {
 if (strpos($url, '//') > 0) {
 // probably starts with protocol, do not alter
 } else {
 // prepend path with current dir separator (OS-independent)
 $path = $this->_currentDir
 . DIRECTORY_SEPARATOR . strtr($url, '/', DIRECTORY_SEPARATOR);
 // update the relative path by the directory of the file that imported this one
 $url = self::getPathDiff(realpath($this->_previewsDir), $path);
 }
 }
 return "url({$quote}{$url}{$quote})";
 }

 /**
 * @param string $from
 * @param string $to
 * @param string $ps
 * @return string
 */
 private function getPathDiff($from, $to, $ps = DIRECTORY_SEPARATOR)
 {
 $realFrom = $this->truepath($from);
 $realTo = $this->truepath($to);

 $arFrom = explode($ps, rtrim($realFrom, $ps));
 $arTo = explode($ps, rtrim($realTo, $ps));
 while (count($arFrom) && count($arTo) && ($arFrom[0] == $arTo[0]))
 {
 array_shift($arFrom);
 array_shift($arTo);
 }
 return str_pad("", count($arFrom) * 3, '..' . $ps) . implode($ps, $arTo);
 }

 /**
 * This function is to replace PHP's extremely buggy realpath().
 * @param string $path The original path, can be relative etc.
 * @return string The resolved path, it might not exist.
 * @see http://stackoverflow.com/questions/4049856/replace-phps-realpath
 */
 function truepath($path)
 {
 // whether $path is unix or not
 $unipath = strlen($path) == 0 || $path{0} != '/';
 // attempts to detect if path is relative in which case, add cwd
 if (strpos($path, ':') === false && $unipath)
 $path = $this->_currentDir . DIRECTORY_SEPARATOR . $path;

 // resolve path parts (single dot, double dot and double delimiters)
 $path = str_replace(array('/', '\\'), DIRECTORY_SEPARATOR, $path);
 $parts = array_filter(explode(DIRECTORY_SEPARATOR, $path), 'strlen');
 $absolutes = array();
 foreach ($parts as $part) {
 if ('.' == $part)
 continue;
 if ('..' == $part) {
 array_pop($absolutes);
 } else {
 $absolutes[] = $part;
 }
 }
 $path = implode(DIRECTORY_SEPARATOR, $absolutes);
 // resolve any symlinks
 if (file_exists($path) && linkinfo($path) > 0)
 $path = readlink($path);
 // put initial separator that could have been lost
 $path = !$unipath ? '/' . $path : $path;
 return $path;
 }
}