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

/**
 * Compress CSS
 *
 * This is a heavy regex-based removal of whitespace, unnecessary
 * comments and tokens, and some CSS value minimization, where practical.
 * Many steps have been taken to avoid breaking comment-based hacks, 
 * including the ie5/mac filter (and its inversion), but expect tricky
 * hacks involving comment tokens in 'content' value strings to break
 * minimization badly. A test suite is available.
 * 
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 * @author http://code.google.com/u/1stvamp/ (Issue 64 patch)
 */
class Minify_CSS_Compressor {

 /**
 * Minify a CSS string
 * 
 * @param string $css
 * 
 * @param array $options (currently ignored)
 * 
 * @return string
 */
 public static function process($css, $options = array())
 {
 $obj = new Minify_CSS_Compressor($options);
 return $obj->_process($css);
 }
 
 /**
 * @var array
 */
 protected $_options = null;
 
 /**
 * Are we "in" a hack? I.e. are some browsers targetted until the next comment?
 *
 * @var bool
 */
 protected $_inHack = false;
 
 
 /**
 * Constructor
 * 
 * @param array $options (currently ignored)
 */
 private function __construct($options) {
 $this->_options = $options;
 }
 
 /**
 * Minify a CSS string
 * 
 * @param string $css
 * 
 * @return string
 */
 protected function _process($css)
 {
 $css = str_replace("\r\n", "\n", $css);
 
 // preserve empty comment after '>'
 // http://www.webdevout.net/css-hacks#in_css-selectors
 $css = preg_replace('@>/\\*\\s*\\*/@', '>/*keep*/', $css);
 
 // preserve empty comment between property and value
 // http://css-discuss.incutio.com/?page=BoxModelHack
 $css = preg_replace('@/\\*\\s*\\*/\\s*:@', '/*keep*/:', $css);
 $css = preg_replace('@:\\s*/\\*\\s*\\*/@', ':/*keep*/', $css);
 
 // apply callback to all valid comments (and strip out surrounding ws
 $css = preg_replace_callback('@\\s*/\\*([\\s\\S]*?)\\*/\\s*@'
 ,array($this, '_commentCB'), $css);

 // remove ws around { } and last semicolon in declaration block
 $css = preg_replace('/\\s*{\\s*/', '{', $css);
 $css = preg_replace('/;?\\s*}\\s*/', '}', $css);
 
 // remove ws surrounding semicolons
 $css = preg_replace('/\\s*;\\s*/', ';', $css);
 
 // remove ws around urls
 $css = preg_replace('/
 url\\( # url(
 \\s*
 ([^\\)]+?) # 1 = the URL (really just a bunch of non right parenthesis)
 \\s*
 \\) # )
 /x', 'url(1ドル)', $css);
 
 // remove ws between rules and colons
 $css = preg_replace('/
 \\s*
 ([{;]) # 1 = beginning of block or rule separator 
 \\s*
 ([\\*_]?[\\w\\-]+) # 2 = property (and maybe IE filter)
 \\s*
 :
 \\s*
 (\\b|[#\'"-]) # 3 = first character of a value
 /x', '1ドル2ドル:3ドル', $css);
 
 // remove ws in selectors
 $css = preg_replace_callback('/
 (?: # non-capture
 \\s*
 [^~>+,\\s]+ # selector part
 \\s*
 [,>+~] # combinators
 )+
 \\s*
 [^~>+,\\s]+ # selector part
 { # open declaration block
 /x'
 ,array($this, '_selectorsCB'), $css);
 
 // minimize hex colors
 $css = preg_replace('/([^=])#([a-f\\d])\2円([a-f\\d])\3円([a-f\\d])\4円([\\s;\\}])/i'
 , '1ドル#2ドル3ドル4ドル5ドル', $css);
 
 // remove spaces between font families
 $css = preg_replace_callback('/font-family:([^;}]+)([;}])/'
 ,array($this, '_fontFamilyCB'), $css);
 
 $css = preg_replace('/@import\\s+url/', '@import url', $css);
 
 // replace any ws involving newlines with a single newline
 $css = preg_replace('/[ \\t]*\\n+\\s*/', "\n", $css);
 
 // separate common descendent selectors w/ newlines (to limit line lengths)
 $css = preg_replace('/([\\w#\\.\\*]+)\\s+([\\w#\\.\\*]+){/', "1ドル\n2ドル{", $css);
 
 // Use newline after 1st numeric value (to limit line lengths).
 $css = preg_replace('/
 ((?:padding|margin|border|outline):\\d+(?:px|em)?) # 1 = prop : 1st numeric value
 \\s+
 /x'
 ,"1ドル\n", $css);
 
 // prevent triggering IE6 bug: http://www.crankygeek.com/ie6pebug/
 $css = preg_replace('/:first-l(etter|ine)\\{/', ':first-l1ドル {', $css);
 
 return trim($css);
 }
 
 /**
 * Replace what looks like a set of selectors 
 *
 * @param array $m regex matches
 * 
 * @return string
 */
 protected function _selectorsCB($m)
 {
 // remove ws around the combinators
 return preg_replace('/\\s*([,>+~])\\s*/', '1ドル', $m[0]);
 }
 
 /**
 * Process a comment and return a replacement
 * 
 * @param array $m regex matches
 * 
 * @return string
 */
 protected function _commentCB($m)
 {
 $hasSurroundingWs = (trim($m[0]) !== $m[1]);
 $m = $m[1]; 
 // $m is the comment content w/o the surrounding tokens, 
 // but the return value will replace the entire comment.
 if ($m === 'keep') {
 return '/**/';
 }
 if ($m === '" "') {
 // component of http://tantek.com/CSS/Examples/midpass.html
 return '/*" "*/';
 }
 if (preg_match('@";\\}\\s*\\}/\\*\\s+@', $m)) {
 // component of http://tantek.com/CSS/Examples/midpass.html
 return '/*";}}/* */';
 }
 if ($this->_inHack) {
 // inversion: feeding only to one browser
 if (preg_match('@
 ^/ # comment started like /*/
 \\s*
 (\\S[\\s\\S]+?) # has at least some non-ws content
 \\s*
 /\\* # ends like /*/ or /**/
 @x', $m, $n)) {
 // end hack mode after this comment, but preserve the hack and comment content
 $this->_inHack = false;
 return "/*/{$n[1]}/**/";
 }
 }
 if (substr($m, -1) === '\\') { // comment ends like \*/
 // begin hack mode and preserve hack
 $this->_inHack = true;
 return '/*\\*/';
 }
 if ($m !== '' && $m[0] === '/') { // comment looks like /*/ foo */
 // begin hack mode and preserve hack
 $this->_inHack = true;
 return '/*/*/';
 }
 if ($this->_inHack) {
 // a regular comment ends hack mode but should be preserved
 $this->_inHack = false;
 return '/**/';
 }
 // Issue 107: if there's any surrounding whitespace, it may be important, so 
 // replace the comment with a single space
 return $hasSurroundingWs // remove all other comments
 ? ' '
 : '';
 }
 
 /**
 * Process a font-family listing and return a replacement
 * 
 * @param array $m regex matches
 * 
 * @return string 
 */
 protected function _fontFamilyCB($m)
 {
 // Issue 210: must not eliminate WS between words in unquoted families
 $pieces = preg_split('/(\'[^\']+\'|"[^"]+")/', $m[1], null, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
 $out = 'font-family:';
 while (null !== ($piece = array_shift($pieces))) {
 if ($piece[0] !== '"' && $piece[0] !== "'") {
 $piece = preg_replace('/\\s+/', ' ', $piece);
 $piece = preg_replace('/\\s?,\\s?/', ',', $piece);
 }
 $out .= $piece;
 }
 return $out . $m[2];
 }
}