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

/**
 * Compress Javascript/CSS using the YUI Compressor
 * 
 * You must set $jarFile and $tempDir before calling the minify functions.
 * Also, depending on your shell's environment, you may need to specify
 * the full path to java in $javaExecutable or use putenv() to setup the
 * Java environment.
 * 
 * <code>
 * Minify_YUICompressor::$jarFile = '/path/to/yuicompressor-2.4.6.jar';
 * Minify_YUICompressor::$tempDir = '/tmp';
 * $code = Minify_YUICompressor::minifyJs(
 * $code
 * ,array('nomunge' => true, 'line-break' => 1000)
 * );
 * </code>
 *
 * Note: In case you run out stack (default is 512k), you may increase stack size in $options:
 * array('stack-size' => '2048k')
 *
 * @todo unit tests, $options docs
 * 
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 */
class Minify_YUICompressor {

 /**
 * Filepath of the YUI Compressor jar file. This must be set before
 * calling minifyJs() or minifyCss().
 *
 * @var string
 */
 public static $jarFile = null;
 
 /**
 * Writable temp directory. This must be set before calling minifyJs()
 * or minifyCss().
 *
 * @var string
 */
 public static $tempDir = null;
 
 /**
 * Filepath of "java" executable (may be needed if not in shell's PATH)
 *
 * @var string
 */
 public static $javaExecutable = 'java';
 
 /**
 * Minify a Javascript string
 * 
 * @param string $js
 * 
 * @param array $options (verbose is ignored)
 * 
 * @see http://www.julienlecomte.net/yuicompressor/README
 * 
 * @return string 
 */
 public static function minifyJs($js, $options = array())
 {
 return self::_minify('js', $js, $options);
 }
 
 /**
 * Minify a CSS string
 * 
 * @param string $css
 * 
 * @param array $options (verbose is ignored)
 * 
 * @see http://www.julienlecomte.net/yuicompressor/README
 * 
 * @return string 
 */
 public static function minifyCss($css, $options = array())
 {
 return self::_minify('css', $css, $options);
 }
 
 private static function _minify($type, $content, $options)
 {
 self::_prepare();
 if (! ($tmpFile = tempnam(self::$tempDir, 'yuic_'))) {
 throw new Exception('Minify_YUICompressor : could not create temp file.');
 }
 file_put_contents($tmpFile, $content);
 exec(self::_getCmd($options, $type, $tmpFile), $output, $result_code);
 unlink($tmpFile);
 if ($result_code != 0) {
 throw new Exception('Minify_YUICompressor : YUI compressor execution failed.');
 }
 return implode("\n", $output);
 }
 
 private static function _getCmd($userOptions, $type, $tmpFile)
 {
 $o = array_merge(
 array(
 'charset' => ''
 ,'line-break' => 5000
 ,'type' => $type
 ,'nomunge' => false
 ,'preserve-semi' => false
 ,'disable-optimizations' => false
	 ,'stack-size' => ''
 )
 ,$userOptions
 );
 $cmd = self::$javaExecutable
	 . (!empty($o['stack-size'])
	 ? ' -Xss' . $o['stack-size']
	 : '')
	 . ' -jar ' . escapeshellarg(self::$jarFile)
 . " --type {$type}"
 . (preg_match('/^[\\da-zA-Z0-9\\-]+$/', $o['charset'])
 ? " --charset {$o['charset']}" 
 : '')
 . (is_numeric($o['line-break']) && $o['line-break'] >= 0
 ? ' --line-break ' . (int)$o['line-break']
 : '');
 if ($type === 'js') {
 foreach (array('nomunge', 'preserve-semi', 'disable-optimizations') as $opt) {
 $cmd .= $o[$opt] 
 ? " --{$opt}"
 : '';
 }
 }
 return $cmd . ' ' . escapeshellarg($tmpFile);
 }
 
 private static function _prepare()
 {
 if (! is_file(self::$jarFile)) {
 throw new Exception('Minify_YUICompressor : $jarFile('.self::$jarFile.') is not a valid file.');
 }
 if (! is_readable(self::$jarFile)) {
 throw new Exception('Minify_YUICompressor : $jarFile('.self::$jarFile.') is not readable.');
 }
 if (! is_dir(self::$tempDir)) {
 throw new Exception('Minify_YUICompressor : $tempDir('.self::$tempDir.') is not a valid direcotry.');
 }
 if (! is_writable(self::$tempDir)) {
 throw new Exception('Minify_YUICompressor : $tempDir('.self::$tempDir.') is not writable.');
 }
 }
}