<?php
/**
 * Class Minify  
 * @package Minify
 */
 
/**
 * Minify - Combines, minifies, and caches JavaScript and CSS files on demand.
 *
 * See README for usage instructions (for now).
 *
 * This library was inspired by jscsscomp by Maxim Martynyuk <flashkot@mail.ru>
 * and by the article "Supercharged JavaScript" by Patrick Hunlock
 * <wb@hunlock.com>.
 *
 * Requires PHP 5.1.0.
 * Tested on PHP 5.1.6.
 *
 * @package Minify
 * @author Ryan Grove <ryan@wonko.com>
 * @author Stephen Clay <steve@mrclay.org>
 * @copyright 2008 Ryan Grove, Stephen Clay. All rights reserved.
 * @license http://opensource.org/licenses/bsd-license.php  New BSD License
 * @version 1.9.0
 * @link http://code.google.com/p/minify/
 */

require_once 'Minify/Source.php';

class Minify {

    const TYPE_CSS = 'text/css';
    const TYPE_HTML = 'text/html';
    // there is some debate over the ideal JS Content-Type, but this is the
    // Apache default and what Yahoo! uses..
    const TYPE_JS = 'application/x-javascript';
    
    /**
     * @var bool Should the un-encoded version be cached? 
     * 
     * True results in more cache files, but lower PHP load if different 
     * encodings are commonly requested.
     */
    public static $cacheUnencodedVersion = true;

    /**
     * Specify a writeable directory for cache files. If not called, Minify
     * will not use a disk cache and, for each 200 response, will need to
     * recombine files, minify and encode the output.
     *
     * @param string $path Full directory path for cache files (should not end
     * in directory separator character). If not provided, Minify will attempt to
     * write to the path returned by sys_get_temp_dir().
     *
     * @return null
     */
    public static function useServerCache($path = null) {
        if (null !== $path) {
            self::$_cachePath = $path;    
        } else {
            require_once 'Solar/Dir.php';
            self::$_cachePath = rtrim(Solar_Dir::tmp(), DIRECTORY_SEPARATOR);
        }
    }

    /**
     * Serve a request for a minified file. 
     * 
     * @param mixed instance of subclass of Minify_Controller_Base or string name of controller. E.g. 'Files'
     * 
     * @param array $options controller/serve options
     * 
     * @return array success, statusCode, content, and headers generated
     * 
     * Here are the available options and defaults in the base controller:
     * 
     * 'isPublic' : send "public" instead of "private" in Cache-Control 
     * headers, allowing shared caches to cache the output. (default true)
     * 
     * 'quiet' : set to true to have no content/headers sent (default false)
     * 
     * 'encodeOutput' : to disable content encoding, set this to false (default true)
     * 
     * 'encodeMethod' : generally you should let this be determined by 
     * HTTP_Encoder (leave null), but you can force a particular encoding
     * to be returned, by setting this to 'gzip', 'deflate', 'compress', or '' 
     * (no encoding)
     * 
     * 'encodeLevel' : level of encoding compression (0 to 9, default 9)
     * 
     * 'contentTypeCharset' : if given, this will be appended to the Content-Type
     * header sent (needed mainly for HTML docs)  
     * 
     * 'setExpires' : set this to a timestamp or GMT date to have Minify send
     * an HTTP Expires header instead of checking for conditional GET (default null). 
     * E.g. (time() + 86400 * 365) for 1yr 
     * Note this has nothing to do with server-side caching.
     * 
     * 'perType' : this is an array of options to send to a particular minifier 
     * function using the content-type as key. E.g. To send the CSS minifier an 
     * option: 
     * <code>
     * $options['perType'][Minify::TYPE_CSS]['optionName'] = 'optionValue';
     * </code>
     * When the CSS minifier is called, the 2nd argument will be
     * array('optionName' => 'optionValue').
     * 
     * Any controller options are documented in that controller's setupSources() method.
     * 
     */
    public static function serve($controller, $options = array()) {
        if (is_string($controller)) {
            // make $controller into object
            $class = 'Minify_Controller_' . $controller;
            if (! class_exists($class, false)) {
                require_once "Minify/Controller/{$controller}.php";    
            }
            $controller = new $class();
        }
        
        // set up controller sources and mix remaining options with
        // controller defaults
        $options = $controller->setupSources($options);
        $options = $controller->analyzeSources($options);
        self::$_options = $controller->mixInDefaultOptions($options);
        
        if (! $controller->sources) {
            // invalid request!
            if (! self::$_options['quiet']) {
                header(self::$_options['badRequestHeader']);
                echo self::$_options['badRequestHeader'];
            }
            list(,$statusCode) = explode(' ', self::$_options['badRequestHeader']);
            return array(
                'success' => false
                ,'statusCode' => (int)$statusCode
                ,'content' => ''
                ,'headers' => array()
            );
        }
        
        self::$_controller = $controller;
        
        $cgOptions = array(
            'lastModifiedTime' => self::$_options['lastModifiedTime']
            ,'isPublic' => self::$_options['isPublic']
        );
        if (null !== self::$_options['setExpires']) {
            $cgOptions['setExpires'] = self::$_options['setExpires'];
        }
        
        // check client cache
        require_once 'HTTP/ConditionalGet.php';
        $cg = new HTTP_ConditionalGet($cgOptions);
        if ($cg->cacheIsValid) {
            // client's cache is valid
            if (! self::$_options['quiet']) {
                $cg->sendHeaders();
            }
            return array(
                'success' => true
                ,'statusCode' => 304 
                ,'content' => ''
                ,'headers' => array()
            );
        }
        // client will need output
        $headers = $cg->getHeaders();
        unset($cg);

        // determine encoding
        if (self::$_options['encodeOutput']) {
            if (self::$_options['encodeMethod'] !== null) {
                // controller specifically requested this
                $contentEncoding = self::$_options['encodeMethod'];
            } else {
                // sniff request header
                require_once 'HTTP/Encoder.php';
                // depending on what the client accepts, $contentEncoding may be 
                // 'x-gzip' while our internal encodeMethod is 'gzip'
                list(self::$_options['encodeMethod'], $contentEncoding) = HTTP_Encoder::getAcceptedEncoding();
            }
        } else {
            self::$_options['encodeMethod'] = ''; // identity (no encoding)
        }
        
        if (null !== self::$_cachePath) {
            self::_setupCache();
            // fetch content from cache file(s).
            $content = self::_fetchContent(self::$_options['encodeMethod']);
            self::$_cache = null;
        } else {
            // no cache, just combine, minify, encode
            $content = self::_combineMinify();
            $content = self::_encode($content);
        }

        // add headers to those from ConditionalGet
        //$headers['Content-Length'] = strlen($content);
        $headers['Content-Type'] = (null !== self::$_options['contentTypeCharset'])
            ? self::$_options['contentType'] . '; charset=' . self::$_options['contentTypeCharset']
            : self::$_options['contentType'];
        if (self::$_options['encodeMethod'] !== '') {
            $headers['Content-Encoding'] = $contentEncoding;
            $headers['Vary'] = 'Accept-Encoding';
        }

        if (! self::$_options['quiet']) {
            // output headers & content
            foreach ($headers as $name => $val) {
                header($name . ': ' . $val);
            }
            echo $content;   
        }
        return array(
            'success' => true
            ,'statusCode' => 200
            ,'content' => $content
            ,'headers' => $headers                
        );
    }
    
    /**
     * @var mixed null if disk cache is not to be used
     */
    protected static $_cachePath = null;

    /**
     * @var Minify_Controller active controller for current request
     */
    protected static $_controller = null;
    
    /**
     * @var array options for current request
     */
    protected static $_options = null;
    
    /**
     * @var Cache_Lite_File cache obj for current request
     */
    protected static $_cache = null;
    
    
    
    /**
     * Fetch encoded content from cache (or generate and store it).
     * 
     * If self::$cacheUnencodedVersion is true and encoded content must be 
     * generated, this function will call itself recursively to fetch (or 
     * generate) the minified content. Otherwise, it will always recombine
     * and reminify files to generate different encodings.  
     * 
     * @param string $encodeMethod
     * 
     * @return string minified, encoded content
     */
    protected static function _fetchContent($encodeMethod)
    {
        $cacheId = self::_getCacheId(self::$_controller->sources, self::$_options) 
            . $encodeMethod;
        $content = self::$_cache->get($cacheId, 'Minify');
        if (false === $content) {
            // must generate
            if ($encodeMethod === '') {
                // generate identity cache to store
                $content = self::_combineMinify();
            } else {
                // fetch identity cache & encode it to store
                if (self::$cacheUnencodedVersion) {
                    // double layer cache
                    $content = self::_fetchContent('');
                } else {
                    // recombine
                    $content = self::_combineMinify();
                }
                $content = self::_encode($content);
            }
            self::$_cache->save($content, $cacheId, 'Minify');
        }
        return $content;
    }
    
    /**
     * Set self::$_cache to a new instance of Cache_Lite_File (patched 2007-10-03)
     * 
     * @return null
     */
    protected static function _setupCache() {
        // until the patch is rolled into PEAR, we'll provide the
        // class in our package
        require_once dirname(__FILE__) . '/Cache/Lite/File.php';

        self::$_cache = new Cache_Lite_File(array(
            'cacheDir' => self::$_cachePath . '/'
            ,'fileNameProtection' => false

            // currently only available in patched Cache_Lite_File
            ,'masterTime' => self::$_options['lastModifiedTime']
        ));
    }
    
    /**
     * Combines sources and minifies the result.
     *
     * @return string
     */
    protected static function _combineMinify() {
        $type = self::$_options['contentType']; // ease readability
        
        // when combining scripts, make sure all statements separated
        $implodeSeparator = ($type === self::TYPE_JS)
            ? ';'
            : '';
        
        // allow the user to pass a particular array of options to each
        // minifier (designated by type). source objects may still override
        // these
        $defaultOptions = isset(self::$_options['perType'][$type])
            ? self::$_options['perType'][$type]
            : array();
        // if minifier not set, default is no minification. source objects
        // may still override this
        $defaultMinifier = isset(self::$_options['minifiers'][$type])
            ? self::$_options['minifiers'][$type]
            : false;
       
        if (Minify_Source::haveNoMinifyPrefs(self::$_controller->sources)) {
            // all source have same options/minifier, better performance
            // to combine, then minify once
            foreach (self::$_controller->sources as $source) {
                $pieces[] = $source->getContent();
            }
            $content = implode($implodeSeparator, $pieces);
            if ($defaultMinifier) {
                self::$_controller->loadMinifier($defaultMinifier);
                $content = call_user_func($defaultMinifier, $content, $defaultOptions);    
            }
        } else {
            // minify each source with its own options and minifier, then combine
            foreach (self::$_controller->sources as $source) {
                // allow the source to override our minifier and options
                $minifier = (null !== $source->minifier)
                    ? $source->minifier
                    : $defaultMinifier;
                $options = (null !== $source->minifyOptions)
                    ? array_merge($defaultOptions, $source->minifyOptions)
                    : $defaultOptions;
                if ($defaultMinifier) {
                    self::$_controller->loadMinifier($minifier);
                    // get source content and minify it
                    $pieces[] = call_user_func($minifier, $source->getContent(), $options);     
                } else {
                    $pieces[] = $source->getContent();     
                }
            }
            $content = implode($implodeSeparator, $pieces);
        }
        
        // do any post-processing (esp. for editing build URIs)
        if (self::$_options['postprocessorRequire']) {
            require_once self::$_options['postprocessorRequire'];
        }
        if (self::$_options['postprocessor']) {
            $content = call_user_func(self::$_options['postprocessor'], $content, $type);
        }
        return $content;
    }
    
    /**
     * Applies HTTP encoding
     *
     * @param string $content
     * 
     * @return string
     */
    protected static function _encode($content)
    {
        if (self::$_options['encodeMethod'] === '' 
            || ! self::$_options['encodeOutput']) {
            // "identity" encoding
            return $content;
        }
        require_once 'HTTP/Encoder.php';
        $encoder = new HTTP_Encoder(array(
            'content' => $content
            ,'method' => self::$_options['encodeMethod']
        ));
        $encoder->encode(self::$_options['encodeLevel']);
        return $encoder->getContent();
    }

    /**
     * Make a unique cache id for for this request.
     * 
     * Any settings that could affect output are taken into consideration  
     *
     * @return string
     */
    protected static function _getCacheId() {
        return md5(serialize(array(
            Minify_Source::getDigest(self::$_controller->sources)
            ,self::$_options['minifiers'] 
            ,self::$_options['perType']
        )));
    }
}