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

/**
 * Helpers for writing Minfy URIs into HTML
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 */
class Minify_HTML_Helper {
 public $rewriteWorks = true;
 public $minAppUri = '/min';
 public $groupsConfigFile = '';

 /**
 * Get an HTML-escaped Minify URI for a group or set of files
 * 
 * @param string|array $keyOrFiles a group key or array of filepaths/URIs
 * @param array $opts options:
 * 'farExpires' : (default true) append a modified timestamp for cache revving
 * 'debug' : (default false) append debug flag
 * 'charset' : (default 'UTF-8') for htmlspecialchars
 * 'minAppUri' : (default '/min') URI of min directory
 * 'rewriteWorks' : (default true) does mod_rewrite work in min app?
 * 'groupsConfigFile' : specify if different
 * @return string
 */
 public static function getUri($keyOrFiles, $opts = array())
 {
 $opts = array_merge(array( // default options
 'farExpires' => true
 ,'debug' => false
 ,'charset' => 'UTF-8'
 ,'minAppUri' => '/min'
 ,'rewriteWorks' => true
 ,'groupsConfigFile' => ''
 ), $opts);
 $h = new self;
 $h->minAppUri = $opts['minAppUri'];
 $h->rewriteWorks = $opts['rewriteWorks'];
 $h->groupsConfigFile = $opts['groupsConfigFile'];
 if (is_array($keyOrFiles)) {
 $h->setFiles($keyOrFiles, $opts['farExpires']);
 } else {
 $h->setGroup($keyOrFiles, $opts['farExpires']);
 }
 $uri = $h->getRawUri($opts['farExpires'], $opts['debug']);
 return htmlspecialchars($uri, ENT_QUOTES, $opts['charset']);
 }

 /**
 * Get non-HTML-escaped URI to minify the specified files
 *
 * @param bool $farExpires
 * @param bool $debug
 * @return string
 */
 public function getRawUri($farExpires = true, $debug = false)
 {
 $path = rtrim($this->minAppUri, '/') . '/';
 if (! $this->rewriteWorks) {
 $path .= '?';
 }
 if (null === $this->_groupKey) {
 // @todo: implement shortest uri
 $path = self::_getShortestUri($this->_filePaths, $path);
 } else {
 $path .= "g=" . $this->_groupKey;
 }
 if ($debug) {
 $path .= "&debug";
 } elseif ($farExpires && $this->_lastModified) {
 $path .= "&" . $this->_lastModified;
 }
 return $path;
 }

 /**
 * Set the files that will comprise the URI we're building
 *
 * @param array $files
 * @param bool $checkLastModified
 */
 public function setFiles($files, $checkLastModified = true)
 {
 $this->_groupKey = null;
 if ($checkLastModified) {
 $this->_lastModified = self::getLastModified($files);
 }
 // normalize paths like in /min/f=<paths>
 foreach ($files as $k => $file) {
 if (0 === strpos($file, '//')) {
 $file = substr($file, 2);
 } elseif (0 === strpos($file, '/')
 || 1 === strpos($file, ':\\')) {
 $file = substr($file, strlen($_SERVER['DOCUMENT_ROOT']) + 1);
 }
 $file = strtr($file, '\\', '/');
 $files[$k] = $file;
 }
 $this->_filePaths = $files;
 }

 /**
 * Set the group of files that will comprise the URI we're building
 *
 * @param string $key
 * @param bool $checkLastModified
 */
 public function setGroup($key, $checkLastModified = true)
 {
 $this->_groupKey = $key;
 if ($checkLastModified) {
 if (! $this->groupsConfigFile) {
 $this->groupsConfigFile = dirname(dirname(dirname(dirname(__FILE__)))) . '/groupsConfig.php';
 }
 if (is_file($this->groupsConfigFile)) {
 $gc = (require $this->groupsConfigFile);
 $keys = explode(',', $key);
 foreach ($keys as $key) {
 if (isset($gc[$key])) {
 $this->_lastModified = self::getLastModified($gc[$key], $this->_lastModified);
 }
 }
 }
 }
 }

 /**
 * Get the max(lastModified) of all files
 *
 * @param array|string $sources
 * @param int $lastModified
 * @return int
 */
 public static function getLastModified($sources, $lastModified = 0)
 {
 $max = $lastModified;
 foreach ((array)$sources as $source) {
 if (is_object($source) && isset($source->lastModified)) {
 $max = max($max, $source->lastModified);
 } elseif (is_string($source)) {
 if (0 === strpos($source, '//')) {
 $source = $_SERVER['DOCUMENT_ROOT'] . substr($source, 1);
 }
 if (is_file($source)) {
 $max = max($max, filemtime($source));
 }
 }
 }
 return $max;
 }

 protected $_groupKey = null; // if present, URI will be like g=...
 protected $_filePaths = array();
 protected $_lastModified = null;

 
 /**
 * In a given array of strings, find the character they all have at
 * a particular index
 *
 * @param array $arr array of strings
 * @param int $pos index to check
 * @return mixed a common char or '' if any do not match
 */
 protected static function _getCommonCharAtPos($arr, $pos) {
 if (!isset($arr[0][$pos])) {
 return '';
 }
 $c = $arr[0][$pos];
 $l = count($arr);
 if ($l === 1) {
 return $c;
 }
 for ($i = 1; $i < $l; ++$i) {
 if ($arr[$i][$pos] !== $c) {
 return '';
 }
 }
 return $c;
 }

 /**
 * Get the shortest URI to minify the set of source files
 *
 * @param array $paths root-relative URIs of files
 * @param string $minRoot root-relative URI of the "min" application
 * @return string
 */
 protected static function _getShortestUri($paths, $minRoot = '/min/') {
 $pos = 0;
 $base = '';
 while (true) {
 $c = self::_getCommonCharAtPos($paths, $pos);
 if ($c === '') {
 break;
 } else {
 $base .= $c;
 }
 ++$pos;
 }
 $base = preg_replace('@[^/]+$@', '', $base);
 $uri = $minRoot . 'f=' . implode(',', $paths);
 
 if (substr($base, -1) === '/') {
 // we have a base dir!
 $basedPaths = $paths;
 $l = count($paths);
 for ($i = 0; $i < $l; ++$i) {
 $basedPaths[$i] = substr($paths[$i], strlen($base));
 }
 $base = substr($base, 0, strlen($base) - 1);
 $bUri = $minRoot . 'b=' . $base . '&f=' . implode(',', $basedPaths);

 $uri = strlen($uri) < strlen($bUri)
 ? $uri
 : $bUri;
 }
 return $uri;
 }
}