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

/**
 * Maintain a single last modification time for a group of Minify sources to
 * allow use of far off Expires headers in Minify.
 * 
 * <code>
 * // in config file
 * $groupSources = array(
 * 'js' => array('file1.js', 'file2.js')
 * ,'css' => array('file1.css', 'file2.css', 'file3.css')
 * )
 * 
 * // during HTML generation
 * $jsBuild = new Minify_Build($groupSources['js']);
 * $cssBuild = new Minify_Build($groupSources['css']);
 * 
 * $script = "<script type='text/javascript' src='"
 * . $jsBuild->uri('/min.php/js') . "'></script>";
 * $link = "<link rel='stylesheet' type='text/css' href='"
 * . $cssBuild->uri('/min.php/css') . "'>";
 * 
 * // in min.php
 * Minify::serve('Groups', array(
 * 'groups' => $groupSources
 * ,'setExpires' => (time() + 86400 * 365)
 * ));
 * </code>
 * 
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 */
class Minify_Build {
 
 /**
 * Last modification time of all files in the build
 * 
 * @var int 
 */
 public $lastModified = 0;
 
 /**
 * String to use as ampersand in uri(). Set this to '&' if
 * you are not HTML-escaping URIs.
 *
 * @var string
 */
 public static $ampersand = '&amp;';
 
 /**
 * Get a time-stamped URI
 * 
 * <code>
 * echo $b->uri('/site.js');
 * // outputs "/site.js?1678242"
 * 
 * echo $b->uri('/scriptaculous.js?load=effects');
 * // outputs "/scriptaculous.js?load=effects&amp1678242"
 * </code>
 *
 * @param string $uri
 * @param boolean $forceAmpersand (default = false) Force the use of ampersand to 
 * append the timestamp to the URI.
 * @return string
 */
 public function uri($uri, $forceAmpersand = false) {
 $sep = ($forceAmpersand || strpos($uri, '?') !== false)
 ? self::$ampersand
 : '?';
 return "{$uri}{$sep}{$this->lastModified}";
 }

	/**
 * Create a build object
 * 
 * @param array $sources array of Minify_Source objects and/or file paths
 * 
 * @return null
 */
 public function __construct($sources) 
 {
 $max = 0;
 foreach ((array)$sources as $source) {
 if ($source instanceof Minify_Source) {
 $max = max($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));
 }
 }
 }
 $this->lastModified = $max;
 }
}