<?
/*
* Gallery - a web based photo album viewer and editor
* Copyright (C) 2000-2001 Bharat Mediratta
* 
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
* 
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* General Public License for more details.
* 
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

/*
* This block selects a random photo for display.  It will only display photos
* from albums that are visible to the public.  It will not display hidden
* photos.  
*
* Once a day (or whatever you set CACHE_EXPIRED to) we scan all albums and
* create a cache file listing each public album and the number of photos it
* contains.  For all subsequent attempts we use that cache file.  This means
* that if you change your albums around it may take a day before this block
* starts (or stops) displaying them.
*/

/*
* With Barca-Hall modifications
*
* Latest revision: 8-Jun-2004 to clean-up HTML output to pass W3C validation.
*
*
* See: http://www.barcahall.com/gallery-block-random.html.
*/

// Hack prevention.
if (!empty($HTTP_GET_VARS["GALLERY_BASEDIR"]) ||
        !empty($HTTP_POST_VARS["GALLERY_BASEDIR"]) ||
        !empty($HTTP_COOKIE_VARS["GALLERY_BASEDIR"])) {
    print "Security violation\n";
    exit;
}

require($GALLERY_BASEDIR . "init.php");

if ($profile) {
    $timer = time();
}

/* Initializing the seed */
srand ((double) microtime() * 1000000);

define(CACHE_FILE, $gallery->app->albumDir . "/block-random.cache");
define(CACHE_EXPIRED, 86400);

// Check the cache file to see if it's up to date
$rebuild = 1;
if (fs_file_exists(CACHE_FILE)) {
    $stat = fs_stat(CACHE_FILE);
    $mtime = $stat[9];
    if (time() - $mtime < CACHE_EXPIRED) {
    $rebuild = 0;
    }
}

// Only select sub-albums that Everybody can access
$everybody = $gallery->userDB->getEverybody();

if ($rebuild) {
    scanAlbums();
    saveCache();
} else {
    readCache();
}

// Parameter: size
// Specify that the thumbnail image should be resized when displayed, 
// to fit a specific dimension in both height and width. Aspect ratio is maintained.
// Intended to reduce the size of images, but if the size specified is larger than either thumbnail dimension, 
// the image will be enlarged (with a corresponding loss of quality.)
// Note: This does not create an additional thumbnail, nor does it alter the existing thumbnail; 
// the image is dynamically scaled by the browser when rendered.
// Example: size=75
// Default: 0, meaning no resize.

if (!empty($HTTP_GET_VARS["size"]))
	$size = $HTTP_GET_VARS["size"];
else
      $size = 0;

// Parameter: domain
// Specify the value to which document.domain should be set.
// Not needed if this page and the page calling it are on the same server.
// Allows the page embedding this random photo page to resize the containing IFRAME, 
// when the two pages are on different servers, but within a common domain (e.g. "www.foo.com" and "gallery.foo.com").
// The value specified must be the common suffix of the two server names, cannot be simply ".com",
// and the calling page must set its document.domain to the same value.
// Example: domain=foo.com
// Default: none. If not specified, no document.domain statement will be executed.

if (!empty($HTTP_GET_VARS["domain"]))
	$domain = $HTTP_GET_VARS["domain"];

// Parameter: target
// Specify the value to be used in the target= attribute of the A tag. 
// Example: target=_top
// Default: _blank

if (!empty($HTTP_GET_VARS["target"]))
	$targetAttr = "target=\"".$HTTP_GET_VARS["target"] ."\"";
else
      $targetAttr = "target=\"_blank\"";

// Parameter: album
// Limit the photo block to only one album (including its sub-albums). 
// Example: album=nytrip
// Default: none.  If not specified, all visible albums will be used.

if (!empty($HTTP_GET_VARS["album"]))
    {
    $album = new Album();
    $album->load($HTTP_GET_VARS["album"]);
    }
else
    $album = chooseAlbum();

if ($album) {
    $index = choosePhoto();
}

if (!$GALLERY_EMBEDDED_INSIDE) {	
   echo "<head>"
      .getStyleSheetLink();
   
   echo "<style type=\"text/css\">";
   echo "BODY { margin:0 0; }";
   if ($album->fields["bgcolor"]) {
     echo "BODY { background-color:".$album->fields[bgcolor]."; }";
   }
   if ($album->fields["textcolor"]) {
     echo "BODY {color:".$album->fields[textcolor]."; }";
   }
   
   echo "</style>";
   if ($domain) {
     echo "<script language='JavaScript'>document.domain='$domain';</script>";
   }
   echo "</head>";
}


if (isset($index)) {
    $id = $album->getPhotoId($index);
    
    echo "<center>"
        ."<a href=\"" .makeAlbumUrl($album->fields["name"], $id) ."\" $targetAttr>"
        .$album->getThumbnailTag($index,$size)
        ."</a>";
    
    $caption = $album->getCaption($index);
    echo "<span class=caption>";
    if ($caption) {
        echo "<br>$caption";
    }
    
    echo "<br><i>From: </i>"
        ."<a href=\"" .makeAlbumUrl($album->fields["name"]) ."\" $targetAttr>"
        .$album->fields["title"]
        ."</a></span></center></body>";
} else 
   {
   // No photo chosen.  Provide link to album itself, otherwise to top-level of gallery.
   if ($album) {
      echo "<center>"
          ."<a href=\"" .makeAlbumUrl($album->fields["name"]) ."\" $targetAttr>"
          .$album->getHighlightAsThumbnailTag($size)
          ."</a><span class=caption><br>"
          ."<a href=\"" .makeAlbumUrl($album->fields["name"]) ."\" $targetAttr>"
          .$album->fields["title"]
          ."</a></span></center></body>";
   } else {
      print  "<center><a href=\"" . makeGalleryUrl("albums.php") . "\" $targetAttr>" . $gallery->app->galleryTitle . "</a></center>"; 
   }

//    print "No photo chosen.";
}

if ($profile) {
    $elapsed = time() - $timer;
    print "<br>Elapsed: $elapsed secs";
}

/*
* --------------------------------------------------
* Support functions
* --------------------------------------------------
*/

function saveCache() {
    global $cache;
    if ($fd = fs_fopen(CACHE_FILE, "w")) {
    foreach ($cache as $key => $val) {
        fwrite($fd, "$key/$val\n");
    }
    fclose($fd);
    }
}

function readCache() {
    global $cache;
    if ($fd = fs_fopen(CACHE_FILE, "r")) {
    while ($line = fgets($fd, 4096)) {
        list($key, $val) = explode("/", $line);
        $cache[$key] = trim($val);
    }
    fclose($fd);
    }
}

function choosePhoto() {
    global $cache;
    global $album;

    $count = $cache[$album->fields["name"]];
    if ($count == 0) {
    // Shouldn't happen
    return null;
    } else if ($count == 1) {
    $choose = 1;
    } else {
    $choose = rand(1, (int) $count);
    $wrap = 0;

    // Skip an item in the album if it is Private (a hidden photo, or a protected sub-album)
    while ( isPrivate($album, $choose) ) {
        $choose++;
        if ($choose > $count) {
           $choose = 1;
           $wrap++;

           if ($wrap == 2) {
              return null;
           }
        }
    }
    }

    /*
     * If we've picked a sub-album, then 
     * make it the chosen album, and 
     * recursively choose a photo from *it*
    */
    $isSubAlbum = FALSE;
    $subAlbumName = '';
    
    // Backwards compatibility was lost in v1.4.3     

    if (method_exists($album, 'isAlbum')) {
        // Gallery v1.4.3 or later
        if ( $album->isAlbum($choose) ) {
            $isSubAlbum = TRUE;
            $subAlbumName = $album->getAlbumName($choose);
        }
    } 
    else {
        // Gallery v1.4.2 or earlier
        if ( $album->isAlbumName($choose) ) {
            $isSubAlbum = TRUE;
            $subAlbumName = $album->isAlbumName($choose);
        }
    }
        
    if ( $isSubAlbum ) {
       $album->load($subAlbumName);
       return choosePhoto();
    } 

    return $choose;
}

function chooseAlbum() {
    global $cache;

    /*
     * The odds that an album will be selected is proportional
     * to the number of (visible) items in the album.
     */

    $total = 0;
    foreach ($cache as $name => $count) {
    if (!$choose) {
        $choose = $name;
    }
    
    $total += $count;
    if ($total != 0 && ($total == 1 || rand(1, $total) <= $count)) {
        $choose = $name;
    }
    }

    if ($choose) {
    $album = new Album();
    $album->load($choose);
    return $album;
    } else {
    return null;
    }
}

function scanAlbums() {
    global $cache;
    global $gallery;
	global $everybody;

    $cache = array();
 //   $everybody = $gallery->userDB->getEverybody();
    $albumDB = new AlbumDB();
    foreach ($albumDB->albumList as $tmpAlbum) {
    if ($everybody->canReadAlbum($tmpAlbum)) {
        $seeHidden = $everybody->canWriteToAlbum($tmpAlbum);
        $numPhotos = $tmpAlbum->numPhotos($seeHidden);
        $name = $tmpAlbum->fields["name"];
        if ($numPhotos > 0) {
        $cache[$name] = $numPhotos;
        }
    }
    }
}

function isPrivate($alb, $idx) {
	global $everybody;
	
	$isSubAlbum = FALSE;
	$subAlbumName = '';
	
    if (method_exists($alb, 'isAlbum')) {
        // Gallery v1.4.3 or later
        $isSubAlbum = $alb->isAlbum($idx);
		$subAlbumName = $alb->getAlbumName($idx);
    } 
    else {
        // Gallery v1.4.2 or earlier
        $isSubAlbum = $alb->isAlbumName($idx);
		$subAlbumName = $alb->isAlbumName($idx);
    }

	if ( $isSubAlbum ) {
	    $tmpAlb = new Album();
		$tmpAlb->load($subAlbumName);
        return ! $everybody->canReadAlbum($tmpAlb);
	}

    return $alb->isHidden($idx);
}

?>