pierre@1: <?php
pierre@1: 
pierre@1: /**
pierre@1:  * @file
pierre@1:  * Ad Channel include file.
pierre@1:  *
pierre@1:  * Copyright (c) 2008-2009.
pierre@1:  *   Jeremy Andrews <jeremy@tag1consulting.com>.
pierre@1:  */
pierre@1: 
pierre@1: /**
pierre@1:  * Filter advertisements not in an appropriate channel, from cache.
pierre@1:  */
pierre@1: function ad_channel_cache_filter($ads) {
pierre@1:   _debug_echo("ad_channel_cache: adserve_cache_filter");
pierre@1: 
pierre@1:   $channels = adserve_cache('get_cache', 'channel');
pierre@1:   $valid = array();
pierre@1:   $nochannel = array();
sly@2:   $nochannel_weight = array();
sly@2:   $matched_channel = array();
pierre@1:   foreach ($ads as $aid) {
pierre@1:     _debug_echo("ad_channel_cache: checking aid($aid)");
pierre@1:     if (is_array($channels['ads']) && isset($channels['ads'][$aid]) &&
pierre@1:         is_array($channels['ads'][$aid])) {
pierre@1:       foreach ($channels['ads'][$aid] as $chid) {
pierre@1:         $channel = $channels['channels'][$chid];
pierre@1:         $display = $channel->display;
pierre@1:         $urls = unserialize($channel->urls);
pierre@1:         $frontpage = adserve_variable('site_frontpage') ? adserve_variable('site_frontpage') : 'node';
pierre@1:         $regexp = '/^('. preg_replace(array('/(\r\n?|\n)/', '/\\\\\*/', '/(^|\|)\\\\<front\\\\>($|\|)/'), array('|', '.*', '\1'. preg_quote($frontpage, '/') .'\2'), preg_quote($urls, '/')) .')$/';
pierre@1:         $match = preg_match($regexp, adserve_variable('url'));
pierre@1:         _debug_echo("ad_channel_cache: checking aid($aid) against channel($chid) path(". adserve_variable('url') .") regexp($regexp) match($match)");
pierre@1:         if ($display == 0) { // display on all except listed urls
pierre@1:           if (empty($urls) || !$match) {
pierre@1:             _debug_echo("ad_channel_cache: aid($aid) is valid");
pierre@1:             $valid[] = $aid;
sly@2:             if ($display == 1) {
sly@2:               $nochannel_weight[$chid] = $channel->no_channel_weight;
sly@2:             }
sly@2:             $matched_channel[$aid] = $chid;
sly@2:             _debug_echo("ad_channel_cache: channel($channel->chid) no_channel_weight(". $nochannel_weight[$chid] .')');
pierre@1:             break;
pierre@1:           }
pierre@1:         }
pierre@1:         else { // display only on listed urls
pierre@1:           if (!empty($urls) && $match) {
pierre@1:             _debug_echo("ad_channel_cache: aid($aid) is valid");
pierre@1:             $valid[] = $aid;
sly@2:             if ($display == 1) {
sly@2:               $nochannel_weight[$chid] = $channel->no_channel_weight;
sly@2:             }
sly@2:             $matched_channel[$aid] = $chid;
pierre@1:             break;
pierre@1:           }
pierre@1:         }
pierre@1:         _debug_echo("ad_channel_cache: aid($aid) is not valid");
pierre@1:       }
pierre@1:     }
pierre@1:     else {
pierre@1:       // no channel information for ad, it's valid
pierre@1:       $display = $channels['display'];
pierre@1:       _debug_echo("ad_channel_cache: aid($aid) has no channel info [$display]");
pierre@1:       switch ($display) {
pierre@1:         case 0:
pierre@1:           $nochannel[] = $aid;
pierre@1:           _debug_echo("ad_channel_cache: aid($aid) is valid if no valid ads found in current channel");
pierre@1:           break;
pierre@1:         case 1:
pierre@1:           $valid[] = $aid;
pierre@1:           _debug_echo("ad_channel_cache: aid($aid) is valid");
pierre@1:           break;
pierre@1:         case 2:
pierre@1:           _debug_echo("ad_channel_cache: aid($aid) is not valid");
pierre@1:           break;
pierre@1:       }
pierre@1:     }
pierre@1:   }
pierre@1: 
sly@2:   // Apply weights, applicable for advertisements that are not assigned to any
sly@2:   // channel.
sly@2:   if (!empty($valid) && !empty($nochannel_weight)) {
sly@2:     $weights = array();
sly@2:     foreach ($valid as $aid) {
sly@2:       if (isset($matched_channel[$aid])) {
sly@2:         $chid = $matched_channel[$aid];
sly@2:         if (isset($nochannel_weight[$chid])) {
sly@2:           $weights[$aid] = $nochannel_weight[$chid];
sly@2:           _debug_echo("ad_channel_cache: ad $aid in channel $chid with weight ". $nochannel_weight[$chid]);
sly@2:         }
sly@2:         else {
sly@2:           // by default, ads are assigned a weight of 100%
sly@2:           $weights[$aid] = 100;
sly@2:           _debug_echo("ad_channel_cache: ad $aid in channel $chid with default weight of 100");
sly@2:         }
sly@2:       }
sly@2:       else {
sly@2:         // by default, ads are assigned a weight of 100%
sly@2:         $weights[$aid] = 100;
sly@2:         _debug_echo("ad_channel_cache: ad $aid in no channel with default weight of 100");
sly@2:       }
sly@2:     }
sly@2:     if (!empty($weights)) {
sly@2:       $gcd = ad_channel_probability_gcd($weights);
sly@2:       $display = array();
sly@2:       _debug_echo("ad_channel_cache: adjusting channel weights, gcd ($gcd)");
sly@2:       foreach ($valid as $aid) {
sly@2:         $weight = $weights[$aid] / $gcd;
sly@2:         for ($i = 1; $i <= $weight; $i++) {
sly@2:           $display[] = $aid;
sly@2:         }
sly@2:       }
sly@2:       $valid = $display;
sly@2:     }
sly@2:   }
sly@2:   else if (empty($valid) && !empty($nochannel)) {
pierre@1:     _debug_echo("ad_channel_cache: using ads with no channel info");
pierre@1:     $valid = $nochannel;
pierre@1:   }
pierre@1: 
pierre@1:   $premiere = adserve_cache('get_cache', 'premiere');
pierre@1:   $premieres = array();
pierre@1:   if (is_array($premiere)) {
pierre@1:     foreach ($valid as $aid) {
pierre@1:       if (in_array($aid, $premiere)) {
pierre@1:         _debug_echo("ad_channel_cache: aid($aid) is premiere advertisement");
pierre@1:         $premieres[$aid] = $aid;
pierre@1:       }
pierre@1:       else {
pierre@1:         _debug_echo("ad_channel_cache: aid($aid) is not a premiere advertisement");
pierre@1:       }
pierre@1:     }
pierre@1:     if (!empty($premieres)) {
pierre@1:       _debug_echo("ad_channel_cache: returning premiere advertisements");
pierre@1:       return $premieres;
pierre@1:     }
pierre@1:   }
pierre@1:   _debug_echo("ad_channel_cache: returning non-premiere advertisements");
pierre@1:   return $valid;
pierre@1: }
sly@2: 
sly@2: /**
sly@2:  * Returns the greatest common divisor of an array of integers.
sly@2:  */
sly@2: function ad_channel_probability_gcd($integers) {
sly@2:   $gcd = array_shift($integers);
sly@2: 
sly@2:   while (!empty($integers)) {
sly@2:     $gcd = _ad_channel_probability_gcd($gcd, array_shift($integers));
sly@2:   }
sly@2:   return $gcd;
sly@2: }
sly@2: 
sly@2: /**
sly@2:  * Helper function to calculate the greatest common divisor using the Euclidean
sly@2:  * algorithm (http://en.wikipedia.org/wiki/Euclidean_algorithm).
sly@2:  */
sly@2: function _ad_channel_probability_gcd($a, $b) {
sly@2:   if ($b == 0) {
sly@2:     return $a;
sly@2:   }
sly@2:   else {
sly@2:     return _ad_channel_probability_gcd($b, $a % $b);
sly@2:   }
sly@2: }