From 8d33ec2d2f8a300c6c95a007c21e2229ed257073 Mon Sep 17 00:00:00 2001
From: Nathan Coad <nathan@thecoads.com>
Date: Sun, 19 Jan 2014 00:40:05 +1100
Subject: [PATCH] Added randomisation to study group calculations

---
 booking.studygroups.inc | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/booking.studygroups.inc b/booking.studygroups.inc
index e6902a0..af318ac 100644
--- a/booking.studygroups.inc
+++ b/booking.studygroups.inc
@@ -201,6 +201,19 @@ function clone_array($copied_array) {
     }, $copied_array);
 }
 
+//taken from http://stackoverflow.com/questions/4102777/php-random-shuffle-array-maintaining-key-value
+function shuffle_assoc($list) { 
+  if (!is_array($list)) return $list; 
+
+  $keys = array_keys($list); 
+  shuffle($keys); 
+  $random = array(); 
+  foreach ($keys as $key) { 
+    $random[$key] = $list[$key]; 
+  }
+  return $random; 
+}
+
 /**
  * Function for calculating who belongs to which study group
  */
@@ -242,7 +255,7 @@ function booking_studygroups_calculate() {
 		
 		//create a temporary copy of the attendee list to work with for this study group
 		$working_list = array();
-		$working_list = clone_array($attendees);
+		$working_list = shuffle_assoc(clone_array($attendees));
 		//set up the iterator
 		$obj = new ArrayObject( $working_list );
 		$it = $obj->getIterator();		
@@ -296,7 +309,7 @@ function booking_studygroups_calculate() {
 			//watchdog('booking', 'Attendee before leader check has id !id.', array('!id' => $it->key()));
 			
 			//check if this attendee is a leader
-			if ($current->processed == 0 && $current->booking_available_lead > 0)
+			if ($current->processed == 0 && $current->booking_available_lead > 0 && $leader_found == FALSE)
 			{
 				drupal_set_message(t('Found available leader with id !id for session !session.', array('!id' => $it->key(), '!session' => $session_id)));
 				
@@ -322,7 +335,7 @@ function booking_studygroups_calculate() {
 				}
 			}
 			//check if this attendee is a helper
-			elseif ($current->processed == 0 && $current->booking_available_help > 0)			
+			elseif ($current->processed == 0 && $current->booking_available_help > 0 && $helper_found == FALSE)			
 			{
 				drupal_set_message(t('Found available helper with id !id for session !session.', array('!id' => $it->key(), '!session' => $session_id)));
 				
@@ -408,8 +421,9 @@ function booking_studygroups_calculate() {
 				
 				}	
 
-				//move to the next attendee in the list
-				$it->next();
+				//move to the next unprocessed attendee in the list
+				while ($it->valid() && $it->current()->processed == 1)
+					$it->next();
 
 			}	//finished looping through session list