<?php

/**
 * @file
 * Admin pages for calculating study group session membership
 */

/**
 * Function for selecting who is available to lead or help sessions
 */

function booking_available_leadhelp_select_form() {
	global $event;
	
	//see http://www.jaypan.com/blog/themeing-drupal-7-forms-tables-checkboxes-or-radios	
	$form = array ();	
	$options = array ();
	$prefix = t("<p>Specify the number of leader or helper sessions for each attendee. Note that this will overwrite the previous value.</p>");
	$session_count = array();
	$session_count['0'] = 0;
	$session_count['1'] = 1;
	$session_count['2'] = 2;	
	$session_count['3'] = 3;	
	$session_count['4'] = 4;
	$session_count['5'] = 5;
	
	$form['booking-leadhelp-count'] = array(
		'#type' => 'select',
		'#title' => t('Set Number of Sessions'),
		'#required' => TRUE,
		'#default_value' => '0',
		'#options' => $session_count,
	);	
	
	$header = array (
		'booking_nid' =>  array('data' => t('Booking ID')),
		'booking_name' =>  array('data' => t('Name')),
		'booking_gender' =>  array('data' => t('Gender')),
		'booking_baptised' =>  array('data' => t('Baptised?')),		
		'booking_age' =>  array('data' => t('Age at start of event')),
		'booking_lead_sessions' => array('data' => t('Total number of groups to lead')),
		'booking_available_lead' => array('data' => t('Remaining slots')),
		'booking_help_sessions' => array('data' => t('Total number of groups to help')),
		'booking_available_help' => array('data' => t('Remaining slots')),
	);	

	$result = db_query("SELECT * FROM {booking_person} p left outer join {booking_leadhelp_list} l on p.nid = l.booking_node_id WHERE p.booking_event_id = :eid ORDER BY p.booking_gender DESC, p.booking_dob, p.booking_baptised", 
					array(':eid' => $event->eid));	

	foreach($result as $data)
	{
		$options[$data->nid] = array (
			'booking_nid' => l(t('!id', array('!id' => $data->nid)),  t('node/!id', array('!id' => $data->nid))),
			'booking_name' => $data->booking_firstname . " " . $data->booking_lastname,
			'booking_gender' => $data->booking_gender == 'M' ? 'Male' : 'Female',
			'booking_baptised' => $data->booking_baptised == 'Y' ? 'Yes' : 'No',
			'booking_age' => _booking_avg_age($data->booking_dob, 1, $event->booking_event_start),
			'booking_lead_sessions' => $data->booking_total_lead === NULL ? '0' : $data->booking_total_lead,
			'booking_available_lead' => $data->booking_available_lead === NULL ? '0' : $data->booking_available_lead,
			'booking_help_sessions' => $data->booking_total_help === NULL ? '0' : $data->booking_total_help,
			'booking_available_help' => $data->booking_available_help === NULL ? '0' : $data->booking_available_help,
		);
	}	

	$form['table'] = array (
		'#type' => 'tableselect',
		'#header' => $header,
		'#options' => $options,
		'#empty' => t('No attendees found.'),
	);
	
	$form['submit-leader'] = array (
		'#type' => 'submit',
		'#value' => t('Set Leader'),
	);
	
	$form['submit-helper'] = array (
		'#type' => 'submit',
		'#value' => t('Set Helper'),
	);	

	return array (
		'first_para' => array (
			'#type' => 'markup',
			'#markup' => $prefix,
		),
		'form' => $form,
	);
}

/**
 * Process the submission for number of study group sessions to lead/help
 */
function booking_available_leadhelp_select_form_submit($form, &$form_state) {
	global $event;
	$counter = 0;
	$checkboxes = $form_state['values']['table'];
	$session_count = $form_state['values']['booking-leadhelp-count'];
 
	foreach($checkboxes as $key => $value)
	{
		if (is_numeric($key)  && $value != 0)
		{	
			//watchdog('booking', 'Checking !nid for entry in the booking_leadhelp_list table', array ('!nid' => $key));
			
			//check if an entry already exists for this person in the booking_leadhelp_list table
		    $person = db_query("SELECT person.booking_node_id " .
						"FROM     {booking_leadhelp_list} person " .
						"WHERE booking_node_id = :nid", 
						array(':nid' => $key))
						->fetchObject();			
			
			if ($form_state['values']['op'] == 'Set Leader')
			{
				watchdog('booking', 'Setting group leader count to !count for !nid', array ('!count' => $session_count, '!nid' => $key));

				if ($person)
				{
					//run an update
					db_update('booking_leadhelp_list')
					->fields(array (
						'booking_total_lead' => $session_count, 
						'booking_available_lead' => $session_count, 
						))
					->condition('booking_node_id', $key)
					->execute();					
				}
				else
				{
					//run an insert
					db_insert('booking_leadhelp_list')
						->fields(array(	
						    'booking_eventid' => $event->eid,
							'booking_node_id' => $key,
							'booking_total_lead' => $session_count, 
							'booking_available_lead' => $session_count,							
							'booking_total_help' => 0, 
							'booking_available_help' => 0,						
					  ))
					  ->execute();					
				} 		
				
			}
			elseif ($form_state['values']['op'] == 'Set Helper')
			{
				watchdog('booking', 'Setting group helper count to !count for !nid', array ('!count' => $session_count, '!nid' => $key));
				
				if ($person)
				{
					//run an update
					db_update('booking_leadhelp_list')
					->fields(array (
						'booking_total_help' => $session_count, 
						'booking_available_help' => $session_count, 
						))
					->condition('booking_node_id', $key)
					->execute();					
				}
				else
				{
					//run an insert
					db_insert('booking_leadhelp_list')
						->fields(array(	
						    'booking_eventid' => $event->eid,
							'booking_node_id' => $key,
							'booking_total_lead' => 0, 
							'booking_available_lead' => 0,							
							'booking_total_help' => $session_count, 
							'booking_available_help' => $session_count,						
					  ))
					  ->execute();					
				}				
				
			}
		
			$counter++;		
		}	
	}
	
	drupal_set_message("Defined leader/helper numbers for $counter people.", 'status', FALSE);
	watchdog('booking', "Defined leader/helper numbers for $counter people.");	
}

/**
 * Function for defining the number of study group sessions
 * Note: This is hard-coded for now in the install file
 */


/**
 * Function to correctly clone an associative array storing objects
 * Taken from http://stackoverflow.com/questions/1532618/is-there-a-function-to-make-a-copy-of-a-php-array-to-another
 */
function clone_array($copied_array) {
    return array_map(function($element) {
        return (
            ((is_array($element))
                ? call_user_func(__FUNCTION__, $element)
                : ((is_object($element))
                    ? clone $element
                    : $element
                )
            )
        );
    }, $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
 */
function booking_studygroups_calculate() {
	global $event;
	
	//master attendee list
	$attendees = array();
	//temporary working copy of attendee list
	$working_list = array();
	//create an array to keep track of the number of people in each session for each group
	$session_count = array();
		
	//delete from booking_studygroup_mapping;
	//alter table booking_studygroup_mapping AUTO_INCREMENT=1;

	//consider using a lock as per https://api.drupal.org/api/drupal/includes!lock.inc/group/lock/7

	//select all the study groups for this event id
	$studygroups_query = db_query("SELECT * FROM {booking_studygroup_list} WHERE booking_eventid = :eid", array(':eid' => $event->eid));
	$studygroups = $studygroups_query->fetchAllAssoc('sid');
	
	//calculate the max number of attendees in a group
	$firstgroup = reset($studygroups);
	$limit = variable_get('booking_regn_limit','500');
	//add an extra one to the maximum size, to cater for some larger groups when the number of people doesn't divide evenly
	$max_people = (int) ($limit / $firstgroup->booking_num_group_sessions) + 1;

	//select all the attendees booked in
	$query = db_query("SELECT p.nid, p.booking_partner_id, p.booking_event_id, p.booking_status, l.booking_total_lead, l.booking_available_lead, l.booking_total_help, l.booking_available_help FROM {booking_person} p left outer join {booking_leadhelp_list} l on p.nid = l.booking_node_id WHERE p.booking_event_id = :eid AND p.booking_status = 1", 
					array(':eid' => $event->eid));
	$attendees = $query->fetchAllAssoc('nid');
	
	//select any entries already in the mapping table
	$group_mapping_query = db_query("SELECT * FROM {booking_studygroup_mapping} WHERE booking_eventid = :eid", array(':eid' => $event->eid));
	$group_mapping = $group_mapping_query->fetchAllAssoc('sid');
	
	//iterate over the attendee associative array and add some fields	
	foreach ($attendees as $person)
	{
		//flag that indicates processed or not
		$person->processed = 0;
		//field that indicates the session id the person is assigned to	
		$person->session = 0;
		$person->is_leader = 0;
		$person->is_helper = 0;
		//convert NULLs into zero
		$person->booking_total_lead = $person->booking_total_lead === NULL ? '0' : $person->booking_total_lead;
		$person->booking_available_lead = $person->booking_available_lead === NULL ? '0' : $person->booking_available_lead;
		$person->booking_total_help = $person->booking_total_help === NULL ? '0' : $person->booking_total_help;
		$person->booking_available_help = $person->booking_available_help === NULL ? '0' : $person->booking_available_help;	
	}
	
	//watchdog('booking', "Attendee list: @info", array('@info' => var_export($attendees, TRUE)));

	//iterate over each study group (eg Monday Tuesday Wednesday etc)
	foreach ($studygroups as $group)
	{
		drupal_set_message(t('Processing study group !group with !sessions sessions.', 
			array('!group' => $group->booking_studygroup_descrip, '!sessions' => $group->booking_num_group_sessions)));
		
		//create a temporary copy of the attendee list to work with for this study group
		$working_list = array();
		$working_list = shuffle_assoc(clone_array($attendees));
		//set up the iterator
		$obj = new ArrayObject( $working_list );
		$it = $obj->getIterator();		
		
		//clear the array keeping track of the number of people in each session for this group
		for ($i = 1; $i <= $group->booking_num_group_sessions; $i++)
			$session_count[$i] = 0;
		
		//reset the iterator to starting position
		$it->rewind();
		
		//watchdog('booking', "Attendee list: @info", array('@info' => var_export($attendees, TRUE)));
		//watchdog('booking', "Attendee list working copy: @info", array('@info' => var_export($working_list, TRUE)));

		$session_id = 1;
		$rewound = FALSE;
		$leader_found = FALSE;
		$helper_found = FALSE;
		
		while (true)
		{
			//if we're at the end of the attendee list, go back to the start
			if (! $it->valid() )
			{
				if ($rewound == TRUE)
				{
					//watchdog('booking', "Already rewound once.");
					drupal_set_message(t("Error: Reached end of attendee list before allocating all study group leaders/helpers for group !group.", 
										array('!group' => $group->booking_studygroup_descrip)), 'error', FALSE);
					//we've already gone back to the start once, don't do it again
					break;
				}
				else
				{
					watchdog('booking', "Rewinding to start of attendee list.");
					$it->rewind();
					$rewound = TRUE;
				}
			}
			
			//check if we have reached the total number of sessions required
			if ($session_id > $group->booking_num_group_sessions)
			{
				break;
			}
			//check if we can increment the session count
			if ($leader_found == TRUE && $helper_found == TRUE)
			{
				$session_id++;
				$leader_found = FALSE;
				$helper_found = FALSE;				
			}

			//get the current attendee element
			$current = $it->current();	
			$key = $it->key();			
			//watchdog('booking', 'Attendee before leader check has id !id.', array('!id' => $it->key()));
			
			//check if this attendee can be a leader
			if ($leader_found == FALSE && $current->processed == 0 && $current->booking_available_lead > 0)
			{
				drupal_set_message(t('Found available leader with id !id for session !session (currently with !num people).', 
						array('!id' => $it->key(), '!session' => $session_id, '!num' => $session_count[$session_id])));
				
				$leader_found = TRUE;
				
				//assign leader to session and mark as processed in the temporary attendee list					
				$current->session = $session_id;
				$current->processed = 1;
				$current->is_leader = 1;

				//keep track of the number of people in this study group session
				$session_count[$session_id]++;
									
				//decrement the number of available leading positions for this user in our master copy of the attendee list
				$attendees[$key]->booking_available_lead = $attendees[$key]->booking_available_lead - 1;
				
				$partner_id = $current->booking_partner_id;
				
				//Check for spouse of leader, allocate to this group also
				if ($partner_id > 0)					
				{
					//add the spouse to the same session and mark as processed in the temporary attendee list
					drupal_set_message(t('Assigning spouse (id !spouse) of id !id to session !session (currently with !num people).', 
						array('!id' => $it->key(), '!session' => $session_id, '!spouse' => $partner_id, '!num' => $session_count[$session_id])));							
					
					//$spouse = ;
					$working_list[$partner_id]->session = $session_id;
					$working_list[$partner_id]->processed = 1;	
					$session_count[$session_id]++;
				}			
			}
			//check if this attendee can be a helper
			elseif ($helper_found == FALSE && $current->processed == 0 && $current->booking_available_help > 0)			
			{
				drupal_set_message(t('Found available helper with id !id for session !session (currently with !num people).', 
									array('!id' => $it->key(), '!session' => $session_id, '!num' => $session_count[$session_id])));
				
				$helper_found = TRUE;
				
				//assign leader to session and mark as processed in the temporary attendee list					
				$current->session = $session_id;
				$current->processed = 1;
				$current->is_helper = 1;
				$session_count[$session_id]++;			
				
				//decrement the number of available helping positions for this user in our master copy of the attendee list
				$attendees[$key]->booking_available_help = $attendees[$key]->booking_available_help - 1;	
				
				$partner_id = $current->booking_partner_id;
				
				//Check for spouse of helper, allocate to this group also
				if ($partner_id > 0)					
				{
					//add the spouse to the same session and mark as processed in the temporary attendee list
					drupal_set_message(t('Assigning spouse (id !spouse) of id !id to session !session.', 
						array('!id' => $it->key(), '!session' => $session_id, '!spouse' => $current->booking_partner_id)));			
					
					$session_count[$session_id]++;								
					$working_list[$partner_id]->session = $session_id;
					$working_list[$partner_id]->processed = 1;		
				}						
			}
			//this attendee can be neither a leader nor a helper, go to the next attendee
			else
			{
				$it->next();
			}
		}
		
		//watchdog('booking', "Attendee list: @info", array('@info' => var_export($session_count, TRUE)));

		//reset the iterator to starting position of the attendee list
		$it->rewind();
		
		//set our counter
		$i = 1;
	
		//iterate over the attendee list
		while ( $it->valid() )
		{		
			//go to the first unprocessed attendee
			while ($it->current()->processed == 1)
			{
				drupal_set_message(t('Person with id !id has already been processed earlier.', array('!id' => $it->key())));
				$it->next();
				//double check we didn't run out of people right here
				if (! $it->valid() )
				{
					drupal_set_message("Ran out of attendees to process.");
					break;
				}										
			}		
			
			//cycle the session counter if we already reached the end
			if ($i > $group->booking_num_group_sessions)
				$i = 1;				

			//check this session has room in it			
			$break_condition = false;
			while ($session_count[$i] >= $max_people)
			{
				drupal_set_message(t("Session ID !id is full, moving to next session for user id !nid", array('!id' => $i, '!nid' => $it->key())));
				$i++;
				//reset the counter if we go past the end
				if ($i > $group->booking_num_group_sessions)
				{
					$i = 1;	
					//make sure we don't get stuck in an infinite loop - only go past the end once
					if ($break_condition == true)
					{
						drupal_set_message("Ran out of sessions that aren't full to place attendees into.");
						break;
					}
					$break_condition = true;
				}			
			}

			//get the current attendee element
			$current = $it->current();					
			
			//assign this attendee to this session if unprocessed so far
			if ($current->processed == 0)
			{				
				drupal_set_message(t('Assigning person with id !id to session !session (now with !num people).', array('!id' => $it->key(), '!session' => $i, '!num' => $session_count[$i])));
				$current->session = $i;
				$current->processed = 1;
				$partner_id = $current->booking_partner_id;
				$session_count[$i]++;

				//check if the attendee was married
				if ($partner_id > 0)				
				{
					//add the spouse to the same session and mark as processed in the temporary attendee list
					drupal_set_message(t('Assigning spouse (id !spouse) of id !id to session !session.', 
						array('!id' => $it->key(), '!session' => $i, '!spouse' => $current->booking_partner_id)));							
					
					$working_list[$partner_id]->session = $i;
					$working_list[$partner_id]->processed = 1;	
					$session_count[$i]++;
				}
			}	

			//move to the next unprocessed attendee in the list
			while ($it->valid() && $it->current()->processed == 1)
			{
				//drupal_set_message(t("Skipping attendee ID !id, already processed.", array('!id' => $it->key())));
				$it->next();
			}
			
			//move to the next session
			$i++;	
		}	//finished looping through attendees for this study group	

		
		//iterate over the attendee list and write to the database the session they're assigned to
		//use the multi-insert query type at https://drupal.org/node/310079
		$insert_query = db_insert('booking_studygroup_mapping')->fields(array('booking_eventid', 'booking_node_id', 
							'booking_studygroup_id', 'booking_session_id', 'booking_is_leader', 'booking_is_helper'));

		foreach($working_list as $person) 
		{		
			
			//TODO: a check to update existing records rather than inserting new one
			//	if already in $group_mapping then just run an update query here
			
			$found = FALSE;
			foreach ($group_mapping as $mapping)
			{
				//check if we can find a study group session already for this user and this study group (eg Monday Tuesday or Wednesday)
				if ($person->nid == $mapping->booking_node_id && $group->sid == $mapping->booking_studygroup_id)
				{
					$found = TRUE;

					drupal_set_message(t('Found existing study group session for user id !id. Running update query on table id !sid to set session id to !session', 
						array('!id' => $person->nid, '!sid' => $mapping->sid, '!session' => $person->session)));
					
					//update the entry			
					db_update('booking_studygroup_mapping')
					  ->fields(array(
						'booking_session_id' => $person->session,
						'booking_is_leader' => $person->is_leader,
						'booking_is_helper' => $person->is_helper,						
						))
					  ->condition('sid', $mapping->sid)
					  ->execute();	
						
					break;
				}
			}
			
			//if we didn't find an existing record, add it to the list to insert
			if (! $found)
			{
				drupal_set_message(t('Found no existing study group session for user id !id. Adding to list of inserts.', 
					array('!id' => $person->nid, '!sid' => $mapping->sid, '!session' => $person->session)));				
				
				
				$record = array(
					'booking_eventid' => $event->eid,
					'booking_node_id' => $person->nid,
					'booking_studygroup_id' => $group->sid,
					'booking_session_id' => $person->session,
					'booking_is_leader' => $person->is_leader,
					'booking_is_helper' => $person->is_helper,
				);
				$insert_query->values($record);
			}
			
		}			
		$insert_query->execute();		
		
		
		//watchdog('booking', "Attendee list: @info", array('@info' => var_export($session_count, TRUE)));
		
		//clear the arrays we've been using for this iteration
		unset($session_count);
		unset($working_list);
		
		//
		
	}	//finished processing study groups	
	
	//watchdog('booking', "Attendee list final version: @info", array('@info' => var_export($attendees, TRUE)));
}

/**
 * Function for listing the study groups and links to view each one
 */
function booking_studygroups_view_summary() {

	global $event;
	$output = "";
	$header = array('Link','Study Group', 'Session Count');
	$attributes = array('style' => 'max-width:30%');	
	
	//get study groups
	$query = db_select('booking_studygroup_list', 's')
		->fields('s')
		->condition('s.booking_eventid', $event->eid, '=');
	$result = $query->execute();
	
	foreach ($result as $group) {
		$rows[] = array(
			l(t('!id', array('!id' => $group->sid)),  t('admin/config/booking/studygroups/!id/view', array('!id' => $group->sid))),
			$group->booking_studygroup_descrip,
			$group->booking_num_group_sessions,
		);
	}	

	//output everything
	$output .= t("<h3>!event Study Groups</h3>", array('!event' => $event->booking_eventname));
	$output .= theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => $attributes));		 

	return $output;
	
}

/**
 * Function for viewing who belongs to which study group
 */
function booking_studygroups_view_form($node, &$form_state, $group_id) {
	global $event;
	
	$form = array();	
	$options = array();
	$last_session = "";

	//attach the custom css
	$form['#attached']['css'] = array(
	  drupal_get_path('module', 'booking') . '/booking.css',
	);
	
	//verify that $group_id is a number
	if (! preg_match('/^[0-9]+$/', $group_id)) {
		drupal_set_message("Error: Invalid study group ID supplied. Unable to view group membership.", 'error', FALSE);
		drupal_goto('admin/config/booking');
		return "";
	}
	
	//collect information on the study group
	$group = db_query("SELECT * FROM {booking_studygroup_list} WHERE booking_eventid = :eid and sid = :sid",
						array(':eid' => $event->eid, ':sid' => $group_id))
			->fetchObject();	
			
	if (! $group)
	{
		drupal_set_message("Error: Could not find matching study group ID. Unable to view group membership.", 'error', FALSE);
		drupal_goto('admin/config/booking');
		return "";			
	}

	$header = array(
		'booking_session_id' => array('data' => t('Study Group Session'), 'field' => 'm.booking_session_id', 'sort' => 'asc'),		
		'booking_name' => array('data' => t('Name'), 'field' => 'p.booking_lastname', 'sort' => 'asc'),
		'booking_is_leader' => array('data' => t('Leader?'), 'field' => 'm.booking_is_leader', 'sort' => 'asc'),
		'booking_is_helper' => array('data' => t('Helper?'), 'field' => 'm.booking_is_helper', 'sort' => 'asc'),
	);	
	
	$query = db_select('booking_person', 'p');
	$query->leftJoin('booking_studygroup_mapping', 'm', 'm.booking_node_id = p.nid');
	
	$db_and = db_and();
	$db_and->condition('p.booking_event_id', $event->eid, '=');
	$db_and->condition('m.booking_studygroup_id', $group_id, '=');
	
	$query->condition($db_and);
	$query->fields('p')->fields('m');
	
	$table_sort = $query->extend('TableSort')->orderbyHeader($header);
	$result = $table_sort->execute();	

	//watchdog('booking', 'Study groups raw data: @info', array ('@info' => var_export($result, TRUE)));

	foreach($result as $data)
	{
		$class = "";
		
		//apply theme as required
		if ($data->booking_is_leader == 1)
			$class = "leader-row";
		elseif ($data->booking_is_helper == 1)
			$class = "helper-row";
		else
			$class = "normal-row";
			
		//Add a different id for first entry of new session, with a border-top to distinguish it
		if ($last_session <> $data->booking_session_id && $last_session <> "")
		{
			if ($class === "leader-row")
				$class = "leader-new-group-row";
			elseif ($class === "helper-row")
				$class = "helper-new-group-row";
			else
				$class = "new-group-row";
		}
		
		$options[$data->nid] = array (
			'booking_session_id' => $data->booking_session_id,
			'booking_name' => $data->booking_firstname . " " . $data->booking_lastname,
			'booking_is_leader' => $data->booking_is_leader == 1 ? 'Yes' : 'No',
			'booking_is_helper' => $data->booking_is_helper == 1 ? 'Yes' : 'No',
			'#attributes' => array('id' => array($class))
		);
		
		$last_session = $data->booking_session_id;
	}	
	
	$prefix = t("<h2>Study Group !descrip</h2>", array('!descrip' => $group->booking_studygroup_descrip));

	$form['table'] = array (
		'#type' => 'tableselect',
		'#header' => $header,
		'#options' => $options,
		//'#attributes' => array('id' => 'sort-table'),
	);

	return array (
		'first_para' => array (
			'#type' => 'markup',
			'#markup' => $prefix,
		),
		'form' => $form,
	);	
	
	
}