<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/

/**
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

/*
	Ability to simply add own rules by doing three things:
		1) Add an appropriate constant
		2) Add a new check array to the global_privmsgs_rules variable and the condition array (if one is required)
		3) Implement the rule logic in the check_rule() function
		4) Add a new language variable to ucp.php

		The user is then able to select the new rule. It will be checked against and handled as specified.
		To add new actions (yes, checks can be added here too) to the rule management, the core code has to be modified.
*/

define('RULE_IS_LIKE', 1);		// Is Like
define('RULE_IS_NOT_LIKE', 2);	// Is Not Like
define('RULE_IS', 3);			// Is
define('RULE_IS_NOT', 4);		// Is Not
define('RULE_BEGINS_WITH', 5);	// Begins with
define('RULE_ENDS_WITH', 6);	// Ends with
define('RULE_IS_FRIEND', 7);	// Is Friend
define('RULE_IS_FOE', 8);		// Is Foe
define('RULE_IS_USER', 9);		// Is User
define('RULE_IS_GROUP', 10);	// Is In Usergroup
define('RULE_ANSWERED', 11);	// Answered
define('RULE_FORWARDED', 12);	// Forwarded
define('RULE_TO_GROUP', 14);	// Usergroup
define('RULE_TO_ME', 15);		// Me

define('ACTION_PLACE_INTO_FOLDER', 1);
define('ACTION_MARK_AS_READ', 2);
define('ACTION_MARK_AS_IMPORTANT', 3);
define('ACTION_DELETE_MESSAGE', 4);

define('CHECK_SUBJECT', 1);
define('CHECK_SENDER', 2);
define('CHECK_MESSAGE', 3);
define('CHECK_STATUS', 4);
define('CHECK_TO', 5);

/**
* Global private message rules
* These rules define what to do if a rule is hit
*/
$global_privmsgs_rules = array(
	CHECK_SUBJECT	=> array(
		RULE_IS_LIKE		=> array('check0' => 'message_subject'),
		RULE_IS_NOT_LIKE	=> array('check0' => 'message_subject'),
		RULE_IS				=> array('check0' => 'message_subject'),
		RULE_IS_NOT			=> array('check0' => 'message_subject'),
		RULE_BEGINS_WITH	=> array('check0' => 'message_subject'),
		RULE_ENDS_WITH		=> array('check0' => 'message_subject'),
	),

	CHECK_SENDER	=> array(
		RULE_IS_LIKE		=> array('check0' => 'username'),
		RULE_IS_NOT_LIKE	=> array('check0' => 'username'),
		RULE_IS				=> array('check0' => 'username'),
		RULE_IS_NOT			=> array('check0' => 'username'),
		RULE_BEGINS_WITH	=> array('check0' => 'username'),
		RULE_ENDS_WITH		=> array('check0' => 'username'),
		RULE_IS_FRIEND		=> array('check0' => 'friend'),
		RULE_IS_FOE			=> array('check0' => 'foe'),
		RULE_IS_USER		=> array('check0' => 'author_id'),
		RULE_IS_GROUP		=> array('check0' => 'author_in_group'),
	),

	CHECK_MESSAGE	=> array(
		RULE_IS_LIKE		=> array('check0' => 'message_text'),
		RULE_IS_NOT_LIKE	=> array('check0' => 'message_text'),
		RULE_IS				=> array('check0' => 'message_text'),
		RULE_IS_NOT			=> array('check0' => 'message_text'),
	),

	CHECK_STATUS	=> array(
		RULE_ANSWERED		=> array('check0' => 'pm_replied'),
		RULE_FORWARDED		=> array('check0' => 'pm_forwarded'),
	),

	CHECK_TO		=> array(
		RULE_TO_GROUP		=> array('check0' => 'to', 'check1' => 'bcc', 'check2' => 'user_in_group'),
		RULE_TO_ME			=> array('check0' => 'to', 'check1' => 'bcc'),
	)
);

/**
* This is for defining which condition fields to show for which Rule
*/
$global_rule_conditions = array(
	RULE_IS_LIKE		=> 'text',
	RULE_IS_NOT_LIKE	=> 'text',
	RULE_IS				=> 'text',
	RULE_IS_NOT			=> 'text',
	RULE_BEGINS_WITH	=> 'text',
	RULE_ENDS_WITH		=> 'text',
	RULE_IS_USER		=> 'user',
	RULE_IS_GROUP		=> 'group'
);

/**
* Get all folder
*/
function get_folder($user_id, $folder_id = false)
{
	global $db, $user, $template;
	global $phpbb_root_path, $phpEx;

	$folder = array();

	// Get folder information
	$sql = 'SELECT folder_id, COUNT(msg_id) as num_messages, SUM(pm_unread) as num_unread
		FROM ' . PRIVMSGS_TO_TABLE . "
		WHERE user_id = $user_id
			AND folder_id <> " . PRIVMSGS_NO_BOX . '
		GROUP BY folder_id';
	$result = $db->sql_query($sql);

	$num_messages = $num_unread = array();
	while ($row = $db->sql_fetchrow($result))
	{
		$num_messages[(int) $row['folder_id']] = $row['num_messages'];
		$num_unread[(int) $row['folder_id']] = $row['num_unread'];
	}
	$db->sql_freeresult($result);

	// Make sure the default boxes are defined
	$available_folder = array(PRIVMSGS_INBOX, PRIVMSGS_OUTBOX, PRIVMSGS_SENTBOX);

	foreach ($available_folder as $default_folder)
	{
		if (!isset($num_messages[$default_folder]))
		{
			$num_messages[$default_folder] = 0;
		}

		if (!isset($num_unread[$default_folder]))
		{
			$num_unread[$default_folder] = 0;
		}
	}

	// Adjust unread status for outbox
	$num_unread[PRIVMSGS_OUTBOX] = $num_messages[PRIVMSGS_OUTBOX];

	$folder[PRIVMSGS_INBOX] = array(
		'folder_name'		=> $user->lang['PM_INBOX'],
		'num_messages'		=> $num_messages[PRIVMSGS_INBOX],
		'unread_messages'	=> $num_unread[PRIVMSGS_INBOX]
	);

	// Custom Folder
	$sql = 'SELECT folder_id, folder_name, pm_count
		FROM ' . PRIVMSGS_FOLDER_TABLE . "
			WHERE user_id = $user_id";
	$result = $db->sql_query($sql);

	while ($row = $db->sql_fetchrow($result))
	{
		$folder[$row['folder_id']] = array(
			'folder_name'		=> $row['folder_name'],
			'num_messages'		=> $row['pm_count'],
			'unread_messages'	=> ((isset($num_unread[$row['folder_id']])) ? $num_unread[$row['folder_id']] : 0)
		);
	}
	$db->sql_freeresult($result);

	$folder[PRIVMSGS_OUTBOX] = array(
		'folder_name'		=> $user->lang['PM_OUTBOX'],
		'num_messages'		=> $num_messages[PRIVMSGS_OUTBOX],
		'unread_messages'	=> $num_unread[PRIVMSGS_OUTBOX]
	);

	$folder[PRIVMSGS_SENTBOX] = array(
		'folder_name'		=> $user->lang['PM_SENTBOX'],
		'num_messages'		=> $num_messages[PRIVMSGS_SENTBOX],
		'unread_messages'	=> $num_unread[PRIVMSGS_SENTBOX]
	);

	// Define Folder Array for template designers (and for making custom folders usable by the template too)
	foreach ($folder as $f_id => $folder_ary)
	{
		$folder_id_name = ($f_id == PRIVMSGS_INBOX) ? 'inbox' : (($f_id == PRIVMSGS_OUTBOX) ? 'outbox' : 'sentbox');

		$template->assign_block_vars('folder', array(
			'FOLDER_ID'			=> $f_id,
			'FOLDER_NAME'		=> $folder_ary['folder_name'],
			'NUM_MESSAGES'		=> $folder_ary['num_messages'],
			'UNREAD_MESSAGES'	=> $folder_ary['unread_messages'],

			'U_FOLDER'			=> ($f_id > 0) ? append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm&amp;folder=' . $f_id) : append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm&amp;folder=' . $folder_id_name),

			'S_CUR_FOLDER'		=> ($f_id === $folder_id) ? true : false,
			'S_UNREAD_MESSAGES'	=> ($folder_ary['unread_messages']) ? true : false,
			'S_CUSTOM_FOLDER'	=> ($f_id > 0) ? true : false)
		);
	}

	if ($folder_id !== false && $folder_id !== PRIVMSGS_HOLD_BOX && !isset($folder[$folder_id]))
	{
		trigger_error('UNKNOWN_FOLDER');
	}

	return $folder;
}

/**
* Delete Messages From Sentbox
* we are doing this here because this saves us a bunch of checks and queries
*/
function clean_sentbox($num_sentbox_messages)
{
	global $db, $user;

	// Check Message Limit
	if ($user->data['message_limit'] && $num_sentbox_messages > $user->data['message_limit'])
	{
		// Delete old messages
		$sql = 'SELECT t.msg_id
			FROM ' . PRIVMSGS_TO_TABLE . ' t, ' . PRIVMSGS_TABLE . ' p
			WHERE t.msg_id = p.msg_id
				AND t.user_id = ' . $user->data['user_id'] . '
				AND t.folder_id = ' . PRIVMSGS_SENTBOX . '
			ORDER BY p.message_time ASC';
		$result = $db->sql_query_limit($sql, ($num_sentbox_messages - $user->data['message_limit']));

		$delete_ids = array();
		while ($row = $db->sql_fetchrow($result))
		{
			$delete_ids[] = $row['msg_id'];
		}
		$db->sql_freeresult($result);
		delete_pm($user->data['user_id'], $delete_ids, PRIVMSGS_SENTBOX);
	}
}

/**
* Check Rule against Message Information
*/
function check_rule(&$rules, &$rule_row, &$message_row, $user_id)
{
	if (!isset($rules[$rule_row['rule_check']][$rule_row['rule_connection']]))
	{
		return false;
	}

	$check_ary = $rules[$rule_row['rule_check']][$rule_row['rule_connection']];

	$result = false;

	$check0 = $message_row[$check_ary['check0']];

	switch ($rule_row['rule_connection'])
	{
		case RULE_IS_LIKE:
			$result = preg_match("/" . preg_quote($rule_row['rule_string'], '/') . '/i', $check0);
		break;

		case RULE_IS_NOT_LIKE:
			$result = !preg_match("/" . preg_quote($rule_row['rule_string'], '/') . '/i', $check0);
		break;

		case RULE_IS:
			$result = ($check0 == $rule_row['rule_string']);
		break;

		case RULE_IS_NOT:
			$result = ($check0 != $rule_row['rule_string']);
		break;

		case RULE_BEGINS_WITH:
			$result = preg_match("/^" . preg_quote($rule_row['rule_string'], '/') . '/i', $check0);
		break;

		case RULE_ENDS_WITH:
			$result = preg_match("/" . preg_quote($rule_row['rule_string'], '/') . '$/i', $check0);
		break;

		case RULE_IS_FRIEND:
		case RULE_IS_FOE:
		case RULE_ANSWERED:
		case RULE_FORWARDED:
			$result = ($check0 == 1);
		break;

		case RULE_IS_USER:
			$result = ($check0 == $rule_row['rule_user_id']);
		break;

		case RULE_IS_GROUP:
			$result = in_array($rule_row['rule_group_id'], $check0);
		break;

		case RULE_TO_GROUP:
			$result = (in_array('g_' . $message_row[$check_ary['check2']], $check0) || in_array('g_' . $message_row[$check_ary['check2']], $message_row[$check_ary['check1']]));
		break;

		case RULE_TO_ME:
			$result = (in_array('u_' . $user_id, $check0) || in_array('u_' . $user_id, $message_row[$check_ary['check1']]));
		break;
	}

	if (!$result)
	{
		return false;
	}

	switch ($rule_row['rule_action'])
	{
		case ACTION_PLACE_INTO_FOLDER:
			return array('action' => $rule_row['rule_action'], 'folder_id' => $rule_row['rule_folder_id']);
		break;

		case ACTION_MARK_AS_READ:
		case ACTION_MARK_AS_IMPORTANT:
			return array('action' => $rule_row['rule_action'], 'pm_unread' => $message_row['pm_unread'], 'pm_marked' => $message_row['pm_marked']);
		break;

		case ACTION_DELETE_MESSAGE:
			global $db;

			// Check for admins/mods - users are not allowed to remove those messages...
			// We do the check here to make sure the data we use is consistent
			$sql = 'SELECT user_id, user_type, user_permissions
				FROM ' . USERS_TABLE . '
				WHERE user_id = ' . (int) $message_row['author_id'];
			$result = $db->sql_query($sql);
			$userdata = $db->sql_fetchrow($result);
			$db->sql_freeresult($result);

			$auth2 = new \phpbb\auth\auth();
			$auth2->acl($userdata);

			if (!$auth2->acl_get('a_') && !$auth2->acl_get('m_') && !$auth2->acl_getf_global('m_'))
			{
				return array('action' => $rule_row['rule_action'], 'pm_unread' => $message_row['pm_unread'], 'pm_marked' => $message_row['pm_marked']);
			}

			return false;
		break;

		default:
			return false;
	}

	return false;
}

/**
* Update user PM count
*/
function update_pm_counts()
{
	global $user, $db;

	// Update unread count
	$sql = 'SELECT COUNT(msg_id) as num_messages
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE pm_unread = 1
			AND folder_id <> ' . PRIVMSGS_OUTBOX . '
			AND user_id = ' . $user->data['user_id'];
	$result = $db->sql_query($sql);
	$user->data['user_unread_privmsg'] = (int) $db->sql_fetchfield('num_messages');
	$db->sql_freeresult($result);

	// Update new pm count
	$sql = 'SELECT COUNT(msg_id) as num_messages
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE pm_new = 1
			AND folder_id IN (' . PRIVMSGS_NO_BOX . ', ' . PRIVMSGS_HOLD_BOX . ')
			AND user_id = ' . $user->data['user_id'];
	$result = $db->sql_query($sql);
	$user->data['user_new_privmsg'] = (int) $db->sql_fetchfield('num_messages');
	$db->sql_freeresult($result);

	$db->sql_query('UPDATE ' . USERS_TABLE . ' SET ' . $db->sql_build_array('UPDATE', array(
		'user_unread_privmsg'	=> (int) $user->data['user_unread_privmsg'],
		'user_new_privmsg'		=> (int) $user->data['user_new_privmsg'],
	)) . ' WHERE user_id = ' . $user->data['user_id']);

	// Ok, here we need to repair something, other boxes than privmsgs_no_box and privmsgs_hold_box should not carry the pm_new flag.
	if (!$user->data['user_new_privmsg'])
	{
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET pm_new = 0
			WHERE pm_new = 1
				AND folder_id NOT IN (' . PRIVMSGS_NO_BOX . ', ' . PRIVMSGS_HOLD_BOX . ')
				AND user_id = ' . $user->data['user_id'];
		$db->sql_query($sql);
	}
}

/**
* Place new messages into appropriate folder
*/
function place_pm_into_folder(&$global_privmsgs_rules, $release = false)
{
	global $db, $user, $config;

	if (!$user->data['user_new_privmsg'])
	{
		return array('not_moved' => 0, 'removed' => 0);
	}

	$user_message_rules = (int) $user->data['user_message_rules'];
	$user_id = (int) $user->data['user_id'];

	$action_ary = $move_into_folder = array();
	$num_removed = 0;

	// Newly processing on-hold messages
	if ($release)
	{
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET folder_id = ' . PRIVMSGS_NO_BOX . '
			WHERE folder_id = ' . PRIVMSGS_HOLD_BOX . "
				AND user_id = $user_id";
		$db->sql_query($sql);
	}

	// Get those messages not yet placed into any box
	$retrieve_sql = 'SELECT t.*, p.*, u.username, u.user_id, u.group_id
		FROM ' . PRIVMSGS_TO_TABLE . ' t, ' . PRIVMSGS_TABLE . ' p, ' . USERS_TABLE . " u
		WHERE t.user_id = $user_id
			AND p.author_id = u.user_id
			AND t.folder_id = " . PRIVMSGS_NO_BOX . '
			AND t.msg_id = p.msg_id';

	// Just place into the appropriate arrays if no rules need to be checked
	if (!$user_message_rules)
	{
		$result = $db->sql_query($retrieve_sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$action_ary[$row['msg_id']][] = array('action' => false);
		}
		$db->sql_freeresult($result);
	}
	else
	{
		$user_rules = $zebra = $check_rows = array();
		$user_ids = $memberships = array();

		// First of all, grab all rules and retrieve friends/foes
		$sql = 'SELECT *
			FROM ' . PRIVMSGS_RULES_TABLE . "
			WHERE user_id = $user_id";
		$result = $db->sql_query($sql);
		$user_rules = $db->sql_fetchrowset($result);
		$db->sql_freeresult($result);

		if (count($user_rules))
		{
			$sql = 'SELECT zebra_id, friend, foe
				FROM ' . ZEBRA_TABLE . "
				WHERE user_id = $user_id";
			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))
			{
				$zebra[$row['zebra_id']] = $row;
			}
			$db->sql_freeresult($result);
		}

		// Now build a bare-bone check_row array
		$result = $db->sql_query($retrieve_sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$check_rows[] = array_merge($row, array(
				'to'				=> explode(':', $row['to_address']),
				'bcc'				=> explode(':', $row['bcc_address']),
				'friend'			=> (isset($zebra[$row['author_id']])) ? $zebra[$row['author_id']]['friend'] : 0,
				'foe'				=> (isset($zebra[$row['author_id']])) ? $zebra[$row['author_id']]['foe'] : 0,
				'user_in_group'		=> array($user->data['group_id']),
				'author_in_group'	=> array())
			);

			$user_ids[] = $row['user_id'];
		}
		$db->sql_freeresult($result);

		// Retrieve user memberships
		if (count($user_ids))
		{
			$sql = 'SELECT *
				FROM ' . USER_GROUP_TABLE . '
				WHERE ' . $db->sql_in_set('user_id', $user_ids) . '
					AND user_pending = 0';
			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))
			{
				$memberships[$row['user_id']][] = $row['group_id'];
			}
			$db->sql_freeresult($result);
		}

		// Now place into the appropriate folder
		foreach ($check_rows as $row)
		{
			// Add membership if set
			if (isset($memberships[$row['author_id']]))
			{
				$row['author_in_group'] = $memberships[$row['user_id']];
			}

			// Check Rule - this should be very quick since we have all information we need
			$is_match = false;
			foreach ($user_rules as $rule_row)
			{
				if (($action = check_rule($global_privmsgs_rules, $rule_row, $row, $user_id)) !== false)
				{
					$is_match = true;
					$action_ary[$row['msg_id']][] = $action;
				}
			}

			if (!$is_match)
			{
				$action_ary[$row['msg_id']][] = array('action' => false);
			}
		}

		unset($user_rules, $zebra, $check_rows, $user_ids, $memberships);
	}

	// We place actions into arrays, to save queries.
	$unread_ids = $delete_ids = $important_ids = array();

	foreach ($action_ary as $msg_id => $msg_ary)
	{
		// It is allowed to execute actions more than once, except placing messages into folder
		$folder_action = $message_removed = false;

		foreach ($msg_ary as $pos => $rule_ary)
		{
			if ($folder_action && $rule_ary['action'] == ACTION_PLACE_INTO_FOLDER)
			{
				continue;
			}

			switch ($rule_ary['action'])
			{
				case ACTION_PLACE_INTO_FOLDER:
					// Folder actions have precedence, so we will remove any other ones
					$folder_action = true;
					$move_into_folder[(int) $rule_ary['folder_id']][] = $msg_id;
				break;

				case ACTION_MARK_AS_READ:
					if ($rule_ary['pm_unread'])
					{
						$unread_ids[] = $msg_id;
					}
				break;

				case ACTION_DELETE_MESSAGE:
					$delete_ids[] = $msg_id;
					$message_removed = true;
				break;

				case ACTION_MARK_AS_IMPORTANT:
					if (!$rule_ary['pm_marked'])
					{
						$important_ids[] = $msg_id;
					}
				break;
			}
		}

		// We place this here because it could happen that the messages are doubled if a rule marks a message and then moves it into a specific
		// folder. Here we simply move the message into the INBOX if it gets not removed and also not put into a custom folder.
		if (!$folder_action && !$message_removed)
		{
			$move_into_folder[PRIVMSGS_INBOX][] = $msg_id;
		}
	}

	// Do not change the order of processing
	// The number of queries needed to be executed here highly depends on the defined rules and are
	// only gone through if new messages arrive.

	// Delete messages
	if (count($delete_ids))
	{
		$num_removed += count($delete_ids);
		delete_pm($user_id, $delete_ids, PRIVMSGS_NO_BOX);
	}

	// Set messages to Unread
	if (count($unread_ids))
	{
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET pm_unread = 0
			WHERE ' . $db->sql_in_set('msg_id', $unread_ids) . "
				AND user_id = $user_id
				AND folder_id = " . PRIVMSGS_NO_BOX;
		$db->sql_query($sql);
	}

	// mark messages as important
	if (count($important_ids))
	{
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET pm_marked = 1 - pm_marked
			WHERE folder_id = ' . PRIVMSGS_NO_BOX . "
				AND user_id = $user_id
				AND " . $db->sql_in_set('msg_id', $important_ids);
		$db->sql_query($sql);
	}

	// Move into folder
	$folder = array();

	if (count($move_into_folder))
	{
		// Determine Full Folder Action - we need the move to folder id later eventually
		$full_folder_action = ($user->data['user_full_folder'] == FULL_FOLDER_NONE) ? ($config['full_folder_action'] - (FULL_FOLDER_NONE*(-1))) : $user->data['user_full_folder'];

		$sql_folder = array_keys($move_into_folder);
		if ($full_folder_action >= 0)
		{
			$sql_folder[] = $full_folder_action;
		}

		$sql = 'SELECT folder_id, pm_count
			FROM ' . PRIVMSGS_FOLDER_TABLE . '
			WHERE ' . $db->sql_in_set('folder_id', $sql_folder) . "
				AND user_id = $user_id";
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$folder[(int) $row['folder_id']] = (int) $row['pm_count'];
		}
		$db->sql_freeresult($result);

		unset($sql_folder);

		if (isset($move_into_folder[PRIVMSGS_INBOX]))
		{
			$sql = 'SELECT COUNT(msg_id) as num_messages
				FROM ' . PRIVMSGS_TO_TABLE . "
				WHERE user_id = $user_id
					AND folder_id = " . PRIVMSGS_INBOX;
			$result = $db->sql_query($sql);
			$folder[PRIVMSGS_INBOX] = (int) $db->sql_fetchfield('num_messages');
			$db->sql_freeresult($result);
		}
	}

	// Here we have ideally only one folder to move into
	foreach ($move_into_folder as $folder_id => $msg_ary)
	{
		$dest_folder = $folder_id;
		$full_folder_action = FULL_FOLDER_NONE;

		// Check Message Limit - we calculate with the complete array, most of the time it is one message
		// But we are making sure that the other way around works too (more messages in queue than allowed to be stored)
		if ($user->data['message_limit'] && $folder[$folder_id] && ($folder[$folder_id] + count($msg_ary)) > $user->data['message_limit'])
		{
			$full_folder_action = ($user->data['user_full_folder'] == FULL_FOLDER_NONE) ? ($config['full_folder_action'] - (FULL_FOLDER_NONE*(-1))) : $user->data['user_full_folder'];

			// If destination folder itself is full...
			if ($full_folder_action >= 0 && ($folder[$full_folder_action] + count($msg_ary)) > $user->data['message_limit'])
			{
				$full_folder_action = $config['full_folder_action'] - (FULL_FOLDER_NONE*(-1));
			}

			// If Full Folder Action is to move to another folder, we simply adjust the destination folder
			if ($full_folder_action >= 0)
			{
				$dest_folder = $full_folder_action;
			}
			else if ($full_folder_action == FULL_FOLDER_DELETE)
			{
				// Delete some messages. NOTE: Ordered by msg_id here instead of message_time!
				$sql = 'SELECT msg_id
					FROM ' . PRIVMSGS_TO_TABLE . "
					WHERE user_id = $user_id
						AND folder_id = $dest_folder
					ORDER BY msg_id ASC";
				$result = $db->sql_query_limit($sql, (($folder[$dest_folder] + count($msg_ary)) - $user->data['message_limit']));

				$delete_ids = array();
				while ($row = $db->sql_fetchrow($result))
				{
					$delete_ids[] = $row['msg_id'];
				}
				$db->sql_freeresult($result);

				$num_removed += count($delete_ids);
				delete_pm($user_id, $delete_ids, $dest_folder);
			}
		}

		//
		if ($full_folder_action == FULL_FOLDER_HOLD)
		{
			$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
				SET folder_id = ' . PRIVMSGS_HOLD_BOX . '
				WHERE folder_id = ' . PRIVMSGS_NO_BOX . "
					AND user_id = $user_id
					AND " . $db->sql_in_set('msg_id', $msg_ary);
			$db->sql_query($sql);
		}
		else
		{
			$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . "
				SET folder_id = $dest_folder, pm_new = 0
				WHERE folder_id = " . PRIVMSGS_NO_BOX . "
					AND user_id = $user_id
					AND pm_new = 1
					AND " . $db->sql_in_set('msg_id', $msg_ary);
			$db->sql_query($sql);

			if ($dest_folder != PRIVMSGS_INBOX)
			{
				$sql = 'UPDATE ' . PRIVMSGS_FOLDER_TABLE . '
					SET pm_count = pm_count + ' . (int) $db->sql_affectedrows() . "
					WHERE folder_id = $dest_folder
						AND user_id = $user_id";
				$db->sql_query($sql);
			}
		}
	}

	if (count($action_ary))
	{
		// Move from OUTBOX to SENTBOX
		// We are not checking any full folder status here... SENTBOX is a special treatment (old messages get deleted)
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET folder_id = ' . PRIVMSGS_SENTBOX . '
			WHERE folder_id = ' . PRIVMSGS_OUTBOX . '
				AND ' . $db->sql_in_set('msg_id', array_keys($action_ary));
		$db->sql_query($sql);
	}

	// Update new/unread count
	update_pm_counts();

	// Now check how many messages got not moved...
	$sql = 'SELECT COUNT(msg_id) as num_messages
		FROM ' . PRIVMSGS_TO_TABLE . "
		WHERE user_id = $user_id
			AND folder_id = " . PRIVMSGS_HOLD_BOX;
	$result = $db->sql_query($sql);
	$num_not_moved = (int) $db->sql_fetchfield('num_messages');
	$db->sql_freeresult($result);

	return array('not_moved' => $num_not_moved, 'removed' => $num_removed);
}

/**
* Move PM from one to another folder
*/
function move_pm($user_id, $message_limit, $move_msg_ids, $dest_folder, $cur_folder_id)
{
	global $db, $user;
	global $phpbb_root_path, $phpEx;

	$num_moved = 0;

	if (!is_array($move_msg_ids))
	{
		$move_msg_ids = array($move_msg_ids);
	}

	if (count($move_msg_ids) && !in_array($dest_folder, array(PRIVMSGS_NO_BOX, PRIVMSGS_OUTBOX, PRIVMSGS_SENTBOX)) &&
		!in_array($cur_folder_id, array(PRIVMSGS_NO_BOX, PRIVMSGS_OUTBOX)) && $cur_folder_id != $dest_folder)
	{
		// We have to check the destination folder ;)
		if ($dest_folder != PRIVMSGS_INBOX)
		{
			$sql = 'SELECT folder_id, folder_name, pm_count
				FROM ' . PRIVMSGS_FOLDER_TABLE . "
				WHERE folder_id = $dest_folder
					AND user_id = $user_id";
			$result = $db->sql_query($sql);
			$row = $db->sql_fetchrow($result);
			$db->sql_freeresult($result);

			if (!$row)
			{
				send_status_line(403, 'Forbidden');
				trigger_error('NOT_AUTHORISED');
			}

			if ($message_limit && $row['pm_count'] + count($move_msg_ids) > $message_limit)
			{
				$message = sprintf($user->lang['NOT_ENOUGH_SPACE_FOLDER'], $row['folder_name']) . '<br /><br />';
				$message .= sprintf($user->lang['CLICK_RETURN_FOLDER'], '<a href="' . append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm&amp;folder=' . $row['folder_id']) . '">', '</a>', $row['folder_name']);
				trigger_error($message);
			}
		}
		else
		{
			$sql = 'SELECT COUNT(msg_id) as num_messages
				FROM ' . PRIVMSGS_TO_TABLE . '
				WHERE folder_id = ' . PRIVMSGS_INBOX . "
					AND user_id = $user_id";
			$result = $db->sql_query($sql);
			$num_messages = (int) $db->sql_fetchfield('num_messages');
			$db->sql_freeresult($result);

			if ($message_limit && $num_messages + count($move_msg_ids) > $message_limit)
			{
				$message = sprintf($user->lang['NOT_ENOUGH_SPACE_FOLDER'], $user->lang['PM_INBOX']) . '<br /><br />';
				$message .= sprintf($user->lang['CLICK_RETURN_FOLDER'], '<a href="' . append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm&amp;folder=inbox') . '">', '</a>', $user->lang['PM_INBOX']);
				trigger_error($message);
			}
		}

		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . "
			SET folder_id = $dest_folder
			WHERE folder_id = $cur_folder_id
				AND user_id = $user_id
				AND " . $db->sql_in_set('msg_id', $move_msg_ids);
		$db->sql_query($sql);
		$num_moved = $db->sql_affectedrows();

		// Update pm counts
		if ($num_moved)
		{
			if (!in_array($cur_folder_id, array(PRIVMSGS_INBOX, PRIVMSGS_OUTBOX, PRIVMSGS_SENTBOX)))
			{
				$sql = 'UPDATE ' . PRIVMSGS_FOLDER_TABLE . "
					SET pm_count = pm_count - $num_moved
					WHERE folder_id = $cur_folder_id
						AND user_id = $user_id";
				$db->sql_query($sql);
			}

			if ($dest_folder != PRIVMSGS_INBOX)
			{
				$sql = 'UPDATE ' . PRIVMSGS_FOLDER_TABLE . "
					SET pm_count = pm_count + $num_moved
					WHERE folder_id = $dest_folder
						AND user_id = $user_id";
				$db->sql_query($sql);
			}
		}
	}
	else if (in_array($cur_folder_id, array(PRIVMSGS_NO_BOX, PRIVMSGS_OUTBOX)))
	{
		trigger_error('CANNOT_MOVE_SPECIAL');
	}

	return $num_moved;
}

/**
* Update unread message status
*/
function update_unread_status($unread, $msg_id, $user_id, $folder_id)
{
	if (!$unread)
	{
		return;
	}

	global $db, $user, $phpbb_container;

	/* @var $phpbb_notifications \phpbb\notification\manager */
	$phpbb_notifications = $phpbb_container->get('notification_manager');

	$phpbb_notifications->mark_notifications('notification.type.pm', $msg_id, $user_id);

	$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . "
		SET pm_unread = 0
		WHERE msg_id = $msg_id
			AND user_id = $user_id
			AND folder_id = $folder_id
			AND pm_unread = 1";
	$db->sql_query($sql);

	// If the message is already marked as read, we just skip the rest to avoid negative PM count
	if (!$db->sql_affectedrows())
	{
		return;
	}

	$sql = 'UPDATE ' . USERS_TABLE . "
		SET user_unread_privmsg = user_unread_privmsg - 1
		WHERE user_id = $user_id";
	$db->sql_query($sql);

	if ($user->data['user_id'] == $user_id)
	{
		$user->data['user_unread_privmsg']--;

		// Try to cope with previous wrong conversions...
		if ($user->data['user_unread_privmsg'] < 0)
		{
			$sql = 'UPDATE ' . USERS_TABLE . "
				SET user_unread_privmsg = 0
				WHERE user_id = $user_id";
			$db->sql_query($sql);

			$user->data['user_unread_privmsg'] = 0;
		}
	}
}

function mark_folder_read($user_id, $folder_id)
{
	global $db;

	$sql = 'SELECT msg_id
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE folder_id = ' . ((int) $folder_id) . '
			AND user_id = ' . ((int) $user_id) . '
			AND pm_unread = 1';
	$result = $db->sql_query($sql);

	while ($row = $db->sql_fetchrow($result))
	{
		update_unread_status(true, $row['msg_id'], $user_id, $folder_id);
	}
	$db->sql_freeresult($result);
}

/**
* Handle all actions possible with marked messages
*/
function handle_mark_actions($user_id, $mark_action)
{
	global $db, $user, $phpbb_root_path, $phpEx, $request;

	$msg_ids		= $request->variable('marked_msg_id', array(0));
	$cur_folder_id	= $request->variable('cur_folder_id', PRIVMSGS_NO_BOX);

	if (!count($msg_ids))
	{
		return false;
	}

	switch ($mark_action)
	{
		case 'mark_important':

			$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . "
				SET pm_marked = 1 - pm_marked
				WHERE folder_id = $cur_folder_id
					AND user_id = $user_id
					AND " . $db->sql_in_set('msg_id', $msg_ids);
			$db->sql_query($sql);

		break;

		case 'delete_marked':

			global $auth;

			if (!$auth->acl_get('u_pm_delete'))
			{
				send_status_line(403, 'Forbidden');
				trigger_error('NO_AUTH_DELETE_MESSAGE');
			}

			if (confirm_box(true))
			{
				delete_pm($user_id, $msg_ids, $cur_folder_id);

				$success_msg = (count($msg_ids) == 1) ? 'MESSAGE_DELETED' : 'MESSAGES_DELETED';
				$redirect = append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm&amp;folder=' . $cur_folder_id);

				meta_refresh(3, $redirect);
				trigger_error($user->lang[$success_msg] . '<br /><br />' . sprintf($user->lang['RETURN_FOLDER'], '<a href="' . $redirect . '">', '</a>'));
			}
			else
			{
				$s_hidden_fields = array(
					'cur_folder_id'	=> $cur_folder_id,
					'mark_option'	=> 'delete_marked',
					'submit_mark'	=> true,
					'marked_msg_id'	=> $msg_ids
				);

				confirm_box(false, 'DELETE_MARKED_PM', build_hidden_fields($s_hidden_fields));
			}

		break;

		default:
			return false;
	}

	return true;
}

/**
* Delete PM(s)
*/
function delete_pm($user_id, $msg_ids, $folder_id)
{
	global $db, $user, $phpbb_container, $phpbb_dispatcher;

	$user_id	= (int) $user_id;
	$folder_id	= (int) $folder_id;

	if (!$user_id)
	{
		return false;
	}

	if (!is_array($msg_ids))
	{
		if (!$msg_ids)
		{
			return false;
		}
		$msg_ids = array($msg_ids);
	}

	if (!count($msg_ids))
	{
		return false;
	}

	/**
	* Get all info for PM(s) before they are deleted
	*
	* @event core.delete_pm_before
	* @var	int	user_id	 ID of the user requested the message delete
	* @var	array	msg_ids	array of all messages to be deleted
	* @var	int	folder_id	ID of the user folder where the messages are stored
	* @since 3.1.0-b5
	*/
	$vars = array('user_id', 'msg_ids', 'folder_id');
	extract($phpbb_dispatcher->trigger_event('core.delete_pm_before', compact($vars)));

	// Get PM Information for later deleting
	$sql = 'SELECT msg_id, pm_unread, pm_new
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE ' . $db->sql_in_set('msg_id', array_map('intval', $msg_ids)) . "
			AND folder_id = $folder_id
			AND user_id = $user_id";
	$result = $db->sql_query($sql);

	$delete_rows = array();
	$num_unread = $num_new = $num_deleted = 0;
	while ($row = $db->sql_fetchrow($result))
	{
		$num_unread += (int) $row['pm_unread'];
		$num_new += (int) $row['pm_new'];

		$delete_rows[$row['msg_id']] = 1;
	}
	$db->sql_freeresult($result);
	unset($msg_ids);

	if (!count($delete_rows))
	{
		return false;
	}

	$db->sql_transaction('begin');

	// if no one has read the message yet (meaning it is in users outbox)
	// then mark the message as deleted...
	if ($folder_id == PRIVMSGS_OUTBOX)
	{
		// Remove PM from Outbox
		$sql = 'DELETE FROM ' . PRIVMSGS_TO_TABLE . "
			WHERE user_id = $user_id AND folder_id = " . PRIVMSGS_OUTBOX . '
				AND ' . $db->sql_in_set('msg_id', array_keys($delete_rows));
		$db->sql_query($sql);

		// Update PM Information for safety
		$sql = 'UPDATE ' . PRIVMSGS_TABLE . " SET message_text = ''
			WHERE " . $db->sql_in_set('msg_id', array_keys($delete_rows));
		$db->sql_query($sql);

		// Set delete flag for those intended to receive the PM
		// We do not remove the message actually, to retain some basic information (sent time for example)
		$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
			SET pm_deleted = 1
			WHERE ' . $db->sql_in_set('msg_id', array_keys($delete_rows));
		$db->sql_query($sql);

		$num_deleted = $db->sql_affectedrows();
	}
	else
	{
		// Delete private message data
		$sql = 'DELETE FROM ' . PRIVMSGS_TO_TABLE . "
			WHERE user_id = $user_id
				AND folder_id = $folder_id
				AND " . $db->sql_in_set('msg_id', array_keys($delete_rows));
		$db->sql_query($sql);
		$num_deleted = $db->sql_affectedrows();
	}

	// if folder id is user defined folder then decrease pm_count
	if (!in_array($folder_id, array(PRIVMSGS_INBOX, PRIVMSGS_OUTBOX, PRIVMSGS_SENTBOX, PRIVMSGS_NO_BOX)))
	{
		$sql = 'UPDATE ' . PRIVMSGS_FOLDER_TABLE . "
			SET pm_count = pm_count - $num_deleted
			WHERE folder_id = $folder_id";
		$db->sql_query($sql);
	}

	// Update unread and new status field
	if ($num_unread || $num_new)
	{
		$set_sql = ($num_unread) ? 'user_unread_privmsg = user_unread_privmsg - ' . $num_unread : '';

		if ($num_new)
		{
			$set_sql .= ($set_sql != '') ? ', ' : '';
			$set_sql .= 'user_new_privmsg = user_new_privmsg - ' . $num_new;
		}

		$db->sql_query('UPDATE ' . USERS_TABLE . " SET $set_sql WHERE user_id = $user_id");

		$user->data['user_new_privmsg'] -= $num_new;
		$user->data['user_unread_privmsg'] -= $num_unread;
	}

	/* @var $phpbb_notifications \phpbb\notification\manager */
	$phpbb_notifications = $phpbb_container->get('notification_manager');

	$phpbb_notifications->delete_notifications('notification.type.pm', array_keys($delete_rows));

	// Now we have to check which messages we can delete completely
	$sql = 'SELECT msg_id
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE ' . $db->sql_in_set('msg_id', array_keys($delete_rows));
	$result = $db->sql_query($sql);

	while ($row = $db->sql_fetchrow($result))
	{
		unset($delete_rows[$row['msg_id']]);
	}
	$db->sql_freeresult($result);

	$delete_ids = array_keys($delete_rows);

	if (count($delete_ids))
	{
		// Check if there are any attachments we need to remove
		/** @var \phpbb\attachment\manager $attachment_manager */
		$attachment_manager = $phpbb_container->get('attachment.manager');
		$attachment_manager->delete('message', $delete_ids, false);
		unset($attachment_manager);

		$sql = 'DELETE FROM ' . PRIVMSGS_TABLE . '
			WHERE ' . $db->sql_in_set('msg_id', $delete_ids);
		$db->sql_query($sql);
	}

	$db->sql_transaction('commit');

	return true;
}

/**
* Delete all PM(s) for a given user and delete the ones without references
*
* @param	int		$user_id	ID of the user whose private messages we want to delete
*
* @return	boolean		False if there were no pms found, true otherwise.
*/
function phpbb_delete_user_pms($user_id)
{
	$user_id = (int) $user_id;

	if (!$user_id)
	{
		return false;
	}

	return phpbb_delete_users_pms(array($user_id));
}

/**
* Delete all PM(s) for given users and delete the ones without references
*
* @param	array		$user_ids	IDs of the users whose private messages we want to delete
*
* @return	boolean		False if there were no pms found, true otherwise.
*/
function phpbb_delete_users_pms($user_ids)
{
	global $db, $phpbb_container;

	$user_id_sql = $db->sql_in_set('user_id', $user_ids);
	$author_id_sql = $db->sql_in_set('author_id', $user_ids);

	// Get PM Information for later deleting
	// The two queries where split, so we can use our indexes
	$undelivered_msg = $delete_ids = array();

	// Part 1: get PMs the user received
	$sql = 'SELECT msg_id
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE ' . $user_id_sql;
	$result = $db->sql_query($sql);

	while ($row = $db->sql_fetchrow($result))
	{
		$msg_id = (int) $row['msg_id'];
		$delete_ids[$msg_id] = $msg_id;
	}
	$db->sql_freeresult($result);

	// Part 2: get PMs the users sent, but are yet to be received.
	// We cannot simply delete them. First we have to check
	// whether another user already received and read the message.
	$sql = 'SELECT msg_id
		FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE ' . $author_id_sql . '
			AND folder_id = ' . PRIVMSGS_NO_BOX;
	$result = $db->sql_query($sql);

	while ($row = $db->sql_fetchrow($result))
	{
		$msg_id = (int) $row['msg_id'];
		$undelivered_msg[$msg_id] = $msg_id;
	}
	$db->sql_freeresult($result);

	if (empty($delete_ids) && empty($undelivered_msg))
	{
		return false;
	}

	$db->sql_transaction('begin');

	/* @var $phpbb_notifications \phpbb\notification\manager */
	$phpbb_notifications = $phpbb_container->get('notification_manager');

	if (!empty($undelivered_msg))
	{
		// A pm is delivered, if for any recipient the message was moved
		// from their NO_BOX to another folder. We do not delete such
		// messages, but only delete them for users, who have not yet
		// received them.
		$sql = 'SELECT msg_id
			FROM ' . PRIVMSGS_TO_TABLE . '
			WHERE ' . $author_id_sql . '
				AND folder_id <> ' . PRIVMSGS_NO_BOX . '
				AND folder_id <> ' . PRIVMSGS_OUTBOX . '
				AND folder_id <> ' . PRIVMSGS_SENTBOX;
		$result = $db->sql_query($sql);

		$delivered_msg = array();
		while ($row = $db->sql_fetchrow($result))
		{
			$msg_id = (int) $row['msg_id'];
			$delivered_msg[$msg_id] = $msg_id;
			unset($undelivered_msg[$msg_id]);
		}
		$db->sql_freeresult($result);

		$undelivered_user = array();

		// Count the messages we delete, so we can correct the user pm data
		$sql = 'SELECT user_id, COUNT(msg_id) as num_undelivered_privmsgs
			FROM ' . PRIVMSGS_TO_TABLE . '
			WHERE ' . $author_id_sql . '
				AND folder_id = ' . PRIVMSGS_NO_BOX . '
					AND ' . $db->sql_in_set('msg_id', array_merge($undelivered_msg, $delivered_msg)) . '
			GROUP BY user_id';
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$num_pms = (int) $row['num_undelivered_privmsgs'];
			$undelivered_user[$num_pms][] = (int) $row['user_id'];

			if (count($undelivered_user[$num_pms]) > 50)
			{
				// If there are too many users affected the query might get
				// too long, so we update the value for the first bunch here.
				$sql = 'UPDATE ' . USERS_TABLE . '
					SET user_new_privmsg = user_new_privmsg - ' . $num_pms . ',
						user_unread_privmsg = user_unread_privmsg - ' . $num_pms . '
					WHERE ' . $db->sql_in_set('user_id', $undelivered_user[$num_pms]);
				$db->sql_query($sql);
				unset($undelivered_user[$num_pms]);
			}
		}
		$db->sql_freeresult($result);

		foreach ($undelivered_user as $num_pms => $undelivered_user_set)
		{
			$sql = 'UPDATE ' . USERS_TABLE . '
				SET user_new_privmsg = user_new_privmsg - ' . $num_pms . ',
					user_unread_privmsg = user_unread_privmsg - ' . $num_pms . '
				WHERE ' . $db->sql_in_set('user_id', $undelivered_user_set);
			$db->sql_query($sql);
		}

		if (!empty($delivered_msg))
		{
			$sql = 'DELETE FROM ' . PRIVMSGS_TO_TABLE . '
				WHERE folder_id = ' . PRIVMSGS_NO_BOX . '
					AND ' . $db->sql_in_set('msg_id', $delivered_msg);
			$db->sql_query($sql);

			$phpbb_notifications->delete_notifications('notification.type.pm', $delivered_msg);
		}

		if (!empty($undelivered_msg))
		{
			$sql = 'DELETE FROM ' . PRIVMSGS_TO_TABLE . '
				WHERE ' . $db->sql_in_set('msg_id', $undelivered_msg);
			$db->sql_query($sql);

			$sql = 'DELETE FROM ' . PRIVMSGS_TABLE . '
				WHERE ' . $db->sql_in_set('msg_id', $undelivered_msg);
			$db->sql_query($sql);

			$phpbb_notifications->delete_notifications('notification.type.pm', $undelivered_msg);
		}
	}

	// Reset the user's pm count to 0
	$sql = 'UPDATE ' . USERS_TABLE . '
		SET user_new_privmsg = 0,
			user_unread_privmsg = 0
		WHERE ' . $user_id_sql;
	$db->sql_query($sql);

	// Delete private message data of the user
	$sql = 'DELETE FROM ' . PRIVMSGS_TO_TABLE . '
		WHERE ' . $user_id_sql;
	$db->sql_query($sql);

	if (!empty($delete_ids))
	{
		// Now we have to check which messages we can delete completely
		$sql = 'SELECT msg_id
			FROM ' . PRIVMSGS_TO_TABLE . '
			WHERE ' . $db->sql_in_set('msg_id', $delete_ids);
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			unset($delete_ids[$row['msg_id']]);
		}
		$db->sql_freeresult($result);

		if (!empty($delete_ids))
		{
			// Check if there are any attachments we need to remove
			/** @var \phpbb\attachment\manager $attachment_manager */
			$attachment_manager = $phpbb_container->get('attachment.manager');
			$attachment_manager->delete('message', $delete_ids, false);
			unset($attachment_manager);

			$sql = 'DELETE FROM ' . PRIVMSGS_TABLE . '
				WHERE ' . $db->sql_in_set('msg_id', $delete_ids);
			$db->sql_query($sql);

			$phpbb_notifications->delete_notifications('notification.type.pm', $delete_ids);
		}
	}

	// Set the remaining author id to anonymous
	// This way users are still able to read messages from users being removed
	$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
		SET author_id = ' . ANONYMOUS . '
		WHERE ' . $author_id_sql;
	$db->sql_query($sql);

	$sql = 'UPDATE ' . PRIVMSGS_TABLE . '
		SET author_id = ' . ANONYMOUS . '
		WHERE ' . $author_id_sql;
	$db->sql_query($sql);

	$db->sql_transaction('commit');

	return true;
}

/**
* Rebuild message header
*/
function rebuild_header($check_ary)
{
	$address = array();

	foreach ($check_ary as $check_type => $address_field)
	{
		// Split Addresses into users and groups
		preg_match_all('/:?(u|g)_([0-9]+):?/', $address_field, $match);

		$u = $g = array();
		foreach ($match[1] as $id => $type)
		{
			${$type}[] = (int) $match[2][$id];
		}

		$_types = array('u', 'g');
		foreach ($_types as $type)
		{
			if (count(${$type}))
			{
				foreach (${$type} as $id)
				{
					$address[$type][$id] = $check_type;
				}
			}
		}
	}

	return $address;
}

/**
* Print out/assign recipient information
*/
function write_pm_addresses($check_ary, $author_id, $plaintext = false)
{
	global $db, $user, $template, $phpbb_root_path, $phpEx, $phpbb_container;

	/** @var \phpbb\group\helper $group_helper */
	$group_helper = $phpbb_container->get('group_helper');

	$addresses = array();

	foreach ($check_ary as $check_type => $address_field)
	{
		if (!is_array($address_field))
		{
			// Split Addresses into users and groups
			preg_match_all('/:?(u|g)_([0-9]+):?/', $address_field, $match);

			$u = $g = array();
			foreach ($match[1] as $id => $type)
			{
				${$type}[] = (int) $match[2][$id];
			}
		}
		else
		{
			$u = $address_field['u'];
			$g = $address_field['g'];
		}

		$address = array();
		if (count($u))
		{
			$sql = 'SELECT user_id, username, user_colour
				FROM ' . USERS_TABLE . '
				WHERE ' . $db->sql_in_set('user_id', $u);
			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))
			{
				if ($check_type == 'to' || $author_id == $user->data['user_id'] || $row['user_id'] == $user->data['user_id'])
				{
					if ($plaintext)
					{
						$address[] = $row['username'];
					}
					else
					{
						$address['user'][$row['user_id']] = array('name' => $row['username'], 'colour' => $row['user_colour']);
					}
				}
			}
			$db->sql_freeresult($result);
		}

		if (count($g))
		{
			if ($plaintext)
			{
				$sql = 'SELECT group_name, group_type
					FROM ' . GROUPS_TABLE . '
						WHERE ' . $db->sql_in_set('group_id', $g);
				$result = $db->sql_query($sql);

				while ($row = $db->sql_fetchrow($result))
				{
					if ($check_type == 'to' || $author_id == $user->data['user_id'] || $row['user_id'] == $user->data['user_id'])
					{
						$address[] = $group_helper->get_name($row['group_name']);
					}
				}
				$db->sql_freeresult($result);
			}
			else
			{
				$sql = 'SELECT g.group_id, g.group_name, g.group_colour, g.group_type, ug.user_id
					FROM ' . GROUPS_TABLE . ' g, ' . USER_GROUP_TABLE . ' ug
						WHERE ' . $db->sql_in_set('g.group_id', $g) . '
						AND g.group_id = ug.group_id
						AND ug.user_pending = 0';
				$result = $db->sql_query($sql);

				while ($row = $db->sql_fetchrow($result))
				{
					if (!isset($address['group'][$row['group_id']]))
					{
						if ($check_type == 'to' || $author_id == $user->data['user_id'] || $row['user_id'] == $user->data['user_id'])
						{
							$row['group_name'] = $group_helper->get_name($row['group_name']);
							$address['group'][$row['group_id']] = array('name' => $row['group_name'], 'colour' => $row['group_colour']);
						}
					}

					if (isset($address['user'][$row['user_id']]))
					{
						$address['user'][$row['user_id']]['in_group'] = $row['group_id'];
					}
				}
				$db->sql_freeresult($result);
			}
		}

		if (count($address) && !$plaintext)
		{
			$template->assign_var('S_' . strtoupper($check_type) . '_RECIPIENT', true);

			foreach ($address as $type => $adr_ary)
			{
				foreach ($adr_ary as $id => $row)
				{
					$tpl_ary = array(
						'IS_GROUP'	=> ($type == 'group') ? true : false,
						'IS_USER'	=> ($type == 'user') ? true : false,
						'UG_ID'		=> $id,
						'NAME'		=> $row['name'],
						'COLOUR'	=> ($row['colour']) ? '#' . $row['colour'] : '',
						'TYPE'		=> $type,
					);

					if ($type == 'user')
					{
						$tpl_ary = array_merge($tpl_ary, array(
							'U_VIEW'		=> get_username_string('profile', $id, $row['name'], $row['colour']),
							'NAME_FULL'		=> get_username_string('full', $id, $row['name'], $row['colour']),
						));
					}
					else
					{
						$tpl_ary = array_merge($tpl_ary, array(
							'U_VIEW'		=> append_sid("{$phpbb_root_path}memberlist.$phpEx", 'mode=group&amp;g=' . $id),
						));
					}

					$template->assign_block_vars($check_type . '_recipient', $tpl_ary);
				}
			}
		}

		$addresses[$check_type] = $address;
	}

	return $addresses;
}

/**
* Get folder status
*/
function get_folder_status($folder_id, $folder)
{
	global $user;

	if (isset($folder[$folder_id]))
	{
		$folder = $folder[$folder_id];
	}
	else
	{
		return false;
	}

	$return = array(
		'folder_name'	=> $folder['folder_name'],
		'cur'			=> $folder['num_messages'],
		'remaining'		=> ($user->data['message_limit']) ? $user->data['message_limit'] - $folder['num_messages'] : 0,
		'max'			=> $user->data['message_limit'],
		'percent'		=> ($user->data['message_limit']) ? (($user->data['message_limit'] > 0) ? floor(($folder['num_messages'] / $user->data['message_limit']) * 100) : 100) : 0,
	);

	$return['message']	= $user->lang('FOLDER_STATUS_MSG', $user->lang('MESSAGES_COUNT', (int) $return['max']), (int) $return['cur'], $return['percent']);

	return $return;
}

//
// COMPOSE MESSAGES
//

/**
* Submit PM
*/
function submit_pm($mode, $subject, &$data_ary, $put_in_outbox = true)
{
	global $db, $auth, $config, $user, $phpbb_root_path, $phpbb_container, $phpbb_dispatcher, $request;

	// We do not handle erasing pms here
	if ($mode == 'delete')
	{
		return false;
	}

	$current_time = time();

	$data = $data_ary;
	/**
	* Get all parts of the PM that are to be submited to the DB.
	*
	* @event core.submit_pm_before
	* @var	string	mode	PM Post mode - post|reply|quote|quotepost|forward|edit
	* @var	string	subject	Subject of the private message
	* @var	array	data	The whole row data of the PM.
	* @since 3.1.0-b3
	*/
	$vars = array('mode', 'subject', 'data');
	extract($phpbb_dispatcher->trigger_event('core.submit_pm_before', compact($vars)));
	$data_ary = $data;
	unset($data);

	// Collect some basic information about which tables and which rows to update/insert
	$sql_data = array();
	$root_level = 0;

	// Recipient Information
	$recipients = $to = $bcc = array();

	if ($mode != 'edit')
	{
		// Build Recipient List
		// u|g => array($user_id => 'to'|'bcc')
		$_types = array('u', 'g');
		foreach ($_types as $ug_type)
		{
			if (isset($data_ary['address_list'][$ug_type]) && count($data_ary['address_list'][$ug_type]))
			{
				foreach ($data_ary['address_list'][$ug_type] as $id => $field)
				{
					$id = (int) $id;

					// Do not rely on the address list being "valid"
					if (!$id || ($ug_type == 'u' && $id == ANONYMOUS))
					{
						continue;
					}

					$field = ($field == 'to') ? 'to' : 'bcc';
					if ($ug_type == 'u')
					{
						$recipients[$id] = $field;
					}
					${$field}[] = $ug_type . '_' . $id;
				}
			}
		}

		if (isset($data_ary['address_list']['g']) && count($data_ary['address_list']['g']))
		{
			// We need to check the PM status of group members (do they want to receive PM's?)
			// Only check if not a moderator or admin, since they are allowed to override this user setting
			$sql_allow_pm = (!$auth->acl_gets('a_', 'm_') && !$auth->acl_getf_global('m_')) ? ' AND u.user_allow_pm = 1' : '';

			$sql = 'SELECT u.user_type, ug.group_id, ug.user_id
				FROM ' . USERS_TABLE . ' u, ' . USER_GROUP_TABLE . ' ug
				WHERE ' . $db->sql_in_set('ug.group_id', array_keys($data_ary['address_list']['g'])) . '
					AND ug.user_pending = 0
					AND u.user_id = ug.user_id
					AND u.user_type IN (' . USER_NORMAL . ', ' . USER_FOUNDER . ')' .
					$sql_allow_pm;
			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))
			{
				$field = ($data_ary['address_list']['g'][$row['group_id']] == 'to') ? 'to' : 'bcc';
				$recipients[$row['user_id']] = $field;
			}
			$db->sql_freeresult($result);
		}

		if (!count($recipients))
		{
			trigger_error('NO_RECIPIENT');
		}
	}

	// First of all make sure the subject are having the correct length.
	$subject = truncate_string($subject);

	$db->sql_transaction('begin');

	$sql = '';

	switch ($mode)
	{
		case 'reply':
		case 'quote':
			$root_level = ($data_ary['reply_from_root_level']) ? $data_ary['reply_from_root_level'] : $data_ary['reply_from_msg_id'];

			// Set message_replied switch for this user
			$sql = 'UPDATE ' . PRIVMSGS_TO_TABLE . '
				SET pm_replied = 1
				WHERE user_id = ' . $data_ary['from_user_id'] . '
					AND msg_id = ' . $data_ary['reply_from_msg_id'];

		// no break

		case 'forward':
		case 'post':
		case 'quotepost':
			$sql_data = array(
				'root_level'		=> $root_level,
				'author_id'			=> $data_ary['from_user_id'],
				'icon_id'			=> $data_ary['icon_id'],
				'author_ip'			=> $data_ary['from_user_ip'],
				'message_time'		=> $current_time,
				'enable_bbcode'		=> $data_ary['enable_bbcode'],
				'enable_smilies'	=> $data_ary['enable_smilies'],
				'enable_magic_url'	=> $data_ary['enable_urls'],
				'enable_sig'		=> $data_ary['enable_sig'],
				'message_subject'	=> $subject,
				'message_text'		=> $data_ary['message'],
				'message_attachment'=> (!empty($data_ary['attachment_data'])) ? 1 : 0,
				'bbcode_bitfield'	=> $data_ary['bbcode_bitfield'],
				'bbcode_uid'		=> $data_ary['bbcode_uid'],
				'to_address'		=> implode(':', $to),
				'bcc_address'		=> implode(':', $bcc),
				'message_reported'	=> 0,
			);
		break;

		case 'edit':
			$sql_data = array(
				'icon_id'			=> $data_ary['icon_id'],
				'message_edit_time'	=> $current_time,
				'enable_bbcode'		=> $data_ary['enable_bbcode'],
				'enable_smilies'	=> $data_ary['enable_smilies'],
				'enable_magic_url'	=> $data_ary['enable_urls'],
				'enable_sig'		=> $data_ary['enable_sig'],
				'message_subject'	=> $subject,
				'message_text'		=> $data_ary['message'],
				'message_attachment'=> (!empty($data_ary['attachment_data'])) ? 1 : 0,
				'bbcode_bitfield'	=> $data_ary['bbcode_bitfield'],
				'bbcode_uid'		=> $data_ary['bbcode_uid']
			);
		break;
	}

	if (count($sql_data))
	{
		if ($mode == 'post' || $mode == 'reply' || $mode == 'quote' || $mode == 'quotepost' || $mode == 'forward')
		{
			$db->sql_query('INSERT INTO ' . PRIVMSGS_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_data));
			$data_ary['msg_id'] = $db->sql_nextid();
		}
		else if ($mode == 'edit')
		{
			$sql = 'UPDATE ' . PRIVMSGS_TABLE . '
				SET message_edit_count = message_edit_count + 1, ' . $db->sql_build_array('UPDATE', $sql_data) . '
				WHERE msg_id = ' . $data_ary['msg_id'];
			$db->sql_query($sql);
		}
	}

	if ($mode != 'edit')
	{
		if ($sql)
		{
			$db->sql_query($sql);
		}
		unset($sql);

		$sql_ary = array();
		foreach ($recipients as $user_id => $type)
		{
			$sql_ary[] = array(
				'msg_id'		=> (int) $data_ary['msg_id'],
				'user_id'		=> (int) $user_id,
				'author_id'		=> (int) $data_ary['from_user_id'],
				'folder_id'		=> PRIVMSGS_NO_BOX,
				'pm_new'		=> 1,
				'pm_unread'		=> 1,
				'pm_forwarded'	=> ($mode == 'forward') ? 1 : 0
			);
		}

		$db->sql_multi_insert(PRIVMSGS_TO_TABLE, $sql_ary);

		$sql = 'UPDATE ' . USERS_TABLE . '
			SET user_new_privmsg = user_new_privmsg + 1, user_unread_privmsg = user_unread_privmsg + 1, user_last_privmsg = ' . time() . '
			WHERE ' . $db->sql_in_set('user_id', array_keys($recipients));
		$db->sql_query($sql);

		// Put PM into outbox
		if ($put_in_outbox)
		{
			$db->sql_query('INSERT INTO ' . PRIVMSGS_TO_TABLE . ' ' . $db->sql_build_array('INSERT', array(
				'msg_id'		=> (int) $data_ary['msg_id'],
				'user_id'		=> (int) $data_ary['from_user_id'],
				'author_id'		=> (int) $data_ary['from_user_id'],
				'folder_id'		=> PRIVMSGS_OUTBOX,
				'pm_new'		=> 0,
				'pm_unread'		=> 0,
				'pm_forwarded'	=> ($mode == 'forward') ? 1 : 0))
			);
		}
	}

	// Set user last post time
	if ($mode == 'reply' || $mode == 'quote' || $mode == 'quotepost' || $mode == 'forward' || $mode == 'post')
	{
		$sql = 'UPDATE ' . USERS_TABLE . "
			SET user_lastpost_time = $current_time
			WHERE user_id = " . $data_ary['from_user_id'];
		$db->sql_query($sql);
	}

	// Submit Attachments
	if (!empty($data_ary['attachment_data']) && $data_ary['msg_id'] && in_array($mode, array('post', 'reply', 'quote', 'quotepost', 'edit', 'forward')))
	{
		$space_taken = $files_added = 0;
		$orphan_rows = array();

		foreach ($data_ary['attachment_data'] as $pos => $attach_row)
		{
			$orphan_rows[(int) $attach_row['attach_id']] = array();
		}

		if (count($orphan_rows))
		{
			$sql = 'SELECT attach_id, filesize, physical_filename
				FROM ' . ATTACHMENTS_TABLE . '
				WHERE ' . $db->sql_in_set('attach_id', array_keys($orphan_rows)) . '
					AND in_message = 1
					AND is_orphan = 1
					AND poster_id = ' . $user->data['user_id'];
			$result = $db->sql_query($sql);

			$orphan_rows = array();
			while ($row = $db->sql_fetchrow($result))
			{
				$orphan_rows[$row['attach_id']] = $row;
			}
			$db->sql_freeresult($result);
		}

		foreach ($data_ary['attachment_data'] as $pos => $attach_row)
		{
			if ($attach_row['is_orphan'] && !isset($orphan_rows[$attach_row['attach_id']]))
			{
				continue;
			}

			if (!$attach_row['is_orphan'])
			{
				// update entry in db if attachment already stored in db and filespace
				$sql = 'UPDATE ' . ATTACHMENTS_TABLE . "
					SET attach_comment = '" . $db->sql_escape($attach_row['attach_comment']) . "'
					WHERE attach_id = " . (int) $attach_row['attach_id'] . '
						AND is_orphan = 0';
				$db->sql_query($sql);
			}
			else
			{
				// insert attachment into db
				if (!@file_exists($phpbb_root_path . $config['upload_path'] . '/' . utf8_basename($orphan_rows[$attach_row['attach_id']]['physical_filename'])))
				{
					continue;
				}

				$space_taken += $orphan_rows[$attach_row['attach_id']]['filesize'];
				$files_added++;

				$attach_sql = array(
					'post_msg_id'		=> $data_ary['msg_id'],
					'topic_id'			=> 0,
					'is_orphan'			=> 0,
					'poster_id'			=> $data_ary['from_user_id'],
					'attach_comment'	=> $attach_row['attach_comment'],
				);

				$sql = 'UPDATE ' . ATTACHMENTS_TABLE . ' SET ' . $db->sql_build_array('UPDATE', $attach_sql) . '
					WHERE attach_id = ' . $attach_row['attach_id'] . '
						AND is_orphan = 1
						AND poster_id = ' . $user->data['user_id'];
				$db->sql_query($sql);
			}
		}

		if ($space_taken && $files_added)
		{
			$config->increment('upload_dir_size', $space_taken, false);
			$config->increment('num_files', $files_added, false);
		}
	}

	// Delete draft if post was loaded...
	$draft_id = $request->variable('draft_loaded', 0);
	if ($draft_id)
	{
		$sql = 'DELETE FROM ' . DRAFTS_TABLE . "
			WHERE draft_id = $draft_id
				AND user_id = " . $data_ary['from_user_id'];
		$db->sql_query($sql);
	}

	$db->sql_transaction('commit');

	// Send Notifications
	$pm_data = array_merge($data_ary, array(
		'message_subject'		=> $subject,
		'recipients'			=> $recipients,
	));

	/* @var $phpbb_notifications \phpbb\notification\manager */
	$phpbb_notifications = $phpbb_container->get('notification_manager');

	if ($mode == 'edit')
	{
		$phpbb_notifications->update_notifications('notification.type.pm', $pm_data);
	}
	else
	{
		$phpbb_notifications->add_notifications('notification.type.pm', $pm_data);
	}

	$data = $data_ary;
	/**
	* Get PM message ID after submission to DB
	*
	* @event core.submit_pm_after
	* @var	string	mode	PM Post mode - post|reply|quote|quotepost|forward|edit
	* @var	string	subject	Subject of the private message
	* @var	array	data	The whole row data of the PM.
	* @var	array	pm_data	The data sent to notification class
	* @since 3.1.0-b5
	*/
	$vars = array('mode', 'subject', 'data', 'pm_data');
	extract($phpbb_dispatcher->trigger_event('core.submit_pm_after', compact($vars)));
	$data_ary = $data;
	unset($data);

	return $data_ary['msg_id'];
}

/**
* Display Message History
*/
function message_history($msg_id, $user_id, $message_row, $folder, $in_post_mode = false)
{
	global $db, $user, $template, $phpbb_root_path, $phpEx, $auth;

	// Select all receipts and the author from the pm we currently view, to only display their pm-history
	$sql = 'SELECT author_id, user_id
		FROM ' . PRIVMSGS_TO_TABLE . "
		WHERE msg_id = $msg_id
			AND folder_id <> " . PRIVMSGS_HOLD_BOX;
	$result = $db->sql_query($sql);

	$recipients = array();
	while ($row = $db->sql_fetchrow($result))
	{
		$recipients[] = (int) $row['user_id'];
		$recipients[] = (int) $row['author_id'];
	}
	$db->sql_freeresult($result);
	$recipients = array_unique($recipients);

	// Get History Messages (could be newer)
	$sql = 'SELECT t.*, p.*, u.*
		FROM ' . PRIVMSGS_TABLE . ' p, ' . PRIVMSGS_TO_TABLE . ' t, ' . USERS_TABLE . ' u
		WHERE t.msg_id = p.msg_id
			AND p.author_id = u.user_id
			AND t.folder_id NOT IN (' . PRIVMSGS_NO_BOX . ', ' . PRIVMSGS_HOLD_BOX . ')
			AND ' . $db->sql_in_set('t.author_id', $recipients, false, true) . "
			AND t.user_id = $user_id";

	// We no longer need those.
	unset($recipients);

	if (!$message_row['root_level'])
	{
		$sql .= " AND (p.root_level = $msg_id OR (p.root_level = 0 AND p.msg_id = $msg_id))";
	}
	else
	{
		$sql .= " AND (p.root_level = " . $message_row['root_level'] . ' OR p.msg_id = ' . $message_row['root_level'] . ')';
	}
	$sql .= ' ORDER BY p.message_time DESC';

	$result = $db->sql_query($sql);
	$row = $db->sql_fetchrow($result);

	if (!$row)
	{
		$db->sql_freeresult($result);
		return false;
	}

	$title = $row['message_subject'];

	$rowset = array();
	$folder_url = append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm') . '&amp;folder=';

	do
	{
		$folder_id = (int) $row['folder_id'];

		$row['folder'][] = (isset($folder[$folder_id])) ? '<a href="' . $folder_url . $folder_id . '">' . $folder[$folder_id]['folder_name'] . '</a>' : $user->lang['UNKNOWN_FOLDER'];

		if (isset($rowset[$row['msg_id']]))
		{
			$rowset[$row['msg_id']]['folder'][] = (isset($folder[$folder_id])) ? '<a href="' . $folder_url . $folder_id . '">' . $folder[$folder_id]['folder_name'] . '</a>' : $user->lang['UNKNOWN_FOLDER'];
		}
		else
		{
			$rowset[$row['msg_id']] = $row;
		}
	}
	while ($row = $db->sql_fetchrow($result));
	$db->sql_freeresult($result);

	if (count($rowset) == 1 && !$in_post_mode)
	{
		return false;
	}

	$title = censor_text($title);

	$url = append_sid("{$phpbb_root_path}ucp.$phpEx", 'i=pm');
	$next_history_pm = $previous_history_pm = $prev_id = 0;

	// Re-order rowset to be able to get the next/prev message rows...
	$rowset = array_values($rowset);

	for ($i = 0, $size = count($rowset); $i < $size; $i++)
	{
		$row = &$rowset[$i];
		$id = (int) $row['msg_id'];

		$author_id	= $row['author_id'];
		$folder_id	= (int) $row['folder_id'];

		$subject	= $row['message_subject'];
		$message	= $row['message_text'];

		$message = censor_text($message);

		$decoded_message = false;

		if ($in_post_mode && $auth->acl_get('u_sendpm') && $author_id != ANONYMOUS)
		{
			$decoded_message = $message;
			decode_message($decoded_message, $row['bbcode_uid']);

			$decoded_message = bbcode_nl2br($decoded_message);
		}

		$parse_flags = ($row['bbcode_bitfield'] ? OPTION_FLAG_BBCODE : 0);
		$parse_flags |= ($row['enable_smilies'] ? OPTION_FLAG_SMILIES : 0);

		$message = generate_text_for_display($message, $row['bbcode_uid'], $row['bbcode_bitfield'], $parse_flags, false);

		$subject = censor_text($subject);

		if ($id == $msg_id)
		{
			$next_history_pm = (isset($rowset[$i + 1])) ? (int) $rowset[$i + 1]['msg_id'] : 0;
			$previous_history_pm = $prev_id;
		}

		$template->assign_block_vars('history_row', array(
			'MESSAGE_AUTHOR_QUOTE'		=> (($decoded_message) ? addslashes(get_username_string('username', $author_id, $row['username'], $row['user_colour'], $row['username'])) : ''),
			'MESSAGE_AUTHOR_FULL'		=> get_username_string('full', $author_id, $row['username'], $row['user_colour'], $row['username']),
			'MESSAGE_AUTHOR_COLOUR'		=> get_username_string('colour', $author_id, $row['username'], $row['user_colour'], $row['username']),
			'MESSAGE_AUTHOR'			=> get_username_string('username', $author_id, $row['username'], $row['user_colour'], $row['username']),
			'U_MESSAGE_AUTHOR'			=> get_username_string('profile', $author_id, $row['username'], $row['user_colour'], $row['username']),

			'SUBJECT'			=> $subject,
			'SENT_DATE'			=> $user->format_date($row['message_time']),
			'MESSAGE'			=> $message,
			'FOLDER'			=> implode($user->lang['COMMA_SEPARATOR'], $row['folder']),
			'DECODED_MESSAGE'	=> $decoded_message,

			'S_CURRENT_MSG'		=> ($row['msg_id'] == $msg_id),
			'S_AUTHOR_DELETED'	=> ($author_id == ANONYMOUS) ? true : false,
			'S_IN_POST_MODE'	=> $in_post_mode,

			'MSG_ID'			=> $row['msg_id'],
			'MESSAGE_TIME'		=> $row['message_time'],
			'USER_ID'			=> $row['user_id'],
			'U_VIEW_MESSAGE'	=> "$url&amp;f=$folder_id&amp;p=" . $row['msg_id'],
			'U_QUOTE'			=> (!$in_post_mode && $auth->acl_get('u_sendpm') && $author_id != ANONYMOUS) ? "$url&amp;mode=compose&amp;action=quote&amp;f=" . $folder_id . "&amp;p=" . $row['msg_id'] : '',
			'U_POST_REPLY_PM'	=> ($author_id != $user->data['user_id'] && $author_id != ANONYMOUS && $auth->acl_get('u_sendpm')) ? "$url&amp;mode=compose&amp;action=reply&amp;f=$folder_id&amp;p=" . $row['msg_id'] : '')
		);
		unset($rowset[$i]);
		$prev_id = $id;
	}

	$template->assign_vars(array(
		'QUOTE_IMG'			=> $user->img('icon_post_quote', $user->lang['REPLY_WITH_QUOTE']),
		'HISTORY_TITLE'		=> $title,

		'U_VIEW_NEXT_HISTORY'		=> ($next_history_pm) ? "$url&amp;p=" . $next_history_pm : '',
		'U_VIEW_PREVIOUS_HISTORY'	=> ($previous_history_pm) ? "$url&amp;p=" . $previous_history_pm : '',
	));

	return true;
}

/**
* Set correct users max messages in PM folder.
* If several group memberships define different amount of messages, the highest will be chosen.
*/
function set_user_message_limit()
{
	global $user, $db, $config;

	// Get maximum about from user memberships
	$message_limit = phpbb_get_max_setting_from_group($db, $user->data['user_id'], 'message_limit');

	// If it is 0, there is no limit set and we use the maximum value within the config.
	$user->data['message_limit'] = (!$message_limit) ? $config['pm_max_msgs'] : $message_limit;
}

/**
 * Get the maximum PM setting for the groups of the user
 *
 * @param \phpbb\db\driver\driver_interface $db
 * @param int $user_id
 * @param string $setting Only 'max_recipients' and 'message_limit' are supported
 * @return int The maximum setting for all groups of the user, unless one group has '0'
 * @throws \InvalidArgumentException If selected group setting is not supported
 */
function phpbb_get_max_setting_from_group(\phpbb\db\driver\driver_interface $db, $user_id, $setting)
{
	if ($setting !== 'max_recipients' && $setting !== 'message_limit')
	{
		throw new InvalidArgumentException('Setting "' . $setting . '" is not supported');
	}

	// Get maximum number of allowed recipients
	$sql = 'SELECT MAX(g.group_' . $setting . ') as max_setting
		FROM ' . GROUPS_TABLE . ' g, ' . USER_GROUP_TABLE . ' ug
		WHERE ug.user_id = ' . (int) $user_id . '
			AND ug.user_pending = 0
			AND ug.group_id = g.group_id';
	$result = $db->sql_query($sql);
	$row = $db->sql_fetchrow($result);
	$db->sql_freeresult($result);
	$max_setting = (int) $row['max_setting'];

	return $max_setting;
}

/**
* Generates an array of coloured recipient names from a list of PMs - (groups & users)
*
* @param	array	$pm_by_id	An array of rows from PRIVMSGS_TABLE, keys are the msg_ids.
*
* @return	array				2D Array: array(msg_id => array('username or group string', ...), ...)
*								Usernames are generated with {@link get_username_string get_username_string}
*								Groups are coloured and have a link to the membership page
*/
function get_recipient_strings($pm_by_id)
{
	global $db, $phpbb_root_path, $phpEx, $user, $phpbb_container;

	/** @var \phpbb\group\helper $group_helper */
	$group_helper = $phpbb_container->get('group_helper');

	$address_list = $recipient_list = $address = array();

	$_types = array('u', 'g');

	foreach ($pm_by_id as $message_id => $row)
	{
		$address[$message_id] = rebuild_header(array('to' => $row['to_address'], 'bcc' => $row['bcc_address']));

		foreach ($_types as $ug_type)
		{
			if (isset($address[$message_id][$ug_type]) && count($address[$message_id][$ug_type]))
			{
				foreach ($address[$message_id][$ug_type] as $ug_id => $in_to)
				{
					$recipient_list[$ug_type][$ug_id] = array('name' => $user->lang['NA'], 'colour' => '');
				}
			}
		}
	}

	foreach ($_types as $ug_type)
	{
		if (!empty($recipient_list[$ug_type]))
		{
			if ($ug_type == 'u')
			{
				$sql = 'SELECT user_id as id, username as name, user_colour as colour
					FROM ' . USERS_TABLE . '
					WHERE ';
			}
			else
			{
				$sql = 'SELECT group_id as id, group_name as name, group_colour as colour, group_type
					FROM ' . GROUPS_TABLE . '
					WHERE ';
			}
			$sql .= $db->sql_in_set(($ug_type == 'u') ? 'user_id' : 'group_id', array_map('intval', array_keys($recipient_list[$ug_type])));

			$result = $db->sql_query($sql);

			while ($row = $db->sql_fetchrow($result))
			{
				if ($ug_type == 'g')
				{
					$row['name'] = $group_helper->get_name($row['name']);
				}

				$recipient_list[$ug_type][$row['id']] = array('name' => $row['name'], 'colour' => $row['colour']);
			}
			$db->sql_freeresult($result);
		}
	}

	foreach ($address as $message_id => $adr_ary)
	{
		foreach ($adr_ary as $type => $id_ary)
		{
			foreach ($id_ary as $ug_id => $_id)
			{
				if ($type == 'u')
				{
					$address_list[$message_id][] = get_username_string('full', $ug_id, $recipient_list[$type][$ug_id]['name'], $recipient_list[$type][$ug_id]['colour']);
				}
				else
				{
					$user_colour = ($recipient_list[$type][$ug_id]['colour']) ? ' style="font-weight: bold; color:#' . $recipient_list[$type][$ug_id]['colour'] . '"' : '';
					$link = '<a href="' . append_sid("{$phpbb_root_path}memberlist.$phpEx", 'mode=group&amp;g=' . $ug_id) . '"' . $user_colour . '>';
					$address_list[$message_id][] = $link . $recipient_list[$type][$ug_id]['name'] . (($link) ? '</a>' : '');
				}
			}
		}
	}

	return $address_list;
}