/include/functions.php

<?php
/**
 * Copyright (C) 2015 Panther (https://www.pantherforum.org)
 * based on code by FluxBB copyright (C) 2008-2012 FluxBB
 * License: http://www.gnu.org/licenses/gpl.html GPL version 3 or higher
 */

//
// Cookie stuff!
//
function check_cookie(&$panther_user)
{
	global $db, $panther_config;
	$now = time();

	// If the cookie is set and it matches the correct pattern, then read the values from it
	if (isset($_COOKIE[$panther_config['o_cookie_name']]) && preg_match('%^(\d+)\|([0-9a-fA-F]+)\|(\d+)\|([0-9a-fA-F]+)$%', $_COOKIE[$panther_config['o_cookie_name']], $matches))
	{
		$cookie = array(
			'user_id'			=> intval($matches[1]),
			'password_hash' 	=> $matches[2],
			'expiration_time'	=> intval($matches[3]),
			'cookie_hash'		=> $matches[4],
		);
	}

	// If it has a non-guest user, and hasn't expired
	if (isset($cookie) && $cookie['user_id'] > 1 && $cookie['expiration_time'] > $now)
	{
		// If the cookie has been tampered with
		if (!panther_hash_equals(hash_hmac('sha512', $cookie['user_id'].'|'.$cookie['expiration_time'], $panther_config['o_cookie_seed'].'_cookie_hash'), $cookie['cookie_hash']))
		{
			$expire = $now + 31536000; // The cookie expires after a year
			panther_setcookie(1, panther_hash(uniqid(rand(), true)), $expire);
			set_default_user();

			return;
		}

		$data = array(
			':id'	=>	$cookie['user_id'],
		);

		// Check if there's a user with the user ID and password hash from the cookie
		$ps = $db->run('SELECT u.*, g.*, o.logged, o.idle FROM '.$db->prefix.'users AS u INNER JOIN '.$db->prefix.'groups AS g ON u.group_id=g.g_id LEFT JOIN '.$db->prefix.'online AS o ON o.user_id=u.id WHERE u.id=:id', $data);
		$panther_user = $ps->fetch();

		// If user authorisation failed
		if (!isset($panther_user['id']) || !panther_hash_equals(hash_hmac('sha512', $panther_user['login_key'], $panther_config['o_cookie_seed'].'_password_hash'), $cookie['password_hash']))
		{
			$expire = $now + 31536000; // The cookie expires after a year
			panther_setcookie(1, panther_hash(uniqid(rand(), true)), $expire);
			set_default_user();

			return;
		}

		// Send a new, updated cookie with a new expiration timestamp
		$expire = ($cookie['expiration_time'] > $now + $panther_config['o_timeout_visit']) ? $now + 1209600 : $now + $panther_config['o_timeout_visit'];
		panther_setcookie($panther_user['id'], $panther_user['login_key'], $expire);

		// Set a default language if the user selected language no longer exists
		if (!file_exists(PANTHER_ROOT.'lang/'.$panther_user['language']))
			$panther_user['language'] = $panther_config['o_default_lang'];

		$style_root = (($panther_config['o_style_path'] != 'style') ? $panther_config['o_style_path'] : PANTHER_ROOT.$panther_config['o_style_path']).'/';

		// Set a default style if the user selected style no longer exists
		if (!file_exists($style_root.$panther_user['style'].'.css'))
			$panther_user['style'] = $panther_config['o_default_style'];

		if (!$panther_user['disp_topics'])
			$panther_user['disp_topics'] = $panther_config['o_disp_topics_default'];

		if (!$panther_user['disp_posts'])
			$panther_user['disp_posts'] = $panther_config['o_disp_posts_default'];

		// Define this if you want this visit to affect the online list and the users last visit data
		if (!defined('PANTHER_QUIET_VISIT'))
		{
			// Update the online list
			if (!$panther_user['logged'])
			{
				$panther_user['logged'] = $now;

				$data = array(
					':id'	=>	$panther_user['id'],
					':ident'	=>	$panther_user['username'],
					':logged'	=>	$panther_user['logged'],
				);

				// REPLACE INTO avoids a user having two rows in the online table
				$db->run('REPLACE INTO '.$db->prefix.'online (user_id, ident, logged) VALUES (:id, :ident, :logged)', $data);

				// Reset tracked topics
				set_tracked_topics(null);
			}
			else
			{
				$data = array(
					':id'	=>	$panther_user['id'],
				);

				// Special case: We've timed out, but no other user has browsed the forums since we timed out
				if ($panther_user['logged'] < ($now-$panther_config['o_timeout_visit']))
				{
					$update = array(
						'last_visit'	=>	$panther_user['logged'],
					);

					$db->update('users', $update, 'id=:id', $data);
					$panther_user['last_visit'] = $panther_user['logged'];
				}

				$update = array(
					'logged'	=>	$now,
				);

				if ($panther_user['idle'] == '1')
					$update['idle'] = 0;

				$db->update('online', $update, 'user_id=:id', $data);

				// Update tracked topics with the current expire time
				if (isset($_COOKIE[$panther_config['o_cookie_name'].'_track']))
					forum_setcookie($panther_config['o_cookie_name'].'_track', $_COOKIE[$panther_config['o_cookie_name'].'_track'], $now + $panther_config['o_timeout_visit']);
			}
		}
		else
		{
			if (!$panther_user['logged'])
				$panther_user['logged'] = $panther_user['last_visit'];
		}

		$panther_user['is_guest'] = false;
		$panther_user['is_admmod'] = $panther_user['g_id'] == PANTHER_ADMIN || $panther_user['g_moderator'] == '1';
		$panther_user['is_admin'] = $panther_user['g_id'] == PANTHER_ADMIN || $panther_user['g_moderator'] == '1' && $panther_user['g_admin'] == '1';
		$panther_user['is_bot'] = false;
	}
	else
		set_default_user();
}

function panther_hash_equals($hash, $input)
{
	if (function_exists('hash_equals'))
		return hash_equals((string)$hash, $input);

	$input_length = strlen($input);
	if ($input_length !== strlen($hash))
		return false;

	$result = 0;
	for ($i = 0; $i < $input_length; $i++)
		$result |= ord($input[$i]) ^ ord($hash[$i]);

	return $result === 0;
}


//
// Try to determine the current URL
//
function get_current_url($max_length = 0)
{
	$protocol = get_current_protocol();
	$port = (isset($_SERVER['SERVER_PORT']) && (($_SERVER['SERVER_PORT'] != '80' && $protocol == 'http') || ($_SERVER['SERVER_PORT'] != '443' && $protocol == 'https')) && strpos($_SERVER['HTTP_HOST'], ':') === false) ? ':'.$_SERVER['SERVER_PORT'] : '';

	$url = urldecode($protocol.'://'.$_SERVER['HTTP_HOST'].$port.$_SERVER['REQUEST_URI']);

	if (strlen($url) <= $max_length || $max_length == 0)
		return $url;

	// We can't find a short enough url
	return null;
}

//
// Fetch the current protocol in use - http or https
//
function get_current_protocol()
{
	$protocol = 'http';

	// Check if the server is claiming to using HTTPS
	if (!empty($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) != 'off')
		$protocol = 'https';

	// If we are behind a reverse proxy try to decide which protocol it is using
	if (defined('FORUM_BEHIND_REVERSE_PROXY'))
	{
		// Check if we are behind a Microsoft based reverse proxy
		if (!empty($_SERVER['HTTP_FRONT_END_HTTPS']) && strtolower($_SERVER['HTTP_FRONT_END_HTTPS']) != 'off')
			$protocol = 'https';

		// Check if we're behind a "proper" reverse proxy, and what protocol it's using
		if (!empty($_SERVER['HTTP_X_FORWARDED_PROTO']))
			$protocol = strtolower($_SERVER['HTTP_X_FORWARDED_PROTO']);
	}

	return $protocol;
}

function check_ssl_state()
{
	global $panther_config;
	if ($panther_config['o_force_ssl'] == '1' && get_current_protocol() == 'http')
	{
		header('Location: '.str_replace('http://', 'https://', get_current_url()));
		exit;
	}
}

//
// Fetch the base_url, optionally support HTTPS and HTTP
//
function get_base_url($support_https = true)
{
	global $panther_config;
	static $base_url;

	if (!$support_https)
		return $panther_config['o_base_url'];

	if (!isset($base_url))
	{
		// Make sure we are using the correct protocol
		$base_url = str_replace(array('http://', 'https://'), get_current_protocol().'://', $panther_config['o_base_url']);
	}

	return $base_url;
}

//
// Fetch admin IDs
//
function get_admin_ids()
{
	if (file_exists(FORUM_CACHE_DIR.'cache_admins.php'))
		include FORUM_CACHE_DIR.'cache_admins.php';

	if (!defined('PANTHER_ADMINS_LOADED'))
	{
		if (!defined('FORUM_CACHE_FUNCTIONS_LOADED'))
			require PANTHER_ROOT.'include/cache.php';

		generate_admins_cache();
		require FORUM_CACHE_DIR.'cache_admins.php';
	}

	return $panther_admins;
}

//
// Fill $panther_user with default values (for guests)
//
function set_default_user()
{
	global $db, $panther_user, $panther_config;

	$remote_addr = get_remote_address();
	$remote_addr = isbotex($remote_addr);

	$data = array(
		':ident'	=>	$remote_addr,
	);

	// Fetch guest user
	$ps = $db->run('SELECT u.*, g.*, o.logged, o.last_post, o.last_search FROM '.$db->prefix.'users AS u INNER JOIN '.$db->prefix.'groups AS g ON u.group_id=g.g_id LEFT JOIN '.$db->prefix.'online AS o ON o.ident=:ident WHERE u.id=1', $data);
	if (!$ps->rowCount())
		error_handler(E_ERROR, 'Unable to fetch guest information. Your database must contain both a guest user and a guest user group.', __FILE__, __LINE__);

	$panther_user = $ps->fetch();

	// Update online list
	if (!$panther_user['logged'])
	{
		$panther_user['logged'] = time();
		$data = array(
			':ident'	=>	$remote_addr,
			':logged'	=>	$panther_user['logged'],
		);

		// REPLACE INTO avoids a user having two rows in the online table
		$db->run('REPLACE INTO '.$db->prefix.'online (user_id, ident, logged) VALUES(1, :ident, :logged)', $data);
	}
	else
	{
		$update = array(
			'logged'	=>	time(),
		);

		$data = array(
			':ident' => $remote_addr,
		);

		$db->update('online', $update, 'ident=:ident', $data);
	}

	$panther_user['disp_topics'] = $panther_config['o_disp_topics_default'];
	$panther_user['disp_posts'] = $panther_config['o_disp_posts_default'];
	$panther_user['timezone'] = $panther_config['o_default_timezone'];
	$panther_user['dst'] = $panther_config['o_default_dst'];
	$panther_user['language'] = $panther_config['o_default_lang'];
	$panther_user['style'] = $panther_config['o_default_style'];
	$panther_user['is_guest'] = true;
	$panther_user['is_admmod'] = false;
	$panther_user['is_admin'] = false;
	$panther_user['is_bot'] = (strpos($remote_addr, '[Bot]') !== false);
}

//
// Set a cookie, Panther style!
// Wrapper for forum_setcookie
//
function panther_setcookie($user_id, $password_hash, $expire)
{
	global $panther_config;
	forum_setcookie($panther_config['o_cookie_name'], $user_id.'|'.hash_hmac('sha512', $password_hash, $panther_config['o_cookie_seed'].'_password_hash').'|'.$expire.'|'.hash_hmac('sha512', $user_id.'|'.$expire, $panther_config['o_cookie_seed'].'_cookie_hash'), $expire);
}

//
// Set a cookie, Panther style!
//
function forum_setcookie($name, $value, $expire)
{
	global $panther_config;

	if ($expire - time() - $panther_config['o_timeout_visit'] < 1)
		$expire = 0;

	// Enable sending of a P3P header
	header('P3P: CP="CUR ADM"');
	setcookie($name, $value, $expire, $panther_config['o_cookie_path'], $panther_config['o_cookie_domain'], $panther_config['o_cookie_secure'], true);
}

//
// Check whether the connecting user is banned (and delete any expired bans while we're at it)
//
function check_bans()
{
	global $db, $panther_config, $lang_common, $panther_user, $panther_bans;

	// Admins and moderators aren't affected
	if ($panther_user['is_admmod'] || !$panther_bans)
		return;

	// Add a dot or a colon (depending on IPv4/IPv6) at the end of the IP address to prevent banned address
	// 192.168.0.5 from matching e.g. 192.168.0.50
	$user_ip = get_remote_address();
	$user_ip .= (strpos($user_ip, '.') !== false) ? '.' : ':';

	$bans_altered = false;
	$is_banned = false;

	foreach ($panther_bans as $cur_ban)
	{
		// Has this ban expired?
		if ($cur_ban['expire'] != '' && $cur_ban['expire'] <= time())
		{
			$data = array(
				':id'	=>	$cur_ban['id'],
			);

			$db->delete('bans', 'id=:id', $data);
			$bans_altered = true;
			continue;
		}

		if ($cur_ban['username'] != '' && utf8_strtolower($panther_user['username']) == utf8_strtolower($cur_ban['username']))
			$is_banned = true;

		if ($cur_ban['ip'] != '')
		{
			$cur_ban_ips = explode(' ', $cur_ban['ip']);

			$num_ips = count($cur_ban_ips);
			for ($i = 0; $i < $num_ips; ++$i)
			{
				// Add the proper ending to the ban
				if (strpos($user_ip, '.') !== false)
					$cur_ban_ips[$i] = $cur_ban_ips[$i].'.';
				else
					$cur_ban_ips[$i] = $cur_ban_ips[$i].':';

				if (substr($user_ip, 0, strlen($cur_ban_ips[$i])) == $cur_ban_ips[$i])
				{
					$is_banned = true;
					break;
				}
			}
		}

		if ($is_banned)
		{
			$data = array(
				':ident'	=>	$panther_user['username'],
			);

			$db->delete('online', 'ident=:ident', $data);
			message($lang_common['Ban message'].' '.(($cur_ban['expire'] != '') ? $lang_common['Ban message 2'].' '.strtolower(format_time($cur_ban['expire'], true)).'. ' : '').(($cur_ban['message'] != '') ? $lang_common['Ban message 3'].'<br /><br /><strong>'.$cur_ban['message'].'</strong><br /><br />' : '<br /><br />').$lang_common['Ban message 4'].' '.$panther_config['o_admin_email'], true);
		}
	}

	// If we removed any expired bans during our run-through, we need to regenerate the bans cache
	if ($bans_altered)
	{
		if (!defined('FORUM_CACHE_FUNCTIONS_LOADED'))
			require PANTHER_ROOT.'include/cache.php';

		generate_bans_cache();
	}
}

//
// Check username
//
function check_username($username, $exclude_id = null)
{
	global $db, $panther_config, $errors, $lang_prof_reg, $lang_register, $lang_common, $panther_bans;

	// Include UTF-8 function
	require_once PANTHER_ROOT.'include/utf8/strcasecmp.php';

	// Convert multiple whitespace characters into one (to prevent people from registering with indistinguishable usernames)
	$username = preg_replace('%\s+%s', ' ', $username);

	// Validate username
	if (panther_strlen($username) < 2)
		$errors[] = $lang_prof_reg['Username too short'];
	else if (panther_strlen($username) > 25) // This usually doesn't happen since the form element only accepts 25 characters
		$errors[] = $lang_prof_reg['Username too long'];
	else if (!strcasecmp($username, 'Guest') || !utf8_strcasecmp($username, $lang_common['Guest']))
		$errors[] = $lang_prof_reg['Username guest'];
	else if (preg_match('%[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}%', $username) || preg_match('%((([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){6}:[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){5}:([0-9A-Fa-f]{1,4}:)?[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){4}:([0-9A-Fa-f]{1,4}:){0,2}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){3}:([0-9A-Fa-f]{1,4}:){0,3}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){2}:([0-9A-Fa-f]{1,4}:){0,4}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){6}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|(([0-9A-Fa-f]{1,4}:){0,5}:((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|(::([0-9A-Fa-f]{1,4}:){0,5}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|([0-9A-Fa-f]{1,4}::([0-9A-Fa-f]{1,4}:){0,5}[0-9A-Fa-f]{1,4})|(::([0-9A-Fa-f]{1,4}:){0,6}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){1,7}:))%', $username))
		$errors[] = $lang_prof_reg['Username IP'];
	else if ((strpos($username, '[') !== false || strpos($username, ']') !== false) && strpos($username, '\'') !== false && strpos($username, '"') !== false)
		$errors[] = $lang_prof_reg['Username reserved chars'];
	else if (preg_match('%(?:\[/?(?:b|u|s|ins|del|em|i|h|colou?r|quote|code|img|url|email|list|\*|topic|post|forum|user)\]|\[(?:img|url|quote|list)=)%i', $username))
		$errors[] = $lang_prof_reg['Username BBCode'];

	// Check username for any censored words
	if ($panther_config['o_censoring'] == '1' && censor_words($username) != $username)
		$errors[] = $lang_register['Username censor'];
	
	$where_cond = '(UPPER(username)=UPPER(:username) OR UPPER(username)=UPPER(:username2)) AND id>1';
	
	$data = array(
		':username'	=>	$username,
		':username2'	=>	ucp_preg_replace('%[^\p{L}\p{N}]%u', '', $username),
	);

	// Check that the username (or a too similar username) is not already registered
	if (!is_null($exclude_id))
	{
		$where_cond .= ' AND id!=:id';
		$data[':id'] = $exclude_id;
	}

	$ps = $db->select('users', 'username', $data, $where_cond);
	if ($ps->rowCount())
	{
		$busy = $ps->fetchColumn();
		$errors[] = $lang_register['Username dupe 1'].' '.$busy.'. '.$lang_register['Username dupe 2'];
	}

	// Check username for any banned usernames
	foreach ($panther_bans as $cur_ban)
	{
		if ($cur_ban['username'] != '' && utf8_strtolower($username) == utf8_strtolower($cur_ban['username']))
		{
			$errors[] = $lang_prof_reg['Banned username'];
			break;
		}
	}
}

//
// Update "Users online"
//
function update_users_online()
{
	global $db, $panther_config, $panther_user;

	$cur_position = substr($_SERVER['REQUEST_URI'], 1);
	$server_base = dirname($_SERVER['PHP_SELF']);

	if ($server_base !== '/')
		$cur_position = substr($cur_position, strlen($server_base));

	$cur_position = ($cur_position == '') ? 'index.php' : $cur_position;

	$now = time();
	$online['users'] = $online['guests'] = array();

	// Fetch all online list entries that are older than "o_timeout_online"
	$ps = $db->run('SELECT o.user_id, o.ident, o.logged, o.idle, u.group_id FROM '.$db->prefix.'online AS o LEFT JOIN '.$db->prefix.'users AS u ON o.user_id=u.id');
	foreach ($ps as $cur_user)
	{
		if ($cur_user['logged'] < ($now - $panther_config['o_timeout_online']))
		{
			// If the entry is a guest, delete it
			if ($cur_user['user_id'] == '1')
			{
				$data = array(
					':ident'	=>	$cur_user['ident']
				);

				$db->delete('online', 'ident=:ident', $data);
			}
			else
			{
				// If the entry is older than "o_timeout_visit", update last_visit for the user in question, then delete him/her from the online list
				if ($cur_user['logged'] < ($now - $panther_config['o_timeout_visit']))
				{
					$update = array(
						'last_visit'	=>	$cur_user['logged'],
					);
					
					$data = array(
						':id'	=>	$cur_user['user_id'],
					);
					
					$db->update('users', $update, 'id=:id', $data);
					$db->delete('online', 'user_id=:id', $data);
				}
			}
		}
		else
		{
			if ($cur_user['user_id'] == 1)
				$online['guests'][] = array('ident' => $cur_user['ident'], 'group_id' => PANTHER_GUEST);
			else
				$online['users'][$cur_user['user_id']] = array('username' => $cur_user['ident'], 'group_id' => $cur_user['group_id'], 'id' => $cur_user['user_id']);
		}
	}
	
	if (!$panther_user['is_bot'])
	{
		$update = array(
			'currently'	=>	$cur_position,
		);
		
		$data = array();
		if ($panther_user['is_guest'])
		{
			$field = 'ident';
			$data[':ident'] = get_remote_address();
		}
		else
		{
			$field = 'user_id';
			$data[':ident'] = $panther_user['id'];
		}

		$db->update('online', $update, $field.'=:ident', $data);
	}
	return $online;
}

//
// Display the profile navigation menu
//
function generate_profile_menu($page = '')
{
	global $lang_profile, $panther_config, $panther_user, $id, $panther_url;
	
	$sections = array(
		array('page' => 'essentials', 'link' => panther_link($panther_url['profile_essentials'], array($id)), 'lang' => $lang_profile['Section essentials']),
		array('page' => 'personal', 'link' => panther_link($panther_url['profile_personal'], array($id)), 'lang' => $lang_profile['Section personal']),
		array('page' => 'messaging', 'link' => panther_link($panther_url['profile_messaging'], array($id)), 'lang' => $lang_profile['Section messaging']),
	);
	
	if ($panther_config['o_avatars'] == '1' || $panther_config['o_signatures'] == '1')
		$sections[] = array('page' => 'personality', 'link' => panther_link($panther_url['profile_personality'], array($id)), 'lang' => $lang_profile['Section personality']);
	
	$sections[] = array('page' => 'display', 'link' => panther_link($panther_url['profile_display'], array($id)), 'lang' => $lang_profile['Section display']);
	$sections[] = array('page' => 'privacy', 'link' => panther_link($panther_url['profile_privacy'], array($id)), 'lang' => $lang_profile['Section privacy']);
	$sections[] = array('page' => 'view', 'link' => panther_link($panther_url['profile_view'], array($id)), 'lang' => $lang_profile['Section view']);

	if ($panther_user['is_admin'] || ($panther_user['g_moderator'] == '1' && $panther_user['g_mod_ban_users'] == '1'))
		$sections[] = array('page' => 'admin', 'link' => panther_link($panther_url['profile_admin'], array($id)), 'lang' => $lang_profile['Section admin']);

	$tpl = load_template('profile_sidebar.tpl');
	echo $tpl->render(
		array(
			'lang_profile' => $lang_profile,
			'sections' => $sections,
			'page' => $page,
		)
	);
}

//
// Display PM menu
//

function generate_pm_menu($page = 2)	// Default to inbox
{
	global $panther_url, $lang_pm, $panther_user, $db;
	static $folders;

	$percent = ($panther_user['g_pm_limit'] != '0') ? round(ceil($panther_user['num_pms'] / $panther_user['g_pm_limit']*100), 0) : 0;
	$limit = ($panther_user['g_pm_limit'] == '0') ? '&infin;' : $panther_user['g_pm_limit'];
	
	$data = array(
		':uid'	=>	$panther_user['id'],
	);

	$folders = array();
	$ps = $db->select('folders', 'name, id', $data, 'user_id=:uid OR user_id=1', 'id, user_id ASC');
	foreach ($ps as $folder)
	{
		$data = array(
			':id'	=>	$folder['id'],
			':uid'	=>	$panther_user['id'],
		);

		$ps1 = $db->select('pms_data', 'COUNT(topic_id)', $data, 'user_id=:uid AND deleted=0 AND (folder_id=:id '.(($folder['id'] == 1) ? 'OR viewed=0)' : ')'));
		$amount = $ps1->fetchColumn();

		$folders[] = array(
			'id' => $folder['id'],
			'link' => panther_link($panther_url['box'], array($folder['id'])),
			'name' => $folder['name'],
			'amount' => $amount,
		);
	}
	
	$tpl = load_template('pm_sidebar.tpl');
	return $tpl->render(
		array(
			'lang_pm' => $lang_pm,
			'folders' => $folders,
			'percent' => $percent,
			'num_pms' => forum_number_format($panther_user['num_pms']),
			'limit' => forum_number_format($limit),
			'blocked_link' => panther_link($panther_url['pms_blocked']),
			'folders_link' => panther_link($panther_url['pms_folders']),
			'page' => $page,
		)
	);
}

//
// Outputs markup to display a user's avatar
//
function generate_avatar_markup($user_id, $user_email, $use_gravatar = 0, $size = array())
{
	global $panther_config;
	static $user_avatar_cache = array();
	$avatar_path = ($panther_config['o_avatars_dir'] != '') ? $panther_config['o_avatars_path'] : PANTHER_ROOT.$panther_config['o_avatars_path'];
	$avatar_dir = ($panther_config['o_avatars_dir'] != '') ? $panther_config['o_avatars_dir'] : get_base_url(true).'/'.$panther_config['o_avatars_path'];

	if (!isset($user_avatar_cache[$user_id]))
	{
		if ($use_gravatar == 1)
		{
			$params = (count($size) == 2) ? array($size[0], $size[1]) : array($panther_config['o_avatars_width'], $panther_config['o_avatars_height']);
			$user_avatar_cache[$user_id] = '<img src="https://www.gravatar.com/avatar.php?gravatar_id='.md5(strtolower($user_email)).'&amp;size='.$params[0].'" width="'.$params[0].'" height="'.$params[1].'" alt="" />';
		}
		else if ($panther_config['o_avatar_upload'] == '1')
		{
			$filetypes = array('jpg', 'gif', 'png');
			foreach ($filetypes as $cur_type)
			{
				$path = $avatar_path.$user_id.'.'.$cur_type;
				$url = $avatar_dir.$user_id.'.'.$cur_type;
				if (file_exists($path) && $img_size = getimagesize($path))
				{
					$size = (count($size) == 2 ? 'width="'.$size[0].'" height="'.$size[1].'"' : $img_size[3]);
					$user_avatar_cache[$user_id] = '<img src="'.$url.'?m='.filemtime($path).'" '.$size.' alt="" />';
					break;
				}
			}
		}

		// If there's no avatar set, we mustn't have one uploaded. Set the default!
		if (!isset($user_avatar_cache[$user_id]))
		{
			$path = $avatar_path.'1.'.$panther_config['o_avatar'];
			$url = $avatar_dir.'1.'.$panther_config['o_avatar'];
			$img_size = getimagesize($path);
			$size = (count($size) == 2 ? 'width="'.$size[0].'" height="'.$size[1].'"' : $img_size[3]);
			$user_avatar_cache[$user_id] = '<img src="'.$url.'?m='.filemtime($path).'" '.$size.' alt="" />';
		}
	}

	return $user_avatar_cache[$user_id];
}

//
// Generate browser's title
//
function generate_page_title($page_title, $p = null)
{
	global $lang_common;

	if (!is_array($page_title))
		$page_title = array($page_title);

	$page_title = array_reverse($page_title);

	if ($p > 1)
		$page_title[0] .= ' ('.sprintf($lang_common['Page'], forum_number_format($p)).')';

	$crumbs = implode($lang_common['Title separator'], $page_title);

	return $crumbs;
}

//
// Save array of tracked topics in cookie
//
function set_tracked_topics($tracked_topics)
{
	global $panther_config;

	$cookie_data = '';
	if (!empty($tracked_topics))
	{
		// Sort the arrays (latest read first)
		arsort($tracked_topics['topics'], SORT_NUMERIC);
		arsort($tracked_topics['forums'], SORT_NUMERIC);

		// Homebrew serialization (to avoid having to run unserialize() on cookie data)
		foreach ($tracked_topics['topics'] as $id => $timestamp)
			$cookie_data .= 't'.$id.'='.$timestamp.';';
		foreach ($tracked_topics['forums'] as $id => $timestamp)
			$cookie_data .= 'f'.$id.'='.$timestamp.';';

		// Enforce a byte size limit (4096 minus some space for the cookie name - defaults to 4048)
		if (strlen($cookie_data) > FORUM_MAX_COOKIE_SIZE)
		{
			$cookie_data = substr($cookie_data, 0, FORUM_MAX_COOKIE_SIZE);
			$cookie_data = substr($cookie_data, 0, strrpos($cookie_data, ';')).';';
		}
	}

	forum_setcookie($panther_config['o_cookie_name'].'_track', $cookie_data, time() + $panther_config['o_timeout_visit']);
	$_COOKIE[$panther_config['o_cookie_name'].'_track'] = $cookie_data; // Set it directly in $_COOKIE as well
}

//
// Extract array of tracked topics from cookie
//
function get_tracked_topics()
{
	global $panther_config;

	$cookie_data = isset($_COOKIE[$panther_config['o_cookie_name'].'_track']) ? $_COOKIE[$panther_config['o_cookie_name'].'_track'] : false;
	if (!$cookie_data)
		return array('topics' => array(), 'forums' => array());

	if (strlen($cookie_data) > FORUM_MAX_COOKIE_SIZE)
		return array('topics' => array(), 'forums' => array());

	// Unserialize data from cookie
	$tracked_topics = array('topics' => array(), 'forums' => array());
	$temp = explode(';', $cookie_data);
	foreach ($temp as $t)
	{
		$type = substr($t, 0, 1) == 'f' ? 'forums' : 'topics';
		$id = intval(substr($t, 1));
		$timestamp = intval(substr($t, strpos($t, '=') + 1));
		if ($id > 0 && $timestamp > 0)
			$tracked_topics[$type][$id] = $timestamp;
	}

	return $tracked_topics;
}

//
// Update posts, topics, last_post, last_post_id and last_poster for a forum
//
function update_forum($forum_id)
{
	global $db;
	$data = array(
		':id'	=>	$forum_id,
	);

	$ps = $db->select('topics', 'COUNT(id), SUM(num_replies)', $data, 'forum_id=:id AND approved=1 AND deleted=0');
	list($num_topics, $num_posts) = $ps->fetch(PDO::FETCH_NUM);

	$num_posts = $num_posts + $num_topics; // $num_posts is only the sum of all replies (we have to add the topic posts)
	$data = array(
		':id'	=>	$forum_id
	);

	$ps = $db->select('topics', 'last_post, last_post_id, last_poster, subject, id', $data, 'forum_id=:id AND approved=1 AND deleted=0 AND moved_to IS NULL ORDER BY last_post DESC LIMIT 1');
	if ($ps->rowCount()) // There are topics in the forum
	{
		list($last_post, $last_post_id, $last_poster, $last_topic, $last_topic_id) = $ps->fetch(PDO::FETCH_NUM);
		$update = array(
			'num_topics'	=>	$num_topics,
			'num_posts'		=>	$num_posts,
			'last_post'		=>	$last_post,
			'last_post_id'	=>	$last_post_id,
			'last_topic'	=>	$last_topic,
			'last_topic_id'	=>	$last_topic_id,
			'last_poster'	=>	$last_poster,
		);

		$data = array(
			':id'	=>	$forum_id,
		);

		$db->update('forums', $update, 'id=:id', $data);
	}
	else // There are no topics
	{
		$data = array(
			':num_topics'	=>	$num_topics,
			':num_posts'	=>	$num_posts,
			':id'		=>	$forum_id,
		);

		// Annoyingly PDO does not allow NULL values to be added in prepared statements. When added it becomes 'NULL', so we have to run the query manually instead.
		$db->run('UPDATE '.$db->prefix.'forums SET num_topics=:num_topics, num_posts=:num_posts, last_post=NULL, last_post_id=NULL, last_poster=NULL, last_topic=\'\', last_topic_id=0 WHERE id=:id', $data);
	}
}

//
// Deletes any avatars owned by the specified user ID
//
function delete_avatar($user_id)
{
	global $panther_config;

	$filetypes = array('jpg', 'gif', 'png');
	$avatar_path = ($panther_config['o_avatars_dir'] != '') ? $panther_config['o_avatars_path'] : PANTHER_ROOT.$panther_config['o_avatars_path'];

	// Delete user avatar
	foreach ($filetypes as $cur_type)
	{
		if (file_exists($avatar_path.$user_id.'.'.$cur_type))
			@unlink($avatar_path.$user_id.'.'.$cur_type);
	}
}

//
// Delete a topic and all of its posts
//
function delete_topic($topic_id)
{
	global $db, $panther_config;

	// Delete the topic and any redirect topics
	attach_delete_thread($topic_id);
	$data = array(
		':id'	=>	$topic_id,
	);

	$topic = array(
		':id'	=>	$topic_id,
		':moved_to'	=>	$topic_id,
	);

	$update = array(
		'deleted'	=>	1,
	);

	$post_ids = array();
	$db->update('topics', $update, 'id=:id OR moved_to=:moved_to', $topic);
	$db->delete('polls', 'topic_id=:id', $data);

	// Get all post IDs from this topic. 
	$ps = $db->select('posts', 'id', $data, 'topic_id=:id');
	foreach ($ps as $cur_post)
		$post_ids[] = $cur_post['id'];

	// Make sure we have a list of post IDs
	if (!empty($post_ids))
	{
		strip_search_index($post_ids);	// Should be an array
		$db->update('posts', $update, 'topic_id=:id', $data);
	}

	if ($panther_config['o_delete_full'] == '1')
		permanently_delete_topic($topic_id);
}

//
// Delete a single post
//
function delete_post($post_id, $topic_id)
{
	global $db, $panther_config;
	$topic_data = array(
		':id'	=>	$topic_id,
	);	

	$post_data = array(
		':id'	=>	$post_id,
	);

	$ps = $db->select('posts', 'id, poster, posted', $topic_data, 'topic_id=:id AND approved=1 AND deleted=0', 'id DESC LIMIT 2');
	list($last_id, ,) = $ps->fetch(PDO::FETCH_NUM);
	list($second_last_id, $second_poster, $second_posted) = $ps->fetch(PDO::FETCH_NUM);

	// Delete the post
	attach_delete_post($post_id);
	$update = array(
		'deleted'	=>	1,
	);

	$db->update('posts', $update, 'id=:id', $post_data);
	strip_search_index(array($post_id));

	// Count number of replies in the topic
	$ps = $db->select('posts', 'COUNT(id)', $topic_data, 'topic_id=:id AND approved=1 AND deleted=0');
	$num_replies = $ps->fetchColumn() - 1; // Decrement the deleted post

	// If the message we deleted is the most recent in the topic (at the end of the topic)
	if ($last_id == $post_id)
	{
		// If there is a $second_last_id there is more than 1 reply to the topic
		if (!empty($second_last_id))
		{
			$update = array(
				'last_post'	=>	$second_posted,
				'last_post_id'	=>	$second_last_id,
				'last_poster'	=>	$second_poster,
				'num_replies'	=>	$num_replies,
			);

			$data = array(
				':id'	=>	$topic_id,
			);

			$db->update('topics', $update, 'id=:id', $data);
		}
		else
		{
			$data = array(
				':id'	=>	$topic_id,
				':num_replies'	=>	$num_replies-1,
			);

			// We deleted the only reply, so now last_post/last_post_id/last_poster is posted/id/poster from the topic itself
			$db->run('UPDATE '.$db->prefix.'topics SET last_post=posted, last_post_id=id, last_poster=poster, num_replies=:num_replies WHERE id=:id', $data);
		}
	}
	else	// Otherwise we just decrement the reply counter
	{
		$update = array(
			'num_replies'	=>	$num_replies,
		);

		$db->update('topics', $update, 'id=:id', $topic_data);
	}

	if ($panther_config['o_delete_full'] == '1')
		permanently_delete_post($post_id);
}

//
// Permanently delete a single post
//
function permanently_delete_post($id)
{
	global $db;
	$data = array(
		':id'	=>	$id,
	);

	$db->delete('posts', 'id=:id AND deleted=1', $data);	// Since we've already stripped the search index, all we need to do is delete the row
}

//
// Permanently delete a topic
//
function permanently_delete_topic($id)
{
	global $db;
	$data = array(
		':id'	=>	$id,
		':moved_to'	=>	$id,
	);

	$db->delete('topics', '(id=:id OR moved_to=:moved_to) AND deleted=1', $data);
	unset($data[':moved_to']);
	$db->delete('posts', 'topic_id=? AND deleted=1', array_values($data));

	// Delete any subscriptions for this topic
	$db->delete('topic_subscriptions', 'topic_id=?', array_values($data));
}

//
// Delete every .php file in the forum's cache directory
//
function forum_clear_cache()
{
	$files = array_diff(scandir(FORUM_CACHE_DIR), array('.', '..'));
	foreach ($files as $file)
	{
		if (substr($file, -4) == '.php')
			@unlink(FORUM_CACHE_DIR.$file);
	}
}

//
// Replace censored words in $text
//
function censor_words($text)
{
	global $db;
	static $search_for, $replace_with;

	// If not already built in a previous call, build an array of censor words and their replacement text
	if (!isset($search_for))
	{
		if (file_exists(FORUM_CACHE_DIR.'cache_censoring.php'))
			include FORUM_CACHE_DIR.'cache_censoring.php';

		if (!defined('PANTHER_CENSOR_LOADED'))
		{
			if (!defined('FORUM_CACHE_FUNCTIONS_LOADED'))
				require PANTHER_ROOT.'include/cache.php';

			generate_censoring_cache();
			require FORUM_CACHE_DIR.'cache_censoring.php';
		}
	}

	if (!empty($search_for))
		$text = substr(ucp_preg_replace($search_for, $replace_with, ' '.$text.' '), 1, -1);

	return $text;
}

//
// Determines the correct title for $user
// $user must contain the elements 'username', 'title', 'posts', 'g_id' and 'g_user_title'
//
function get_title($user)
{
	global $panther_bans, $lang_common, $panther_config;
	static $ban_list, $panther_ranks;

	// If not already built in a previous call, build an array of lowercase banned usernames
	if (empty($ban_list))
	{
		$ban_list = array();

		foreach ($panther_bans as $cur_ban)
			$ban_list[] = utf8_strtolower($cur_ban['username']);
	}

	// If not already loaded in a previous call, load the cached ranks
	if ($panther_config['o_ranks'] == '1' && !defined('PANTHER_RANKS_LOADED'))
	{
		if (file_exists(FORUM_CACHE_DIR.'cache_ranks.php'))
			include FORUM_CACHE_DIR.'cache_ranks.php';

		if (!defined('PANTHER_RANKS_LOADED'))
		{
			if (!defined('FORUM_CACHE_FUNCTIONS_LOADED'))
				require PANTHER_ROOT.'include/cache.php';

			generate_ranks_cache();
			require FORUM_CACHE_DIR.'cache_ranks.php';
		}
	}
	// If the user has a custom title
	if ($user['title'] != '')
		$user_title = $user['title'];
	// If the user is banned
	else if (in_array(utf8_strtolower($user['username']), $ban_list))
		$user_title = $lang_common['Banned'];
	// If the user group has a default user title
	else if ($user['g_user_title'] != '')
		$user_title = $user['g_user_title'];
	// If the user is a guest
	else if ($user['g_id'] == PANTHER_GUEST)
		$user_title = $lang_common['Guest'];
	// If nothing else helps, we assign the default
	else
	{
		// Are there any ranks?
		if ($panther_config['o_ranks'] == '1' && !empty($panther_ranks))
		{
			foreach ($panther_ranks as $cur_rank)
			{
				if ($user['num_posts'] >= $cur_rank['min_posts'])
					$user_title = $cur_rank['rank'];
			}
		}

		// If the user didn't "reach" any rank (or if ranks are disabled), we assign the default
		if (!isset($user_title))
		  $user_title = $lang_common['Member'];
	}

	return $user_title;
}

//
// Generate a string with numbered links (for multipage scripts)
//
function paginate($num_pages, $cur_page, $link, $args = null)
{
	global $lang_common, $panther_config, $panther_url;

	$pages = array();
	$link_to_all = false;

	// If $cur_page == -1, we link to all pages (used in viewforum.php)
	if ($cur_page == -1)
	{
		$cur_page = 1;
		$link_to_all = true;
	}

	if ($num_pages > 1)
	{
		if ($cur_page > 1)
			$pages[] = array('item' => true, 'href' => str_replace('#', '', get_sublink($link, $panther_url['page'], ($cur_page - 1), $args)), 'current' => $lang_common['Previous']);
		
		if ($cur_page > 3)
		{
			$pages[] = array('item' => (empty($pages) ? true : false), 'href' => $link, 'current' => 1);
			if ($cur_page > 5)
				$pages[] = $lang_common['Spacer'];
		}

		// Don't ask me how the following works. It just does, OK? =)
		for ($current = ($cur_page == 5) ? $cur_page - 3 : $cur_page - 2, $stop = ($cur_page + 4 == $num_pages) ? $cur_page + 4 : $cur_page + 3; $current < $stop; ++$current)
		{
			if ($current < 1 || $current > $num_pages)
				continue;
			else if ($current != $cur_page || $link_to_all)
				$pages[] = array('item' => (empty($pages) ? true : false), 'href' => str_replace('#', '', get_sublink($link, $panther_url['page'], $current, $args)), 'current' => forum_number_format($current));
			else
				$pages[] = array('item' => (empty($pages) ? true : false), 'current' => forum_number_format($current));
		}

		if ($cur_page <= ($num_pages-3))
		{
			if ($cur_page != ($num_pages-3) && $cur_page != ($num_pages-4))
				$pages[] = $lang_common['Spacer'];

			$pages[] = array('item' => (empty($pages) ? true : false), 'href' => get_sublink($link, $panther_url['page'], $num_pages, $args), 'current' => forum_number_format($num_pages));
		}

		// Add a next page link
		if ($num_pages > 1 && !$link_to_all && $cur_page < $num_pages)
			$pages[] = array('item' => (empty($pages) ? true : false), 'rel' => 'next', 'href' => get_sublink($link, $panther_url['page'], ($cur_page + 1), $args), 'current' => $lang_common['Next']);
	}

	$tpl = load_template('pagination.tpl');
	return $tpl->render(
		array(
			'num_pages' => $num_pages,
			'cur_page' => $cur_page,
			'pages' => $pages,
			'link' => $link,
		)
	);
}

//
// Display a message
//
function message($message, $no_back_link = false, $http_status = null)
{
	global $db, $lang_common, $panther_config, $panther_start, $tpl_main, $panther_user, $panther_url;

	// Did we receive a custom header?
	if (!is_null($http_status))
		header('HTTP/1.1 '.$http_status);

	if (!defined('PANTHER_HEADER'))
	{
		$page_title = array($panther_config['o_board_title'], $lang_common['Info']);
		define('PANTHER_ACTIVE_PAGE', 'index');
		require PANTHER_ROOT.'header.php';
	}

	$tpl = load_template('message.tpl');
	echo $tpl->render(
		array(
			'lang_common' => $lang_common,
			'message' => $message,
			'no_back_link' => $no_back_link,
		)
	);

	require PANTHER_ROOT.'footer.php';
}

//
// Format a time string according to $time_format and time zones
//
function format_time($timestamp, $date_only = false, $date_format = null, $time_format = null, $time_only = false, $no_text = false)
{
	global $lang_common, $panther_user, $forum_date_formats, $forum_time_formats;

	if ($timestamp == '')
		return $lang_common['Never'];

	$diff = ($panther_user['timezone'] + $panther_user['dst']) * 3600;
	$timestamp += $diff;
	$now = time();

	if(is_null($date_format))
		$date_format = $forum_date_formats[$panther_user['date_format']];

	if(is_null($time_format))
		$time_format = $forum_time_formats[$panther_user['time_format']];

	$date = gmdate($date_format, $timestamp);
	$today = gmdate($date_format, $now+$diff);
	$yesterday = gmdate($date_format, $now+$diff-86400);

	if (!$no_text)
	{
		if ($date == $today)
			$date = $lang_common['Today'];
		else if ($date == $yesterday)
			$date = $lang_common['Yesterday'];
	}

	if ($date_only)
		return $date;
	else if ($time_only)
		return gmdate($time_format, $timestamp);
	else
		return $date.' '.gmdate($time_format, $timestamp);
}


//
// A wrapper for PHP's number_format function
//
function forum_number_format($number, $decimals = 0)
{
	global $lang_common;

	return is_numeric($number) ? number_format($number, $decimals, $lang_common['lang_decimal_point'], $lang_common['lang_thousands_sep']) : $number;
}

//
// Generate a random key of length $len
//
function random_key($len, $readable = false, $hash = false)
{
	if (!function_exists('secure_random_bytes'))
		include PANTHER_ROOT.'include/srand.php';

	$key = secure_random_bytes($len);

	if ($hash)
		return substr(bin2hex($key), 0, $len);
	else if ($readable)
	{
		$chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

		$result = '';
		for ($i = 0; $i < $len; ++$i)
			$result .= substr($chars, (ord($key[$i]) % strlen($chars)), 1);

		return $result;
	}

	return $key;
}

//
// Make sure that user is using a valid token
// 
function confirm_referrer($script, $use_ip = true)
{
	global $lang_common, $panther_user;

	// Yeah, pretty complex ternary =)
	$sent_hash = ((isset($_POST['csrf_token'])) ? panther_trim($_POST['csrf_token']) : (isset($_GET['csrf_token']) ? panther_trim($_GET['csrf_token']) : ''));

	if (!panther_hash_equals(generate_csrf_token($script, $use_ip), $sent_hash))
		message($lang_common['Bad referrer']);
}

//
// Generate a csrf token
//
function generate_csrf_token($script = 'nothing', $use_ip = true)
{
	global $panther_user;

	$script = ($script != 'nothing') ? $script : panther_trim(basename($_SERVER['SCRIPT_NAME']));
	return panther_hash($panther_user['id'].$script.$panther_user['salt'].(($use_ip ? get_remote_address() : '')).$panther_user['login_key']);
}

//
// Validate the given redirect URL, use the fallback otherwise
//
function validate_redirect($redirect_url, $fallback_url)
{
	$referrer = parse_url(strtolower($redirect_url));

	// Make sure the host component exists
	if (!isset($referrer['host']))
		$referrer['host'] = '';

	// Remove www subdomain if it exists
	if (strpos($referrer['host'], 'www.') === 0)
		$referrer['host'] = substr($referrer['host'], 4);

	// Make sure the path component exists
	if (!isset($referrer['path']))
		$referrer['path'] = '';

	$valid = parse_url(strtolower(get_base_url()));

	// Remove www subdomain if it exists
	if (strpos($valid['host'], 'www.') === 0)
		$valid['host'] = substr($valid['host'], 4);

	// Make sure the path component exists
	if (!isset($valid['path']))
		$valid['path'] = '';

	if ($referrer['host'] == $valid['host'] && preg_match('%^'.preg_quote($valid['path'], '%').'/(.*?)\.php%i', $referrer['path']))
		return $redirect_url;
	else
		return $fallback_url;
}

//
// Generate a random password of length $len
// Compatibility wrapper for random_key
//
function random_pass($len)
{
	return random_key($len, true);
}

//
// Compute a hash of $str
//
function panther_hash($str)
{
	return hash('sha512', $str);
}

//
// Try to determine the correct remote IP-address
//
function get_remote_address()
{
	$remote_addr = $_SERVER['REMOTE_ADDR'];

	// If we are behind a reverse proxy try to find the real users IP
	if (defined('FORUM_BEHIND_REVERSE_PROXY'))
	{
		if (isset($_SERVER['HTTP_X_FORWARDED_FOR']))
		{
			// The general format of the field is:
			// X-Forwarded-For: client1, proxy1, proxy2
			// where the value is a comma+space separated list of IP addresses, the left-most being the farthest downstream client,
			// and each successive proxy that passed the request adding the IP address where it received the request from.
			$forwarded_for = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
			$forwarded_for = trim($forwarded_for[0]);

			if (@preg_match('%^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$%', $forwarded_for) || @preg_match('%^((([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){6}:[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){5}:([0-9A-Fa-f]{1,4}:)?[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){4}:([0-9A-Fa-f]{1,4}:){0,2}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){3}:([0-9A-Fa-f]{1,4}:){0,3}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){2}:([0-9A-Fa-f]{1,4}:){0,4}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){6}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|(([0-9A-Fa-f]{1,4}:){0,5}:((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|(::([0-9A-Fa-f]{1,4}:){0,5}((\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b)\.){3}(\b((25[0-5])|(1\d{2})|(2[0-4]\d)|(\d{1,2}))\b))|([0-9A-Fa-f]{1,4}::([0-9A-Fa-f]{1,4}:){0,5}[0-9A-Fa-f]{1,4})|(::([0-9A-Fa-f]{1,4}:){0,6}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){1,7}:))$%', $forwarded_for))
				$remote_addr = $forwarded_for;
		}
	}

	return $remote_addr;
}

//
// Calls htmlspecialchars with a few options already set
// As of 1.1.0, this has been deprecated and will be removed soon. Use Twig instead.
//
function panther_htmlspecialchars($str)
{
	return htmlspecialchars($str, ENT_QUOTES, 'UTF-8');
}

//
// Calls htmlspecialchars_decode with a few options already set
//
function panther_htmlspecialchars_decode($str)
{
	if (function_exists('htmlspecialchars_decode'))
		return htmlspecialchars_decode($str, ENT_QUOTES);

	static $translations;
	if (!isset($translations))
	{
		$translations = get_html_translation_table(HTML_SPECIALCHARS, ENT_QUOTES);
		$translations['&#039;'] = '\''; // get_html_translation_table doesn't include &#039; which is what htmlspecialchars translates ' to, but apparently that is okay?! http://bugs.php.net/bug.php?id=25927
		$translations = array_flip($translations);
	}

	return strtr($str, $translations);
}

//
// A wrapper for utf8_strlen for compatibility
//
function panther_strlen($str)
{
	return utf8_strlen($str);
}

//
// Convert \r\n and \r to \n
//
function panther_linebreaks($str)
{
	return str_replace(array("\r\n", "\r"), "\n", $str);
}

//
// A wrapper for utf8_trim for compatibility
//
function panther_trim($str, $charlist = false)
{
	return is_string($str) ? utf8_trim($str, $charlist) : '';
}

//
// Checks if a string is in all uppercase
//
function is_all_uppercase($string)
{
	return utf8_strtoupper($string) == $string && utf8_strtolower($string) != $string;
}

//
// Inserts $element into $input at $offset
// $offset can be either a numerical offset to insert at (eg: 0 inserts at the beginning of the array)
// or a string, which is the key that the new element should be inserted before
// $key is optional: it's used when inserting a new key/value pair into an associative array
//
function array_insert(&$input, $offset, $element, $key = null)
{
	if (is_null($key))
		$key = $offset;

	// Determine the proper offset if we're using a string
	if (!is_int($offset))
		$offset = array_search($offset, array_keys($input), true);

	// Out of bounds checks
	if ($offset > count($input))
		$offset = count($input);
	else if ($offset < 0)
		$offset = 0;

	$input = array_merge(array_slice($input, 0, $offset), array($key => $element), array_slice($input, $offset));
}

//
// Return a template object from Twig
//
function load_template($tpl_file)
{
	global $panther_user, $panther_config, $tpl_manager;
	
	$style_root = (($panther_config['o_style_path'] != 'style') ? $panther_config['o_style_path'] : PANTHER_ROOT.$panther_config['o_style_path']).'/'.$panther_user['style'].'/templates/';
	if (file_exists($style_root.$tpl_file))
		$tpl_file = $tpl_manager->loadTemplate('@style/'.$tpl_file);
	else
		$tpl_file = $tpl_manager->loadTemplate('@core/'.$tpl_file);

	return $tpl_file;
}

//
// Display a message when board is in maintenance mode
//
function maintenance_message()
{
	global $db, $panther_config, $lang_common, $panther_user;

	// Send no-cache headers
	header('Expires: Thu, 21 Jul 1977 07:30:00 GMT'); // When yours truly first set eyes on this world! :)
	header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
	header('Cache-Control: post-check=0, pre-check=0', false);
	header('Pragma: no-cache'); // For HTTP/1.0 compatibility

	// Send the Content-type header in case the web server is setup to send something else
	header('Content-type: text/html; charset=utf-8');

	// Deal with newlines, tabs and multiple spaces
	$pattern = array("\t", '  ', '  ');
	$replace = array('&#160; &#160; ', '&#160; ', ' &#160;');
	$message = str_replace($pattern, $replace, $panther_config['o_maintenance_message']);

	$tpl = load_template('maintenance.tpl');
	echo $tpl->render(
		array(
			'lang_common' => $lang_common,
			'message' => $message,
			'page_title' => generate_page_title(array($panther_config['o_board_title'], $lang_common['Maintenance'])),
			'style' => (($panther_config['o_style_dir']) != '' ? $panther_config['o_style_dir'] : get_base_url().'/style/').$panther_user['style'],
			'panther_config' => $panther_config,
		)
	);

	// End the transaction
	$db->end_transaction();

	exit;
}

//
// Display $message and redirect user to $destination_url
//
function redirect($destination_url, $message)
{
	global $db, $panther_config, $lang_common, $panther_user;

	// Prefix with base_url (unless there's already a valid URI)
	if (strpos($destination_url, 'http://') !== 0 && strpos($destination_url, 'https://') !== 0 && strpos($destination_url, '/') !== 0)
		$destination_url = get_base_url(true).'/'.$destination_url;

	// Do a little spring cleaning
	$destination_url = preg_replace('%([\r\n])|(\%0[ad])|(;\s*data\s*:)%i', '', $destination_url);

	// If the delay is 0 seconds, we might as well skip the redirect all together
	if ($panther_config['o_redirect_delay'] == '0')
	{
		$db->end_transaction();

		header('Location: '.str_replace('&amp;', '&', $destination_url));
		exit;
	}

	// Send no-cache headers
	header('Expires: Thu, 21 Jul 1977 07:30:00 GMT'); // When yours truly first set eyes on this world! :)
	header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
	header('Cache-Control: post-check=0, pre-check=0', false);
	header('Pragma: no-cache'); // For HTTP/1.0 compatibility

	// Send the Content-type header in case the web server is setup to send something else
	header('Content-type: text/html; charset=utf-8');

	$tpl = load_template('redirect.tpl');
	echo $tpl->render(
		array(
			'lang_common' => $lang_common,
			'destination_url' => $destination_url,
			'message' => $message,
			'queries' => ($panther_config['o_show_queries'] == '1') ? display_saved_queries() : '',
			'panther_config' => $panther_config,
			'page_title' => generate_page_title(array($panther_config['o_board_title'], $lang_common['Redirecting'])),
			'css_url' => (($panther_config['o_style_dir']) != '' ? $panther_config['o_style_dir'] : get_base_url().'/style/').$panther_user['style'],
		)
	);
	
	$db->end_transaction();
	exit;
}

//
// Handle PHP errors
//

function error_handler($errno = 0, $errstr = 'Error', $errfile = 'unknown', $errline = 0)
{
	global $panther_config, $lang_common, $panther_user, $panther_url;

	if (!is_int($errno)) // Make sure set_exception_handler doesn't intefere
	{
		$errstr = $errno;
		$errno = 1;
	}

	// Needed to ensure it doesn't appear after completion on every page
	if ($errno < 1)
		exit;

	$error = error_get_last();
	
	//