<?php
/************************************************************************
 * MXChange v0.2.1                                    Start: 12/16/2008 *
 * ===============                              Last change: 12/16/2008 *
 *                                                                      *
 * -------------------------------------------------------------------- *
 * File              : filters.php                                      *
 * -------------------------------------------------------------------- *
 * Short description : Functions for filter system                      *
 * -------------------------------------------------------------------- *
 * Kurzbeschreibung  : Funktionen fuer Filter-System                    *
 * -------------------------------------------------------------------- *
 *                                                                      *
 * -------------------------------------------------------------------- *
 * Copyright (c) 2003 - 2008 by Roland Haeder                           *
 * For more information visit: http://www.mxchange.org                  *
 *                                                                      *
 * This program is free software; you can redistribute it and/or modify *
 * it under the terms of the GNU General Public License as published by *
 * the Free Software Foundation; either version 2 of the License, or    *
 * (at your option) any later version.                                  *
 *                                                                      *
 * This program is distributed in the hope that it will be useful,      *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of       *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
 * GNU General Public License for more details.                         *
 *                                                                      *
 * You should have received a copy of the GNU General Public License    *
 * along with this program; if not, write to the Free Software          *
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,               *
 * MA  02110-1301  USA                                                  *
 ************************************************************************/

// Some security stuff...
if (!defined('__SECURITY')) {
	$INC = substr(dirname(__FILE__), 0, strpos(dirname(__FILE__), "/inc") + 4)."/security.php";
	require($INC);
}

// Init "generic filter system"
function INIT_FILTER_SYSTEM () {
	global $filters, $loadedFilters, $counter;

	// Is the filter already initialized?
	if ((isset($filters)) && (is_array($filters))) {
		// Then abort here
		ADD_FATAL(FILTER_FAILED_ALREADY_INIT);
		return false;
	} // END - if

	// Init the filter system (just some ideas)
	$filters = array(
		// Filters for pre-init phase
		'preinit'   => array(),
		// Filters for post-init phase
		'postinit'  => array(),
		// Filters for shutdown phase
		'shutdown'  => array()
	);

	// Init loaded filters and counter
	$loadedFilters =  array();
	$counter = array();

	// Load all saved filers if sql_patches is updated
	if (GET_EXT_VERSION("sql_patches") >= "0.5.9") {
		// Init add
		$ADD = "";
		if (GET_EXT_VERSION("sql_patches") >= "0.6.0") $ADD = ", `filter_counter`";

		// Load all active filers
		$result = SQL_QUERY("SELECT `filter_name`, `filter_function`, `filter_active`".$ADD."
FROM `"._MYSQL_PREFIX."_filters`
ORDER BY `filter_id` ASC", __FILE__, __LINE__);

		// Are there entries?
		if (SQL_NUMROWS($result) > 0) {
			// Load all filters
			while ($filterArray = SQL_FETCHARRAY($result)) {
				// Get filter name and function
				$filterName     = $filterArray['filter_name'];
				$filterFunction = $filterArray['filter_function'];

				// Set counter to default
				$counter[$filterName][$filterFunction] = 0;

				// Mark this filter as loaded (from database)
				$loadedFilters[$filterName][$filterFunction] = true;

				// Set this filter
				$filters[$filterName][$filterFunction] = $filterArray['filter_active'];

				// Is the array element for counter there?
				if (isset($filterArray['filter_counter'])) {
					// Then use this value!
					$counter[$filterName][$filterFunction] = $filterArray['filter_counter'];
				} // END - if
			} // END - while
		} // END - if
	
		// Free result
		SQL_FREERESULT($result);
	} // END - if

	// Init filters
	REGISTER_FILTER('init', 'UPDATE_LOGIN_DATA');

	// Login failtures handler
	REGISTER_FILTER('post_youhere_line', 'CALL_HANDLER_LOGIN_FAILTURES');

	// Filters for pre-extension-registration
	REGISTER_FILTER('pre_extension_installed', 'RUN_SQLS');

	// Filters for post-extension-registration
	REGISTER_FILTER('post_extension_installed', 'AUTO_ACTIVATE_EXTENSION');
	REGISTER_FILTER('post_extension_installed', 'SOLVE_TASK');
	REGISTER_FILTER('post_extension_installed', 'LOAD_INCLUDES');

	// Solving tasks
	REGISTER_FILTER('solve_task', 'SOLVE_TASK');

	// Loading includes in general
	REGISTER_FILTER('load_includes', 'LOAD_INCLUDES');

	// Run SQLs
	REGISTER_FILTER('run_sqls', 'RUN_SQLS');

	// Admin ACL check
	REGISTER_FILTER('check_admin_acl', 'CHECK_ADMIN_ACL');

	// Register shutdown filters
	REGISTER_FILTER('shutdown', 'FLUSH_FILTERS');
}

// "Registers" a new filter function
function REGISTER_FILTER ($filterName, $filterFunction, $silentAbort = true, $force = false, $dry_run = false) {
	global $filters, $counter;

	// Extend the filter function name
	$filterFunction = sprintf("FILTER_%s", strtoupper($filterFunction));

	// Is that filter already there?
	if ((isset($filters[$filterName][$filterFunction])) && (!$force)) {
		// Then abort here
		if (!$silentAbort) {
			ADD_FATAL(sprintf(FILTER_FAILED_ALREADY_ADDED, $filterFunction, $filterName));
		} // END - if

		// Abort here
		return false;
	} // END - if

	// Is the function there?
	if (!function_exists($filterFunction)) {
		// Then abort here
		ADD_FATAL(sprintf(FILTER_FAILED_NOT_FOUND, $filterFunction, $filterName));
		return false;
	} // END - if

	// Shall we add it?
	if (!$dry_run) {
		// Simply add it to the array
		$filters[$filterName][$filterFunction] = "Y";
		$counter[$filterName][$filterFunction] = 0;
	} // END - if
}

// "Unregisters" a filter from the given chain
function UNREGISTER_FILTER ($filterName, $filterFunction, $force = false, $dry_run = false) {
	global $filters, $counter, $loadedFilters;

	// Extend the filter function name only if not loaded from database
	if (!isset($loadedFilters[$filterName][$filterFunction])) {
		$filterFunction = sprintf("FILTER_%s", strtoupper($filterFunction));
	} // END - if

	// Is that filter there?
	if ((!isset($filters[$filterName][$filterFunction])) && (!$force)) {
		// Not found, so abort here
		ADD_FATAL(sprintf(FILTER_FAILED_NOT_REMOVED, $filterFunction, $filterName));
		return false;
	} // END - if

	// Shall we remove? (default, not while just showing an extension removal)
	if (!$dry_run) {
		// Mark for filter removal
		$filters[$filterName][$filterFunction] = "R";
		unset($counter[$filterName][$filterFunction]);
	} // END  - if
}

// "Runs" the given filters, data is optional and can be any type of data
function RUN_FILTER ($filterName, $data = null, $silentAbort = true) {
	global $filters, $counter;

	// Is that filter chain there?
	if (!isset($filters[$filterName])) {
		// Then abort here (quick'N'dirty hack)
		if ((!$silentAbort) && (defined('FILTER_FAILED_NO_FILTER_FOUND'))) {
			// Add fatal message
			ADD_FATAL(sprintf(FILTER_FAILED_NO_FILTER_FOUND, $filterName));
		} // END - if

		// Abort here
		return false;
	} // END - if

	// Default return value
	$returnValue = $data;

	// Then run all filters
	foreach ($filters[$filterName] as $filterFunction=>$active) {
		// Debug message
		//* DEBUG: */ echo __FUNCTION__."(<font color=\"#0000aa\">".__LINE__."</font>): name={$filterName},func={$filterFunction},active={$active}<br />\n";

		// Is the filter active?
		if ($active == "Y") {
			// Is this filter there?
			if (!function_exists($filterFunction)) {
				// Unregister it
				UNREGISTER_FILTER($filterName, $filterFunction);

				// Skip this entry
				continue;
			} // END - if

			// Call the filter chain
			$returnValue = call_user_func_array($filterFunction, array($returnValue));

			// Update usage counter
			$counter[$filterName][$filterFunction]++;
		} // END - if
	} // END - foreach

	// Return the filtered content
	return $returnValue;
}

// -----------------------------------------------------------------------------
// Generic filter functions we always need
// -----------------------------------------------------------------------------

// Filter for flushing all new filters to the database
function FILTER_FLUSH_FILTERS () {
	global $filters, $counter, $link, $loadedFilters, $SQLs;

	// Clear all previous SQL queries
	$SQLs = array();

	// Is a database link here and not in installation mode?
	if ((!is_resource($link)) && (!isBooleanConstantAndTrue('mxchange_installing'))) {
		// Abort here
		ADD_FATAL(sprintf(FILTER_FLUSH_FAILED_NO_DATABASE, $filterFunction, $filterName));
		return false;
	} // END - if

	// Is the extension sql_patches updated?
	if (EXT_VERSION_IS_OLDER("sql_patches", "0.5.9")) {
		// Abort silently here
		return false;
	} // END - if

	// Nothing is added/remove by default
	$inserted = 0; $removed = 0;

	// Prepare SQL queries
	$insertSQL = "INSERT INTO `"._MYSQL_PREFIX."_filters` (`filter_name`,`filter_function`,`filter_active`) VALUES";
	$removeSQL = "DELETE LOW_PRIORITY FROM `"._MYSQL_PREFIX."_filters` WHERE";

	// Write all filters to database
	foreach ($filters as $filterName => $filterArray) {
		// Walk through all filters
		foreach ($filterArray as $filterFunction => $active) {
			// Is this filter loaded?
			if (!isset($loadedFilters[$filterName][$filterFunction])) {
				// Add this filter (all filters are active by default)
				$insertSQL .= sprintf("('%s','%s','Y'),", $filterName, $filterFunction);
				$inserted++;
			} elseif ($active == "R") {
				// Remove this filter
				$removeSQL .= sprintf(" (`filter_name`='%s' AND `filter_function`='%s') OR", $filterName, $filterFunction);
				$removed++;
			}
		} // END - foreach
	} // END - foreach

	// Something has been added?
	if ($inserted > 0) {
		// Finish SQL command
		$insertSQL = substr($insertSQL, 0, -1);

		// And run it
		$SQLs[] = $insertSQL;
	} // END - if

	// Something has been removed?
	if ($removed > 0) {
		// Finish SQL command
		$removeSQL = substr($removeSQL, 0, -2) . "LIMIT ".$removed;

		// And run it
		$SQLs[] = $removeSQL;
	} // END - if

	// Shall we update usage counters (ONLY FOR DEBUGGING!)
	if (getConfig('update_filter_usage') == "Y") {
		// Update all counters
		foreach ($counter as $filterName => $filterArray) {
			// Walk through all filters
			foreach ($filterArray as $filterFunction => $cnt) {
				// Construct and add the query
				$SQLs[] = sprintf("UPDATE `"._MYSQL_PREFIX."_filters` SET `filter_counter`=%s WHERE `filter_name`='%s' AND `filter_function`='%s' LIMIT 1",
					bigintval($cnt),
					$filterName,
					$filterFunction
				);
			} // END - foreach
		} // END - foreach
	} // END - if

	// Run the run_sqls filter in non-dry mode
	RUN_FILTER('run_sqls', array('dry_run' => false, 'sqls' => $SQLs));
}

// Filter for calling the handler for login failtures
function FILTER_CALL_HANDLER_LOGIN_FAILTURES ($data) {
	// Init content
	$content = $data;

	// Handle failed logins here if not in guest
	//* DEBUG: */ print __FUNCTION__."(<font color=\"#0000aa\">".__LINE__."</font>):type={$data['type']},action={$GLOBALS['action']},what={$GLOBALS['what']},lvl={$data['access_level']}<br />\n";
	if ((($data['type'] == "what") || ($data['type'] == "action") && ((!isset($GLOBALS['what'])) || ($GLOBALS['what'] == "overview") || ($GLOBALS['what'] == getConfig('index_home')))) && ($data['access_level'] != "guest") && ((GET_EXT_VERSION("sql_patches") >= "0.4.7") || (GET_EXT_VERSION("admins") >= "0.7.0"))) {
		// Handle failture
		$content['content'] .= HANDLE_LOGIN_FAILTURES($data['access_level']);
	} // END - if

	// Return the content
	return $content;
}

// Filter for redirecting to logout if sql_patches has been installed
function FILTER_REDIRECT_TO_LOGOUT_SQL_PATCHES () {
	// Remove this filter
	UNREGISTER_FILTER('shutdown', __FUNCTION__);

	// Is the element set?
	if (isset($GLOBALS['ext_load_mode'])) {
		// Redirect here
		LOAD_URL("modules.php?module=admin&logout=1&".$GLOBALS['ext_load_mode']."=sql_patches");
	} // END - if

	// This should not happen!
	DEBUG_LOG(__FUNCTION__, __LINE__, "Cannot auto-logout because no extension load-mode has been set.");
}

// Filter for auto-activation of a extension
function FILTER_AUTO_ACTIVATE_EXTENSION ($data) {
	global $EXT_ALWAYS_ACTIVE;

	// Is this extension always activated?
	if ($EXT_ALWAYS_ACTIVE == "Y") {
		// Then activate the extension
		//* DEBUG: */ echo __FUNCTION__."(<font color=\"#0000aa\">".__LINE__."</font>): ext_name={$data['ext_name']}<br />\n";
		ACTIVATE_EXTENSION($data['ext_name']);
	} // END - if

	// Return the data
	return $data;
}

// Filter for solving task given task
function FILTER_SOLVE_TASK ($data) {
	// Don't solve anything if no admin!
	if (!IS_ADMIN()) return $data;

	// Is this a direct task id or array element task_id is found?
	if (is_int($data)) {
		// Then solve it...
		ADMIN_SOLVE_TASK($data);
	} elseif ((is_array($data)) && (isset($data['task_id']))) {
		// Solve it...
		ADMIN_SOLVE_TASK($data['task_id']);
	}

	// Return the data
	return $data;
}

// Filter to load include files
function FILTER_LOAD_INCLUDES ($data) {
	global $CSS;

	// Default is $data as inclusion list
	$INC_POOL = $data;

	// Is it an array?
	if ((!isset($data)) || (!is_array($data))) {
		// Then abort here
		DEBUG_LOG(__FILE__, __LINE__, "INC_POOL is no array!");
		return $data;
	} elseif (isset($data['inc_pool'])) {
		// Use this as new inclusion pool!
		$INC_POOL = $data['inc_pool'];
	}

	// Check for added include files
	if (count($INC_POOL) > 0) {
		// Loads every include file
		foreach ($INC_POOL as $FQFN) {
			require_once($FQFN);
		} // END - foreach

		// Reset array
		if (isset($data['inc_pool'])) $data['inc_pool'] = array();
	} // END - if

	// Continue with processing
	return $data;
}

// Filter for running SQL commands
function FILTER_RUN_SQLS ($data) {
	// Is the array there?
	if ((isset($data['sqls'])) && ((!isset($data['dry_run'])) || ($data['dry_run'] == false))) {
		// Run SQL commands
		foreach ($data['sqls'] as $sql) {
			$sql = trim($sql);
			if (!empty($sql)) {
				// Do we have an "ALTER TABLE" command?
				if (substr(strtolower($sql), 0, 11) == "alter table") {
					// Analyse the alteration command
					SQL_ALTER_TABLE($sql, __FILE__, __LINE__);
				} else {
					// Run regular SQL command
					$result = SQL_QUERY($sql, __FILE__, __LINE__, false);
				}
			} // END - if
		} // END - foreach
	} // END - if
}

// Filter for updating/validating login data
function FILTER_UPDATE_LOGIN_DATA () {
	global $LAST;
	if (!is_array($LAST)) $LAST = array();

	// Recheck if logged in
	if (!IS_MEMBER()) return false;

	// Secure user ID
	$GLOBALS['userid'] = bigintval(get_session('userid'));

	// Extract last online time (life) and how long is auto-login valid (time)
	$newl = time() + bigintval(get_session('lifetime'));

	// Load last module and last online time
	$result = SQL_QUERY_ESC("SELECT last_module, last_online FROM `"._MYSQL_PREFIX."_user_data` WHERE userid=%s LIMIT 1", array($GLOBALS['userid']), __FILE__, __LINE__);
	if (SQL_NUMROWS($result) == 1) {
		// Load last module and online time
		list($mod, $onl) = SQL_FETCHROW($result);
		SQL_FREERESULT($result);

		// Maybe first login time?
		if (empty($mod)) $mod = "login";

		if (set_session("userid", $GLOBALS['userid'], $newl, COOKIE_PATH) && set_session("u_hash", get_session('u_hash'), $newl, COOKIE_PATH) && set_session("lifetime", bigintval(get_session('lifetime')), $newl, COOKIE_PATH)) {
			// This will be displayed on welcome page! :-)
			if (empty($LAST['module'])) {
				$LAST['module'] = $mod; $LAST['online'] = $onl;
			} // END - if

			// "what" not set?
			if (empty($GLOBALS['what'])) {
				// Fix it to default
			 	$GLOBALS['what'] = "welcome";
			 	if (getConfig('index_home') != "") $GLOBALS['what'] = getConfig('index_home');
			} // END - if

			// Update last module / online time
			SQL_QUERY_ESC("UPDATE `"._MYSQL_PREFIX."_user_data` SET last_module='%s', last_online=UNIX_TIMESTAMP(), REMOTE_ADDR='%s' WHERE userid=%s LIMIT 1",
				array($GLOBALS['what'], GET_REMOTE_ADDR(), $GLOBALS['userid']), __FILE__, __LINE__);
		}
	}  else {
		// Destroy session, we cannot update!
		destroy_user_session();
	}
}

// Filter for checking admin ACL
function FILTER_CHECK_ADMIN_ACL () {
	// Extension not installed so it's always allowed to access everywhere!
	$ret = true;

	// Ok, Cookie-Update done
	if (GET_EXT_VERSION("admins") >= "0.3") {
		// Check if action GET variable was set
		$action = SQL_ESCAPE($GLOBALS['action']);
		if (!empty($GLOBALS['what'])) {
			// Get action value by what-value
			$action = GET_ACTION("admin", $GLOBALS['what']);
		} // END - if

		// Check for access control line of current menu entry
		$ret = ADMINS_CHECK_ACL($action, $GLOBALS['what']);
	} // END - if

	// Return result
	return $ret;
}

//
?>