<?php

/*

 * Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between

 * Copyright (C) 2006-2009 Dan Fuhry

 *

 * This program is Free Software; you can redistribute 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 details.

 */

/**

 * Class used to handle and process plugin requests and loading. Singleton.

 * @package Enano

 * @author Dan Fuhry <dan@enanocms.org>

 * @copyright (C) 2006-2008 Enano Project

 * @license GNU General Public License <http://enanocms.org/Special:GNU_General_Public_License>

 */

class pluginLoader {

	/**

 	* The list of hooks registered.

 	* @var array

 	* @access private

 	*/

	var $hook_list;

	/**

 	* The list of plugins that should be loaded. Used only by common.php.

 	* @var array

 	* @access private

 	*/

	var $load_list;

	/**

 	* The list of plugins that are loaded currently. This is only used by the loaded() method which in turn is

 	* used by template files with the <!-- IFPLUGIN --> special tag.

 	* @var array

 	* @access private

 	*/

	var $loaded_plugins;

	/**

 	* The list of plugins that are always loaded because they're part of the Enano core. This cannot be modified

 	* by any external code because user plugins are loaded after the load_list is calculated. Can be useful in

 	* alternative administration panel frameworks that need the list of system plugins.

 	* @var array

 	*/

	var $system_plugins = Array('SpecialUserFuncs.php','SpecialUserPrefs.php','SpecialPageFuncs.php','SpecialAdmin.php','SpecialCSS.php','SpecialUpdownload.php','SpecialSearch.php','PrivateMessages.php','SpecialGroups.php', 'SpecialLog.php', 'DemoMode.php');

	/**

 	* Name kept for compatibility. Effectively a constructor. Calculates the list of plugins that should be loaded

 	* and puts that list in the $load_list property. Plugin developers have absolutely no use for this whatsoever.

 	*/

	function loadAll() 

	{

		global $db, $session, $paths, $template, $plugins; // Common objects

		$GLOBALS['plugins_cache'] = array();

		// if we're in an upgrade, just skip this step

		if ( defined('IN_ENANO_UPGRADE') )

		{

			$this->load_list = array();

			return false;

		}

		$dir = ENANO_ROOT.'/plugins/';

		$plugin_list = $this->get_plugin_list();

		$this->load_list = array();

		foreach ( $plugin_list as $filename => $data )

		{

			if ( !$data['system plugin'] && ( $data['status'] & PLUGIN_OUTOFDATE || $data['status'] & PLUGIN_DISABLED || !$data['installed'] ) )

				continue;

			$this->load_list[] = $filename;

			$this->loaded_plugins[$filename] = $data;

		}

	}

	/**

 	* Name kept for compatibility. This method is used to add a new hook into the code somewhere. Plugins are encouraged

 	* to set hooks and hook into other plugins in a fail-safe way, this encourages reuse of code. Returns an array, whose

 	* values should be eval'ed.

 	* @example <code>

 	$code = $plugins->setHook('my_hook_name');

 	foreach ( $code as $cmd )

 	{

 		eval($cmd);

 	}

 	</code>

 	* @param string The name of the hook.

 	* @param array Deprecated.

 	*/

	function setHook($name, $dont_split = false)

	{

		if ( !empty($this->hook_list[$name]) && is_array($this->hook_list[$name]) )

		{

			if ( $dont_split )

				return $this->hook_list[$name];

			return array(implode("\n", $this->hook_list[$name]));

		}

		else

		{

			return Array();

		}

	}

	/**

 	* Attaches to a hook effectively scheduling some code to be run at that point. You should try to keep hooks clean by

 	* making a function that has variables that need to be modified passed by reference.

 	* @example Simple example: <code>

 	$plugins->attachHook('render_wikiformat_pre', '$text = str_replace("Goodbye, Mr. Chips", "Hello, Mr. Carrots", $text);');

 	</code>

 	* @example More complicated example: <code>

 	$plugins->attachHook('render_wikiformat_pre', 'myplugin_parser_ext($text);');

 	// Notice that $text is passed by reference.

 	function myplugin_parser_ext(&$text)

 	{

 		$text = str_replace("Goodbye, Mr. Chips", "Hello, Mr. Carrots", $text);

 	}

 	</code>

 	*/

	function attachHook($name, $code)

	{

		if ( !isset($this->hook_list[$name]) )

		{

			$this->hook_list[$name] = Array();

		}

		$this->hook_list[$name][] = $code;

	}

	/**

 	* Tell whether a plugin is loaded or not.

 	* @param string The filename of the plugin

 	* @return bool

 	*/

	function loaded($plugid)

	{

		return isset( $this->loaded_plugins[$plugid] );

	}

	/**

 	* Parses all special comment blocks in a plugin and returns an array in the format:

 	<code>

 	array(

 			0 => array(

 					'block' => 'upgrade',

 					// parsed from the block's parameters section

 						'release_from' => '1.0b1',

 						'release_to' => '1.0b2',

 					'value' => 'foo'

 				),

 			1 => array(

 					...

 				)

 		);

 	</code>

 	* @param string Path to plugin file

 	* @param string Optional. The type of block to fetch. If this is specified, only the block type specified will be read, all others will be discarded.

 	* @return array

 	*/

	public static function parse_plugin_blocks($file, $type = false)

	{

		if ( !file_exists($file) )

		{

			return array();

		}

		$blocks = array();

		$contents = @file_get_contents($file);

		if ( empty($contents) )

		{

			return array();

		}

		// The "\r?" in this regular expression is the result of an embarrassing failure during a job related meeting.

		// I was demoing the authoring of an Enano plugin and simply could not figure out why the plugin would not

		// show up in the admin panel.

		$regexp = '#^/\*\*!([a-z0-9_]+)'  // block header and type

						. '(([\s]+[a-z0-9_]+[\s]*=[\s]*".+?"[\s]*;)*)' // parameters

						. '[\s]*\*\*' . "\r?\n"      // spacing and header close

						. '([\w\W]+?)' . "\r?\n"     // value

						. '\*\*!\*/'              // closing comment

						. '#m';

		// Match out all blocks

		$results = preg_match_all($regexp, $contents, $blocks);

		$return = array();

		foreach ( $blocks[0] as $i => $_ )

		{

			if ( is_string($type) && $blocks[1][$i] !== $type )

				continue;

			$value =& $blocks[4][$i];

			// parse includes

			preg_match_all('/^!include [\'"]?(.+?)[\'"]?$/m', $value, $includes);

			foreach ( $includes[0] as $i => $replace )

			{

				$filename = ENANO_ROOT . '/' . $includes[1][$i];

				if ( @file_exists( $filename ) && @is_readable( $filename ) )

				{

					$contents = @file_get_contents($filename);

					$value = str_replace_once($replace, $contents, $value);

				}

			}

			$el = self::parse_vars($blocks[2][$i]);

			$el['block'] = $blocks[1][$i];

			$el['value'] = $value;

			$return[] = $el;

		}

		return $return;

	}

	private static function parse_vars($var_block)

	{

		preg_match_all('/[\s]+([a-z0-9_]+)[\s]*=[\s]*"(.+?)";/', $var_block, $matches);

		$return = array();

		foreach ( $matches[0] as $i => $_ )

		{

			$return[ $matches[1][$i] ] = $matches[2][$i];

		}

		return $return;

	}

	/**

 	* Reads all plugins in the filesystem and cross-references them with the database, providing a very complete summary of plugins

 	* on the site.

 	* @param array If specified, will restrict scanned files to this list. Defaults to null, which means all PHP files will be scanned.

 	* @param bool If true, allows using cached information. Defaults to true.

 	* @return array

 	*/

	function get_plugin_list($restrict = null, $use_cache = true)

	{

		global $db, $session, $paths, $template, $plugins; // Common objects

		// Scan all plugins

		$plugin_list = array();

		$ta = 0;

		// won't load twice (failsafe automatic skip)

		$this->load_plugins_cache();

		global $plugins_cache;

		if ( $use_cache && !empty($plugins_cache) )

		{

			return $plugins_cache;

		}

		else

		{

			// blank array - effectively skips importing the cache

			$plugins_cache = array();

		}

		// List all plugins

		if ( $dirh = @opendir( ENANO_ROOT . '/plugins' ) )

		{

			while ( $dh = @readdir($dirh) )

			{

				if ( !preg_match('/\.php$/i', $dh) )

					continue;

				if ( is_array($restrict) )

					if ( !in_array($dh, $restrict) )

						continue;

				// it's a PHP file, attempt to read metadata

				$fullpath = ENANO_ROOT . "/plugins/$dh";

				$plugin_meta = $this->read_plugin_headers($fullpath, $use_cache);

				if ( is_array($plugin_meta) )

				{

					// all checks passed

					$plugin_list[$dh] = $plugin_meta;

				}

			}

		}

		// Populate with additional metadata from database

		$q = $db->sql_query('SELECT plugin_id, plugin_filename, plugin_version, plugin_flags FROM ' . table_prefix . 'plugins;');

		if ( !$q )

			$db->_die();

		while ( $row = $db->fetchrow() )

		{

			if ( !isset($plugin_list[ $row['plugin_filename'] ]) )

			{

				// missing plugin file, don't report (for now)

				continue;

			}

			$filename =& $row['plugin_filename'];

			$plugin_list[$filename]['installed'] = true;

			$plugin_list[$filename]['status'] = PLUGIN_INSTALLED;

			$plugin_list[$filename]['plugin id'] = $row['plugin_id'];

			if ( $row['plugin_version'] != $plugin_list[$filename]['version'] )

			{

				$plugin_list[$filename]['status'] |= PLUGIN_OUTOFDATE;

				$plugin_list[$filename]['version installed'] = $row['plugin_version'];

			}

			if ( $row['plugin_flags'] & PLUGIN_DISABLED )

			{

				$plugin_list[$filename]['status'] |= PLUGIN_DISABLED;

			}

		}

		$db->free_result();

		// sort it all out by filename

		ksort($plugin_list);

		// done

		return $plugin_list;

	}

	/**

 	* Retrieves the metadata block from a plugin file

 	* @param string Path to plugin file (full path)

 	* @return array

 	*/

	function read_plugin_headers($fullpath, $use_cache = true)

	{

		global $plugins_cache;

		$dh = basename($fullpath);

		// first can we use cached info?

		if ( isset($plugins_cache[$dh]) && $plugins_cache[$dh]['file md5'] === $this->md5_header($fullpath) )

		{

			$plugin_meta = $plugins_cache[$dh];

		}

		else

		{

			// the cache is out of date if we reached here -- regenerate

			if ( $use_cache )

				$this->generate_plugins_cache();

			// pass 1: try to read a !info block

			$blockdata = $this->parse_plugin_blocks($fullpath, 'info');

			if ( empty($blockdata) )

			{

				// no !info block, check for old header

				$fh = @fopen($fullpath, 'r');

				if ( !$fh )

					// can't read, bail out

					return false;

				$plugin_data = array();

				for ( $i = 0; $i < 8; $i++ )

				{

					$plugin_data[] = @fgets($fh, 8096);

				}

				// close our file handle

				fclose($fh);

				// is the header correct?

				if ( trim($plugin_data[0]) != '<?php' || trim($plugin_data[1]) != '/*' )

				{

					// nope. get out.

					return false;

				}

				// parse all the variables

				$plugin_meta = array();

				for ( $i = 2; $i <= 7; $i++ )

				{

					if ( !preg_match('/^([A-z0-9 ]+?): (.+?)$/', trim($plugin_data[$i]), $match) )

						return false;

					$plugin_meta[ strtolower($match[1]) ] = $match[2];

				}

			}

			else

			{

				// parse JSON block

				$plugin_data =& $blockdata[0]['value'];

				$plugin_data = enano_clean_json(enano_trim_json($plugin_data));

				try

				{

					$plugin_meta_uc = enano_json_decode($plugin_data);

				}

				catch ( Exception $e )

				{

					return false;

				}

				// convert all the keys to lowercase

				$plugin_meta = array();

				foreach ( $plugin_meta_uc as $key => $value )

				{

					$plugin_meta[ strtolower($key) ] = $value;

				}

			}

		}

		if ( !isset($plugin_meta) || !is_array(@$plugin_meta) )

		{

			// parsing didn't work.

			return false;

		}

		// check for required keys

		$required_keys = array('plugin name', 'plugin uri', 'description', 'author', 'version', 'author uri');

		foreach ( $required_keys as $key )

		{

			if ( !isset($plugin_meta[$key]) )

				// not set, skip this plugin

				return false;

		}

		// decide if it's a system plugin

		$plugin_meta['system plugin'] = in_array($dh, $this->system_plugins);

		// reset installed variable

		$plugin_meta['installed'] = false;

		$plugin_meta['status'] = 0;

		return $plugin_meta;

	}

	/**

 	* Attempts to cache plugin information in a file to speed fetching.

 	*/

	function generate_plugins_cache()

	{

		if ( getConfig('cache_thumbs') != '1' )

			return;

		// fetch the most current info

		$plugin_info = $this->get_plugin_list(null, false);

		foreach ( $plugin_info as $plugin => &$info )

		{

			$info['file md5'] = $this->md5_header(ENANO_ROOT . "/plugins/$plugin");

		}

		$this->update_plugins_cache($plugin_info);

		$GLOBALS['plugins_cache'] = $plugin_info;

		return true;

	}

	/**

 	* Writes an information array to the cache file.

 	* @param array

 	* @access private

 	*/

	function update_plugins_cache($plugin_info)

	{

		global $cache;

		try

		{

			$result = $cache->store('plugins', $plugin_info, -1);

		}

		catch ( Exception $e )

		{

			return false;

		}

		return $result;

	}

	/**

 	* Loads the plugins cache if any.

 	*/

	function load_plugins_cache()

	{

		global $cache;

		if ( $data = $cache->fetch('plugins') )

		{

			$GLOBALS['plugins_cache'] = $data;

		}

	}

	/**

 	* Calculates the MD5 sum of the first 10 lines of a file. Useful for caching plugin header information.

 	* @param string File

 	* @return string

 	*/

	function md5_header($file)

	{

		$fh = @fopen($file, 'r');

		if ( !$fh )

			return false;

		$i = 0;

		$h = '';

		while ( $i < 10 )

		{