<?php

/**
 * Loader class for the Google Sitemap Generator
 *
 * This class takes care of the sitemap plugin and tries to load the different parts as late as possible.
 * On normal requests, only this small class is loaded. When the sitemap needs to be rebuild, the generator itself is loaded.
 * The last stage is the user interface which is loaded when the administration page is requested.
 *
 * @author Arne Brachhold
 * @package sitemap
 */
class GoogleSitemapGeneratorLoader {

	/**
	 * @var Version of the generator in SVN
	 */
	private static $svnVersion = '$Id$';


	/**
	 * Enabled the sitemap plugin with registering all required hooks
	 *
	 * @uses add_action Adds actions for admin menu, executing pings and handling robots.txt
	 * @uses add_filter Adds filtes for admin menu icon and contexual help
	 * @uses GoogleSitemapGeneratorLoader::SetupRewriteHooks() Registeres the rewrite hooks
	 * @uses GoogleSitemapGeneratorLoader::CallShowPingResult() Shows the ping result on request
	 * @uses GoogleSitemapGeneratorLoader::ActivateRewrite() Writes rewrite rules the first time
	 */
	public static function Enable() {

		//Register the sitemap creator to wordpress...
		add_action('admin_menu', array(__CLASS__, 'RegisterAdminPage'));

		//Nice icon for Admin Menu (requires Ozh Admin Drop Down Plugin)
		add_filter('ozh_adminmenu_icon', array(__CLASS__, 'RegisterAdminIcon'));

		//Additional links on the plugin page
		add_filter('plugin_row_meta', array(__CLASS__, 'RegisterPluginLinks'), 10, 2);

		//Listen to ping request
		add_action('sm_ping', array(__CLASS__, 'CallSendPing'), 10, 1);

		//Existing page was published
		add_action('publish_post', array(__CLASS__, 'SchedulePing'), 999, 1);
		add_action('publish_page', array(__CLASS__, 'SchedulePing'), 9999, 1);
		add_action('delete_post', array(__CLASS__, 'SchedulePing'), 9999, 1);

		//Robots.txt request
		add_action('do_robots', array(__CLASS__, 'CallDoRobots'), 100, 0);

		//Help topics for context sensitive help
		add_filter('contextual_help_list', array(__CLASS__, 'CallHtmlShowHelpList'), 9999, 2);

		//Set up hooks for adding permalinks, query vars
		self::SetupQueryVars();
		self::SetupRewriteHooks();

		//Check if the result of a ping request should be shown
		if(!empty($_GET["sm_ping_service"])) {
			self::CallShowPingResult();
		}

		//Fix rewrite rules if not already done on activation hook. This happens on network activation for example.
		if(get_option("sm_rewrite_done", null) != self::$svnVersion) {
			self::ActivateRewrite();
		}
	}

	/**
	 * Sets up the query vars and template redirect hooks
	 * @uses GoogleSitemapGeneratorLoader::RegisterQueryVars
	 * @uses GoogleSitemapGeneratorLoader::DoTemplateRedirect
	 * @uses GoogleSitemapGeneratorLoader::KillFrontpageQuery
	 * @since 4.0
	 */
	public static function SetupQueryVars() {

		add_filter('query_vars', array(__CLASS__, 'RegisterQueryVars'), 1, 1);
		
		add_filter('template_redirect', array(__CLASS__, 'DoTemplateRedirect'), 1, 0);

		add_filter('parse_request', array(__CLASS__, 'KillFrontpageQuery'), 1, 0);
	}

	/**
	 * Register the plugin specific "xml_sitemap" query var
	 *
	 * @since 4.0
	 * @param $vars Array Array of existing query_vars
	 * @return Array An aarray containing the new query vars
	 */
	public static function RegisterQueryVars($vars) {
		array_push($vars, 'xml_sitemap');
		return $vars;
	}

	/**
	 * Registers the plugin specific rewrite rules
	 *
	 * @since 4.0
	 * @param $wpRules Array of existing rewrite rules
	 * @return Array An array containing the new rewrite rules
	 */
	public static function AddRewriteRules($wpRules) {
		$smRules = array(
			'sitemap-?([a-zA-Z0-9\-_]+)?\.xml$' => 'index.php?xml_sitemap=params=$matches[1]',
			'sitemap-?([a-zA-Z0-9\-_]+)?\.xml\.gz$' => 'index.php?xml_sitemap=params=$matches[1];zip=true',
			'sitemap-?([a-zA-Z0-9\-_]+)?\.html$' => 'index.php?xml_sitemap=params=$matches[1];html=true',
			'sitemap-?([a-zA-Z0-9\-_]+)?\.html.gz$' => 'index.php?xml_sitemap=params=$matches[1];html=true;zip=true'
		);
		return array_merge($smRules,$wpRules);
	}

	/**
	 * Adds the filters for wp rewrite rule adding
	 *
	 * @since 4.0
	 * @uses add_filter()
	 */
	public static function SetupRewriteHooks() {
		add_filter('rewrite_rules_array', array(__CLASS__, 'AddRewriteRules'), 1, 1);
	}

	/**
	 * Flushes the rewrite rules
	 *
	 * @since 4.0
	 * @global $wp_rewrite WP_Rewrite
	 * @uses WP_Rewrite::flush_rules()
	 */
	public static function ActivateRewrite() {
		global $wp_rewrite;
		$wp_rewrite->flush_rules(false);
		update_option("sm_rewrite_done", self::$svnVersion);
	}

	/**
	 * Handled the plugin activation on installation
	 *
	 * @uses GoogleSitemapGeneratorLoader::ActivateRewrite
	 * @since 4.0
	 */
	public static function ActivatePlugin() {
		self::SetupRewriteHooks();
		self::ActivateRewrite();
	}

	/**
	 * Handled the plugin deactivation
	 *
	 * @uses GoogleSitemapGeneratorLoader::ActivateRewrite
	 * @since 4.0
	 */
	public static function DeactivatePlugin() {
		delete_option("sm_rewrite_done");
	}


	/**
	 * Handles the plugin output on template redirection if the xml_sitemap query var is present.
	 *
	 * @since 4.0
	 * @global $wp_query  The WordPress query object
	 */
	public static function DoTemplateRedirect() {
		global $wp_query;
		if(!empty($wp_query->query_vars["xml_sitemap"])) {
			$wp_query->is_404 = false;
			$wp_query->is_feed = true;
			self::CallShowSitemap($wp_query->query_vars["xml_sitemap"]);
		}
	}

	function KillFrontpageQuery() {
		add_filter('posts_request', array('GoogleSitemapGeneratorLoader', 'KillFrontpagePosts'), 1000, 2);
	}

	function KillFrontpagePosts($sql, &$query) {
		// The main query is running on the front page
		// And the currently running query is that main query
		if(!empty($query->query_vars["xml_sitemap"])) {
			// We only want to do this once: remove the filter
			remove_filter('posts_request', array('GoogleSitemapGeneratorLoader', 'KillFrontpagePosts'), 1000, 2);
			// Kill the FOUND_ROWS() query too
			$query->query_vars['no_found_rows'] = true;
			//Workaround for preventing to fetch sticky posts
			$query->is_home = false;
			//Prevent sending of 404 (it would happen because we didn't find any posts). Setting is_404 to true skips that check.
			$query->is_404 = true;
			return "SELECT SQL_CALC_FOUND_ROWS ID FROM {$GLOBALS['wpdb']->posts} WHERE ID = 0"; // Kill the query doesnt work anymore. Now try to select no matching posts :(
		}
		return $sql;
	}


	/**
	 * Registers the plugin in the admin menu system
	 *
	 * @uses add_options_page()
	 */
	public static function RegisterAdminPage() {
		if(function_exists('add_options_page')) {
			add_options_page(__('XML-Sitemap Generator', 'sitemap'), __('XML-Sitemap', 'sitemap'), 'level_10', self::GetBaseName(), array(__CLASS__, 'CallHtmlShowOptionsPage'));
		}
	}

	/**
	 * Returns a nice icon for the Ozh Admin Menu if the {@param $hook} equals to the sitemap plugin
	 *
	 * @param string $hook The hook to compare
	 * @return string The path to the icon
	 */
	public static function RegisterAdminIcon($hook) {
		if($hook == self::GetBaseName() && function_exists('plugins_url')) {
			return plugins_url('img/icon-arne.gif', self::GetBaseName());
		}
		return $hook;
	}

	/**
	 * Registers additional links for the sitemap plugin on the WP plugin configuration page
	 *
	 * Registers the links if the $file param equals to the sitemap plugin
	 * @param $links Array An array with the existing links
	 * @param $file string The file to compare to
	 */
	public static function RegisterPluginLinks($links, $file) {
		$base = self::GetBaseName();
		if($file == $base) {
			$links[] = '<a href="options-general.php?page=' . self::GetBaseName() . '">' . __('Settings', 'sitemap') . '</a>';
			$links[] = '<a href="http://www.arnebrachhold.de/redir/sitemap-plist-faq/">' . __('FAQ', 'sitemap') . '</a>';
			$links[] = '<a href="http://www.arnebrachhold.de/redir/sitemap-plist-support/">' . __('Support', 'sitemap') . '</a>';
			$links[] = '<a href="http://www.arnebrachhold.de/redir/sitemap-plist-donate/">' . __('Donate', 'sitemap') . '</a>';
		}
		return $links;
	}

	/**
	 * Schedules pinging the search engines
	 *
	 * @static
	 * @return void
	 */
	public static function SchedulePing() {
		wp_schedule_single_event(time(),'sm_ping');
	}

	/**
	 * Invokes the HtmlShowOptionsPage method of the generator
	 * @uses GoogleSitemapGeneratorLoader::LoadPlugin()
	 * @uses GoogleSitemapGenerator::HtmlShowOptionsPage()
	 */
	public static function CallHtmlShowOptionsPage() {
		if(self::LoadPlugin()) {
			GoogleSitemapGenerator::GetInstance()->HtmlShowOptionsPage();
		}
	}

	/**
	 * Invokes the ShowPingResult method of the generator
	 * @uses GoogleSitemapGeneratorLoader::LoadPlugin()
	 * @uses GoogleSitemapGenerator::ShowPingResult()
	 */
	public static function CallShowPingResult() {
		if(self::LoadPlugin()) {
			GoogleSitemapGenerator::GetInstance()->ShowPingResult();
		}
	}

	/**
	 * Invokes the ShowPingResult method of the generator
	 * @uses GoogleSitemapGeneratorLoader::LoadPlugin()
	 * @uses GoogleSitemapGenerator::SendPing()
	 */
	public static function CallSendPing() {
		if(self::LoadPlugin()) {
			GoogleSitemapGenerator::GetInstance()->SendPing();
		}
	}

	/**
	 * Invokes the ShowSitemap method of the generator
	 * @uses GoogleSitemapGeneratorLoader::LoadPlugin()
	 * @uses GoogleSitemapGenerator::ShowSitemap()
	 */
	public static function CallShowSitemap($options) {
		if(self::LoadPlugin()) {
			GoogleSitemapGenerator::GetInstance()->ShowSitemap($options);
		}
	}

	/**
	 * Invokes the DoRobots method of the generator
	 * @uses GoogleSitemapGeneratorLoader::LoadPlugin()
	 * @uses GoogleSitemapGenerator::DoRobots()
	 */
	public static function CallDoRobots() {
		if(self::LoadPlugin()) {
			GoogleSitemapGenerator::GetInstance()->DoRobots();
		}
	}

	/**
	 * Displays the help links in the upper Help Section of WordPress
	 *
	 * @param $filterVal Array The existing links
	 * @param $screen Object The current screen object
	 * @return Array The new links
	 */
	public static function CallHtmlShowHelpList($filterVal, $screen) {

		$id = get_plugin_page_hookname(self::GetBaseName(), 'options-general.php');

		//WP 3.0 passes a screen object instead of a string
		if(is_object($screen)) $screen = $screen->id;

		if($screen == $id) {
			$links = array(
				__('Plugin Homepage', 'sitemap') => 'http://www.arnebrachhold.de/redir/sitemap-help-home/',
				__('My Sitemaps FAQ', 'sitemap') => 'http://www.arnebrachhold.de/redir/sitemap-help-faq/'
			);

			$filterVal[$id] = '';

			$i = 0;
			foreach($links AS $text => $url) {
				$filterVal[$id] .= '<a href="' . $url . '">' . $text . '</a>' . ($i < (count($links) - 1) ? ' | ' : '');
				$i++;
			}
		}
		return $filterVal;
	}


	/**
	 * Loads the actual generator class and tries to raise the memory and time limits if not already done by WP
	 *
	 * @uses GoogleSitemapGenerator::Enable()
	 * @return boolean true if run successfully
	 */
	public static function LoadPlugin() {

		if(!class_exists("GoogleSitemapGenerator")) {

			$mem = abs(intval(@ini_get('memory_limit')));
			if($mem && $mem < 128) {
				@ini_set('memory_limit', '128M');
			}

			$time = abs(intval(@ini_get("max_execution_time")));
			if($time != 0 && $time < 120) {
				@set_time_limit(120);
			}

			$path = trailingslashit(dirname(__FILE__));

			if(!file_exists($path . 'sitemap-core.php')) return false;
			require_once($path . 'sitemap-core.php');
		}

		GoogleSitemapGenerator::Enable();
		return true;
	}

	/**
	 * Returns the plugin basename of the plugin (using __FILE__)
	 *
	 * @return string The plugin basename, "sitemap" for example
	 */
	public static function GetBaseName() {
		return plugin_basename(sm_GetInitFile());
	}

	/**
	 * Returns the name of this loader script, using sm_GetInitFile
	 *
	 * @return string The sm_GetInitFile value
	 */
	public static function GetPluginFile() {
		return sm_GetInitFile();
	}

	/**
	 * Returns the plugin version
	 *
	 * Uses the WP API to get the meta data from the top of this file (comment)
	 *
	 * @return string The version like 3.1.1
	 */
	public static function GetVersion() {
		if(!isset($GLOBALS["sm_version"])) {
			if(!function_exists('get_plugin_data')) {
				if(file_exists(ABSPATH . 'wp-admin/includes/plugin.php')) {
					require_once(ABSPATH . 'wp-admin/includes/plugin.php');
				}
				else return "0.ERROR";
			}
			$data = get_plugin_data(self::GetPluginFile(), false, false);
			$GLOBALS["sm_version"] = $data['Version'];
		}
		return $GLOBALS["sm_version"];
	}

	public static function GetSvnVersion() {
		return self::$svnVersion;
	}
}

//Enable the plugin for the init hook, but only if WP is loaded. Calling this php file directly will do nothing.
if(defined('ABSPATH') && defined('WPINC')) {
	add_action("init", array("GoogleSitemapGeneratorLoader", "Enable"), 1000, 0);
	register_activation_hook(sm_GetInitFile(), array('GoogleSitemapGeneratorLoader', 'ActivatePlugin'));
	register_deactivation_hook(sm_GetInitFile(), array('GoogleSitemapGeneratorLoader', 'DeactivatePlugin'));
}