<?php

/*
	Question2Answer by Gideon Greenspan and contributors

	http://www.question2answer.org/


	File: qa-plugin/xml-sitemap/qa-xml-sitemap.php
	Version: See define()s at top of qa-include/qa-base.php
	Description: Page module class for XML sitemap plugin


	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.

	More about this license: http://www.question2answer.org/license.php
*/

	class qa_xml_sitemap {

		private $directory;
		private $urltoroot;

		public function load_module($directory, $urltoroot)
		{
			$this->directory=$directory;
			$this->urltoroot=$urltoroot;
		}


		public function option_default($option)
		{
			switch ($option) {
				case 'xml_sitemap_show_questions':
				case 'xml_sitemap_show_users':
				case 'xml_sitemap_show_tag_qs':
				case 'xml_sitemap_show_category_qs':
				case 'xml_sitemap_show_categories':
					return true;
					break;
			}
		}


		public function admin_form()
		{
			require_once QA_INCLUDE_DIR.'qa-util-sort.php';

			$saved=false;

			if (qa_clicked('xml_sitemap_save_button')) {
				qa_opt('xml_sitemap_show_questions', (int)qa_post_text('xml_sitemap_show_questions_field'));

				if (!QA_FINAL_EXTERNAL_USERS)
					qa_opt('xml_sitemap_show_users', (int)qa_post_text('xml_sitemap_show_users_field'));

				if (qa_using_tags())
					qa_opt('xml_sitemap_show_tag_qs', (int)qa_post_text('xml_sitemap_show_tag_qs_field'));

				if (qa_using_categories()) {
					qa_opt('xml_sitemap_show_category_qs', (int)qa_post_text('xml_sitemap_show_category_qs_field'));
					qa_opt('xml_sitemap_show_categories', (int)qa_post_text('xml_sitemap_show_categories_field'));
				}

				$saved=true;
			}

			$form=array(
				'ok' => $saved ? 'XML sitemap settings saved' : null,

				'fields' => array(
					'questions' => array(
						'label' => 'Include question pages',
						'type' => 'checkbox',
						'value' => (int)qa_opt('xml_sitemap_show_questions'),
						'tags' => 'name="xml_sitemap_show_questions_field"',
					),
				),

				'buttons' => array(
					array(
						'label' => 'Save Changes',
						'tags' => 'name="xml_sitemap_save_button"',
					),
				),
			);

			if (!QA_FINAL_EXTERNAL_USERS)
				$form['fields']['users']=array(
					'label' => 'Include user pages',
					'type' => 'checkbox',
					'value' => (int)qa_opt('xml_sitemap_show_users'),
					'tags' => 'name="xml_sitemap_show_users_field"',
				);

			if (qa_using_tags())
				$form['fields']['tagqs']=array(
					'label' => 'Include question list for each tag',
					'type' => 'checkbox',
					'value' => (int)qa_opt('xml_sitemap_show_tag_qs'),
					'tags' => 'name="xml_sitemap_show_tag_qs_field"',
				);

			if (qa_using_categories()) {
				$form['fields']['categoryqs']=array(
					'label' => 'Include question list for each category',
					'type' => 'checkbox',
					'value' => (int)qa_opt('xml_sitemap_show_category_qs'),
					'tags' => 'name="xml_sitemap_show_category_qs_field"',
				);

				$form['fields']['categories']=array(
					'label' => 'Include category browser',
					'type' => 'checkbox',
					'value' => (int)qa_opt('xml_sitemap_show_categories'),
					'tags' => 'name="xml_sitemap_show_categories_field"',
				);
			}

			return $form;
		}


		public function suggest_requests()
		{
			return array(
				array(
					'title' => 'XML Sitemap',
					'request' => 'sitemap.xml',
					'nav' => null, // 'M'=main, 'F'=footer, 'B'=before main, 'O'=opposite main, null=none
				),
			);
		}


		public function match_request($request)
		{
			return ($request=='sitemap.xml');
		}


		public function process_request($request)
		{
			@ini_set('display_errors', 0); // we don't want to show PHP errors inside XML

			$siteurl=qa_opt('site_url');

			header('Content-type: text/xml; charset=utf-8');

			echo '<?xml version="1.0" encoding="UTF-8"?>'."\n";
			echo '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">'."\n";


		//	Question pages

			if (qa_opt('xml_sitemap_show_questions')) {
				$hotstats=qa_db_read_one_assoc(qa_db_query_sub(
					"SELECT MIN(hotness) AS base, MAX(hotness)-MIN(hotness) AS spread FROM ^posts WHERE type='Q'"
				));

				$nextpostid=0;

				while (1) {
					$questions=qa_db_read_all_assoc(qa_db_query_sub(
						"SELECT postid, title, hotness FROM ^posts WHERE postid>=# AND type='Q' ORDER BY postid LIMIT 100",
						$nextpostid
					));

					if (!count($questions))
						break;

					foreach ($questions as $question) {
						$this->sitemap_output(qa_q_request($question['postid'], $question['title']),
							0.1+0.9*($question['hotness']-$hotstats['base'])/(1+$hotstats['spread']));
						$nextpostid=max($nextpostid, $question['postid']+1);
					}
				}
			}


		//	User pages

			if ((!QA_FINAL_EXTERNAL_USERS) && qa_opt('xml_sitemap_show_users')) {
				$nextuserid=0;

				while (1) {
					$users=qa_db_read_all_assoc(qa_db_query_sub(
						"SELECT userid, handle FROM ^users WHERE userid>=# ORDER BY userid LIMIT 100",
						$nextuserid
					));

					if (!count($users))
						break;

					foreach ($users as $user) {
						$this->sitemap_output('user/'.$user['handle'], 0.25);
						$nextuserid=max($nextuserid, $user['userid']+1);
					}
				}
			}


		//	Tag pages

			if (qa_using_tags() && qa_opt('xml_sitemap_show_tag_qs')) {
				$nextwordid=0;

				while (1) {
					$tagwords=qa_db_read_all_assoc(qa_db_query_sub(
						"SELECT wordid, word, tagcount FROM ^words WHERE wordid>=# AND tagcount>0 ORDER BY wordid LIMIT 100",
						$nextwordid
					));

					if (!count($tagwords))
						break;

					foreach ($tagwords as $tagword) {
						$this->sitemap_output('tag/'.$tagword['word'], 0.5/(1+(1/$tagword['tagcount']))); // priority between 0.25 and 0.5 depending on tag frequency
						$nextwordid=max($nextwordid, $tagword['wordid']+1);
					}
				}
			}


		//	Question list for each category

			if (qa_using_categories() && qa_opt('xml_sitemap_show_category_qs')) {
				$nextcategoryid=0;

				while (1) {
					$categories=qa_db_read_all_assoc(qa_db_query_sub(
						"SELECT categoryid, backpath FROM ^categories WHERE categoryid>=# AND qcount>0 ORDER BY categoryid LIMIT 2",
						$nextcategoryid
					));

					if (!count($categories))
						break;

					foreach ($categories as $category) {
						$this->sitemap_output('questions/'.implode('/', array_reverse(explode('/', $category['backpath']))), 0.5);
						$nextcategoryid=max($nextcategoryid, $category['categoryid']+1);
					}
				}
			}


		//	Pages in category browser

			if (qa_using_categories() && qa_opt('xml_sitemap_show_categories')) {
				$this->sitemap_output('categories', 0.5);

				$nextcategoryid=0;

				while (1) { // only find categories with a child
					$categories=qa_db_read_all_assoc(qa_db_query_sub(
						"SELECT parent.categoryid, parent.backpath FROM ^categories AS parent ".
						"JOIN ^categories AS child ON child.parentid=parent.categoryid WHERE parent.categoryid>=# GROUP BY parent.categoryid LIMIT 100",
						$nextcategoryid
					));

					if (!count($categories))
						break;

					foreach ($categories as $category) {
						$this->sitemap_output('categories/'.implode('/', array_reverse(explode('/', $category['backpath']))), 0.5);
						$nextcategoryid=max($nextcategoryid, $category['categoryid']+1);
					}
				}
			}


		//	Finish up...

			echo "</urlset>\n";

			return null;
		}


		private function sitemap_output($request, $priority)
		{
			echo "\t<url>\n".
				"\t\t<loc>".qa_xml(qa_path($request, null, qa_opt('site_url')))."</loc>\n".
				"\t\t<priority>".max(0, min(1.0, $priority))."</priority>\n".
				"\t</url>\n";
		}

	}


/*
	Omit PHP closing tag to help avoid accidental output
*/