<?php
/*
	Question2Answer by Gideon Greenspan and contributors
	http://www.question2answer.org/

	Description: Common functions for creating theme-ready structures from data


	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
*/

if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
	header('Location: ../../');
	exit;
}

define('QA_PAGE_FLAGS_EXTERNAL', 1);
define('QA_PAGE_FLAGS_NEW_WINDOW', 2);


/**
 * Return textual representation of $seconds
 * @param $seconds
 * @return mixed|string
 */
function qa_time_to_string($seconds)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$seconds = max($seconds, 1);

	$scales = array(
		31557600 => array('main/1_year', 'main/x_years'),
		2629800 => array('main/1_month', 'main/x_months'),
		604800 => array('main/1_week', 'main/x_weeks'),
		86400 => array('main/1_day', 'main/x_days'),
		3600 => array('main/1_hour', 'main/x_hours'),
		60 => array('main/1_minute', 'main/x_minutes'),
		1 => array('main/1_second', 'main/x_seconds'),
	);

	foreach ($scales as $scale => $phrases) {
		if ($seconds >= $scale) {
			$count = floor($seconds / $scale);

			if ($count == 1)
				$string = qa_lang($phrases[0]);
			else
				$string = qa_lang_sub($phrases[1], $count);

			break;
		}
	}

	return $string;
}


/**
 * Check if $post is by user $userid, or if post is anonymous and $userid not specified, then
 * check if $post is by the anonymous user identified by $cookieid
 * @param $post
 * @param $userid
 * @param $cookieid
 * @return bool
 */
function qa_post_is_by_user($post, $userid, $cookieid)
{
	// In theory we should only test against NULL here, i.e. use isset($post['userid'])
	// but the risk of doing so is so high (if a bug creeps in that allows userid=0)
	// that I'm doing a tougher test. This will break under a zero user or cookie id.

	if (@$post['userid'] || $userid)
		return @$post['userid'] == $userid;
	elseif (@$post['cookieid'])
		return strcmp($post['cookieid'], $cookieid) == 0;

	return false;
}


/**
 * Return array which maps the 'userid' and/or 'lastuserid' of each user to its HTML representation.
 * For internal user management, corresponding 'handle' and/or 'lasthandle' are required in each element.
 *
 * @param array $useridhandles  User IDs or usernames.
 * @param bool $microdata  Whether to include microdata.
 * @return array  The HTML.
 */
function qa_userids_handles_html($useridhandles, $microdata = false)
{
	require_once QA_INCLUDE_DIR . 'app/users.php';

	if (QA_FINAL_EXTERNAL_USERS) {
		$keyuserids = array();

		foreach ($useridhandles as $useridhandle) {
			if (isset($useridhandle['userid']))
				$keyuserids[$useridhandle['userid']] = true;

			if (isset($useridhandle['lastuserid']))
				$keyuserids[$useridhandle['lastuserid']] = true;
		}

		if (count($keyuserids))
			return qa_get_users_html(array_keys($keyuserids), true, qa_path_to_root(), $microdata);

		return array();
	} else {
		$usershtml = array();
		$favoritemap = qa_get_favorite_non_qs_map();

		foreach ($useridhandles as $useridhandle) {
			// only add each user to the array once
			$uid = isset($useridhandle['userid']) ? $useridhandle['userid'] : null;
			if ($uid && !isset($usershtml[$uid])) {
				$usershtml[$uid] = qa_get_one_user_html($useridhandle['handle'], $microdata, @$favoritemap['user'][$uid]);
			}

			$luid = isset($useridhandle['lastuserid']) ? $useridhandle['lastuserid'] : null;
			if ($luid && !isset($usershtml[$luid])) {
				$usershtml[$luid] = qa_get_one_user_html($useridhandle['lasthandle'], $microdata, @$favoritemap['user'][$luid]);
			}
		}

		return $usershtml;
	}
}


/**
 * Get an array listing all of the logged in user's favorite items, except their favorited questions (these are excluded because
 * users tend to favorite many more questions than other things.) The top-level array can contain three keys - 'user' for favorited
 * users, 'tag' for tags, 'category' for categories. The next level down has the identifier for each favorited entity in the *key*
 * of the array, and true for its value. If no user is logged in the empty array is returned. The result is cached for future calls.
 */
function qa_get_favorite_non_qs_map()
{
	global $qa_favorite_non_qs_map;

	if (!isset($qa_favorite_non_qs_map)) {
		$qa_favorite_non_qs_map = array();
		$loginuserid = qa_get_logged_in_userid();

		if (isset($loginuserid)) {
			require_once QA_INCLUDE_DIR . 'db/selects.php';
			require_once QA_INCLUDE_DIR . 'util/string.php';

			$favoritenonqs = qa_db_get_pending_result('favoritenonqs', qa_db_user_favorite_non_qs_selectspec($loginuserid));

			foreach ($favoritenonqs as $favorite) {
				switch ($favorite['type']) {
					case QA_ENTITY_USER:
						$qa_favorite_non_qs_map['user'][$favorite['userid']] = true;
						break;

					case QA_ENTITY_TAG:
						$qa_favorite_non_qs_map['tag'][qa_strtolower($favorite['tags'])] = true;
						break;

					case QA_ENTITY_CATEGORY:
						$qa_favorite_non_qs_map['category'][$favorite['categorybackpath']] = true;
						break;
				}
			}
		}
	}

	return $qa_favorite_non_qs_map;
}


/**
 * Convert textual tag to HTML representation, linked to its tag page.
 *
 * @param string $tag  The tag.
 * @param bool $microdata  Whether to include microdata.
 * @param bool $favorited  Show the tag as favorited.
 * @return string  The tag HTML.
 */
function qa_tag_html($tag, $microdata = false, $favorited = false)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$url = qa_path_html('tag/' . $tag);
	$attrs = $microdata ? ' rel="tag"' : '';
	$class = $favorited ? ' qa-tag-favorited' : '';

	return '<a href="' . $url . '"' . $attrs . ' class="qa-tag-link' . $class . '">' . qa_html($tag) . '</a>';
}


/**
 * Given $navcategories retrieved for $categoryid from the database (using qa_db_category_nav_selectspec(...)),
 * return an array of elements from $navcategories for the hierarchy down to $categoryid.
 * @param $navcategories
 * @param $categoryid
 * @return array
 */
function qa_category_path($navcategories, $categoryid)
{
	$upcategories = array();

	for ($upcategory = @$navcategories[$categoryid]; isset($upcategory); $upcategory = @$navcategories[$upcategory['parentid']])
		$upcategories[$upcategory['categoryid']] = $upcategory;

	return array_reverse($upcategories, true);
}


/**
 * Given $navcategories retrieved for $categoryid from the database (using qa_db_category_nav_selectspec(...)),
 * return some HTML that shows the category hierarchy down to $categoryid.
 * @param $navcategories
 * @param $categoryid
 * @return string
 */
function qa_category_path_html($navcategories, $categoryid)
{
	$categories = qa_category_path($navcategories, $categoryid);

	$html = '';
	foreach ($categories as $category)
		$html .= (strlen($html) ? ' / ' : '') . qa_html($category['title']);

	return $html;
}


/**
 * Given $navcategories retrieved for $categoryid from the database (using qa_db_category_nav_selectspec(...)),
 * return a Q2A request string that represents the category hierarchy down to $categoryid.
 * @param $navcategories
 * @param $categoryid
 * @return string
 */
function qa_category_path_request($navcategories, $categoryid)
{
	$categories = qa_category_path($navcategories, $categoryid);

	$request = '';
	foreach ($categories as $category)
		$request .= (strlen($request) ? '/' : '') . $category['tags'];

	return $request;
}


/**
 * Return HTML to use for $ip address, which links to appropriate page with $anchorhtml
 * @param $ip
 * @param null $anchorhtml
 * @return mixed|string
 */
function qa_ip_anchor_html($ip, $anchorhtml = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	if (!strlen($anchorhtml))
		$anchorhtml = qa_html($ip);

	return '<a href="' . qa_path_html('ip/' . $ip) . '" title="' . qa_lang_html_sub('main/ip_address_x', qa_html($ip)) . '" class="qa-ip-link">' . $anchorhtml . '</a>';
}


/**
 * Given $post retrieved from database, return array of mostly HTML to be passed to theme layer.
 * $userid and $cookieid refer to the user *viewing* the page.
 * $usershtml is an array of [user id] => [HTML representation of user] built ahead of time.
 * $dummy is a placeholder (used to be $categories parameter but that's no longer needed)
 * $options is an array which sets what is displayed (see qa_post_html_defaults() in /qa-include/app/options.php)
 * If something is missing from $post (e.g. ['content']), correponding HTML also omitted.
 * @param $post
 * @param $userid
 * @param $cookieid
 * @param $usershtml
 * @param $dummy
 * @param array $options
 * @return array
 */
function qa_post_html_fields($post, $userid, $cookieid, $usershtml, $dummy, $options = array())
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'app/updates.php';
	require_once QA_INCLUDE_DIR . 'app/posts.php';

	if (isset($options['blockwordspreg']))
		require_once QA_INCLUDE_DIR . 'util/string.php';

	$fields = array('raw' => $post);

	// Useful stuff used throughout function

	$postid = $post['postid'];
	$isquestion = $post['basetype'] == 'Q';
	$isanswer = $post['basetype'] == 'A';
	$iscomment = $post['basetype'] == 'C';
	$isbyuser = qa_post_is_by_user($post, $userid, $cookieid);
	$anchor = urlencode(qa_anchor($post['basetype'], $postid));
	$elementid = isset($options['elementid']) ? $options['elementid'] : $anchor;
	$microdata = qa_opt('use_microdata') && !empty($options['contentview']);
	$isselected = @$options['isselected'];
	$favoritedview = @$options['favoritedview'];
	$favoritemap = $favoritedview ? qa_get_favorite_non_qs_map() : array();

	// High level information

	$fields['hidden'] = isset($post['hidden']) ? $post['hidden'] : null;
	$fields['queued'] = isset($post['queued']) ? $post['queued'] : null;
	$fields['tags'] = 'id="' . qa_html($elementid) . '"';

	$fields['classes'] = ($isquestion && $favoritedview && @$post['userfavoriteq']) ? 'qa-q-favorited' : '';
	if ($isquestion && qa_post_is_closed($post)) {
		$fields['classes'] = ltrim($fields['classes'] . ' qa-q-closed');
	}

	if ($microdata) {
		if ($isanswer) {
			$fields['tags'] .= ' itemprop="suggestedAnswer' . ($isselected ? ' acceptedAnswer' : '') . '" itemscope itemtype="https://schema.org/Answer"';
		}
		if ($iscomment) {
			$fields['tags'] .= ' itemscope itemtype="https://schema.org/Comment"';
		}
	}

	// Question-specific stuff (title, URL, tags, answer count, category)

	if ($isquestion) {
		if (isset($post['title'])) {
			$fields['url'] = qa_q_path_html($postid, $post['title']);

			if (isset($options['blockwordspreg']))
				$post['title'] = qa_block_words_replace($post['title'], $options['blockwordspreg']);

			$fields['title'] = qa_html($post['title']);
			if ($microdata) {
				$fields['title'] = '<span itemprop="name">' . $fields['title'] . '</span>';
			}

			/*if (isset($post['score'])) // useful for setting match thresholds
				$fields['title'].=' <small>('.$post['score'].')</small>';*/
		}

		if (@$options['tagsview'] && isset($post['tags'])) {
			$fields['q_tags'] = array();

			$tags = qa_tagstring_to_tags($post['tags']);
			foreach ($tags as $tag) {
				if (isset($options['blockwordspreg']) && count(qa_block_words_match_all($tag, $options['blockwordspreg']))) // skip censored tags
					continue;

				$fields['q_tags'][] = qa_tag_html($tag, $microdata, @$favoritemap['tag'][qa_strtolower($tag)]);
			}
		}

		if (@$options['answersview'] && isset($post['acount'])) {
			$fields['answers_raw'] = $post['acount'];

			$fields['answers'] = ($post['acount'] == 1) ? qa_lang_html_sub_split('main/1_answer', '1', '1')
				: qa_lang_html_sub_split('main/x_answers', qa_format_number($post['acount'], 0, true));

			$fields['answer_selected'] = isset($post['selchildid']);
		}

		if (@$options['viewsview'] && isset($post['views'])) {
			$fields['views_raw'] = $post['views'];

			$fields['views'] = ($post['views'] == 1) ? qa_lang_html_sub_split('main/1_view', '1', '1') :
				qa_lang_html_sub_split('main/x_views', qa_format_number($post['views'], 0, true));
		}

		if (@$options['categoryview'] && isset($post['categoryname']) && isset($post['categorybackpath'])) {
			$favoriteclass = '';

			if (isset($favoritemap['category']) && !empty($favoritemap['category'])) {
				if (isset($favoritemap['category'][$post['categorybackpath']])) {
					$favoriteclass = ' qa-cat-favorited';
				} else {
					foreach ($favoritemap['category'] as $categorybackpath => $dummy) {
						if (substr('/' . $post['categorybackpath'], -strlen($categorybackpath)) == $categorybackpath)
							$favoriteclass = ' qa-cat-parent-favorited';
					}
				}
			}

			$fields['where'] = qa_lang_html_sub_split('main/in_category_x',
				'<a href="' . qa_path_html(@$options['categorypathprefix'] . implode('/', array_reverse(explode('/', $post['categorybackpath'])))) .
				'" class="qa-category-link' . $favoriteclass . '">' . qa_html($post['categoryname']) . '</a>');
		}
	}

	// Answer-specific stuff (selection)

	if ($isanswer) {
		$fields['selected'] = $isselected;

		if ($isselected)
			$fields['select_text'] = qa_lang_html('question/select_text');
	}

	// Post content

	if (@$options['contentview'] && isset($post['content'])) {
		$viewer = qa_load_viewer($post['content'], $post['format']);

		$fields['content'] = $viewer->get_html($post['content'], $post['format'], array(
			'blockwordspreg' => @$options['blockwordspreg'],
			'showurllinks' => @$options['showurllinks'],
			'linksnewwindow' => @$options['linksnewwindow'],
		));

		if ($microdata) {
			$fields['content'] = '<div itemprop="text">' . $fields['content'] . '</div>';
		}

		// this is for backwards compatibility with any existing links using the old style of anchor
		// that contained the post id only (changed to be valid under W3C specifications)
		$fields['content'] = '<a name="' . qa_html($postid) . '"></a>' . $fields['content'];
	}

	// Voting stuff

	if (@$options['voteview']) {
		$voteview = $options['voteview'];

		// Calculate raw values and pass through

		if (@$options['ovoteview'] && isset($post['opostid'])) {
			$upvotes = (int)@$post['oupvotes'];
			$downvotes = (int)@$post['odownvotes'];
			$fields['vote_opostid'] = true; // for voters/flaggers layer
		} else {
			$upvotes = (int)@$post['upvotes'];
			$downvotes = (int)@$post['downvotes'];
		}

		$netvotes = $upvotes - $downvotes;

		$fields['upvotes_raw'] = $upvotes;
		$fields['downvotes_raw'] = $downvotes;
		$fields['netvotes_raw'] = $netvotes;

		// Create HTML versions...

		$upvoteshtml = qa_html(qa_format_number($upvotes, 0, true));
		$downvoteshtml = qa_html(qa_format_number($downvotes, 0, true));

		if ($netvotes >= 1)
			$netvotesPrefix = '+';
		elseif ($netvotes <= -1)
			$netvotesPrefix = '&ndash;';
		else
			$netvotesPrefix = '';

		$netvotes = abs($netvotes);
		$netvoteshtml = $netvotesPrefix . qa_html(qa_format_number($netvotes, 0, true));

		// Pass information on vote viewing

		// $voteview will be one of:
		// updown, updown-disabled-page, updown-disabled-level, updown-uponly-level, updown-disabled-approve, updown-uponly-approve
		// net, net-disabled-page, net-disabled-level, net-uponly-level, net-disabled-approve, net-uponly-approve

		$fields['vote_view'] = (substr($voteview, 0, 6) == 'updown') ? 'updown' : 'net';

		$fields['vote_on_page'] = strpos($voteview, '-disabled-page') ? 'disabled' : 'enabled';

		if ($iscomment) {
			// for comments just show number, no additional text
			$fields['upvotes_view'] = array('prefix' => '', 'data' => $upvoteshtml, 'suffix' => '');
			$fields['downvotes_view'] = array('prefix' => '', 'data' => $downvoteshtml, 'suffix' => '');
			$fields['netvotes_view'] = array('prefix' => '', 'data' => $netvoteshtml, 'suffix' => '');
		} else {
			$fields['upvotes_view'] = $upvotes == 1
				? qa_lang_html_sub_split('main/1_liked', $upvoteshtml, '1')
				: qa_lang_html_sub_split('main/x_liked', $upvoteshtml);
			$fields['downvotes_view'] = $downvotes == 1
				? qa_lang_html_sub_split('main/1_disliked', $downvoteshtml, '1')
				: qa_lang_html_sub_split('main/x_disliked', $downvoteshtml);
			$fields['netvotes_view'] = $netvotes == 1
				? qa_lang_html_sub_split('main/1_vote', $netvoteshtml, '1')
				: qa_lang_html_sub_split('main/x_votes', $netvoteshtml);
		}

		// schema.org microdata - vote display might be formatted (e.g. '2k') so we use meta tag for true count
		if ($microdata) {
			$fields['netvotes_view']['suffix'] .= ' <meta itemprop="upvoteCount" content="' . qa_html($upvotes - $downvotes) . '"/>';
			$fields['upvotes_view']['suffix'] .= ' <meta itemprop="upvoteCount" content="' . qa_html($upvotes) . '"/>';
		}

		// Voting buttons

		$fields['vote_tags'] = 'id="voting_' . qa_html($postid) . '"';
		$onclick = 'onclick="return qa_vote_click(this);"';

		if ($fields['hidden']) {
			$fields['vote_state'] = 'disabled';
			$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_hidden_post') . '"';
			$fields['vote_down_tags'] = $fields['vote_up_tags'];

		} elseif ($fields['queued']) {
			$fields['vote_state'] = 'disabled';
			$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_queued') . '"';
			$fields['vote_down_tags'] = $fields['vote_up_tags'];

		} elseif ($isbyuser) {
			$fields['vote_state'] = 'disabled';
			$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_my_post') . '"';
			$fields['vote_down_tags'] = $fields['vote_up_tags'];

		} elseif (strpos($voteview, '-disabled-')) {
			$fields['vote_state'] = (@$post['uservote'] > 0) ? 'voted_up_disabled' : ((@$post['uservote'] < 0) ? 'voted_down_disabled' : 'disabled');

			if (strpos($voteview, '-disabled-page'))
				$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_q_page_only') . '"';
			elseif (strpos($voteview, '-disabled-approve'))
				$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_approve') . '"';
			else
				$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_disabled_level') . '"';

			$fields['vote_down_tags'] = $fields['vote_up_tags'];

		} elseif (@$post['uservote'] > 0) {
			$fields['vote_state'] = 'voted_up';
			$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/voted_up_popup') . '" name="' . qa_html('vote_' . $postid . '_0_' . $elementid) . '" ' . $onclick;
			$fields['vote_down_tags'] = ' ';

		} elseif (@$post['uservote'] < 0) {
			$fields['vote_state'] = 'voted_down';
			$fields['vote_up_tags'] = ' ';
			$fields['vote_down_tags'] = 'title="' . qa_lang_html('main/voted_down_popup') . '" name="' . qa_html('vote_' . $postid . '_0_' . $elementid) . '" ' . $onclick;

		} else {
			$fields['vote_up_tags'] = 'title="' . qa_lang_html('main/vote_up_popup') . '" name="' . qa_html('vote_' . $postid . '_1_' . $elementid) . '" ' . $onclick;

			if (strpos($voteview, '-uponly-level')) {
				$fields['vote_state'] = 'up_only';
				$fields['vote_down_tags'] = 'title="' . qa_lang_html('main/vote_disabled_down') . '"';

			} elseif (strpos($voteview, '-uponly-approve')) {
				$fields['vote_state'] = 'up_only';
				$fields['vote_down_tags'] = 'title="' . qa_lang_html('main/vote_disabled_down_approve') . '"';

			} else {
				$fields['vote_state'] = 'enabled';
				$fields['vote_down_tags'] = 'title="' . qa_lang_html('main/vote_down_popup') . '" name="' . qa_html('vote_' . $postid . '_-1_' . $elementid) . '" ' . $onclick;
			}
		}
	}

	// Flag count

	if (@$options['flagsview'] && @$post['flagcount']) {
		$fields['flags'] = ($post['flagcount'] == 1) ? qa_lang_html_sub_split('main/1_flag', '1', '1')
			: qa_lang_html_sub_split('main/x_flags', $post['flagcount']);
	}

	// Created when and by whom

	$fields['meta_order'] = qa_lang_html('main/meta_order'); // sets ordering of meta elements which can be language-specific

	if (@$options['whatview']) {
		$fields['what'] = qa_lang_html($isquestion ? 'main/asked' : ($isanswer ? 'main/answered' : 'main/commented'));

		if (@$options['whatlink'] && strlen(@$options['q_request'])) {
			$fields['what_url'] = $post['basetype'] == 'Q'
				? qa_path_html($options['q_request'])
				: qa_path_html($options['q_request'], array('show' => $postid), null, null, qa_anchor($post['basetype'], $postid));
			if ($microdata) {
				$fields['what_url_tags'] = ' itemprop="url"';
			}
		}
	}

	if (isset($post['created']) && @$options['whenview']) {
		$fields['when'] = qa_when_to_html($post['created'], @$options['fulldatedays']);

		if ($microdata) {
			$gmdate = gmdate('Y-m-d\TH:i:sO', $post['created']);
			$fields['when']['data'] = '<time itemprop="dateCreated" datetime="' . $gmdate . '" title="' . $gmdate . '">' . $fields['when']['data'] . '</time>';
		}
	}

	if (@$options['whoview']) {
		$fields['who'] = qa_who_to_html($isbyuser, @$post['userid'], $usershtml, @$options['ipview'] ? @inet_ntop(@$post['createip']) : null, $microdata, $post['name']);

		if (isset($post['points'])) {
			if (@$options['pointsview'])
				$fields['who']['points'] = ($post['points'] == 1) ? qa_lang_html_sub_split('main/1_point', '1', '1')
					: qa_lang_html_sub_split('main/x_points', qa_format_number($post['points'], 0, true));

			if (isset($options['pointstitle']))
				$fields['who']['title'] = qa_get_points_title_html($post['points'], $options['pointstitle']);
		}

		if (isset($post['level']))
			$fields['who']['level'] = qa_html(qa_user_level_string($post['level']));
	}

	if (@$options['avatarsize'] > 0) {
		if (QA_FINAL_EXTERNAL_USERS)
			$fields['avatar'] = qa_get_external_avatar_html($post['userid'], $options['avatarsize'], false);
		else
			$fields['avatar'] = qa_get_user_avatar_html(@$post['flags'], @$post['email'], @$post['handle'],
				@$post['avatarblobid'], @$post['avatarwidth'], @$post['avatarheight'], $options['avatarsize']);
	}

	// Updated when and by whom

	if (@$options['updateview'] && isset($post['updated']) &&
		($post['updatetype'] != QA_UPDATE_SELECTED || $isselected) && // only show selected change if it's still selected
		( // otherwise check if one of these conditions is fulfilled...
			(!isset($post['created'])) || // ... we didn't show the created time (should never happen in practice)
			($post['hidden'] && ($post['updatetype'] == QA_UPDATE_VISIBLE)) || // ... the post was hidden as the last action
			(qa_post_is_closed($post) && $post['updatetype'] == QA_UPDATE_CLOSED) || // ... the post was closed as the last action
			(abs($post['updated'] - $post['created']) > 300) || // ... or over 5 minutes passed between create and update times
			($post['lastuserid'] != $post['userid']) // ... or it was updated by a different user
		)
	) {
		switch ($post['updatetype']) {
			case QA_UPDATE_TYPE:
			case QA_UPDATE_PARENT:
				$langstring = 'main/moved';
				break;

			case QA_UPDATE_CATEGORY:
				$langstring = 'main/recategorized';
				break;

			case QA_UPDATE_VISIBLE:
				$langstring = $post['hidden'] ? 'main/hidden' : 'main/reshown';
				break;

			case QA_UPDATE_CLOSED:
				$langstring = qa_post_is_closed($post) ? 'main/closed' : 'main/reopened';
				break;

			case QA_UPDATE_TAGS:
				$langstring = 'main/retagged';
				break;

			case QA_UPDATE_SELECTED:
				$langstring = 'main/selected';
				break;

			default:
				$langstring = 'main/edited';
				break;
		}

		$fields['what_2'] = qa_lang_html($langstring);

		if (@$options['whenview']) {
			$fields['when_2'] = qa_when_to_html($post['updated'], @$options['fulldatedays']);

			if ($microdata) {
				$gmdate = gmdate('Y-m-d\TH:i:sO', $post['updated']);
				$fields['when_2']['data'] = '<time itemprop="dateModified" datetime="' . $gmdate . '" title="' . $gmdate . '">' . $fields['when_2']['data'] . '</time>';
			}
		}

		if (isset($post['lastuserid']) && @$options['whoview'])
			$fields['who_2'] = qa_who_to_html(isset($userid) && ($post['lastuserid'] == $userid), $post['lastuserid'], $usershtml, @$options['ipview'] ? @inet_ntop($post['lastip']) : null, false);
	}


	// That's it!

	return $fields;
}


/**
 * Generate array of mostly HTML representing a message, to be passed to theme layer.
 *
 * @param array $message  The message object (as retrieved from database).
 * @param array $options  Viewing options (see qa_message_html_defaults() in /qa-include/app/options.php).
 * @return array  The HTML.
 */
function qa_message_html_fields($message, $options = array())
{
	require_once QA_INCLUDE_DIR . 'app/users.php';

	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$fields = array('raw' => $message);
	$fields['tags'] = 'id="m' . qa_html($message['messageid']) . '"';

	// message content
	$viewer = qa_load_viewer($message['content'], $message['format']);

	$fields['content'] = $viewer->get_html($message['content'], $message['format'], array(
		'blockwordspreg' => @$options['blockwordspreg'],
		'showurllinks' => @$options['showurllinks'],
		'linksnewwindow' => @$options['linksnewwindow'],
	));

	// set ordering of meta elements which can be language-specific
	$fields['meta_order'] = qa_lang_html('main/meta_order');

	$fields['what'] = qa_lang_html('main/written');

	// when it was written
	if (@$options['whenview'])
		$fields['when'] = qa_when_to_html($message['created'], @$options['fulldatedays']);

	// who wrote it, and their avatar
	if (@$options['towhomview']) {
		// for sent private messages page (i.e. show who message was sent to)
		$fields['who'] = qa_lang_html_sub_split('main/to_x', qa_get_one_user_html($message['tohandle'], false));
		$fields['avatar'] = qa_get_user_avatar_html(@$message['toflags'], @$message['toemail'], @$message['tohandle'],
			@$message['toavatarblobid'], @$message['toavatarwidth'], @$message['toavatarheight'], $options['avatarsize']);
	} else {
		// for everything else (received private messages, wall messages)
		if (@$options['whoview']) {
			$fields['who'] = qa_lang_html_sub_split('main/by_x', qa_get_one_user_html($message['fromhandle'], false));
		}
		if (@$options['avatarsize'] > 0) {
			$fields['avatar'] = qa_get_user_avatar_html(@$message['fromflags'], @$message['fromemail'], @$message['fromhandle'],
				@$message['fromavatarblobid'], @$message['fromavatarwidth'], @$message['fromavatarheight'], $options['avatarsize']);
		}
	}

	return $fields;
}


/**
 * Generate array of split HTML (prefix, data, suffix) to represent author of post.
 *
 * @param bool $isbyuser True if the current user made the post.
 * @param int $postuserid The post user's ID.
 * @param array $usershtml Array of HTML representing usernames.
 * @param string $ip The post user's IP.
 * @param bool|string $microdata Whether to include microdata.
 * @param string $name The author's username.
 * @return array The HTML.
 */
function qa_who_to_html($isbyuser, $postuserid, $usershtml, $ip = null, $microdata = false, $name = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	if (isset($postuserid) && isset($usershtml[$postuserid])) {
		$whohtml = $usershtml[$postuserid];
	} else {
		if (strlen($name))
			$whohtml = qa_html($name);
		elseif ($isbyuser)
			$whohtml = qa_lang_html('main/me');
		else
			$whohtml = qa_lang_html('main/anonymous');

		if ($microdata) {
			// duplicate HTML from qa_get_one_user_html()
			$whohtml = '<span itemprop="author" itemscope itemtype="https://schema.org/Person"><span itemprop="name">' . $whohtml . '</span></span>';
		}

		if (isset($ip))
			$whohtml = qa_ip_anchor_html($ip, $whohtml);
	}

	return qa_lang_html_sub_split('main/by_x', $whohtml);
}


/**
 * Generate array of split HTML (prefix, data, suffix) to represent a timestamp, optionally with the full date.
 *
 * @param int $timestamp  Unix timestamp.
 * @param int $fulldatedays  Number of days after which to show the full date.
 * @return array  The HTML.
 */
function qa_when_to_html($timestamp, $fulldatedays)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$interval = qa_opt('db_time') - $timestamp;

	if ($interval < 0 || (isset($fulldatedays) && $interval > 86400 * $fulldatedays)) {
		// full style date
		$stampyear = date('Y', $timestamp);
		$thisyear = date('Y', qa_opt('db_time'));

		$dateFormat = qa_lang($stampyear == $thisyear ? 'main/date_format_this_year' : 'main/date_format_other_years');
		$replaceData = array(
			'^day' => date(qa_lang('main/date_day_min_digits') == 2 ? 'd' : 'j', $timestamp),
			'^month' => qa_lang('main/date_month_' . date('n', $timestamp)),
			'^year' => date(qa_lang('main/date_year_digits') == 2 ? 'y' : 'Y', $timestamp),
		);

		return array(
			'data' => qa_html(strtr($dateFormat, $replaceData)),
		);

	} else {
		// ago-style date
		return qa_lang_html_sub_split('main/x_ago', qa_html(qa_time_to_string($interval)));
	}
}


/**
 * Return array of mostly HTML to be passed to theme layer, to *link* to an answer, comment or edit on
 * $question, as retrieved from database, with fields prefixed 'o' for the answer, comment or edit.
 * $userid, $cookieid, $usershtml, $options are passed through to qa_post_html_fields(). If $question['opersonal']
 * is set and true then the item is displayed with its personal relevance to the user (for user updates page).
 * @param $question
 * @param $userid
 * @param $cookieid
 * @param $usershtml
 * @param $dummy
 * @param $options
 * @return array
 */
function qa_other_to_q_html_fields($question, $userid, $cookieid, $usershtml, $dummy, $options)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'app/updates.php';

	$fields = qa_post_html_fields($question, $userid, $cookieid, $usershtml, null, $options);

	switch ($question['obasetype'] . '-' . @$question['oupdatetype']) {
		case 'Q-':
			$langstring = 'main/asked';
			break;

		case 'Q-' . QA_UPDATE_VISIBLE:
			if (@$question['opersonal'])
				$langstring = $question['hidden'] ? 'misc/your_q_hidden' : 'misc/your_q_reshown';
			else
				$langstring = $question['hidden'] ? 'main/hidden' : 'main/reshown';
			break;

		case 'Q-' . QA_UPDATE_CLOSED:
			$isClosed = qa_post_is_closed($question);
			if (@$question['opersonal'])
				$langstring = $isClosed ? 'misc/your_q_closed' : 'misc/your_q_reopened';
			else
				$langstring = $isClosed ? 'main/closed' : 'main/reopened';
			break;

		case 'Q-' . QA_UPDATE_TAGS:
			$langstring = @$question['opersonal'] ? 'misc/your_q_retagged' : 'main/retagged';
			break;

		case 'Q-' . QA_UPDATE_CATEGORY:
			$langstring = @$question['opersonal'] ? 'misc/your_q_recategorized' : 'main/recategorized';
			break;

		case 'A-':
			$langstring = @$question['opersonal'] ? 'misc/your_q_answered' : 'main/answered';
			break;

		case 'A-' . QA_UPDATE_SELECTED:
			$langstring = @$question['opersonal'] ? 'misc/your_a_selected' : 'main/answer_selected';
			break;

		case 'A-' . QA_UPDATE_VISIBLE:
			if (@$question['opersonal'])
				$langstring = $question['ohidden'] ? 'misc/your_a_hidden' : 'misc/your_a_reshown';
			else
				$langstring = $question['ohidden'] ? 'main/hidden' : 'main/answer_reshown';
			break;

		case 'A-' . QA_UPDATE_CONTENT:
			$langstring = @$question['opersonal'] ? 'misc/your_a_edited' : 'main/answer_edited';
			break;

		case 'Q-' . QA_UPDATE_FOLLOWS:
			$langstring = @$question['opersonal'] ? 'misc/your_a_questioned' : 'main/asked_related_q';
			break;

		case 'C-':
			$langstring = 'main/commented';
			break;

		case 'C-' . QA_UPDATE_C_FOR_Q:
			$langstring = @$question['opersonal'] ? 'misc/your_q_commented' : 'main/commented';
			break;

		case 'C-' . QA_UPDATE_C_FOR_A:
			$langstring = @$question['opersonal'] ? 'misc/your_a_commented' : 'main/commented';
			break;

		case 'C-' . QA_UPDATE_FOLLOWS:
			$langstring = @$question['opersonal'] ? 'misc/your_c_followed' : 'main/commented';
			break;

		case 'C-' . QA_UPDATE_TYPE:
			$langstring = @$question['opersonal'] ? 'misc/your_c_moved' : 'main/comment_moved';
			break;

		case 'C-' . QA_UPDATE_VISIBLE:
			if (@$question['opersonal'])
				$langstring = $question['ohidden'] ? 'misc/your_c_hidden' : 'misc/your_c_reshown';
			else
				$langstring = $question['ohidden'] ? 'main/hidden' : 'main/comment_reshown';
			break;

		case 'C-' . QA_UPDATE_CONTENT:
			$langstring = @$question['opersonal'] ? 'misc/your_c_edited' : 'main/comment_edited';
			break;

		case 'Q-' . QA_UPDATE_CONTENT:
		default:
			$langstring = @$question['opersonal'] ? 'misc/your_q_edited' : 'main/edited';
			break;
	}

	$fields['what'] = qa_lang_html($langstring);

	if (@$question['opersonal'])
		$fields['what_your'] = true;

	if ($question['obasetype'] != 'Q' || @$question['oupdatetype'] == QA_UPDATE_FOLLOWS)
		$fields['what_url'] = qa_q_path_html($question['postid'], $question['title'], false, $question['obasetype'], $question['opostid']);

	if (@$options['contentview'] && !empty($question['ocontent'])) {
		$viewer = qa_load_viewer($question['ocontent'], $question['oformat']);

		$fields['content'] = $viewer->get_html($question['ocontent'], $question['oformat'], array(
			'blockwordspreg' => @$options['blockwordspreg'],
			'showurllinks' => @$options['showurllinks'],
			'linksnewwindow' => @$options['linksnewwindow'],
		));
	}

	if (@$options['whenview'])
		$fields['when'] = qa_when_to_html($question['otime'], @$options['fulldatedays']);

	if (@$options['whoview']) {
		$isbyuser = qa_post_is_by_user(array('userid' => $question['ouserid'], 'cookieid' => @$question['ocookieid']), $userid, $cookieid);

		$fields['who'] = qa_who_to_html($isbyuser, $question['ouserid'], $usershtml, @$options['ipview'] ? @inet_ntop(@$question['oip']) : null, false, @$question['oname']);
		if (isset($question['opoints'])) {
			if (@$options['pointsview'])
				$fields['who']['points'] = ($question['opoints'] == 1) ? qa_lang_html_sub_split('main/1_point', '1', '1')
					: qa_lang_html_sub_split('main/x_points', qa_format_number($question['opoints'], 0, true));

			if (isset($options['pointstitle']))
				$fields['who']['title'] = qa_get_points_title_html($question['opoints'], $options['pointstitle']);
		}

		if (isset($question['olevel']))
			$fields['who']['level'] = qa_html(qa_user_level_string($question['olevel']));
	}

	unset($fields['flags']);
	if (@$options['flagsview'] && @$question['oflagcount']) {
		$fields['flags'] = ($question['oflagcount'] == 1) ? qa_lang_html_sub_split('main/1_flag', '1', '1')
			: qa_lang_html_sub_split('main/x_flags', $question['oflagcount']);
	}

	unset($fields['avatar']);
	if (@$options['avatarsize'] > 0) {
		if (QA_FINAL_EXTERNAL_USERS)
			$fields['avatar'] = qa_get_external_avatar_html($question['ouserid'], $options['avatarsize'], false);
		else
			$fields['avatar'] = qa_get_user_avatar_html($question['oflags'], $question['oemail'], $question['ohandle'],
				$question['oavatarblobid'], $question['oavatarwidth'], $question['oavatarheight'], $options['avatarsize']);
	}

	return $fields;
}


/**
 * Based on the elements in $question, return HTML to be passed to theme layer to link
 * to the question, or to an associated answer, comment or edit.
 * @param $question
 * @param $userid
 * @param $cookieid
 * @param $usershtml
 * @param $dummy
 * @param $options
 * @return array
 */
function qa_any_to_q_html_fields($question, $userid, $cookieid, $usershtml, $dummy, $options)
{
	if (isset($question['opostid']))
		$fields = qa_other_to_q_html_fields($question, $userid, $cookieid, $usershtml, null, $options);
	else
		$fields = qa_post_html_fields($question, $userid, $cookieid, $usershtml, null, $options);

	return $fields;
}


/**
 * Each element in $questions represents a question and optional associated answer, comment or edit, as retrieved from database.
 * Return it sorted by the date appropriate for each element, without removing duplicate references to the same question.
 * @param $questions
 * @return mixed
 */
function qa_any_sort_by_date($questions)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'util/sort.php';

	foreach ($questions as $key => $question) // collect information about action referenced by each $question
		$questions[$key]['sort'] = -(isset($question['opostid']) ? $question['otime'] : $question['created']);

	qa_sort_by($questions, 'sort');

	return $questions;
}


/**
 * Each element in $questions represents a question and optional associated answer, comment or edit, as retrieved from database.
 * Return it sorted by the date appropriate for each element, and keep only the first item related to each question.
 * @param $questions
 * @return array
 */
function qa_any_sort_and_dedupe($questions)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'util/sort.php';

	foreach ($questions as $key => $question) { // collect information about action referenced by each $question
		if (isset($question['opostid'])) {
			$questions[$key]['_time'] = $question['otime'];
			$questions[$key]['_type'] = $question['obasetype'];
			$questions[$key]['_userid'] = @$question['ouserid'];
		} else {
			$questions[$key]['_time'] = $question['created'];
			$questions[$key]['_type'] = 'Q';
			$questions[$key]['_userid'] = $question['userid'];
		}

		$questions[$key]['sort'] = -$questions[$key]['_time'];
	}
	qa_sort_by($questions, 'sort');

	$keepquestions = array(); // now remove duplicate references to same question
	foreach ($questions as $question) { // going in order from most recent to oldest
		$laterquestion = @$keepquestions[$question['postid']];

		if (isset($laterquestion)) {
			// the two events were within 5 minutes of each other
			$close_events = abs($laterquestion['_time'] - $question['_time']) < 300;

			$later_edit =
				@$laterquestion['oupdatetype'] &&  // the more recent reference was an edit
				!@$question['oupdatetype'] &&  // this is not an edit
				$laterquestion['_type'] == $question['_type'] &&  // the same part (Q/A/C) is referenced here
				$laterquestion['_userid'] == $question['_userid'];  // the same user made the later edit

			// this question (in an update list) is personal to the user, but the other one was not
			$this_personal = @$question['opersonal'] && !@$laterquestion['opersonal'];

			if ($close_events && ($later_edit || $this_personal)) {
				// Remove any previous instance of the post to force a new position
				unset($keepquestions[$question['postid']]);
				$keepquestions[$question['postid']] = $question;
			}
		} else  // keep this reference if there is no more recent one
			$keepquestions[$question['postid']] = $question;
	}

	return $keepquestions;
}


/**
 * Each element in $questions represents a question and optional associated answer, comment or edit, as retrieved from database.
 * Return an array of elements (userid,handle) for the appropriate user for each element.
 * @param $questions
 * @return array
 */
function qa_any_get_userids_handles($questions)
{
	$userids_handles = array();

	foreach ($questions as $question) {
		if (isset($question['opostid'])) {
			$userids_handles[] = array(
				'userid' => @$question['ouserid'],
				'handle' => @$question['ohandle'],
			);
		} else {
			$userids_handles[] = array(
				'userid' => @$question['userid'],
				'handle' => @$question['handle'],
			);
		}
	}

	return $userids_handles;
}


/**
 * Return $html with any URLs converted into links (with nofollow and in a new window if $newwindow).
 * Closing parentheses/brackets are removed from the link if they don't have a matching opening one. This avoids creating
 * incorrect URLs from (http://www.question2answer.org) but allow URLs such as http://www.wikipedia.org/Computers_(Software)
 * @param $html
 * @param bool $newwindow
 * @return mixed
 */
function qa_html_convert_urls($html, $newwindow = false)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$uc = 'a-z\x{00a1}-\x{ffff}';
	$url_regex = '#\b((?:https?|ftp)://(?:[0-9' . $uc . '][0-9' . $uc . '-]*\.)+[' . $uc . ']{2,}(?::\d{2,5})?(?:/(?:[^\s<>]*[^\s<>\.])?)?)#iu';

	// get matches and their positions
	if (preg_match_all($url_regex, $html, $matches, PREG_OFFSET_CAPTURE)) {
		$brackets = array(
			')' => '(',
			'}' => '{',
			']' => '[',
		);

		// loop backwards so we substitute correctly
		for ($i = count($matches[1]) - 1; $i >= 0; $i--) {
			$match = $matches[1][$i];
			$text_url = $match[0];
			$removed = '';
			$lastch = substr($text_url, -1);

			// exclude bracket from link if no matching bracket
			while (array_key_exists($lastch, $brackets)) {
				$open_char = $brackets[$lastch];
				$num_open = substr_count($text_url, $open_char);
				$num_close = substr_count($text_url, $lastch);

				if ($num_close == $num_open + 1) {
					$text_url = substr($text_url, 0, -1);
					$removed = $lastch . $removed;
					$lastch = substr($text_url, -1);
				} else
					break;
			}

			$target = $newwindow ? ' target="_blank"' : '';
			$replace = '<a href="' . $text_url . '" rel="nofollow"' . $target . '>' . $text_url . '</a>' . $removed;
			$html = substr_replace($html, $replace, $match[1], strlen($match[0]));
		}
	}

	return $html;
}


/**
 * Return HTML representation of $url (if it appears to be an URL), linked with nofollow and in a new window if $newwindow
 * @param $url
 * @param bool $newwindow
 * @return mixed|string
 */
function qa_url_to_html_link($url, $newwindow = false)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	if (is_numeric(strpos($url, '.'))) {
		$linkurl = $url;
		if (!is_numeric(strpos($linkurl, ':/')))
			$linkurl = 'http://' . $linkurl;

		return '<a href="' . qa_html($linkurl) . '" rel="nofollow"' . ($newwindow ? ' target="_blank"' : '') . '>' . qa_html($url) . '</a>';

	} else
		return qa_html($url);
}


/**
 * Return $htmlmessage with ^1...^6 substituted for links to log in or register or confirm email and come back to $topage with $params
 * @param $htmlmessage
 * @param null $topage
 * @param null $params
 * @return string
 */
function qa_insert_login_links($htmlmessage, $topage = null, $params = null)
{
	require_once QA_INCLUDE_DIR . 'app/users.php';

	$userlinks = qa_get_login_links(qa_path_to_root(), isset($topage) ? qa_path($topage, $params, '') : null);

	return strtr(
		$htmlmessage,

		array(
			'^1' => empty($userlinks['login']) ? '' : '<a href="' . qa_html($userlinks['login']) . '">',
			'^2' => empty($userlinks['login']) ? '' : '</a>',
			'^3' => empty($userlinks['register']) ? '' : '<a href="' . qa_html($userlinks['register']) . '">',
			'^4' => empty($userlinks['register']) ? '' : '</a>',
			'^5' => empty($userlinks['confirm']) ? '' : '<a href="' . qa_html($userlinks['confirm']) . '">',
			'^6' => empty($userlinks['confirm']) ? '' : '</a>',
		)
	);
}


/**
 * Return structure to pass through to theme layer to show linked page numbers for $request.
 * Q2A uses offset-based paging, i.e. pages are referenced in the URL by a 'start' parameter.
 * $start is current offset, there are $pagesize items per page and $count items in total
 * (unless $hasmore is true in which case there are at least $count items).
 * Show links to $prevnext pages before and after this one and include $params in the URLs.
 * @param $request
 * @param $start
 * @param $pagesize
 * @param $count
 * @param $prevnext
 * @param array $params
 * @param bool $hasmore
 * @param null $anchor
 * @return array|null
 */
function qa_html_page_links($request, $start, $pagesize, $count, $prevnext, $params = array(), $hasmore = false, $anchor = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$thispage = 1 + floor($start / $pagesize);
	$lastpage = ceil(min((int)$count, 1 + QA_MAX_LIMIT_START) / $pagesize);

	if ($thispage > 1 || $lastpage > $thispage) {
		$links = array('label' => qa_lang_html('main/page_label'), 'items' => array());

		$keypages[1] = true;

		for ($page = max(2, min($thispage, $lastpage) - $prevnext); $page <= min($thispage + $prevnext, $lastpage); $page++)
			$keypages[$page] = true;

		$keypages[$lastpage] = true;

		if ($thispage > 1) {
			$links['items'][] = array(
				'type' => 'prev',
				'label' => qa_lang_html('main/page_prev'),
				'page' => $thispage - 1,
				'ellipsis' => false,
			);
		}

		foreach (array_keys($keypages) as $page) {
			$links['items'][] = array(
				'type' => ($page == $thispage) ? 'this' : 'jump',
				'label' => $page,
				'page' => $page,
				'ellipsis' => (($page < $lastpage) || $hasmore) && (!isset($keypages[$page + 1])),
			);
		}

		if ($thispage < $lastpage) {
			$links['items'][] = array(
				'type' => 'next',
				'label' => qa_lang_html('main/page_next'),
				'page' => $thispage + 1,
				'ellipsis' => false,
			);
		}

		foreach ($links['items'] as $key => $link) {
			if ($link['page'] != $thispage) {
				$params['start'] = $pagesize * ($link['page'] - 1);
				$links['items'][$key]['url'] = qa_path_html($request, $params, null, null, $anchor);
			}
		}

	} else
		$links = null;

	return $links;
}


/**
 * Return HTML that suggests browsing all questions (in the category specified by $categoryrequest, if
 * it's not null) and also popular tags if $usingtags is true
 * @param bool $usingtags
 * @param null $categoryrequest
 * @return mixed|string
 */
function qa_html_suggest_qs_tags($usingtags = false, $categoryrequest = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$hascategory = strlen($categoryrequest);

	$htmlmessage = $hascategory ? qa_lang_html('main/suggest_category_qs') :
		($usingtags ? qa_lang_html('main/suggest_qs_tags') : qa_lang_html('main/suggest_qs'));

	return strtr(
		$htmlmessage,

		array(
			'^1' => '<a href="' . qa_path_html('questions' . ($hascategory ? ('/' . $categoryrequest) : '')) . '">',
			'^2' => '</a>',
			'^3' => '<a href="' . qa_path_html('tags') . '">',
			'^4' => '</a>',
		)
	);
}


/**
 * Return HTML that suggest getting things started by asking a question, in $categoryid if not null
 * @param null $categoryid
 * @return mixed|string
 */
function qa_html_suggest_ask($categoryid = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$htmlmessage = qa_lang_html('main/suggest_ask');

	return strtr(
		$htmlmessage,

		array(
			'^1' => '<a href="' . qa_path_html('ask', strlen($categoryid) ? array('cat' => $categoryid) : null) . '">',
			'^2' => '</a>',
		)
	);
}


/**
 * Return the navigation structure for the category hierarchical menu, with $selectedid selected,
 * and links beginning with $pathprefix, and showing question counts if $showqcount
 * @param $categories
 * @param null $selectedid
 * @param string $pathprefix
 * @param bool $showqcount
 * @param null $pathparams
 * @return array|mixed
 */
function qa_category_navigation($categories, $selectedid = null, $pathprefix = '', $showqcount = true, $pathparams = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$parentcategories = array();

	foreach ($categories as $category)
		$parentcategories[$category['parentid']][] = $category;

	$selecteds = qa_category_path($categories, $selectedid);
	$favoritemap = qa_get_favorite_non_qs_map();

	return qa_category_navigation_sub($parentcategories, null, $selecteds, $pathprefix, $showqcount, $pathparams, $favoritemap);
}


/**
 * Recursion function used by qa_category_navigation(...) to build hierarchical category menu.
 * @param $parentcategories
 * @param $parentid
 * @param $selecteds
 * @param $pathprefix
 * @param $showqcount
 * @param $pathparams
 * @param null $favoritemap
 * @return array|mixed
 */
function qa_category_navigation_sub($parentcategories, $parentid, $selecteds, $pathprefix, $showqcount, $pathparams, $favoritemap = null)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$navigation = array();

	if (!isset($parentid)) {
		$navigation['all'] = array(
			'url' => qa_path_html($pathprefix, $pathparams),
			'label' => qa_lang_html('main/all_categories'),
			'selected' => !count($selecteds),
			'categoryid' => null,
		);
	}

	if (isset($parentcategories[$parentid])) {
		foreach ($parentcategories[$parentid] as $category) {
			$navigation[qa_html($category['tags'])] = array(
				'url' => qa_path_html($pathprefix . $category['tags'], $pathparams),
				'label' => qa_html($category['title']),
				'popup' => qa_html(@$category['content']),
				'selected' => isset($selecteds[$category['categoryid']]),
				'note' => $showqcount ? ('(' . qa_html(qa_format_number($category['qcount'], 0, true)) . ')') : null,
				'subnav' => qa_category_navigation_sub($parentcategories, $category['categoryid'], $selecteds,
					$pathprefix . $category['tags'] . '/', $showqcount, $pathparams, $favoritemap),
				'categoryid' => $category['categoryid'],
				'favorited' => @$favoritemap['category'][$category['backpath']],
			);
		}
	}

	return $navigation;
}


/**
 * Return the sub navigation structure for user listing pages
 */
function qa_users_sub_navigation()
{
	if (QA_FINAL_EXTERNAL_USERS) {
		return null;
	}

	$menuItems = array();

	$moderatorPlus = qa_get_logged_in_level() >= QA_USER_LEVEL_MODERATOR;
	$showNewUsersPage = !qa_user_permit_error('permit_view_new_users_page');
	$showSpecialUsersPage = !qa_user_permit_error('permit_view_special_users_page');

	if ($moderatorPlus || $showNewUsersPage || $showSpecialUsersPage) {
		// We want to show this item when more than one item should be displayed
		$menuItems['users$'] = array(
			'label' => qa_lang_html('main/highest_users'),
			'url' => qa_path_html('users'),
		);
	}

	if ($showNewUsersPage) {
		$menuItems['users/new'] = array(
			'label' => qa_lang_html('main/newest_users'),
			'url' => qa_path_html('users/new'),
		);
	}

	if ($showSpecialUsersPage) {
		$menuItems['users/special'] = array(
			'label' => qa_lang('users/special_users'),
			'url' => qa_path_html('users/special'),
		);
	}

	if ($moderatorPlus) {
		$menuItems['users/blocked'] = array(
			'label' => qa_lang('users/blocked_users'),
			'url' => qa_path_html('users/blocked'),
		);
	}

	return $menuItems;
}


/**
 * Return the sub navigation structure for navigating between the different pages relating to a user
 * @param $handle
 * @param $selected
 * @param bool $ismyuser
 * @return array
 */
function qa_user_sub_navigation($handle, $selected, $ismyuser = false)
{
	$navigation = array(
		'profile' => array(
			'label' => qa_lang_html_sub('profile/user_x', qa_html($handle)),
			'url' => qa_path_html('user/' . $handle),
		),

		'account' => array(
			'label' => qa_lang_html('misc/nav_my_details'),
			'url' => qa_path_html('account'),
		),

		'favorites' => array(
			'label' => qa_lang_html('misc/nav_my_favorites'),
			'url' => qa_path_html('favorites'),
		),

		'wall' => array(
			'label' => qa_lang_html('misc/nav_user_wall'),
			'url' => qa_path_html('user/' . $handle . '/wall'),
		),

		'messages' => array(
			'label' => qa_lang_html('misc/nav_user_pms'),
			'url' => qa_path_html('messages'),
		),

		'activity' => array(
			'label' => qa_lang_html('misc/nav_user_activity'),
			'url' => qa_path_html('user/' . $handle . '/activity'),
		),

		'questions' => array(
			'label' => qa_lang_html('misc/nav_user_qs'),
			'url' => qa_path_html('user/' . $handle . '/questions'),
		),

		'answers' => array(
			'label' => qa_lang_html('misc/nav_user_as'),
			'url' => qa_path_html('user/' . $handle . '/answers'),
		),
	);

	if (isset($navigation[$selected]))
		$navigation[$selected]['selected'] = true;

	if (QA_FINAL_EXTERNAL_USERS || !qa_opt('allow_user_walls'))
		unset($navigation['wall']);

	if (QA_FINAL_EXTERNAL_USERS || !$ismyuser)
		unset($navigation['account']);

	if (!$ismyuser)
		unset($navigation['favorites']);

	if (QA_FINAL_EXTERNAL_USERS || !$ismyuser || !qa_opt('allow_private_messages') || !qa_opt('show_message_history'))
		unset($navigation['messages']);

	return $navigation;
}


/**
 * Return the sub navigation structure for private message pages
 * @deprecated 1.8.0 This menu is no longer used.
 * @param null $selected
 * @return array
 */
function qa_messages_sub_navigation($selected = null)
{
	$navigation = array(
		'inbox' => array(
			'label' => qa_lang_html('misc/inbox'),
			'url' => qa_path_html('messages'),
		),

		'outbox' => array(
			'label' => qa_lang_html('misc/outbox'),
			'url' => qa_path_html('messages/sent'),
		),
	);

	if (isset($navigation[$selected]))
		$navigation[$selected]['selected'] = true;

	return $navigation;
}


/**
 * Return the sub navigation structure for user account pages.
 *
 * @deprecated Deprecated from 1.6.3; use `qa_user_sub_navigation()` instead.
 */
function qa_account_sub_navigation()
{
	return array(
		'account' => array(
			'label' => qa_lang_html('misc/nav_my_details'),
			'url' => qa_path_html('account'),
		),

		'favorites' => array(
			'label' => qa_lang_html('misc/nav_my_favorites'),
			'url' => qa_path_html('favorites'),
		),
	);
}


/**
 * Return the url for $page retrieved from the database
 * @param $page
 * @return string
 */
function qa_custom_page_url($page)
{
	return ($page['flags'] & QA_PAGE_FLAGS_EXTERNAL)
		? (is_numeric(strpos($page['tags'], '://')) ? $page['tags'] : qa_path_to_root() . $page['tags'])
		: qa_path($page['tags']);
}


/**
 * Add an element to the $navigation array corresponding to $page retrieved from the database
 * @param $navigation
 * @param $page
 */
function qa_navigation_add_page(&$navigation, $page)
{
	if (!isset($page['permit']) || !qa_permit_value_error($page['permit'], qa_get_logged_in_userid(), qa_get_logged_in_level(), qa_get_logged_in_flags())) {
		$url = qa_custom_page_url($page);

		$navigation[($page['flags'] & QA_PAGE_FLAGS_EXTERNAL) ? ('custom-' . $page['pageid']) : ($page['tags'] . '$')] = array(
			'url' => qa_html($url),
			'label' => qa_html($page['title']),
			'opposite' => ($page['nav'] == 'O'),
			'target' => ($page['flags'] & QA_PAGE_FLAGS_NEW_WINDOW) ? '_blank' : null,
			'selected' => ($page['flags'] & QA_PAGE_FLAGS_EXTERNAL) && (($url == qa_path(qa_request())) || ($url == qa_self_html())),
		);
	}
}


/**
 * Convert an admin option for matching into a threshold for the score given by database search
 * @param $match
 * @return int
 */
function qa_match_to_min_score($match)
{
	return 10 - 2 * $match;
}


/**
 * Adds JavaScript to the page to handle toggling of form fields based on other fields.
 *
 * @param array $qa_content  Page content array.
 * @param array $effects  List of rules for element toggling, with the structure:
 *   array('target1' => 'source1', 'target2' => 'source2', ...)
 *   When the source expression is true, the DOM element ID represented by target is shown. The
 *   source can be a combination of ID as a JS expression.
 */
function qa_set_display_rules(&$qa_content, $effects)
{
	$keysourceids = array();
	$jsVarRegex = '/[A-Za-z_][A-Za-z0-9_]*/';

	// extract all JS variable names in all sources
	foreach ($effects as $target => $sources) {
		if (preg_match_all($jsVarRegex, $sources, $matches)) {
			foreach ($matches[0] as $element) {
				if (!in_array($element, $keysourceids))
					$keysourceids[] = $element;
			}
		}
	}

	$funcOrd = isset($qa_content['script_lines']) ? count($qa_content['script_lines']) : 0;
	$function = "qa_display_rule_$funcOrd";
	$optVar = "qa_optids_$funcOrd";

	// set up variables
	$funcscript = array("var $optVar = " . json_encode($keysourceids) . ";");

	// check and set all display rules
	$funcscript[] = "function {$function}(first) {";
	$funcscript[] = "\tvar opts = {};";
	$funcscript[] = "\tfor (var i = 0; i < {$optVar}.length; i++) {";
	$funcscript[] = "\t\tvar e = document.getElementById({$optVar}[i]);";
	$funcscript[] = "\t\topts[{$optVar}[i]] = e && (e.checked || (e.options && e.options[e.selectedIndex].value));";
	$funcscript[] = "\t}";
	foreach ($effects as $target => $sources) {
		$sourcesobj = preg_replace($jsVarRegex, 'opts.$0', $sources);
		$funcscript[] = "\tqa_display_rule_show(" . qa_js($target) . ", (" . $sourcesobj . "), first);";
	}
	$funcscript[] = "}";

	// set default state of options
	$loadscript = array(
		"for (var i = 0; i < {$optVar}.length; i++) {",
		"\t$('#'+{$optVar}[i]).change(function() { " . $function . "(false); });",
		"}",
		"{$function}(true);",
	);

	$qa_content['script_lines'][] = $funcscript;
	$qa_content['script_onloads'][] = $loadscript;
}


/**
 * Set up $qa_content and $field (with HTML name $fieldname) for tag auto-completion, where
 * $exampletags are suggestions and $completetags are simply the most popular ones. Show up to $maxtags.
 * @param $qa_content
 * @param $field
 * @param $fieldname
 * @param $tags
 * @param $exampletags
 * @param $completetags
 * @param $maxtags
 */
function qa_set_up_tag_field(&$qa_content, &$field, $fieldname, $tags, $exampletags, $completetags, $maxtags)
{
	$template = '<a href="#" class="qa-tag-link" onclick="return qa_tag_click(this);">^</a>';

	$qa_content['script_var']['qa_tag_template'] = $template;
	$qa_content['script_var']['qa_tag_onlycomma'] = (int)qa_opt('tag_separator_comma');
	$qa_content['script_var']['qa_tags_examples'] = qa_html(implode(',', $exampletags));
	$qa_content['script_var']['qa_tags_complete'] = qa_html(implode(',', $completetags));
	$qa_content['script_var']['qa_tags_max'] = (int)$maxtags;

	$separatorcomma = qa_opt('tag_separator_comma');

	$field['label'] = qa_lang_html($separatorcomma ? 'question/q_tags_comma_label' : 'question/q_tags_label');
	$field['value'] = qa_html(implode($separatorcomma ? ', ' : ' ', $tags));
	$field['tags'] = 'name="' . $fieldname . '" id="tags" autocomplete="off" onkeyup="qa_tag_hints();" onmouseup="qa_tag_hints();"';

	$sdn = ' style="display:none;"';

	$field['note'] =
		'<span id="tag_examples_title"' . (count($exampletags) ? '' : $sdn) . '>' . qa_lang_html('question/example_tags') . '</span>' .
		'<span id="tag_complete_title"' . $sdn . '>' . qa_lang_html('question/matching_tags') . '</span><span id="tag_hints">';

	foreach ($exampletags as $tag)
		$field['note'] .= str_replace('^', qa_html($tag), $template) . ' ';

	$field['note'] .= '</span>';
	$field['note_force'] = true;
}


/**
 * Get a list of user-entered tags submitted from a field that was created with qa_set_up_tag_field(...)
 * @param $fieldname
 * @return array
 */
function qa_get_tags_field_value($fieldname)
{
	require_once QA_INCLUDE_DIR . 'util/string.php';

	$text = qa_remove_utf8mb4(qa_post_text($fieldname));

	if (qa_opt('tag_separator_comma'))
		return array_unique(preg_split('/\s*,\s*/', trim(qa_strtolower(strtr($text, '/', ' '))), -1, PREG_SPLIT_NO_EMPTY));
	else
		return array_unique(qa_string_to_words($text, true, false, false, false));
}


/**
 * Set up $qa_content and $field (with HTML name $fieldname) for hierarchical category navigation, with the initial value
 * set to $categoryid (and $navcategories retrieved for $categoryid using qa_db_category_nav_selectspec(...)).
 * If $allownone is true, it will allow selection of no category. If $allownosub is true, it will allow a category to be
 * selected without selecting a subcategory within. Set $maxdepth to the maximum depth of category that can be selected
 * (or null for no maximum) and $excludecategoryid to a category that should not be included.
 * @param $qa_content
 * @param $field
 * @param $fieldname
 * @param $navcategories
 * @param $categoryid
 * @param $allownone
 * @param $allownosub
 * @param null $maxdepth
 * @param null $excludecategoryid
 */
function qa_set_up_category_field(&$qa_content, &$field, $fieldname, $navcategories, $categoryid, $allownone, $allownosub, $maxdepth = null, $excludecategoryid = null)
{
	$pathcategories = qa_category_path($navcategories, $categoryid);

	$startpath = '';
	foreach ($pathcategories as $category)
		$startpath .= '/' . $category['categoryid'];

	if (isset($maxdepth))
		$maxdepth = min(QA_CATEGORY_DEPTH, $maxdepth);
	else
		$maxdepth = QA_CATEGORY_DEPTH;

	$qa_content['script_onloads'][] = sprintf('qa_category_select(%s, %s);', qa_js($fieldname), qa_js($startpath));

	$qa_content['script_var']['qa_cat_exclude'] = $excludecategoryid;
	$qa_content['script_var']['qa_cat_allownone'] = (int)$allownone;
	$qa_content['script_var']['qa_cat_allownosub'] = (int)$allownosub;
	$qa_content['script_var']['qa_cat_maxdepth'] = $maxdepth;

	$field['type'] = 'select';
	$field['tags'] = sprintf('name="%s_0" id="%s_0" onchange="qa_category_select(%s);"', $fieldname, $fieldname, qa_js($fieldname));
	$field['options'] = array();

	// create the menu that will be shown if Javascript is disabled

	if ($allownone)
		$field['options'][''] = qa_lang_html('main/no_category'); // this is also copied to first menu created by Javascript

	$keycategoryids = array();

	if ($allownosub) {
		$category = @$navcategories[$categoryid];

		$upcategory = @$navcategories[$category['parentid']]; // first get supercategories
		while (isset($upcategory)) {
			$keycategoryids[$upcategory['categoryid']] = true;
			$upcategory = @$navcategories[$upcategory['parentid']];
		}

		$keycategoryids = array_reverse($keycategoryids, true);

		$depth = count($keycategoryids); // number of levels above

		if (isset($category)) {
			$depth++; // to count category itself

			foreach ($navcategories as $navcategory) // now get siblings and self
				if (!strcmp($navcategory['parentid'], $category['parentid']))
					$keycategoryids[$navcategory['categoryid']] = true;
		}

		if ($depth < $maxdepth)
			foreach ($navcategories as $navcategory) // now get children, if not too deep
				if (!strcmp($navcategory['parentid'], $categoryid))
					$keycategoryids[$navcategory['categoryid']] = true;

	} else {
		$haschildren = false;

		foreach ($navcategories as $navcategory) {
			// check if it has any children
			if (!strcmp($navcategory['parentid'], $categoryid)) {
				$haschildren = true;
				break;
			}
		}

		if (!$haschildren)
			$keycategoryids[$categoryid] = true; // show this category if it has no children
	}

	foreach ($keycategoryids as $keycategoryid => $dummy)
		if (strcmp($keycategoryid, $excludecategoryid))
			$field['options'][$keycategoryid] = qa_category_path_html($navcategories, $keycategoryid);

	$field['value'] = @$field['options'][$categoryid];
	$field['note'] =
		'<div id="' . $fieldname . '_note">' .
		'<noscript style="color:red;">' . qa_lang_html('question/category_js_note') . '</noscript>' .
		'</div>';
}


/**
 * Get the user-entered category id submitted from a field that was created with qa_set_up_category_field(...)
 * @param $fieldname
 * @return mixed|null
 */
function qa_get_category_field_value($fieldname)
{
	for ($level = QA_CATEGORY_DEPTH; $level >= 1; $level--) {
		$levelid = qa_post_text($fieldname . '_' . $level);
		if (strlen($levelid))
			return $levelid;
	}

	if (!isset($levelid)) { // no Javascript-generated menu was present so take original menu
		$levelid = qa_post_text($fieldname . '_0');
		if (strlen($levelid))
			return $levelid;
	}

	return null;
}


/**
 * Set up $qa_content and add to $fields to allow the user to enter their name for a post if they are not logged in
 * $inname is from previous submission/validation. Pass $fieldprefix to add a prefix to the form field name used.
 * @param $qa_content
 * @param $fields
 * @param $inname
 * @param string $fieldprefix
 */
function qa_set_up_name_field(&$qa_content, &$fields, $inname, $fieldprefix = '')
{
	$fields['name'] = array(
		'label' => qa_lang_html('question/anon_name_label'),
		'tags' => 'name="' . $fieldprefix . 'name"',
		'value' => qa_html($inname),
	);
}


/**
 * Set up $qa_content and add to $fields to allow user to set if they want to be notified regarding their post.
 * $basetype is 'Q', 'A' or 'C' for question, answer or comment. $login_email is the email of logged in user,
 * or null if this is an anonymous post. $innotify, $inemail and $errors_email are from previous submission/validation.
 * Pass $fieldprefix to add a prefix to the form field names and IDs used.
 * @param $qa_content
 * @param $fields
 * @param $basetype
 * @param $login_email
 * @param $innotify
 * @param $inemail
 * @param $errors_email
 * @param string $fieldprefix
 */
function qa_set_up_notify_fields(&$qa_content, &$fields, $basetype, $login_email, $innotify, $inemail, $errors_email, $fieldprefix = '')
{
	$fields['notify'] = array(
		'tags' => 'name="' . $fieldprefix . 'notify"',
		'type' => 'checkbox',
		'value' => qa_html($innotify),
	);

	switch ($basetype) {
		case 'Q':
			$labelaskemail = qa_lang_html('question/q_notify_email');
			$labelonly = qa_lang_html('question/q_notify_label');
			$labelgotemail = qa_lang_html('question/q_notify_x_label');
			break;

		case 'A':
			$labelaskemail = qa_lang_html('question/a_notify_email');
			$labelonly = qa_lang_html('question/a_notify_label');
			$labelgotemail = qa_lang_html('question/a_notify_x_label');
			break;

		case 'C':
			$labelaskemail = qa_lang_html('question/c_notify_email');
			$labelonly = qa_lang_html('question/c_notify_label');
			$labelgotemail = qa_lang_html('question/c_notify_x_label');
			break;
	}

	if (empty($login_email)) {
		$fields['notify']['label'] =
			'<span id="' . $fieldprefix . 'email_shown">' . $labelaskemail . '</span>' .
			'<span id="' . $fieldprefix . 'email_hidden" style="display:none;">' . $labelonly . '</span>';

		$fields['notify']['tags'] .= ' id="' . $fieldprefix . 'notify" onclick="if (document.getElementById(\'' . $fieldprefix . 'notify\').checked) document.getElementById(\'' . $fieldprefix . 'email\').focus();"';
		$fields['notify']['tight'] = true;

		$fields['email'] = array(
			'id' => $fieldprefix . 'email_display',
			'tags' => 'name="' . $fieldprefix . 'email" id="' . $fieldprefix . 'email"',
			'value' => qa_html($inemail),
			'note' => qa_lang_html('question/notify_email_note'),
			'error' => qa_html($errors_email),
		);

		qa_set_display_rules($qa_content, array(
			$fieldprefix . 'email_display' => $fieldprefix . 'notify',
			$fieldprefix . 'email_shown' => $fieldprefix . 'notify',
			$fieldprefix . 'email_hidden' => '!' . $fieldprefix . 'notify',
		));

	} else {
		$fields['notify']['label'] = str_replace('^', qa_html($login_email), $labelgotemail);
	}
}


/**
 * Return the theme that should be used for displaying the page
 * @return string
 */
function qa_get_site_theme()
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	return qa_opt(qa_is_mobile_probably() ? 'site_theme_mobile' : 'site_theme');
}


/**
 * Return the initialized class for $theme (or the default if it's gone), passing $template, $content and $request.
 * Also applies any registered plugin layers.
 * @param $theme
 * @param $template
 * @param $content
 * @param $request
 * @return qa_html_theme_base
 */
function qa_load_theme_class($theme, $template, $content, $request)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	global $qa_layers;

	// First load the default class

	require_once QA_INCLUDE_DIR . 'qa-theme-base.php';

	$classname = 'qa_html_theme_base';

	// Then load the selected theme if valid, otherwise load the Classic theme

	if (!file_exists(QA_THEME_DIR . $theme . '/qa-styles.css'))
		$theme = 'Classic';

	$themeroothtml = qa_html(qa_path_to_root() . 'qa-theme/' . $theme . '/');

	if (file_exists(QA_THEME_DIR . $theme . '/qa-theme.php')) {
		require_once QA_THEME_DIR . $theme . '/qa-theme.php';

		if (class_exists('qa_html_theme'))
			$classname = 'qa_html_theme';
	}

	// Create the list of layers to load

	$loadlayers = $qa_layers;

	if (!qa_user_maximum_permit_error('permit_view_voters_flaggers')) {
		$loadlayers[] = array(
			'directory' => QA_INCLUDE_DIR . 'plugins/',
			'include' => 'qa-layer-voters-flaggers.php',
			'urltoroot' => null,
		);
	}

	// Then load any theme layers using some class-munging magic (substitute class names)

	$layerindex = 0;

	foreach ($loadlayers as $layer) {
		$filename = $layer['directory'] . $layer['include'];
		$layerphp = file_get_contents($filename);

		if (strlen($layerphp)) {
			// include file name in layer class name to make debugging easier if there is an error
			$newclassname = 'qa_layer_' . (++$layerindex) . '_from_' . preg_replace('/[^A-Za-z0-9_]+/', '_', basename($layer['include']));

			if (preg_match('/\s+class\s+qa_html_theme_layer\s+extends\s+qa_html_theme_base\s+/im', $layerphp) != 1)
				qa_fatal_error('Class for layer must be declared as "class qa_html_theme_layer extends qa_html_theme_base" in ' . $layer['directory'] . $layer['include']);

			$searchwordreplace = array(
				'qa_html_theme_base::qa_html_theme_base' => $classname . '::__construct', // PHP5 constructor fix
				'parent::qa_html_theme_base' => 'parent::__construct', // PHP5 constructor fix
				'qa_html_theme_layer' => $newclassname,
				'qa_html_theme_base' => $classname,
				'QA_HTML_THEME_LAYER_DIRECTORY' => "'" . $layer['directory'] . "'",
				'QA_HTML_THEME_LAYER_URLTOROOT' => "'" . qa_path_to_root() . $layer['urltoroot'] . "'",
			);

			foreach ($searchwordreplace as $searchword => $replace) {
				if (preg_match_all('/\W(' . preg_quote($searchword, '/') . ')\W/im', $layerphp, $matches, PREG_PATTERN_ORDER | PREG_OFFSET_CAPTURE)) {
					$searchmatches = array_reverse($matches[1]); // don't use preg_replace due to complication of escaping replacement phrase

					foreach ($searchmatches as $searchmatch)
						$layerphp = substr_replace($layerphp, $replace, $searchmatch[1], strlen($searchmatch[0]));
				}
			}

			// echo '<pre style="text-align:left;">'.htmlspecialchars($layerphp).'</pre>'; // to debug munged code

			qa_eval_from_file($layerphp, $filename);

			$classname = $newclassname;
		}
	}

	// Finally, instantiate the object

	$themeclass = new $classname($template, $content, $themeroothtml, $request);

	return $themeclass;
}


/**
 * Return an instantiation of the appropriate editor module class, given $content in $format
 * Pass the preferred module name in $editorname, on return it will contain the name of the module used.
 * @param $content string
 * @param $format string
 * @param $editorname string
 * @return object
 */
function qa_load_editor($content, $format, &$editorname)
{
	$maxeditor = qa_load_module('editor', $editorname); // take preferred one first

	if (isset($maxeditor) && method_exists($maxeditor, 'calc_quality')) {
		$maxquality = $maxeditor->calc_quality($content, $format);
		if ($maxquality >= 0.5)
			return $maxeditor;

	} else
		$maxquality = 0;

	$editormodules = qa_load_modules_with('editor', 'calc_quality');
	foreach ($editormodules as $tryname => $tryeditor) {
		$tryquality = $tryeditor->calc_quality($content, $format);

		if ($tryquality > $maxquality) {
			$maxeditor = $tryeditor;
			$maxquality = $tryquality;
			$editorname = $tryname;
		}
	}

	return $maxeditor;
}


/**
 * Return a form field from the $editor module while making necessary modifications to $qa_content. The parameters
 * $content, $format, $fieldname, $rows and $focusnow are passed through to the module's get_field() method. ($focusnow
 * is deprecated as a parameter to get_field() but it's still passed through for old editor modules.) Based on
 * $focusnow and $loadnow, also add the editor's load and/or focus scripts to $qa_content's onload handlers.
 * @param $editor object
 * @param array $qa_content
 * @param string $content
 * @param string $format
 * @param string $fieldname
 * @param int $rows
 * @param bool $focusnow
 * @param bool $loadnow
 * @return string|array
 */
function qa_editor_load_field($editor, &$qa_content, $content, $format, $fieldname, $rows, $focusnow = false, $loadnow = true)
{
	if (!isset($editor))
		qa_fatal_error('No editor found for format: ' . $format);

	$field = $editor->get_field($qa_content, $content, $format, $fieldname, $rows, $focusnow);

	$onloads = array();

	if ($loadnow && method_exists($editor, 'load_script'))
		$onloads[] = $editor->load_script($fieldname);

	if ($focusnow && method_exists($editor, 'focus_script'))
		$onloads[] = $editor->focus_script($fieldname);

	if (count($onloads))
		$qa_content['script_onloads'][] = $onloads;

	return $field;
}


/**
 * Return an instantiation of the appropriate viewer module class, given $content in $format
 * @param string $content
 * @param string $format
 * @return object
 */
function qa_load_viewer($content, $format)
{
	$maxviewer = null;
	$maxquality = 0;

	$viewermodules = qa_load_modules_with('viewer', 'calc_quality');

	foreach ($viewermodules as $tryviewer) {
		$tryquality = $tryviewer->calc_quality($content, $format);

		if ($tryquality > $maxquality) {
			$maxviewer = $tryviewer;
			$maxquality = $tryquality;
		}
	}

	return $maxviewer;
}


/**
 * Return the plain text rendering of $content in $format, passing $options to the appropriate module
 * @param string $content
 * @param string $format
 * @param array $options
 * @return string
 */
function qa_viewer_text($content, $format, $options = array())
{
	$viewer = qa_load_viewer($content, $format);
	return $viewer->get_text($content, $format, $options);
}


/**
 * Return the HTML rendering of $content in $format, passing $options to the appropriate module
 * @param string $content
 * @param string $format
 * @param array $options
 * @return string
 */
function qa_viewer_html($content, $format, $options = array())
{
	$viewer = qa_load_viewer($content, $format);
	return $viewer->get_html($content, $format, $options);
}

/**
 * Retrieve title from HTTP POST, appropriately sanitised.
 * @param string $fieldname
 * @return string
 */
function qa_get_post_title($fieldname)
{
	require_once QA_INCLUDE_DIR . 'util/string.php';

	return qa_remove_utf8mb4(qa_post_text($fieldname));
}

/**
 * Retrieve the POST from an editor module's HTML field named $contentfield, where the editor's name was in HTML field $editorfield
 * Assigns the module's output to $incontent and $informat, editor's name in $ineditor, text rendering of content in $intext
 * @param $editorfield
 * @param $contentfield
 * @param $ineditor
 * @param $incontent
 * @param $informat
 * @param $intext
 */
function qa_get_post_content($editorfield, $contentfield, &$ineditor, &$incontent, &$informat, &$intext)
{
	require_once QA_INCLUDE_DIR . 'util/string.php';

	$ineditor = qa_post_text($editorfield);
	$editor = qa_load_module('editor', $ineditor);
	$readdata = $editor->read_post($contentfield);

	// sanitise 4-byte Unicode
	$incontent = qa_remove_utf8mb4($readdata['content']);
	$informat = $readdata['format'];
	$intext = qa_remove_utf8mb4(qa_viewer_text($incontent, $informat));
}


/**
 * Check if any of the 'content', 'format' or 'text' elements have changed between $oldfields and $fields
 * If so, recalculate $fields['text'] based on $fields['content'] and $fields['format']
 * @param $fields
 * @param $oldfields
 */
function qa_update_post_text(&$fields, $oldfields)
{
	if (strcmp($oldfields['content'], $fields['content']) ||
		strcmp($oldfields['format'], $fields['format']) ||
		strcmp($oldfields['text'], $fields['text'])
	) {
		$fields['text'] = qa_viewer_text($fields['content'], $fields['format']);
	}
}


/**
 * Return the <img...> HTML to display avatar $blobid whose stored size is $width and $height
 * Constrain the image to $size (width AND height) and pad it to that size if $padding is true
 * @param $blobId
 * @param $width
 * @param $height
 * @param $size
 * @param bool $padding
 * @return null|string
 */
function qa_get_avatar_blob_html($blobId, $width, $height, $size, $padding = false)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'util/image.php';
	require_once QA_INCLUDE_DIR . 'app/users.php';

	if (strlen($blobId) == 0 || (int)$size <= 0) {
		return null;
	}

	$avatarLink = qa_html(qa_get_avatar_blob_url($blobId, $size));

	qa_image_constrain($width, $height, $size);

	$params = array(
		$avatarLink,
		$width && $height ? sprintf(' width="%d" height="%d"', $width, $height) : '',
	);

	$html = vsprintf('<img src="%s"%s class="qa-avatar-image" alt=""/>', $params);

	if ($padding && $width && $height) {
		$padleft = floor(($size - $width) / 2);
		$padright = $size - $width - $padleft;
		$padtop = floor(($size - $height) / 2);
		$padbottom = $size - $height - $padtop;
		$html = sprintf('<span style="display:inline-block; padding:%dpx %dpx %dpx %dpx;">%s</span>', $padtop, $padright, $padbottom, $padleft, $html);
	}

	return $html;
}


/**
 * Return the <img...> HTML to display the Gravatar for $email, constrained to $size
 * @param $email
 * @param $size
 * @return mixed|null|string
 */
function qa_get_gravatar_html($email, $size)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	require_once QA_INCLUDE_DIR . 'app/users.php';

	$avatarLink = qa_html(qa_get_gravatar_url($email, $size));

	$size = (int)$size;
	if ($size > 0) {
		return sprintf('<img src="%s" width="%d" height="%d" class="qa-avatar-image" alt="" />', $avatarLink, $size, $size);
	} else {
		return null;
	}
}


/**
 * Retrieve the appropriate user title from $pointstitle for a user with $userpoints points, or null if none
 * @param $userpoints
 * @param $pointstitle
 * @return null
 */
function qa_get_points_title_html($userpoints, $pointstitle)
{
	foreach ($pointstitle as $points => $title) {
		if ($userpoints >= $points)
			return $title;
	}

	return null;
}


/**
 * Return an form to add to the $qa_content['notices'] array for displaying a user notice with id $noticeid
 * and $content. Pass the raw database information for the notice in $rawnotice.
 * @param $noticeid
 * @param $content
 * @param null $rawnotice
 * @return array
 */
function qa_notice_form($noticeid, $content, $rawnotice = null)
{
	$elementid = 'notice_' . $noticeid;

	return array(
		'id' => qa_html($elementid),
		'raw' => $rawnotice,
		'form_tags' => 'method="post" action="' . qa_self_html() . '"',
		'form_hidden' => array('code' => qa_get_form_security_code('notice-' . $noticeid)),
		'close_tags' => 'name="' . qa_html($elementid) . '" onclick="return qa_notice_click(this);"',
		'content' => $content,
	);
}


/**
 * Return a form to set in $qa_content['favorite'] for the favoriting button for entity $entitytype with $entityid.
 * Set $favorite to whether the entity is currently a favorite and a description title for the button in $title.
 * @param $entitytype
 * @param $entityid
 * @param $favorite
 * @param $title
 * @return array
 */
function qa_favorite_form($entitytype, $entityid, $favorite, $title)
{
	return array(
		'form_tags' => 'method="post" action="' . qa_self_html() . '"',
		'form_hidden' => array('code' => qa_get_form_security_code('favorite-' . $entitytype . '-' . $entityid)),
		'favorite_tags' => 'id="favoriting"',
		($favorite ? 'favorite_remove_tags' : 'favorite_add_tags') =>
			'title="' . qa_html($title) . '" name="' . qa_html('favorite_' . $entitytype . '_' . $entityid . '_' . (int)!$favorite) . '" onclick="return qa_favorite_click(this);"',
	);
}

/**
 * Format a number using the decimal point and thousand separator specified in the language files.
 * If the number is compacted it is turned into a string such as 17.3k (only the thousand/million
 * cases are currently supported).
 *
 * @since 1.8.0
 * @param integer $number Number to be formatted
 * @param integer $decimals Amount of decimals to use (ignored if number gets shortened)
 * @param bool $compact Whether the number can be shown as compact or not
 * @return string The formatted number as a string
 */
function qa_format_number($number, $decimals = 0, $compact = false)
{
	if (qa_to_override(__FUNCTION__)) { $args=func_get_args(); return qa_call_override(__FUNCTION__, $args); }

	$suffix = '';

	if ($compact && qa_opt('show_compact_numbers')) {
		// when compacting we keep 2-3 significant figures (e.g. 9.1k, 234k)
		if ($number >= 1000000) {
			$number /= 1000000;
			$suffix = qa_lang_html('main/_millions_suffix');
			$decimals = $number < 100 ? 1 : 0;
		} elseif ($number >= 1000) {
			$number /= 1000;
			$suffix = qa_lang_html('main/_thousands_suffix');
			$decimals = $number < 100 ? 1 : 0;
		}
	}

	return number_format(
		$number,
		$decimals,
		qa_lang_html('main/_decimal_point'),
		qa_lang_html('main/_thousands_separator')
	) . $suffix;
}
