Pepperminty-Wiki/core.php

<?php
$start_time = time(true);

// For debugging purposes. Remove or comment out for live sites.
// This will always be commented out for a release.
if(file_exists("php_error.php"))
{
    require("php_error.php");
    \php_error\reportErrors([ "error_reporting_on" => E_ALL | E_STRICT ]);
}

{settings}

///////////////////////////////////////////////////////////////////////////////////////////////
/////////////// Do not edit below this line unless you know what you are doing! ///////////////
///////////////////////////////////////////////////////////////////////////////////////////////
$version = "{version}";
/// Environment ///
$env = new stdClass();
$env->action = $settings->defaultaction;
$env->page = "";
$env->user = "Anonymous";
$env->is_logged_in = false;
$env->is_admin = false;
$env->storage_prefix = $settings->data_storage_dir . DIRECTORY_SEPARATOR;
/// Paths ///
$paths = new stdClass();
$paths->pageindex = "pageindex.json"; // The pageindex
$paths->searchindex = "invindex.json"; // The inverted index used for searching
$paths->idindex = "idindex.json"; // The index that converts ids to page names

// Prepend the storage data directory to all the defined paths.
foreach ($paths as &$path) {
    $path = $env->storage_prefix . $path;
}

$paths->upload_file_prefix = "Files/"; // The prefix to append to uploaded files

session_start();
///////// Login System /////////
// Clear expired sessions
if(isset($_SESSION["$settings->sessionprefix-expiretime"]) and
   $_SESSION["$settings->sessionprefix-expiretime"] < time())
{
	// Clear the session variables
	$_SESSION = [];
	session_destroy();
	$env->is_logged_in = false;
	$env->user = "Anonymous";
}

if(!isset($_SESSION[$settings->sessionprefix . "-user"]) and
  !isset($_SESSION[$settings->sessionprefix . "-pass"]))
{
	// The user is not logged in
	$env->is_logged_in = false;
}
else
{
	$env->user = $_SESSION[$settings->sessionprefix . "-user"];
	$env->pass = $_SESSION[$settings->sessionprefix . "-pass"];
	if($settings->users[$env->user] == $env->pass)
	{
		// The user is logged in
		$env->is_logged_in = true;
	}
	else
	{
		// The user's login details are invalid (what is going on here?)
		// Unset the session variables, treat them as an anonymous user,
		// and get out of here
		$env->is_logged_in = false;
		$env->user = "Anonymous";
		$env->pass = "";
		// Clear the session data
		$_SESSION = []; //delete all the variables
		session_destroy(); //destroy the session
	}
}
//check to see if the currently logged in user is an admin
$env->is_admin = false;
if($env->is_logged_in)
{
	foreach($settings->admins as $admin_username)
	{
		if($admin_username == $env->user)
		{
			$env->is_admin = true;
			break;
		}
	}
}
/////// Login System End ///////

///////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////// Functions ////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////

/*
 * @summary	Converts a filesize into a human-readable string.
 * @source	http://php.net/manual/en/function.filesize.php#106569
 * @editor	Starbeamrainbowlabs
 *
 * @param	$bytes		 - The number of bytes to convert.
 * @param	$decimals	 - The number of decimal places to preserve.
 */
function human_filesize($bytes, $decimals = 2)
{
	$sz = ["B", "KB", "MB", "GB", "TB", "PB", "EB", "YB", "ZB"];
	$factor = floor((strlen($bytes) - 1) / 3);
	return sprintf("%.{$decimals}f", $bytes / pow(1024, $factor)) . @$sz[$factor];
}
/*
 * @summary	Calculates the time sincce a particular timestamp and returns a
 * 			human-readable result.
 * @source	http://snippets.pro/snippet/137-php-convert-the-timestamp-to-human-readable-format/
 *
 * @param $time - The timestamp to convert.
 *
 * @returns {string} - The time since the given timestamp pas a human-readable string.
 */
function human_time_since($time)
{
	$timediff = time() - $time;
	$tokens = array (
		31536000 => 'year',
		2592000 => 'month',
		604800 => 'week',
		86400 => 'day',
		3600 => 'hour',
		60 => 'minute',
		1 => 'second'
	);
	foreach ($tokens as $unit => $text) {
		if ($timediff < $unit) continue;
		$numberOfUnits = floor($timediff / $unit);
		return $numberOfUnits.' '.$text.(($numberOfUnits>1)?'s':'').' ago';
	}
}

/*
 * @summary A recursive glob() function.
 *
 * @param $pattern - The glob pattern to use to find filenames.
 * @param $flags - The glob flags to use when finding filenames.
 *
 * @returns {array} - An array of the filepaths that match the given glob.
 */
// From http://in.php.net/manual/en/function.glob.php#106595
function glob_recursive($pattern, $flags = 0)
{
	$files = glob($pattern, $flags);
	foreach (glob(dirname($pattern).'/*', GLOB_ONLYDIR|GLOB_NOSORT) as $dir)
	{
		$prefix = "$dir/";
		// Remove the "./" from the beginning if it exists
		if(substr($prefix, 0, 2) == "./") $prefix = substr($prefix, 2);
		$files = array_merge($files, glob_recursive($prefix . basename($pattern), $flags));
	}
	return $files;
}

/*
 * @summary Gets a list of all the sub pages of the current page.
 *
 * @param $pageindex - The pageindex to use to search.
 * @param $pagename - The name of the page to list the sub pages of.
 *
 * @returns An objectt containing all the subpages, and their respective distances from the given page name in the pageindex tree.
 */
function get_subpages($pageindex, $pagename)
{
	$pagenames = get_object_vars($pageindex);
	$result = new stdClass();

	$stem = "$pagename/";
	$stem_length = strlen($stem);
	foreach($pagenames as $entry => $value)
	{
		if(substr($entry, 0, $stem_length) == $stem)
		{
			// We found a subpage

			// Extract the subpage's key relative to the page that we are searching for
			$subpage_relative_key = substr($entry, $stem_length, -3);
			// Calculate how many times removed the current subpage is from the current page. 0 = direct descendant.
			$times_removed = substr_count($subpage_relative_key, "/");
			// Store the name of the subpage we found
			$result->$entry = $times_removed;
		}
	}

	unset($pagenames);
	return $result;
}

/*
 * @summary Makes sure that a subpage's parents exist. Note this doesn't check the pagename itself.
 *
 * @param The pagename to check.
 *
 */
function check_subpage_parents($pagename)
{
	global $pageindex, $paths;
	// Save the new pageindex and return if there aren't any more parent pages to check
	if(strpos($pagename, "/") === false)
	{
		file_put_contents($paths->pageindex, json_encode($pageindex, JSON_PRETTY_PRINT));
		return;
	}

	$parent_pagename = substr($pagename, 0, strrpos($pagename, "/"));
	$parent_page_filename = "$parent_pagename.md";
	if(!file_exists($parent_page_filename))
	{
		// This parent page doesn't exist! Create it and add it to the page index.
		touch($parent_page_filename, 0);

		$newentry = new stdClass();
		$newentry->filename = $parent_page_filename;
		$newentry->size = 0;
		$newentry->lastmodified = 0;
		$newentry->lasteditor = "none";
		$pageindex->$parent_pagename = $newentry;
	}

	check_subpage_parents($parent_pagename);
}

/*
 * @summary makes a path safe
 *
 * @details paths may only contain alphanumeric characters, spaces, underscores, and dashes
 */
function makepathsafe($string)
{
	$string = preg_replace("/[^0-9a-zA-Z\_\-\ \/\.]/i", "", $string);
	$string = preg_replace("/\.+/", ".", $string);
	return $string;
}

/*
 * @summary Hides an email address from bots by adding random html entities.
 *
 * @returns The mangled email address.
 */
function hide_email($str)
{
	$hidden_email = "";
	for($i = 0; $i < strlen($str); $i++)
	{
		if($str[$i] == "@")
		{
			$hidden_email .= "&#" . ord("@") . ";";
			continue;
		}
		if(rand(0, 1) == 0)
			$hidden_email .= $str[$i];
		else
			$hidden_email .= "&#" . ord($str[$i]) . ";";
	}

	return $hidden_email;
}
/*
 * @summary Checks to see if $haystack starts with $needle.
 *
 * @param $haystack {string} The string to search.
 * @param $needle {string} The string to search for at the beginning of $haystack.
 *
 * @returns {boolean} Whether $needle can be found at the beginning of $haystack.
 */
function starts_with($haystack, $needle)
{
     $length = strlen($needle);
     return (substr($haystack, 0, $length) === $needle);
}
/**
 * mb_stripos all occurences
 * from http://www.pontikis.net/tip/?id=16
 * based on http://www.php.net/manual/en/function.strpos.php#87061
 *
 * Find all occurrences of a needle in a haystack (case-insensitive, UTF8)
 *
 * @param string $haystack
 * @param string $needle
 * @return array or false
 */
function mb_stripos_all($haystack, $needle) {
	$s = 0; $i = 0;
	while(is_integer($i)) {
		$i = function_exists("mb_stripos") ? mb_stripos($haystack, $needle, $s) : stripos($haystack, $needle, $s);
		if(is_integer($i)) {
			$aStrPos[] = $i;
			$s = $i + (function_exists("mb_strlen") ? mb_strlen($needle) : strlen($needle));
		}
	}
	if(isset($aStrPos))
		return $aStrPos;
	else
		return false;
}

function system_mime_type_extensions() {
	global $settings;
    # Returns the system MIME type mapping of MIME types to extensions, as defined in /etc/mime.types (considering the first
    # extension listed to be canonical).
    $out = array();
    $file = fopen($settings->mime_extension_mappings_location, 'r');
    while(($line = fgets($file)) !== false) {
        $line = trim(preg_replace('/#.*/', '', $line));
        if(!$line)
            continue;
        $parts = preg_split('/\s+/', $line);
        if(count($parts) == 1)
            continue;
        $type = array_shift($parts);
        if(!isset($out[$type]))
            $out[$type] = array_shift($parts);
    }
    fclose($file);
    return $out;
}
function system_mime_type_extension($type) {
    # Returns the canonical file extension for the MIME type specified, as defined in /etc/mime.types (considering the first
    # extension listed to be canonical).
    #
    # $type - the MIME type
    static $exts;
    if(!isset($exts))
        $exts = system_mime_type_extensions();
    return isset($exts[$type]) ? $exts[$type] : null;
}

///////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////// Security and Consistency Measures ////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////

/*
 * Sort out the pageindex. Create it if it doesn't exist, and load + parse it
 * if it does.
 */
if(!file_exists($paths->pageindex))
{
	$existingpages = glob_recursive($env->storage_prefix . "*.md");
	$pageindex = new stdClass();
	// We use a for loop here because foreach doesn't loop over new values inserted
	// while we were looping
	for($i = 0; $i < count($existingpages); $i++)
	{
		$pagefilename = $existingpages[$i];

		// Create a new entry
		$newentry = new stdClass();
		$newentry->filename = utf8_encode(substr($pagefilename, strlen($env->storage_prefix))); // Store the filename
		$newentry->size = filesize($pagefilename); // Store the page size
		$newentry->lastmodified = filemtime($pagefilename); // Store the date last modified
		// Todo find a way to keep the last editor independent of the page index
		$newentry->lasteditor = utf8_encode("unknown"); // Set the editor to "unknown"
		// Extract the name of the (sub)page without the ".md" or the storage dir
		$pagekey = utf8_encode(substr($pagefilename, strlen($env->storage_prefix), -3));
        
        // Calculate the position of the last dot in the file name
        $last_dot_pos = strrpos($newentry->filename, ".");
        // Keep everything up to the last dot
        $uploaded_file_path = substr($newentry->filename, 0, $last_dot_pos);
        // Work out the location of the next last dot
        $next_dot_pos = strrpos($uploaded_file_path, ".");
        if(
           // There is another dot in the uploaded file path
           $next_dot_pos !== false &&
           // This other dot is after the last slash
           $next_dot_pos >= strrpos($uploaded_file_path, "/") &&
           // The file actually exists
           file_exists($env->storage_prefix . $uploaded_file_path))
        {
            // This page (potentially) has an associated file!
            // Let's investigate.
            
            // Blindly add the file to the pageindex for now.
            // Future We might want to do a security check on the file later on. File a bug if you think this is a good idea.
            $newentry->uploadedfile = true; // Yes this page does have an uploaded file associated with it
            $newentry->uploadedfilepath = $uploaded_file_path; // It's stored here
            
            // Work out what kind of file it really is
            $mimechecker = finfo_open(FILEINFO_MIME_TYPE);
            $newentry->uploadedfilemime = finfo_file($mimechecker, $env->storage_prefix . $uploaded_file_path);
        }
        
        
		// Subpage parent checker
		if(strpos($pagekey, "/") !== false)
		{
			// We have a sub page people
			// Work out what our direct parent's key must be in order to check to
			// make sure that it actually exists. If it doesn't, then we need to
			// create it.
			$subpage_parent_key = substr($pagekey, 0, strrpos($pagekey, "/"));
			$subpage_parent_filename = "$env->storage_prefix$subpage_parent_key.md";
			if(array_search($subpage_parent_filename, $existingpages) === false)
			{
				// Our parent page doesn't actually exist - create it
				touch($subpage_parent_filename, 0);
				// Furthermore, we should add this page to the list of existing pages
				// in order for it to be indexed
				$existingpages[] = $subpage_parent_filename;
			}
		}

		// Store the new entry in the new page index
		$pageindex->$pagekey = $newentry;
	}
	file_put_contents($paths->pageindex, json_encode($pageindex, JSON_PRETTY_PRINT));
	unset($existingpages);
}
else
{
	$pageindex_read_start = microtime(true);
	$pageindex = json_decode(file_get_contents($paths->pageindex));
	header("x-pageindex-decode-time: " . round(microtime(true) - $pageindex_read_start, 6) . "ms");
}

//////////////////////////
///// Page id system /////
//////////////////////////
if(!file_exists($paths->idindex))
	file_put_contents($paths->idindex, "{}");
$idindex = json_decode(file_get_contents($paths->idindex));
class ids
{
	/*
	 * @summary Gets the page id associated with the given pagename.
	 */
	public static function getid($pagename)
	{
		global $idindex;

		foreach ($idindex as $id => $entry)
		{
			if($entry == $pagename)
				return $id;
		}

		// This pagename doesn't have an id - assign it one quick!
		return self::assign($pagename);
	}

	/*
	 * @summary Gets the page name associated with the given page id.
	 */
	public static function getpagename($id)
	{
		global $idindex;

		if(!isset($idindex->$id))
			return false;
		else
			return $idindex->$id;
	}
    
    /*
     * @summary Moves a page in the id index from $oldpagename to $newpagename.
     *          Note that this function doesn't perform any special checks to
     *          make sure that the destination name doesn't already exist.
     */
    public static function movepagename($oldpagename, $newpagename)
    {
        global $idindex, $paths;
        
        $pageid = self::getid($oldpagename);
        $idindex->$pageid = $newpagename;
        
        file_put_contents($paths->idindex, json_encode($idindex));
    }
    
    /*
     * @summary Removes the given page name from the id index. Note that this
     *          function doesn't handle multiple entries with the same name.
     */
    public static function deletepagename($pagename)
    {
        global $idindex, $paths;
        
        // Get the id of the specified page
        $pageid = self::getid($pagename);
        // Remove it from the pageindex
        unset($idindex->$pageid);
        // Save the id index
        file_put_contents($paths->idindex, json_encode($idindex));
    }

	/*
	 * @summary Assigns an id to a pagename. Doesn't check to make sure that
	 * 			pagename doesn't exist in the pageindex.
	 */
	protected static function assign($pagename)
	{
		global $idindex, $paths;

		$nextid = count(array_keys(get_object_vars($idindex)));

		if(isset($idindex->$nextid))
			throw new Exception("The pageid is corrupt! Pepperminty Wiki generated the id $nextid, but that id is already in use.");

		// Update the id index
		$idindex->$nextid = utf8_encode($pagename);

		// Save the id index
		file_put_contents($paths->idindex, json_encode($idindex));

		return $nextid;
	}
}
//////////////////////////
//////////////////////////

// Work around an Opera + Syntaxtic bug where there is no margin at the left
// hand side if there isn't a query string when accessing a .php file.
if(!isset($_GET["action"]) and !isset($_GET["page"]))
{
	http_response_code(302);
	header("location: index.php?action=$settings->defaultaction&page=$settings->defaultpage");
	exit();
}

// Make sure that the action is set
if(!isset($_GET["action"]))
	$_GET["action"] = $settings->defaultaction;
// Make sure that the page is set
if(!isset($_GET["page"]) or strlen($_GET["page"]) === 0)
	$_GET["page"] = $settings->defaultpage;

// Redirect the user to the safe version of the path if they entered an unsafe character
if(makepathsafe($_GET["page"]) !== $_GET["page"])
{
	http_response_code(301);
	header("location: index.php?action=" . rawurlencode($_GET["action"]) . "&page=" . makepathsafe($_GET["page"]));
	header("x-requested-page: " . $_GET["page"]);
	header("x-actual-page: " . makepathsafe($_GET["page"]));
	exit();
}

// Finish setting up the environment object
$env->page = $_GET["page"];
$env->action = strtolower($_GET["action"]);

///////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////// HTML fragments //////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////
class page_renderer
{
	public static $html_template = "<!DOCTYPE html>
<html>
	<head>
		<meta charset='utf-8' />
		<title>{title}</title>
		<meta name='viewport' content='width=device-width, initial-scale=1' />
		<link rel='shortcut-icon' href='{favicon-url}' />
		<link rel='icon' href='{favicon-url}' />
		{header-html}
	</head>
	<body>
		{body}
		<!-- Took {generation-time-taken} seconds to generate -->
	</body>
</html>
";

	public static $main_content_template = "{navigation-bar}
		<h1 class='sitename'>{sitename}</h1>
		<main>
		{content}
		</main>

		<footer>
			<p>{footer-message}</p>
			<p>Powered by Pepperminty Wiki {version}, which was built by <a href='//starbeamrainbowlabs.com/'>Starbeamrainbowlabs</a>. Send bugs to 'bugs at starbeamrainbowlabs dot com' or <a href='//github.com/sbrl/Pepperminty-Wiki' title='Github Issue Tracker'>open an issue</a>.</p>
			<p>Your local friendly administrators are {admins-name-list}.</p>
			<p>This wiki is managed by <a href='mailto:{admin-details-email}'>{admin-details-name}</a>.</p>
		</footer>
		{navigation-bar-bottom}
		{all-pages-datalist}";
	public static $minimal_content_template = "<main class='printable'>{content}</main>
		<footer class='printable'>
			<hr class='footerdivider' />
			<p><em>From {sitename}, which is managed by {admin-details-name}.</em></p>
			<p>{footer-message}</p>
			<p><em>Timed at {generation-date}</em></p>
			<p><em>Powered by Pepperminty Wiki {version}.</em></p>
		</footer>";

	// An array of functions that have been registered to process the
	// find / replace array before the page is rendered. Note that the function
	// should take a *reference* to an array as its only argument.
	protected static $part_processors = [];

	// Registers a function as a part post processor.
	public static function register_part_preprocessor($function)
	{
		global $settings;

		// Make sure that the function we are about to register is valid
		if(!is_callable($function))
		{
			http_response_code(500);
			$admin_name = $settings->admindetails["name"];
			$admin_email = hide_email($settings->admindetails["email"]);
			exit(page_renderer::render("$settings->sitename - Module Error", "<p>$settings->sitename has got a misbehaving module installed that tried to register an invalid HTML handler with the page renderer. Please contact $settings->sitename's administrator $admin_name at <a href='mailto:$admin_email'>$admin_email</a>."));
		}

		self::$part_processors[] = $function;

		return true;
	}

	public static function render($title, $content, $body_template = false)
	{
		global $settings, $start_time, $version;

		if($body_template === false)
			$body_template = self::$main_content_template;

		if(strlen($settings->logo_url) > 0)
		{
			// A logo url has been specified
			$logo_html = "<img class='logo' src='$settings->logo_url' />";
			switch($settings->logo_position)
			{
				case "left":
					$logo_html = "$logo_html $settings->sitename";
					break;
				case "right":
					$logo_html .= " $settings->sitename";
					break;
				default:
					throw new Exception("Invalid logo_position '$settings->logo_position'. Valid values are either \"left\" or \"right\" and are case sensitive.");
			}
		}

		$parts = [
			"{body}" => $body_template,

			"{sitename}" => $logo_html,
			"{version}" => $version,
			"{favicon-url}" => $settings->favicon,
			"{header-html}" => self::get_css_as_html(),

			"{navigation-bar}" => self::render_navigation_bar($settings->nav_links, $settings->nav_links_extra, "top"),
			"{navigation-bar-bottom}" => self::render_navigation_bar($settings->nav_links_bottom, [], "bottom"),

			"{admin-details-name}" => $settings->admindetails["name"],
			"{admin-details-email}" => $settings->admindetails["email"],

			"{admins-name-list}" => implode(", ", $settings->admins),

			"{generation-date}" => date("l jS \of F Y \a\\t h:ia T"),

			"{all-pages-datalist}" => self::generate_all_pages_datalist(),

			"{footer-message}" => $settings->footer_message,

			/// Secondary Parts ///

			"{content}" => $content,
			"{title}" => $title,
		];

		// Pass the parts through the part processors
		foreach(self::$part_processors as $function)
		{
			$function($parts);
		}

		$result = self::$html_template;

		$result = str_replace(array_keys($parts), array_values($parts), $result);

		$result = str_replace([

		], [
		], $result);

		$result = str_replace("{generation-time-taken}", microtime(true) - $start_time, $result);
		return $result;
	}
	public static function render_main($title, $content)
	{
		return self::render($title, $content, self::$main_content_template);
	}
	public static function render_minimal($title, $content)
	{
		return self::render($title, $content, self::$minimal_content_template);
	}
    
	public static function get_css_as_html()
	{
		global $settings;

		if(preg_match("/^[^\/]*\/\/|^\//", $settings->css))
			return "<link rel='stylesheet' href='$settings->css' />";
		else
			return "<style>$settings->css</style>";
	}

	public static $nav_divider = "<span class='nav-divider inflexible'> | </span>";

	/*
	 * @summary Function to render a navigation bar from an array of links. See
	 * 			$settings->nav_links for format information.
	 *
	 * @param $nav_links - The links to add to the navigation bar.
	 * @param $nav_links_extra - The extra nav links to add to the "More..."
	 * 							 menu.
	 */
	public static function render_navigation_bar($nav_links, $nav_links_extra, $class = "")
	{
		global $settings, $env;
		$result = "<nav class='$class'>\n";

		// Loop over all the navigation links
		foreach($nav_links as $item)
		{
			if(is_string($item))
			{
				// The item is a string
				switch($item)
				{
					//keywords
					case "user-status":
						if($env->is_logged_in)
						{
							$result .= "<span class='inflexible'>Logged in as " . self::render_username($env->user) . ".</span> "/* . page_renderer::$nav_divider*/;
							$result .= "<span><a href='index.php?action=logout'>Logout</a></span>";
							$result .= page_renderer::$nav_divider;
						}
						else
							$result .= "<span class='inflexible'>Browsing as Anonymous.</span>" . /*page_renderer::$nav_divider . */"<span><a href='index.php?action=login'>Login</a></span>" . page_renderer::$nav_divider;
						break;

					case "search": // Displays a search bar
						$result .= "<span class='inflexible'><form method='get' action='index.php' style='display: inline;'><input type='search' name='page' list='allpages' placeholder='Type a page name here and hit enter' /><input type='hidden' name='search-redirect' value='true' /></form></span>";
						break;

					case "divider": // Displays a divider
						$result .= page_renderer::$nav_divider;
						break;

					case "menu":
						$result .= "<span class='inflexible nav-more'><label for='more-menu-toggler'>More...</label>
<input type='checkbox' class='off-screen' id='more-menu-toggler' />";
						$result .= page_renderer::render_navigation_bar($nav_links_extra, [], "nav-more-menu");
						$result .= "</span>";
						break;

					// It isn't a keyword, so just output it directly
					default:
						$result .= "<span>$item</span>";
				}
			}
			else
			{
				// Output the item as a link to a url
				$result .= "<span><a href='" . str_replace("{page}", $env->page, $item[1]) . "'>$item[0]</a></span>";
			}
		}

		$result .= "</nav>";
		return $result;
	}
	public static function render_username($name)
	{
		global $settings;
		$result = "";
		if(in_array($name, $settings->admins))
			$result .= $settings->admindisplaychar;
		$result .= $name;

		return $result;
	}

	public static function generate_all_pages_datalist()
	{
		global $pageindex;

		$result = "<datalist id='allpages'>\n";
		foreach($pageindex as $pagename => $pagedetails)
		{
			$result .= "\t\t\t<option value='$pagename' />\n";
		}
		$result .= "\t\t</datalist>";

		return $result;
	}
}

//////////////////////////////////////
///// Extra consistency measures /////
//////////////////////////////////////
// Redirect to the search page if there isn't a page with the requested name
if(!isset($pageindex->{$env->page}) and isset($_GET["search-redirect"]))
{
	http_response_code(307);
	$url = "?action=search&query=" . rawurlencode($env->page);
	header("location: $url");
	exit(page_renderer::render("Non existent page - $settings->sitename", "<p>There isn't a page on $settings->sitename with that name. However, you could <a href='$url'>search for this page name</a> in other pages.</p>
		<p>Alternatively, you could <a href='?action=edit&page=" . rawurlencode($env->page) . "&create=true'>create this page</a>.</p>"));
}

// Redirect the user to the login page if:
//  - A login is required to view this wiki
//  - The user isn't already requesting the login page
// Note we use $_GET here because $env->action isn't populated at this point
if($settings->require_login_view === true && // If this site requires a login in order to view pages
   !$env->is_logged_in && // And the user isn't logged in
   $_GET["action"] !== "login") // And the user isn't requesting the login page
{
    // Redirect the user to the login page
    http_response_code(307);
    $url = "?action=login&returnto=" . rawurlencode($_SERVER["REQUEST_URI"]) . "&required=true";
    header("location: $url");
    exit(page_renderer::render("Login required - $settings->sitename", "<p>$settings->sitename requires that you login before you are able to access it.</p>
        <p><a href='$url'>Login</a>.</p>"));
}
//////////////////////////////////////
//////////////////////////////////////

//////////////////////////
///  Module functions  ///
//////////////////////////
// These functions are	//
// used by modules to	//
// register themselves	//
// or new pages.		//
//////////////////////////
$modules = []; // List that contains all the loaded modules
// Function to register a module
function register_module($moduledata)
{
	global $modules;
	//echo("registering module\n");
	//var_dump($moduledata);
	$modules[] = $moduledata;
}

// Function to register an action handler
$actions = new stdClass();
function add_action($action_name, $func)
{
	global $actions;
	//echo("adding $action_name\n");
	$actions->$action_name = $func;
}

// Function to register a new parser.
$parsers = [
	"none" => function() {
		throw new Exception("No parser registered!");
	}
];
function add_parser($name, $parser_code)
{
	global $parsers;
	if(isset($parsers[$name]))
		throw new Exception("Can't register parser with name '$name' because a parser with that name already exists.");

	$parsers[$name] = $parser_code;
}
function parse_page_source($source)
{
	global $settings, $parsers;
	if(!isset($parsers[$settings->parser]))
		exit(page_renderer::render_main("Parsing error - $settings->sitename", "<p>Parsing some page source data failed. This is most likely because $settings->sitename has the parser setting set incorrectly. Please contact <a href='mailto:" . hide_email($settings->admindetails["email"]) . "'>" . $settings->admindetails["name"] . "</a>, your $settings->sitename Administrator."));

/* Not needed atm because escaping happens when saving, not when rendering *
	if($settings->clean_raw_html)
		$source = htmlentities($source, ENT_QUOTES | ENT_HTML5);
*/
	return $parsers[$settings->parser]($source);
}

// Function to register a new proprocessor that will be executed just before
// an edit is saved.
$save_preprocessors = [];
function register_save_preprocessor($func)
{
	global $save_preprocessors;
	$save_preprocessors[] = $func;
}

//////////////////////////////////////////////////////////////////


// %next_module% //


// Execute each module's code
foreach($modules as $moduledata)
{
	$moduledata["code"]();
}
// Make sure that the credits page exists
if(!isset($actions->credits))
{
	exit(page_renderer::render_main("Error - $settings->$sitename", "<p>No credits page detected. The credits page is a required module!</p>"));
}

// Perform the appropriate action
$action_name = $env->action;
if(isset($actions->$action_name))
{
	$req_action_data = $actions->$action_name;
	$req_action_data();
}
else
{
	exit(page_renderer::render_main("Error - $settings->sitename", "<p>No action called " . strtolower($_GET["action"]) ." has been registered. Perhaps you are missing a module?</p>"));
}

?>