<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace core\output;

use block_manager;
use cache;
use cache_store;
use core_component;
use core_cssparser;
use core_minify;
use core_php_time_limit;
use core_rtlcss;
use core_scss;
use core_useragent;
use core\context\system as context_system;
use core\exception\coding_exception;
use core\output\renderer_factory\renderer_factory_interface as renderer_factory;
use core\output\renderer_factory\standard_renderer_factory;
use dml_exception;
use moodle_page;
use moodle_url;
use stdClass;

// phpcs:disable moodle.NamingConventions.ValidVariableName.VariableNameUnderscore
// phpcs:disable moodle.NamingConventions.ValidVariableName.MemberNameUnderscore

/**
 * This class represents the configuration variables of a Moodle theme.
 *
 * All the variables with access: public below (with a few exceptions that are marked)
 * are the properties you can set in your themes config.php file.
 *
 * There are also some methods and protected variables that are part of the inner
 * workings of Moodle's themes system. If you are just editing a themes config.php
 * file, you can just ignore those, and the following information for developers.
 *
 * Normally, to create an instance of this class, you should use the
 * {@see theme_config::load()} factory method to load a themes config.php file.
 * However, normally you don't need to bother, because moodle_page (that is, $PAGE)
 * will create one for you, accessible as $PAGE->theme.
 *
 * @copyright 2009 Tim Hunt
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @package core
 * @category output
 */
class theme_config {
    /**
     * @var string Default theme, used when requested theme not found.
     */
    const DEFAULT_THEME = 'boost';

    /** The key under which the SCSS file is stored amongst the CSS files. */
    const SCSS_KEY = '__SCSS__';

    /**
     * @var array You can base your theme on other themes by linking to the other theme as
     * parents. This lets you use the CSS and layouts from the other themes
     * (see {@see theme_config::$layouts}).
     * That makes it easy to create a new theme that is similar to another one
     * but with a few changes. In this themes CSS you only need to override
     * those rules you want to change.
     */
    public $parents;

    /**
     * @var array The names of all the stylesheets from this theme that you would
     * like included, in order. Give the names of the files without .css.
     */
    public $sheets = [];

    /**
     * @var array The names of all the stylesheets from parents that should be excluded.
     * true value may be used to specify all parents or all themes from one parent.
     * If no value specified value from parent theme used.
     */
    public $parents_exclude_sheets = null;

    /**
     * @var array List of plugin sheets to be excluded.
     * If no value specified value from parent theme used.
     */
    public $plugins_exclude_sheets = null;

    /**
     * @var array List of style sheets that are included in the text editor bodies.
     * Sheets from parent themes are used automatically and can not be excluded.
     */
    public $editor_sheets = [];

    /**
     * @var bool Whether a fallback version of the stylesheet will be used
     * whilst the final version is generated.
     */
    public $usefallback = false;

    /**
     * @var array The names of all the javascript files this theme that you would
     * like included from head, in order. Give the names of the files without .js.
     */
    public $javascripts = [];

    /**
     * @var array The names of all the javascript files this theme that you would
     * like included from footer, in order. Give the names of the files without .js.
     */
    public $javascripts_footer = [];

    /**
     * @var array The names of all the javascript files from parents that should
     * be excluded. true value may be used to specify all parents or all themes
     * from one parent.
     * If no value specified value from parent theme used.
     */
    public $parents_exclude_javascripts = null;

    /**
     * @var array Which file to use for each page layout.
     *
     * This is an array of arrays. The keys of the outer array are the different layouts.
     * Pages in Moodle are using several different layouts like 'normal', 'course', 'home',
     * 'popup', 'form', .... The most reliable way to get a complete list is to look at
     * {@link http://cvs.moodle.org/moodle/theme/base/config.php?view=markup the base theme config.php file}.
     * That file also has a good example of how to set this setting.
     *
     * For each layout, the value in the outer array is an array that describes
     * how you want that type of page to look. For example
     * <pre>
     *   $THEME->layouts = array(
     *       // Most pages - if we encounter an unknown or a missing page type, this one is used.
     *       'standard' => array(
     *           'theme' = 'mytheme',
     *           'file' => 'normal.php',
     *           'regions' => array('side-pre', 'side-post'),
     *           'defaultregion' => 'side-post'
     *       ),
     *       // The site home page.
     *       'home' => array(
     *           'theme' = 'mytheme',
     *           'file' => 'home.php',
     *           'regions' => array('side-pre', 'side-post'),
     *           'defaultregion' => 'side-post'
     *       ),
     *       // ...
     *   );
     * </pre>
     *
     * 'theme' name of the theme where is the layout located
     * 'file' is the layout file to use for this type of page.
     * layout files are stored in layout subfolder
     * 'regions' This lists the regions on the page where blocks may appear. For
     * each region you list here, your layout file must include a call to
     * <pre>
     *   echo $OUTPUT->blocks_for_region($regionname);
     * </pre>
     * or equivalent so that the blocks are actually visible.
     *
     * 'defaultregion' If the list of regions is non-empty, then you must pick
     * one of the one of them as 'default'. This has two meanings. First, this is
     * where new blocks are added. Second, if there are any blocks associated with
     * the page, but in non-existent regions, they appear here. (Imaging, for example,
     * that someone added blocks using a different theme that used different region
     * names, and then switched to this theme.)
     */
    public $layouts = [];

    /**
     * @var string Name of the renderer factory class to use. Must implement the
     * {@see renderer_factory} interface.
     *
     * This is an advanced feature. Moodle output is generated by 'renderers',
     * you can customise the HTML that is output by writing custom renderers,
     * and then you need to specify 'renderer factory' so that Moodle can find
     * your renderers.
     *
     * There are some renderer factories supplied with Moodle. Please follow these
     * links to see what they do.
     * <ul>
     * <li>{@see standard_renderer_factory} - the default.</li>
     * <li>{@see theme_overridden_renderer_factory} - use this if you want to write
     *      your own custom renderers in a lib.php file in this theme (or the parent theme).</li>
     * </ul>
     */
    public $rendererfactory = standard_renderer_factory::class;

    /**
     * @var string Function to do custom CSS post-processing.
     *
     * This is an advanced feature. If you want to do custom post-processing on the
     * CSS before it is output (for example, to replace certain variable names
     * with particular values) you can give the name of a function here.
     */
    public $csspostprocess = null;

    /**
     * @var string Function to do custom CSS post-processing on a parsed CSS tree.
     *
     * This is an advanced feature. If you want to do custom post-processing on the
     * CSS before it is output, you can provide the name of the function here. The
     * function will receive a CSS tree document as first parameter, and the theme_config
     * object as second parameter. A return value is not required, the tree can
     * be edited in place.
     */
    public $csstreepostprocessor = null;

    /**
     * @var string Accessibility: Right arrow-like character is
     * used in the breadcrumb trail, course navigation menu
     * (previous/next activity), calendar, and search forum block.
     * If the theme does not set characters, appropriate defaults
     * are set automatically. Please DO NOT
     * use &lt; &gt; &raquo; - these are confusing for blind users.
     */
    public $rarrow = null;

    /**
     * @var string Accessibility: Left arrow-like character is
     * used in the breadcrumb trail, course navigation menu
     * (previous/next activity), calendar, and search forum block.
     * If the theme does not set characters, appropriate defaults
     * are set automatically. Please DO NOT
     * use &lt; &gt; &raquo; - these are confusing for blind users.
     */
    public $larrow = null;

    /**
     * @var string Accessibility: Up arrow-like character is used in
     * the book heirarchical navigation.
     * If the theme does not set characters, appropriate defaults
     * are set automatically. Please DO NOT
     * use ^ - this is confusing for blind users.
     */
    public $uarrow = null;

    /**
     * @var string Accessibility: Down arrow-like character.
     * If the theme does not set characters, appropriate defaults
     * are set automatically.
     */
    public $darrow = null;

    /**
     * @var bool Some themes may want to disable ajax course editing.
     */
    public $enablecourseajax = true;

    /**
     * @var string Determines served document types
     *  - 'html5' the only officially supported doctype in Moodle
     *  - 'xhtml5' may be used in development for validation (not intended for production servers!)
     *  - 'xhtml' XHTML 1.0 Strict for legacy themes only
     */
    public $doctype = 'html5';

    /**
     * @var string|false requiredblocks If set to a string, will list the block types that cannot be deleted. Defaults to
     *                                   navigation and settings.
     */
    public $requiredblocks = false;

    // The Following properties are not configurable from theme config.php.

    /**
     * @var string The name of this theme. Set automatically when this theme is
     * loaded. This can not be set in theme config.php
     */
    public $name;

    /**
     * @var string The folder where this themes files are stored. This is set
     * automatically. This can not be set in theme config.php
     */
    public $dir;

    /**
     * @var stdClass Theme settings stored in config_plugins table.
     * This can not be set in theme config.php
     */
    public $settings = null;

    /**
     * @var bool If set to true and the theme enables the dock then  blocks will be able
     * to be moved to the special dock
     */
    public $enable_dock = false;

    /**
     * @var bool If set to true then this theme will not be shown in the theme selector unless
     * theme designer mode is turned on.
     */
    public $hidefromselector = false;

    /**
     * @var array list of YUI CSS modules to be included on each page. This may be used
     * to remove cssreset and use cssnormalise module instead.
     */
    public $yuicssmodules = ['cssreset', 'cssfonts', 'cssgrids', 'cssbase'];

    /**
     * An associative array of block manipulations that should be made if the user is using an rtl language.
     * The key is the original block region, and the value is the block region to change to.
     * This is used when displaying blocks for regions only.
     * @var array
     */
    public $blockrtlmanipulations = [];

    /**
     * @var renderer_factory Instance of the renderer_factory implementation
     * we are using. Implementation detail.
     */
    protected $rf = null;

    /**
     * @var array List of parent config objects.
     **/
    protected $parent_configs = [];

    /**
     * Used to determine whether we can serve SVG images or not.
     * @var bool
     */
    private $usesvg = null;

    /**
     * Whether in RTL mode or not.
     * @var bool
     */
    protected $rtlmode = false;

    /**
     * The SCSS file to compile (without .scss), located in the scss/ folder of the theme.
     * Or a Closure, which receives the theme_config as argument and must
     * return the SCSS content.
     * @var string|Closure
     */
    public $scss = false;

    /**
     * Local cache of the SCSS property.
     * @var false|array
     */
    protected $scsscache = null;

    /**
     * The name of the function to call to get the SCSS code to inject.
     * @var string
     */
    public $extrascsscallback = null;

    /**
     * The name of the function to call to get SCSS to prepend.
     * @var string
     */
    public $prescsscallback = null;

    /**
     * Sets the render method that should be used for rendering custom block regions by scripts such as my/index.php
     * Defaults to {@see core_renderer::blocks_for_region()}
     * @var string
     */
    public $blockrendermethod = null;

    /**
     * Remember the results of icon remapping for the current page.
     * @var array
     */
    public $remapiconcache = [];

    /**
     * The name of the function to call to get precompiled CSS.
     * @var string
     */
    public $precompiledcsscallback = null;

    /**
     * Whether the theme uses course index.
     * @var bool
     */
    public $usescourseindex = false;

    /**
     * Configuration for the page activity header
     * @var array
     */
    public $activityheaderconfig = [];

    /**
     * For backward compatibility with old themes.
     * BLOCK_ADDBLOCK_POSITION_DEFAULT, BLOCK_ADDBLOCK_POSITION_FLATNAV.
     * @var int
     */
    public $addblockposition;

    /**
     * editor_scss file(s) provided by this theme.
     * @var array
     */
    public $editor_scss;

    /**
     * Name of the class extending \core\output\icon_system.
     * @var string
     */
    public $iconsystem;

    /**
     * Theme defines its own editing mode switch.
     * @var bool
     */
    public $haseditswitch = false;

    /**
     * Allows a theme to customise primary navigation by specifying the list of items to remove.
     * @var array
     */
    public $removedprimarynavitems = [];

    /**
     * Load the config.php file for a particular theme, and return an instance
     * of this class. (That is, this is a factory method.)
     *
     * @param string $themename the name of the theme.
     * @return theme_config an instance of this class.
     */
    public static function load($themename) {
        global $CFG;

        // Load theme settings from db.
        try {
            $settings = get_config('theme_' . $themename);
        } catch (dml_exception $e) {
            // Most probably moodle tables not created yet.
            $settings = new stdClass();
        }

        if ($config = self::find_theme_config($themename, $settings)) {
            return new self($config);
        } else if ($themename == self::DEFAULT_THEME) {
            throw new coding_exception('Default theme ' . self::DEFAULT_THEME . ' not available or broken!');
        } else if ($config = self::find_theme_config($CFG->theme, $settings)) {
            debugging('This page should be using theme ' . $themename .
                    ' which cannot be initialised. Falling back to the site theme ' . $CFG->theme, DEBUG_NORMAL);
            return new self($config);
        } else {
            // Bad luck, the requested theme has some problems - admin see details in theme config.
            debugging('This page should be using theme ' . $themename .
                    ' which cannot be initialised. Nor can the site theme ' . $CFG->theme .
                    '. Falling back to ' . self::DEFAULT_THEME, DEBUG_NORMAL);
            return new self(self::find_theme_config(self::DEFAULT_THEME, $settings));
        }
    }

    /**
     * Theme diagnostic code. It is very problematic to send debug output
     * to the actual CSS file, instead this functions is supposed to
     * diagnose given theme and highlights all potential problems.
     * This information should be available from the theme selection page
     * or some other debug page for theme designers.
     *
     * @param string $themename
     * @return array description of problems
     */
    public static function diagnose($themename) {
        // TODO: MDL-21108.
        return [];
    }

    /**
     * Private constructor, can be called only from the factory method.
     * @param stdClass $config
     */
    private function __construct($config) {
        global $CFG; // Needed for included lib.php files.

        $this->settings = $config->settings;
        $this->name     = $config->name;
        $this->dir      = $config->dir;

        if ($this->name != self::DEFAULT_THEME) {
            $baseconfig = self::find_theme_config(self::DEFAULT_THEME, $this->settings);
        } else {
            $baseconfig = $config;
        }

        // Ensure that each of the configurable properties defined below are also defined at the class level.
        $configurable = [
            'parents', 'sheets', 'parents_exclude_sheets', 'plugins_exclude_sheets', 'usefallback',
            'javascripts', 'javascripts_footer', 'parents_exclude_javascripts',
            'enablecourseajax', 'requiredblocks',
            'rendererfactory', 'csspostprocess', 'editor_sheets', 'editor_scss', 'rarrow', 'larrow', 'uarrow', 'darrow',
            'hidefromselector', 'doctype', 'yuicssmodules', 'blockrtlmanipulations', 'blockrendermethod',
            'scss', 'extrascsscallback', 'prescsscallback', 'csstreepostprocessor', 'addblockposition',
            'iconsystem', 'precompiledcsscallback', 'haseditswitch', 'usescourseindex', 'activityheaderconfig',
            'removedprimarynavitems',
        ];

        foreach ($config as $key => $value) {
            if (in_array($key, $configurable)) {
                $this->$key = $value;
            }
        }

        // Verify all parents and load configs and renderers.
        foreach ($this->parents as $parent) {
            if (!$parent_config = self::find_theme_config($parent, $this->settings)) {
                // This is not good - better exclude faulty parents.
                continue;
            }
            $libfile = $parent_config->dir . '/lib.php';
            if (is_readable($libfile)) {
                // Theme may store various function here.
                include_once($libfile);
            }
            $renderersfile = $parent_config->dir . '/renderers.php';
            if (is_readable($renderersfile)) {
                // May contain core and plugin renderers and renderer factory.
                include_once($renderersfile);
            }
            $this->parent_configs[$parent] = $parent_config;
        }
        $libfile = $this->dir . '/lib.php';
        if (is_readable($libfile)) {
            // Theme may store various function here.
            include_once($libfile);
        }
        $rendererfile = $this->dir . '/renderers.php';
        if (is_readable($rendererfile)) {
            // May contain core and plugin renderers and renderer factory.
            include_once($rendererfile);
        } else {
            // Check if renderers.php file is missnamed renderer.php.
            if (is_readable($this->dir . '/renderer.php')) {
                debugging('Developer hint: ' . $this->dir . '/renderer.php should be renamed to ' . $this->dir . "/renderers.php.
                    See: http://docs.moodle.org/dev/Output_renderers#Theme_renderers.", DEBUG_DEVELOPER);
            }
        }

        // Cascade all layouts properly, giving precedence to the current theme.
        $this->layouts = $baseconfig->layouts;
        // Then merge layouts from parent themes in reverse order (first the parent then the child).
        foreach (array_reverse($this->parent_configs) as $parent) {
            if (!empty($parent->layouts)) {
                foreach ($parent->layouts as $layout => $value) {
                    if (!empty($value)) {
                        $this->layouts[$layout] = $value;
                    }
                }
            }
        }
        // Finally, merge current theme layouts (highest precedence).
        if (!empty($config->layouts)) {
            foreach ($config->layouts as $layout => $value) {
                if (!empty($value)) {
                    $this->layouts[$layout] = $value;
                }
            }
        }
        // Fix arrows if needed.
        $this->check_theme_arrows();
    }

    /**
     * Let the theme initialise the page object (usually $PAGE).
     *
     * This may be used for example to request jQuery in add-ons.
     *
     * @param moodle_page $page
     */
    public function init_page(moodle_page $page) {
        $themeinitfunction = 'theme_' . $this->name . '_page_init';
        if (function_exists($themeinitfunction)) {
            $themeinitfunction($page);
        }
    }

    /**
     * Checks if arrows $THEME->rarrow, $THEME->larrow, $THEME->uarrow, $THEME->darrow have been set (theme/-/config.php).
     * If not it applies sensible defaults.
     *
     * Accessibility: right and left arrow Unicode characters for breadcrumb, calendar,
     * search forum block, etc. Important: these are 'silent' in a screen-reader
     * (unlike &gt; &raquo;), and must be accompanied by text.
     */
    private function check_theme_arrows() {
        if (!isset($this->rarrow) && !isset($this->larrow)) {
            // Default, looks good in Win XP/IE 6, Win/Firefox 1.5, Win/Netscape 8...
            // Also OK in Win 9x/2K/IE 5.x.
            $this->rarrow = '&#x25BA;';
            $this->larrow = '&#x25C4;';
            $this->uarrow = '&#x25B2;';
            $this->darrow = '&#x25BC;';
            if (empty($_SERVER['HTTP_USER_AGENT'])) {
                $uagent = '';
            } else {
                $uagent = $_SERVER['HTTP_USER_AGENT'];
            }
            if (
                false !== strpos($uagent, 'Opera')
                || false !== strpos($uagent, 'Mac')
            ) {
                // Looks good in Win XP/Mac/Opera 8/9, Mac/Firefox 2, Camino, Safari.
                // Not broken in Mac/IE 5, Mac/Netscape 7 (?).
                $this->rarrow = '&#x25B6;&#xFE0E;';
                $this->larrow = '&#x25C0;&#xFE0E;';
            } else if (
                (false !== strpos($uagent, 'Konqueror'))
                || (false !== strpos($uagent, 'Android'))
            ) {
                // The fonts on Android don't include the characters required for this to work as expected.
                // So we use the same ones Konqueror uses.
                $this->rarrow = '&rarr;';
                $this->larrow = '&larr;';
                $this->uarrow = '&uarr;';
                $this->darrow = '&darr;';
            } else if (
                isset($_SERVER['HTTP_ACCEPT_CHARSET'])
                && false === stripos($_SERVER['HTTP_ACCEPT_CHARSET'], 'utf-8')
            ) {
                // Win/IE 5 doesn't set ACCEPT_CHARSET, but handles Unicode.
                // To be safe, non-Unicode browsers!
                $this->rarrow = '&gt;';
                $this->larrow = '&lt;';
                $this->uarrow = '^';
                $this->darrow = 'v';
            }

            // RTL support - in RTL languages, swap r and l arrows.
            if (right_to_left()) {
                $t = $this->rarrow;
                $this->rarrow = $this->larrow;
                $this->larrow = $t;
            }
        }
    }

    /**
     * Returns output renderer prefixes, these are used when looking
     * for the overridden renderers in themes.
     *
     * @return array
     */
    public function renderer_prefixes() {
        global $CFG; // Just in case the included files need it.

        $prefixes = ['theme_' . $this->name];

        foreach ($this->parent_configs as $parent) {
            $prefixes[] = 'theme_' . $parent->name;
        }

        return $prefixes;
    }

    /**
     * Returns the stylesheet URL of this editor content
     *
     * @param bool $encoded false means use & and true use &amp; in URLs
     * @return moodle_url
     */
    public function editor_css_url($encoded = true) {
        global $CFG;
        $rev = theme_get_revision();
        $type = 'editor';
        if (right_to_left()) {
            $type .= '-rtl';
        }

        if ($rev > -1) {
            $themesubrevision = theme_get_sub_revision_for_theme($this->name);

            // Provide the sub revision to allow us to invalidate cached theme CSS
            // on a per theme basis, rather than globally.
            if ($themesubrevision && $themesubrevision > 0) {
                $rev .= "_{$themesubrevision}";
            }

            $url = new moodle_url("/theme/styles.php");
            if (!empty($CFG->slasharguments)) {
                $url->set_slashargument("/{$this->name}/{$rev}/{$type}", 'noparam', true);
            } else {
                $url->params([
                    'theme' => $this->name,
                    'rev' => $rev,
                    'type' => $type,
                ]);
            }
        } else {
            $url = new moodle_url('/theme/styles_debug.php', [
                'theme' => $this->name,
                'type' => $type,
            ]);
        }
        return $url;
    }

    /**
     * Returns the content of the CSS to be used in editor content
     *
     * @return array
     */
    public function editor_css_files() {
        $files = [];

        // First editor plugins.
        $plugins = core_component::get_plugin_list('editor');
        foreach ($plugins as $plugin => $fulldir) {
            $sheetfile = "$fulldir/editor_styles.css";
            if (is_readable($sheetfile)) {
                $files['plugin_' . $plugin] = $sheetfile;
            }

            $subplugintypes = core_component::get_subplugins("editor_{$plugin}") ?? [];
            // Fetch sheets for any editor subplugins.
            foreach ($subplugintypes as $plugintype => $subplugins) {
                foreach ($subplugins as $subplugin) {
                    $plugindir = core_component::get_plugin_directory($plugintype, $subplugin);
                    $sheetfile = "{$plugindir}/editor_styles.css";
                    if (is_readable($sheetfile)) {
                        $files["{$plugintype}_{$subplugin}"] = $sheetfile;
                    }
                }
            }
        }

        // Then parent themes - base first, the immediate parent last.
        foreach (array_reverse($this->parent_configs) as $parent_config) {
            if (empty($parent_config->editor_sheets)) {
                continue;
            }
            foreach ($parent_config->editor_sheets as $sheet) {
                $sheetfile = "$parent_config->dir/style/$sheet.css";
                if (is_readable($sheetfile)) {
                    $files['parent_' . $parent_config->name . '_' . $sheet] = $sheetfile;
                }
            }
        }
        // Finally this theme.
        if (!empty($this->editor_sheets)) {
            foreach ($this->editor_sheets as $sheet) {
                $sheetfile = "$this->dir/style/$sheet.css";
                if (is_readable($sheetfile)) {
                    $files['theme_' . $sheet] = $sheetfile;
                }
            }
        }

        return $files;
    }

    /**
     * Compiles and returns the content of the SCSS to be used in editor content
     *
     * @return string Compiled CSS from the editor SCSS
     */
    public function editor_scss_to_css() {
        $css = '';
        $dir = $this->dir;
        $filenames = [];

        // Use editor_scss file(s) provided by this theme if set.
        if (!empty($this->editor_scss)) {
            $filenames = $this->editor_scss;
        } else {
            // If no editor_scss set, move up theme hierarchy until one is found (if at all).
            // This is so child themes only need to set editor_scss if an override is required.
            foreach (array_reverse($this->parent_configs) as $parentconfig) {
                if (!empty($parentconfig->editor_scss)) {
                    $dir = $parentconfig->dir;
                    $filenames = $parentconfig->editor_scss;

                    // Config found, stop looking.
                    break;
                }
            }
        }

        if (!empty($filenames)) {
            $compiler = new core_scss();

            foreach ($filenames as $filename) {
                $compiler->set_file("{$dir}/scss/{$filename}.scss");

                try {
                    $css .= $compiler->to_css();
                } catch (\Exception $e) {
                    debugging('Error while compiling editor SCSS: ' . $e->getMessage(), DEBUG_DEVELOPER);
                }
            }
        }

        return $css;
    }

    /**
     * Get the stylesheet URL of this theme.
     *
     * @param moodle_page $page Not used... deprecated?
     * @return moodle_url[]
     */
    public function css_urls(moodle_page $page) {
        global $CFG;

        $rev = theme_get_revision();

        $urls = [];

        $svg = $this->use_svg_icons();
        $separate = (core_useragent::is_ie() && !core_useragent::check_ie_version('10'));

        if ($rev > -1) {
            $filename = right_to_left() ? 'all-rtl' : 'all';
            $url = new moodle_url("/theme/styles.php");
            $themesubrevision = theme_get_sub_revision_for_theme($this->name);

            // Provide the sub revision to allow us to invalidate cached theme CSS
            // on a per theme basis, rather than globally.
            if ($themesubrevision && $themesubrevision > 0) {
                $rev .= "_{$themesubrevision}";
            }

            if (!empty($CFG->slasharguments)) {
                $slashargs = '';
                if (!$svg) {
                    // We add a simple /_s to the start of the path.
                    // The underscore is used to ensure that it isn't a valid theme name.
                    $slashargs .= '/_s' . $slashargs;
                }
                $slashargs .= '/' . $this->name . '/' . $rev . '/' . $filename;
                if ($separate) {
                    $slashargs .= '/chunk0';
                }
                $url->set_slashargument($slashargs, 'noparam', true);
            } else {
                $params = ['theme' => $this->name, 'rev' => $rev, 'type' => $filename];
                if (!$svg) {
                    // We add an SVG param so that we know not to serve SVG images.
                    // We do this because all modern browsers support SVG and this param will one day be removed.
                    $params['svg'] = '0';
                }
                if ($separate) {
                    $params['chunk'] = '0';
                }
                $url->params($params);
            }
            $urls[] = $url;
        } else {
            $baseurl = new moodle_url('/theme/styles_debug.php');

            $css = $this->get_css_files(true);
            if (!$svg) {
                // We add an SVG param so that we know not to serve SVG images.
                // We do this because all modern browsers support SVG and this param will one day be removed.
                $baseurl->param('svg', '0');
            }
            if (right_to_left()) {
                $baseurl->param('rtl', 1);
            }
            if ($separate) {
                // We might need to chunk long files.
                $baseurl->param('chunk', '0');
            }
            if (core_useragent::is_ie()) {
                // Lalala, IE does not allow more than 31 linked CSS files from main document.
                $urls[] = new moodle_url($baseurl, ['theme' => $this->name, 'type' => 'ie', 'subtype' => 'plugins']);
                foreach ($css['parents'] as $parent => $sheets) {
                    // We need to serve parents individually otherwise we may easily exceed the style limit IE imposes (4096).
                    $urls[] = new moodle_url($baseurl, [
                        'theme' => $this->name,
                        'type' => 'ie',
                        'subtype' => 'parents',
                        'sheet' => $parent,
                    ]);
                }
                if ($this->get_scss_property()) {
                    // No need to define the type as IE here.
                    $urls[] = new moodle_url($baseurl, ['theme' => $this->name, 'type' => 'scss']);
                }
                $urls[] = new moodle_url($baseurl, ['theme' => $this->name, 'type' => 'ie', 'subtype' => 'theme']);
            } else {
                foreach ($css['plugins'] as $plugin => $unused) {
                    $urls[] = new moodle_url($baseurl, ['theme' => $this->name, 'type' => 'plugin', 'subtype' => $plugin]);
                }
                foreach ($css['parents'] as $parent => $sheets) {
                    foreach ($sheets as $sheet => $unused2) {
                        $urls[] = new moodle_url($baseurl, [
                            'theme' => $this->name,
                            'type' => 'parent',
                            'subtype' => $parent,
                            'sheet' => $sheet,
                        ]);
                    }
                }
                foreach ($css['theme'] as $sheet => $filename) {
                    if ($sheet === self::SCSS_KEY) {
                        // This is the theme SCSS file.
                        $urls[] = new moodle_url($baseurl, ['theme' => $this->name, 'type' => 'scss']);
                    } else {
                        // Sheet first in order to make long urls easier to read.
                        $urls[] = new moodle_url($baseurl, ['sheet' => $sheet, 'theme' => $this->name, 'type' => 'theme']);
                    }
                }
            }
        }

        // Allow themes to change the css url to something like theme/mytheme/mycss.php.
        component_callback('theme_' . $this->name, 'alter_css_urls', [&$urls]);
        return $urls;
    }

    /**
     * Get the whole css stylesheet for production mode.
     *
     * NOTE: this method is not expected to be used from any addons.
     *
     * @return string CSS markup compressed
     */
    public function get_css_content() {

        $csscontent = '';
        foreach ($this->get_css_files(false) as $type => $value) {
            foreach ($value as $identifier => $val) {
                if (is_array($val)) {
                    foreach ($val as $v) {
                        $csscontent .= file_get_contents($v) . "\n";
                    }
                } else {
                    if ($type === 'theme' && $identifier === self::SCSS_KEY) {
                        // We need the content from SCSS because this is the SCSS file from the theme.
                        if ($compiled = $this->get_css_content_from_scss(false)) {
                            $csscontent .= $compiled;
                        } else {
                            // The compiler failed so default back to any precompiled css that might
                            // exist.
                            $csscontent .= $this->get_precompiled_css_content();
                        }
                    } else {
                        $csscontent .= file_get_contents($val) . "\n";
                    }
                }
            }
        }
        $csscontent = $this->post_process($csscontent);
        $csscontent = core_minify::css($csscontent);

        return $csscontent;
    }
    /**
     * Set post processed CSS content cache.
     *
     * @param string $csscontent The post processed CSS content.
     * @return bool True if the content was successfully cached.
     */
    public function set_css_content_cache($csscontent) {

        $cache = cache::make('core', 'postprocessedcss');
        $key = $this->get_css_cache_key();

        return $cache->set($key, $csscontent);
    }

    /**
     * Return whether the post processed CSS content has been cached.
     *
     * @return bool Whether the post-processed CSS is available in the cache.
     */
    public function has_css_cached_content() {

        $key = $this->get_css_cache_key();
        $cache = cache::make('core', 'postprocessedcss');

        return $cache->has($key);
    }

    /**
     * Return cached post processed CSS content.
     *
     * @return bool|string The cached css content or false if not found.
     */
    public function get_css_cached_content() {

        $key = $this->get_css_cache_key();
        $cache = cache::make('core', 'postprocessedcss');

        return $cache->get($key);
    }

    /**
     * Generate the css content cache key.
     *
     * @return string The post processed css cache key.
     */
    public function get_css_cache_key() {
        $nosvg = (!$this->use_svg_icons()) ? 'nosvg_' : '';
        $rtlmode = ($this->rtlmode == true) ? 'rtl' : 'ltr';

        return $nosvg . $this->name . '_' . $rtlmode;
    }

    /**
     * Get the theme designer css markup,
     * the parameters are coming from css_urls().
     *
     * NOTE: this method is not expected to be used from any addons.
     *
     * @param string $type
     * @param string $subtype
     * @param string $sheet
     * @return string CSS markup
     */
    public function get_css_content_debug($type, $subtype, $sheet) {
        if ($type === 'scss') {
            // The SCSS file of the theme is requested.
            $csscontent = $this->get_css_content_from_scss(true);
            if ($csscontent !== false) {
                return $this->post_process($csscontent);
            }
            return '';
        }

        $cssfiles = [];
        $css = $this->get_css_files(true);

        if ($type === 'ie') {
            // IE is a sloppy browser with weird limits, sorry.
            if ($subtype === 'plugins') {
                $cssfiles = $css['plugins'];
            } else if ($subtype === 'parents') {
                if (empty($sheet)) { // phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedIf
                    // Do not bother with the empty parent here.
                } else {
                    // Build up the CSS for that parent so we can serve it as one file.
                    foreach ($css[$subtype][$sheet] as $parent => $css) {
                        $cssfiles[] = $css;
                    }
                }
            } else if ($subtype === 'theme') {
                $cssfiles = $css['theme'];
                foreach ($cssfiles as $key => $value) {
                    if (in_array($key, [self::SCSS_KEY])) {
                        // Remove the SCSS file from the theme CSS files.
                        // The SCSS files use the type 'scss', not 'ie'.
                        unset($cssfiles[$key]);
                    }
                }
            }
        } else if ($type === 'plugin') {
            if (isset($css['plugins'][$subtype])) {
                $cssfiles[] = $css['plugins'][$subtype];
            }
        } else if ($type === 'parent') {
            if (isset($css['parents'][$subtype][$sheet])) {
                $cssfiles[] = $css['parents'][$subtype][$sheet];
            }
        } else if ($type === 'theme') {
            if (isset($css['theme'][$sheet])) {
                $cssfiles[] = $css['theme'][$sheet];
            }
        }

        $csscontent = '';
        foreach ($cssfiles as $file) {
            $contents = file_get_contents($file);
            $contents = $this->post_process($contents);
            $comment = "/** Path: $type $subtype $sheet.' **/\n";
            $stats = '';
            $csscontent .= $comment . $stats . $contents . "\n\n";
        }

        return $csscontent;
    }

    /**
     * Get the whole css stylesheet for editor iframe.
     *
     * NOTE: this method is not expected to be used from any addons.
     *
     * @return string CSS markup
     */
    public function get_css_content_editor() {
        $css = '';
        $cssfiles = $this->editor_css_files();

        // If editor has static CSS, include it.
        foreach ($cssfiles as $file) {
            $css .= file_get_contents($file) . "\n";
        }

        // If editor has SCSS, compile and include it.
        if (($convertedscss = $this->editor_scss_to_css())) {
            $css .= $convertedscss;
        }

        $output = $this->post_process($css);

        return $output;
    }

    /**
     * Returns an array of organised CSS files required for this output.
     *
     * @param bool $themedesigner
     * @return array nested array of file paths
     */
    protected function get_css_files($themedesigner) {
        global $CFG;

        $cache = null;
        $cachekey = 'cssfiles';
        if ($themedesigner) {
            require_once($CFG->dirroot . '/lib/csslib.php');
            // We need some kind of caching here because otherwise the page navigation becomes
            // way too slow in theme designer mode. Feel free to create full cache definition later...
            $cache = cache::make_from_params(cache_store::MODE_APPLICATION, 'core', 'themedesigner', ['theme' => $this->name]);
            if ($files = $cache->get($cachekey)) {
                if ($files['created'] > time() - THEME_DESIGNER_CACHE_LIFETIME) {
                    unset($files['created']);
                    return $files;
                }
            }
        }

        $cssfiles = ['plugins' => [], 'parents' => [], 'theme' => []];

        // Get all plugin sheets.
        $excludes = $this->resolve_excludes('plugins_exclude_sheets');
        if ($excludes !== true) {
            foreach (core_component::get_plugin_types() as $type => $unused) {
                if ($type === 'theme' || (!empty($excludes[$type]) && $excludes[$type] === true)) {
                    continue;
                }
                $plugins = core_component::get_plugin_list($type);
                foreach ($plugins as $plugin => $fulldir) {
                    if (
                        !empty($excludes[$type])
                        && is_array($excludes[$type])
                        && in_array($plugin, $excludes[$type])
                    ) {
                        continue;
                    }

                    // Get the CSS from the plugin.
                    $sheetfile = "$fulldir/styles.css";
                    if (is_readable($sheetfile)) {
                        $cssfiles['plugins'][$type . '_' . $plugin] = $sheetfile;
                    }

                    // Create a list of candidate sheets from parents (direct parent last) and current theme.
                    $candidates = [];
                    foreach (array_reverse($this->parent_configs) as $parent_config) {
                        $candidates[] = $parent_config->name;
                    }
                    $candidates[] = $this->name;

                    // Add the sheets found.
                    foreach ($candidates as $candidate) {
                        $sheetthemefile = "$fulldir/styles_{$candidate}.css";
                        if (is_readable($sheetthemefile)) {
                            $cssfiles['plugins'][$type . '_' . $plugin . '_' . $candidate] = $sheetthemefile;
                        }
                    }
                }
            }
        }

        // Find out wanted parent sheets.
        $excludes = $this->resolve_excludes('parents_exclude_sheets');
        if ($excludes !== true) {
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                $parent = $parent_config->name;
                if (empty($parent_config->sheets) || (!empty($excludes[$parent]) && $excludes[$parent] === true)) {
                    continue;
                }
                foreach ($parent_config->sheets as $sheet) {
                    if (
                        !empty($excludes[$parent]) && is_array($excludes[$parent])
                            && in_array($sheet, $excludes[$parent])
                    ) {
                        continue;
                    }

                    // We never refer to the parent LESS files.
                    $sheetfile = "$parent_config->dir/style/$sheet.css";
                    if (is_readable($sheetfile)) {
                        $cssfiles['parents'][$parent][$sheet] = $sheetfile;
                    }
                }
            }
        }

        // Current theme sheets.
        // We first add the SCSS file because we want the CSS ones to
        // be included after the SCSS code.
        if ($this->get_scss_property()) {
            $cssfiles['theme'][self::SCSS_KEY] = true;
        }
        if (is_array($this->sheets)) {
            foreach ($this->sheets as $sheet) {
                $sheetfile = "$this->dir/style/$sheet.css";
                if (is_readable($sheetfile) && !isset($cssfiles['theme'][$sheet])) {
                    $cssfiles['theme'][$sheet] = $sheetfile;
                }
            }
        }

        if ($cache) {
            $files = $cssfiles;
            $files['created'] = time();
            $cache->set($cachekey, $files);
        }
        return $cssfiles;
    }

    /**
     * Return the CSS content generated from the SCSS file.
     *
     * @param bool $themedesigner True if theme designer is enabled.
     * @return bool|string Return false when the compilation failed. Else the compiled string.
     */
    protected function get_css_content_from_scss($themedesigner) {
        global $CFG;

        [$paths, $scss] = $this->get_scss_property();
        if (!$scss) {
            throw new coding_exception('The theme did not define a SCSS file, or it is not readable.');
        }

        // We might need more memory/time to do this, so let's play safe.
        raise_memory_limit(MEMORY_EXTRA);
        core_php_time_limit::raise(300);

        // TODO: MDL-62757 When changing anything in this method please do not forget to check
        // if the validate() method in class admin_setting_configthemepreset needs updating too.

        $cachedir = make_localcache_directory('scsscache-' . $this->name, false);
        $cacheoptions = [];
        if ($themedesigner) {
            $cacheoptions = [
                  'cacheDir' => $cachedir,
                  'prefix' => 'scssphp_',
                  'forceRefresh' => false,
            ];
        } else {
            if (file_exists($cachedir)) {
                remove_dir($cachedir);
            }
        }

        // Set-up the compiler.
        $compiler = new core_scss($cacheoptions);

        if ($this->supports_source_maps($themedesigner)) {
            // Enable source maps.
            $compiler->setSourceMapOptions([
                'sourceMapBasepath' => str_replace('\\', '/', $CFG->dirroot),
                'sourceMapRootpath' => $CFG->wwwroot . '/',
            ]);
            $compiler->setSourceMap($compiler::SOURCE_MAP_INLINE);
        }

        $compiler->prepend_raw_scss($this->get_pre_scss_code());
        if (is_string($scss)) {
            $compiler->set_file($scss);
        } else {
            $compiler->append_raw_scss($scss($this));
            $compiler->setImportPaths($paths);
        }
        $compiler->append_raw_scss($this->get_extra_scss_code());

        try {
            // Compile!
            $compiled = $compiler->to_css();
        } catch (\Exception $e) {
            $compiled = false;
            debugging('Error while compiling SCSS: ' . $e->getMessage(), DEBUG_DEVELOPER);
        }

        // Try to save memory.
        $compiler = null;
        unset($compiler);

        return $compiled;
    }

    /**
     * Return the precompiled CSS if the precompiledcsscallback exists.
     *
     * @return string Return compiled css.
     */
    public function get_precompiled_css_content() {
        $configs = array_reverse($this->parent_configs) + [$this];
        $css = '';

        foreach ($configs as $config) {
            if (isset($config->precompiledcsscallback)) {
                $function = $config->precompiledcsscallback;
                if (function_exists($function)) {
                    $css .= $function($this);
                }
            }
        }
        return $css;
    }

    /**
     * Get the icon system to use.
     *
     * @return string
     */
    public function get_icon_system() {

        // Getting all the candidate functions.
        $system = false;
        if (isset($this->iconsystem) && icon_system::is_valid_system($this->iconsystem)) {
            return $this->iconsystem;
        }
        foreach ($this->parent_configs as $parent_config) {
            if (isset($parent_config->iconsystem) && icon_system::is_valid_system($parent_config->iconsystem)) {
                return $parent_config->iconsystem;
            }
        }
        return icon_system::STANDARD;
    }

    /**
     * Return extra SCSS code to add when compiling.
     *
     * This is intended to be used by themes to inject some SCSS code
     * before it gets compiled. If you want to inject variables you
     * should use {@see self::get_scss_variables()}.
     *
     * @return string The SCSS code to inject.
     */
    public function get_extra_scss_code() {
        $content = '';

        // Getting all the candidate functions.
        $candidates = [];
        foreach (array_reverse($this->parent_configs) as $parent_config) {
            if (!isset($parent_config->extrascsscallback)) {
                continue;
            }
            $candidates[] = $parent_config->extrascsscallback;
        }

        if (isset($this->extrascsscallback)) {
            $candidates[] = $this->extrascsscallback;
        }

        // Calling the functions.
        foreach ($candidates as $function) {
            if (function_exists($function)) {
                $content .= "\n/** Extra SCSS from $function **/\n" . $function($this) . "\n";
            }
        }

        return $content;
    }

    /**
     * SCSS code to prepend when compiling.
     *
     * This is intended to be used by themes to inject SCSS code before it gets compiled.
     *
     * @return string The SCSS code to inject.
     */
    public function get_pre_scss_code() {
        $content = '';

        // Getting all the candidate functions.
        $candidates = [];
        foreach (array_reverse($this->parent_configs) as $parent_config) {
            if (!isset($parent_config->prescsscallback)) {
                continue;
            }
            $candidates[] = $parent_config->prescsscallback;
        }

        if (isset($this->prescsscallback)) {
            $candidates[] = $this->prescsscallback;
        }

        // Calling the functions.
        foreach ($candidates as $function) {
            if (function_exists($function)) {
                $content .= "\n/** Pre-SCSS from $function **/\n" . $function($this) . "\n";
            }
        }

        return $content;
    }

    /**
     * Get the SCSS property.
     *
     * This resolves whether a SCSS file (or content) has to be used when generating
     * the stylesheet for the theme. It will look at parents themes and check the
     * SCSS properties there.
     *
     * @return array|false False when SCSS is not used.
     *         An array with the import paths, and the path to the SCSS file or Closure as second.
     */
    public function get_scss_property() {
        if ($this->scsscache === null) {
            $configs = [$this] + $this->parent_configs;
            $scss = null;

            foreach ($configs as $config) {
                $path = "{$config->dir}/scss";

                // We collect the SCSS property until we've found one.
                if (empty($scss) && !empty($config->scss)) {
                    $candidate = is_string($config->scss) ? "{$path}/{$config->scss}.scss" : $config->scss;
                    if ($candidate instanceof \Closure) {
                        $scss = $candidate;
                    } else if (is_string($candidate) && is_readable($candidate)) {
                        $scss = $candidate;
                    }
                }

                // We collect the import paths once we've found a SCSS property.
                if ($scss && is_dir($path)) {
                    $paths[] = $path;
                }
            }

            $this->scsscache = $scss !== null ? [$paths, $scss] : false;
        }

        return $this->scsscache;
    }

    /**
     * Generate a URL to the file that serves theme JavaScript files.
     *
     * If we determine that the theme has no relevant files, then we return
     * early with a null value.
     *
     * @param bool $inhead true means head url, false means footer
     * @return moodle_url|null
     */
    public function javascript_url($inhead) {
        global $CFG;

        $rev = theme_get_revision();
        $params = ['theme' => $this->name, 'rev' => $rev];
        $params['type'] = $inhead ? 'head' : 'footer';

        // Return early if there are no files to serve.
        if (count($this->javascript_files($params['type'])) === 0) {
            return null;
        }

        if (!empty($CFG->slasharguments) && $rev > 0) {
            $url = new moodle_url("/theme/javascript.php");
            $url->set_slashargument('/' . $this->name . '/' . $rev . '/' . $params['type'], 'noparam', true);
            return $url;
        } else {
            return new moodle_url('/theme/javascript.php', $params);
        }
    }

    /**
     * Get the URL's for the JavaScript files used by this theme.
     * They won't be served directly, instead they'll be mediated through
     * theme/javascript.php.
     *
     * @param string $type Either javascripts_footer, or javascripts
     * @return array
     */
    public function javascript_files($type) {
        if ($type === 'footer') {
            $type = 'javascripts_footer';
        } else {
            $type = 'javascripts';
        }

        $js = [];
        // Find out wanted parent javascripts.
        $excludes = $this->resolve_excludes('parents_exclude_javascripts');
        if ($excludes !== true) {
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                $parent = $parent_config->name;
                if (empty($parent_config->$type)) {
                    continue;
                }
                if (!empty($excludes[$parent]) && $excludes[$parent] === true) {
                    continue;
                }
                foreach ($parent_config->$type as $javascript) {
                    if (
                        !empty($excludes[$parent])
                        && is_array($excludes[$parent])
                        && in_array($javascript, $excludes[$parent])
                    ) {
                        continue;
                    }
                    $javascriptfile = "$parent_config->dir/javascript/$javascript.js";
                    if (is_readable($javascriptfile)) {
                        $js[] = $javascriptfile;
                    }
                }
            }
        }

        // Current theme javascripts.
        if (is_array($this->$type)) {
            foreach ($this->$type as $javascript) {
                $javascriptfile = "$this->dir/javascript/$javascript.js";
                if (is_readable($javascriptfile)) {
                    $js[] = $javascriptfile;
                }
            }
        }
        return $js;
    }

    /**
     * Resolves an exclude setting to the themes setting is applicable or the
     * setting of its closest parent.
     *
     * @param string $variable The name of the setting the exclude setting to resolve
     * @param string $default
     * @return mixed
     */
    protected function resolve_excludes($variable, $default = null) {
        $setting = $default;
        if (is_array($this->{$variable}) || $this->{$variable} === true) {
            $setting = $this->{$variable};
        } else {
            foreach ($this->parent_configs as $parent_config) { // The immediate parent first, base last.
                if (!isset($parent_config->{$variable})) {
                    continue;
                }
                if (is_array($parent_config->{$variable}) || $parent_config->{$variable} === true) {
                    $setting = $parent_config->{$variable};
                    break;
                }
            }
        }
        return $setting;
    }

    /**
     * Returns the content of the one huge javascript file merged from all theme javascript files.
     *
     * @param bool $type
     * @return string
     */
    public function javascript_content($type) {
        $jsfiles = $this->javascript_files($type);
        $js = '';
        foreach ($jsfiles as $jsfile) {
            $js .= file_get_contents($jsfile) . "\n";
        }
        return $js;
    }

    /**
     * Post processes CSS.
     *
     * This method post processes all of the CSS before it is served for this theme.
     * This is done so that things such as image URL's can be swapped in and to
     * run any specific CSS post process method the theme has requested.
     * This allows themes to use CSS settings.
     *
     * @param string $css The CSS to process.
     * @return string The processed CSS.
     */
    public function post_process($css) {
        // Now resolve all image locations.
        if (preg_match_all('/\[\[pix:([a-z0-9_]+\|)?([^\]]+)\]\]/', $css, $matches, PREG_SET_ORDER)) {
            $replaced = [];
            foreach ($matches as $match) {
                if (isset($replaced[$match[0]])) {
                    continue;
                }
                $replaced[$match[0]] = true;
                $imagename = $match[2];
                $component = rtrim($match[1], '|');
                $imageurl = $this->image_url($imagename, $component)->out(false);
                // We do not need full url because the image.php is always in the same dir.
                $imageurl = preg_replace('|^http.?://[^/]+|', '', $imageurl);
                $css = str_replace($match[0], $imageurl, $css);
            }
        }

        // Now resolve all font locations.
        if (preg_match_all('/\[\[font:([a-z0-9_]+\|)?([^\]]+)\]\]/', $css, $matches, PREG_SET_ORDER)) {
            $replaced = [];
            foreach ($matches as $match) {
                if (isset($replaced[$match[0]])) {
                    continue;
                }
                $replaced[$match[0]] = true;
                $fontname = $match[2];
                $component = rtrim($match[1], '|');
                $fonturl = $this->font_url($fontname, $component)->out(false);
                // We do not need full url because the font.php is always in the same dir.
                $fonturl = preg_replace('|^http.?://[^/]+|', '', $fonturl);
                $css = str_replace($match[0], $fonturl, $css);
            }
        }

        // Now resolve all theme settings or do any other postprocessing.
        // This needs to be done before calling core parser, since the parser strips [[settings]] tags.
        $csspostprocess = $this->csspostprocess;
        if ($csspostprocess && function_exists($csspostprocess)) {
            $css = $csspostprocess($css, $this);
        }

        // Post processing using an object representation of CSS.
        $treeprocessor = $this->get_css_tree_post_processor();
        $needsparsing = !empty($treeprocessor) || !empty($this->rtlmode);
        if ($needsparsing) {
            // We might need more memory/time to do this, so let's play safe.
            raise_memory_limit(MEMORY_EXTRA);
            core_php_time_limit::raise(300);

            $parser = new core_cssparser($css);
            $csstree = $parser->parse();
            unset($parser);

            if ($this->rtlmode) {
                $this->rtlize($csstree);
            }

            if ($treeprocessor) {
                $treeprocessor($csstree, $this);
            }

            $css = $csstree->render();
            unset($csstree);
        }

        return $css;
    }

    /**
     * Flip a stylesheet to RTL.
     *
     * @param mixed $csstree The parsed CSS tree structure to flip.
     * @return void
     */
    protected function rtlize($csstree) {
        $rtlcss = new core_rtlcss($csstree);
        $rtlcss->flip();
    }

    /**
     * Return the direct URL for an image from the pix folder.
     *
     * Use this function sparingly and never for icons. For icons use pix_icon or the pix helper in a mustache template.
     *
     * @deprecated since Moodle 3.3
     * @param string $imagename the name of the icon.
     * @param string $component specification of one plugin like in get_string()
     * @return moodle_url
     */
    public function pix_url($imagename, $component) {
        debugging('pix_url is deprecated. Use image_url for images and pix_icon for icons.', DEBUG_DEVELOPER);
        return $this->image_url($imagename, $component);
    }

    /**
     * Return the direct URL for an image from the pix folder.
     *
     * Use this function sparingly and never for icons. For icons use pix_icon or the pix helper in a mustache template.
     *
     * @param string $imagename the name of the icon.
     * @param string $component specification of one plugin like in get_string()
     * @return moodle_url
     */
    public function image_url($imagename, $component) {
        global $CFG;

        $params = ['theme' => $this->name];
        $svg = $this->use_svg_icons();

        if (empty($component) || $component === 'moodle' || $component === 'core') {
            $params['component'] = 'core';
        } else {
            $params['component'] = $component;
        }

        $rev = theme_get_revision();
        if ($rev != -1) {
            $params['rev'] = $rev;
        }

        $params['image'] = $imagename;

        $url = new moodle_url("/theme/image.php");
        if (!empty($CFG->slasharguments) && $rev > 0) {
            $path = '/' . $params['theme'] . '/' . $params['component'] . '/' . $params['rev'] . '/' . $params['image'];
            if (!$svg) {
                // We add a simple /_s to the start of the path.
                // The underscore is used to ensure that it isn't a valid theme name.
                $path = '/_s' . $path;
            }
            $url->set_slashargument($path, 'noparam', true);
        } else {
            if (!$svg) {
                // We add an SVG param so that we know not to serve SVG images.
                // We do this because all modern browsers support SVG and this param will one day be removed.
                $params['svg'] = '0';
            }
            $url->params($params);
        }

        return $url;
    }

    /**
     * Return the URL for a font
     *
     * @param string $font the name of the font (including extension).
     * @param string $component specification of one plugin like in get_string()
     * @return moodle_url
     */
    public function font_url($font, $component) {
        global $CFG;

        $params = ['theme' => $this->name];

        if (empty($component) || $component === 'moodle' || $component === 'core') {
            $params['component'] = 'core';
        } else {
            $params['component'] = $component;
        }

        $rev = theme_get_revision();
        if ($rev != -1) {
            $params['rev'] = $rev;
        }

        $params['font'] = $font;

        $url = new moodle_url("/theme/font.php");
        if (!empty($CFG->slasharguments) && $rev > 0) {
            $path = '/' . $params['theme'] . '/' . $params['component'] . '/' . $params['rev'] . '/' . $params['font'];
            $url->set_slashargument($path, 'noparam', true);
        } else {
            $url->params($params);
        }

        return $url;
    }

    /**
     * Returns URL to the stored file via pluginfile.php.
     *
     * Note the theme must also implement pluginfile.php handler,
     * theme revision is used instead of the itemid.
     *
     * @param string $setting
     * @param string $filearea
     * @return string protocol relative URL or null if not present
     */
    public function setting_file_url($setting, $filearea) {
        global $CFG;

        if (empty($this->settings->$setting)) {
            return null;
        }

        $component = 'theme_' . $this->name;
        $itemid = theme_get_revision();
        $filepath = $this->settings->$setting;
        $syscontext = context_system::instance();

        $url = moodle_url::make_file_url(
            "$CFG->wwwroot/pluginfile.php",
            "/$syscontext->id/$component/$filearea/$itemid" . $filepath,
        );

        // Now this is tricky because the we can not hardcode http or https here, lets use the relative link.
        // Note: unfortunately moodle_url does not support //urls yet.

        $url = preg_replace('|^https?://|i', '//', $url->out(false));

        return $url;
    }

    /**
     * Serve the theme setting file.
     *
     * @param string $filearea
     * @param array $args
     * @param bool $forcedownload
     * @param array $options
     * @return bool may terminate if file not found or donotdie not specified
     */
    public function setting_file_serve($filearea, $args, $forcedownload, $options) {
        global $CFG;
        require_once("$CFG->libdir/filelib.php");

        $syscontext = context_system::instance();
        $component = 'theme_' . $this->name;

        $revision = array_shift($args);
        if ($revision < 0) {
            $lifetime = 0;
        } else {
            $lifetime = 60 * 60 * 24 * 60;
            // By default, theme files must be cache-able by both browsers and proxies.
            if (!array_key_exists('cacheability', $options)) {
                $options['cacheability'] = 'public';
            }
        }

        $fs = get_file_storage();
        $relativepath = implode('/', $args);

        $fullpath = "/{$syscontext->id}/{$component}/{$filearea}/0/{$relativepath}";
        $fullpath = rtrim($fullpath, '/');
        if ($file = $fs->get_file_by_hash(sha1($fullpath))) {
            send_stored_file($file, $lifetime, 0, $forcedownload, $options);
            return true;
        } else {
            send_file_not_found();
        }
    }

    /**
     * Resolves the real image location.
     *
     * $svg was introduced as an arg in 2.4. It is important because not all supported browsers support the use of SVG
     * and we need a way in which to turn it off.
     * By default SVG won't be used unless asked for. This is done for two reasons:
     *   1. It ensures that we don't serve svg images unless we really want to. The admin has selected to force them, of the users
     *      browser supports SVG.
     *   2. We only serve SVG images from locations we trust. This must NOT include any areas where the image may have been uploaded
     *      by the user due to security concerns.
     *
     * @param string $image name of image, may contain relative path
     * @param string $component
     * @param bool|null $svg Should SVG images also be looked for? If null, falls back to auto-detection of browser support
     * @return string full file path
     */
    public function resolve_image_location($image, $component, $svg = false) {
        global $CFG;

        if (!is_bool($svg)) {
            // If $svg isn't a bool then we need to decide for ourselves.
            $svg = $this->use_svg_icons();
        }

        if ($component === 'moodle' || $component === 'core' || empty($component)) {
            if ($imagefile = $this->image_exists("$this->dir/pix_core/$image", $svg)) {
                return $imagefile;
            }
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                if ($imagefile = $this->image_exists("$parent_config->dir/pix_core/$image", $svg)) {
                    return $imagefile;
                }
            }
            if ($imagefile = $this->image_exists("$CFG->dataroot/pix/$image", $svg)) {
                return $imagefile;
            }
            if ($imagefile = $this->image_exists("$CFG->dirroot/pix/$image", $svg)) {
                return $imagefile;
            }
            return null;
        } else if ($component === 'theme') { // Exception.
            if ($image === 'favicon') {
                return "$this->dir/pix/favicon.ico";
            }
            if ($imagefile = $this->image_exists("$this->dir/pix/$image", $svg)) {
                return $imagefile;
            }
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                if ($imagefile = $this->image_exists("$parent_config->dir/pix/$image", $svg)) {
                    return $imagefile;
                }
            }
            return null;
        } else {
            if (strpos($component, '_') === false) {
                $component = "mod_{$component}";
            }
            [$type, $plugin] = explode('_', $component, 2);

            // In Moodle 4.0 we introduced a new image format.
            // Support that image format here.
            $candidates = [$image];

            if ($type === 'mod') {
                if ($image === 'icon' || $image === 'monologo') {
                    $candidates = ['monologo', 'icon'];
                    if ($image === 'icon') {
                        debugging(
                            "The 'icon' image for activity modules has been replaced with a new 'monologo'. " .
                                "Please update your calling code to fetch the new icon where possible. " .
                                "Called for component {$component}.",
                            DEBUG_DEVELOPER
                        );
                    }
                }
            }
            foreach ($candidates as $image) {
                if ($imagefile = $this->image_exists("$this->dir/pix_plugins/$type/$plugin/$image", $svg)) {
                    return $imagefile;
                }

                // Base first, the immediate parent last.
                foreach (array_reverse($this->parent_configs) as $parentconfig) {
                    if ($imagefile = $this->image_exists("$parentconfig->dir/pix_plugins/$type/$plugin/$image", $svg)) {
                        return $imagefile;
                    }
                }
                if ($imagefile = $this->image_exists("$CFG->dataroot/pix_plugins/$type/$plugin/$image", $svg)) {
                    return $imagefile;
                }
                $dir = core_component::get_plugin_directory($type, $plugin);
                if ($imagefile = $this->image_exists("$dir/pix/$image", $svg)) {
                    return $imagefile;
                }
            }
            return null;
        }
    }

    /**
     * Resolves the real font location.
     *
     * @param string $font name of font file
     * @param string $component
     * @return string full file path
     */
    public function resolve_font_location($font, $component) {
        global $CFG;

        if ($component === 'moodle' || $component === 'core' || empty($component)) {
            if (file_exists("$this->dir/fonts_core/$font")) {
                return "$this->dir/fonts_core/$font";
            }
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                if (file_exists("$parent_config->dir/fonts_core/$font")) {
                    return "$parent_config->dir/fonts_core/$font";
                }
            }
            if (file_exists("$CFG->dataroot/fonts/$font")) {
                return "$CFG->dataroot/fonts/$font";
            }
            if (file_exists("$CFG->dirroot/lib/fonts/$font")) {
                return "$CFG->dirroot/lib/fonts/$font";
            }
            return null;
        } else if ($component === 'theme') { // Exception.
            if (file_exists("$this->dir/fonts/$font")) {
                return "$this->dir/fonts/$font";
            }
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                if (file_exists("$parent_config->dir/fonts/$font")) {
                    return "$parent_config->dir/fonts/$font";
                }
            }
            return null;
        } else {
            if (strpos($component, '_') === false) {
                $component = 'mod_' . $component;
            }
            [$type, $plugin] = explode('_', $component, 2);

            if (file_exists("$this->dir/fonts_plugins/$type/$plugin/$font")) {
                return "$this->dir/fonts_plugins/$type/$plugin/$font";
            }
            foreach (array_reverse($this->parent_configs) as $parent_config) { // Base first, the immediate parent last.
                if (file_exists("$parent_config->dir/fonts_plugins/$type/$plugin/$font")) {
                    return "$parent_config->dir/fonts_plugins/$type/$plugin/$font";
                }
            }
            if (file_exists("$CFG->dataroot/fonts_plugins/$type/$plugin/$font")) {
                return "$CFG->dataroot/fonts_plugins/$type/$plugin/$font";
            }
            $dir = core_component::get_plugin_directory($type, $plugin);
            if (file_exists("$dir/fonts/$font")) {
                return "$dir/fonts/$font";
            }
            return null;
        }
    }

    /**
     * Return true if we should look for SVG images as well.
     *
     * @return bool
     */
    public function use_svg_icons() {
        if ($this->usesvg === null) {
            $this->usesvg = core_useragent::supports_svg();
        }

        return $this->usesvg;
    }

    /**
     * Forces the usesvg setting to either true or false, avoiding any decision making.
     *
     * This function should only ever be used when absolutely required, and before any generation of image URL's has occurred.
     * DO NOT ABUSE THIS FUNCTION... not that you'd want to right ;)
     *
     * @param bool $setting True to force the use of svg when available, null otherwise.
     */
    public function force_svg_use($setting) {
        $this->usesvg = (bool)$setting;
    }

    /**
     * Set to be in RTL mode.
     *
     * This will likely be used when post processing the CSS before serving it.
     *
     * @param bool $inrtl True when in RTL mode.
     */
    public function set_rtl_mode($inrtl = true) {
        $this->rtlmode = $inrtl;
    }

    /**
     * Checks if source maps are supported
     *
     * @param bool $themedesigner True if theme designer is enabled.
     * @return boolean True if source maps are supported.
     */
    public function supports_source_maps($themedesigner): bool {
        if (empty($this->rtlmode) && $themedesigner) {
            return true;
        }
        return false;
    }

    /**
     * Whether the theme is being served in RTL mode.
     *
     * @return bool True when in RTL mode.
     */
    public function get_rtl_mode() {
        return $this->rtlmode;
    }

    /**
     * Checks if file with any image extension exists.
     *
     * The order to these images was adjusted prior to the release of 2.4
     * At that point the were the following image counts in Moodle core:
     *
     *     - png = 667 in pix dirs (1499 total)
     *     - gif = 385 in pix dirs (606 total)
     *     - jpg = 62  in pix dirs (74 total)
     *     - jpeg = 0  in pix dirs (1 total)
     *
     * There is work in progress to move towards SVG presently hence that has been prioritiesed.
     *
     * @param string $filepath
     * @param bool $svg If set to true SVG images will also be looked for.
     * @return string image name with extension
     */
    private static function image_exists($filepath, $svg = false) {
        if ($svg && file_exists("$filepath.svg")) {
            return "$filepath.svg";
        } else if (file_exists("$filepath.png")) {
            return "$filepath.png";
        } else if (file_exists("$filepath.gif")) {
            return "$filepath.gif";
        } else if (file_exists("$filepath.jpg")) {
            return "$filepath.jpg";
        } else if (file_exists("$filepath.jpeg")) {
            return "$filepath.jpeg";
        } else {
            return false;
        }
    }

    /**
     * Loads the theme config from config.php file.
     *
     * @param string $themename
     * @param stdClass $settings from config_plugins table
     * @param boolean $parentscheck true to also check the parents.    .
     * @return ?stdClass The theme configuration
     */
    private static function find_theme_config($themename, $settings, $parentscheck = true) {
        // We have to use the variable name $THEME (upper case) because that
        // is what is used in theme config.php files.

        if (!$dir = self::find_theme_location($themename)) {
            return null;
        }

        $THEME = new stdClass();
        $THEME->name     = $themename;
        $THEME->dir      = $dir;
        $THEME->settings = $settings;

        global $CFG; // Just in case somebody tries to use $CFG in theme config.
        include("$THEME->dir/config.php");

        // Verify the theme configuration is OK.
        if (!is_array($THEME->parents)) {
            // Parents option is mandatory now.
            return null;
        } else {
            // We use $parentscheck to only check the direct parents (avoid infinite loop).
            if ($parentscheck) {
                // Find all parent theme configs.
                foreach ($THEME->parents as $parent) {
                    $parentconfig = self::find_theme_config($parent, $settings, false);
                    if (empty($parentconfig)) {
                        return null;
                    }
                }
            }
        }

        return $THEME;
    }

    /**
     * Finds the theme location and verifies the theme has all needed files
     * and is not obsoleted.
     *
     * @param string $themename
     * @return string full dir path or null if not found
     */
    private static function find_theme_location($themename) {
        global $CFG;

        if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
            $dir = "$CFG->dirroot/theme/$themename";
        } else if (!empty($CFG->themedir) && file_exists("$CFG->themedir/$themename/config.php")) {
            $dir = "$CFG->themedir/$themename";
        } else {
            return null;
        }

        if (file_exists("$dir/styles.php")) {
            // Legacy theme - needs to be upgraded - upgrade info is displayed on the admin settings page.
            return null;
        }

        return $dir;
    }

    /**
     * Get the renderer for a part of Moodle for this theme.
     *
     * @param moodle_page $page the page we are rendering
     * @param string $component the name of part of moodle. E.g. 'core', 'quiz', 'qtype_multichoice'.
     * @param string $subtype optional subtype such as 'news' resulting to 'mod_forum_news'
     * @param string $target one of rendering target constants
     * @return renderer_base the requested renderer.
     */
    public function get_renderer(moodle_page $page, $component, $subtype = null, $target = null) {
        if (is_null($this->rf)) {
            $classname = $this->rendererfactory;
            $this->rf = new $classname($this);
        }

        return $this->rf->get_renderer($page, $component, $subtype, $target);
    }

    /**
     * Get the information from {@see $layouts} for this type of page.
     *
     * @param string $pagelayout the the page layout name.
     * @return array the appropriate part of {@see $layouts}.
     */
    protected function layout_info_for_page($pagelayout) {
        if (array_key_exists($pagelayout, $this->layouts)) {
            return $this->layouts[$pagelayout];
        } else {
            debugging('Invalid page layout specified: ' . $pagelayout);
            return $this->layouts['standard'];
        }
    }

    /**
     * Given the settings of this theme, and the page pagelayout, return the
     * full path of the page layout file to use.
     *
     * Used by {@see core_renderer::header()}.
     *
     * @param string $pagelayout the the page layout name.
     * @return string Full path to the lyout file to use
     */
    public function layout_file($pagelayout) {
        global $CFG;

        $layoutinfo = $this->layout_info_for_page($pagelayout);
        $layoutfile = $layoutinfo['file'];

        if (array_key_exists('theme', $layoutinfo)) {
            $themes = [$layoutinfo['theme']];
        } else {
            $themes = array_merge([$this->name], $this->parents);
        }

        foreach ($themes as $theme) {
            if ($dir = $this->find_theme_location($theme)) {
                $path = "$dir/layout/$layoutfile";

                // Check the template exists, return general base theme template if not.
                if (is_readable($path)) {
                    return $path;
                }
            }
        }

        throw new coding_exception('Can not find layout file for: ' . $pagelayout . ' (' . $layoutfile . ')');
    }

    /**
     * Returns auxiliary page layout options specified in layout configuration array.
     *
     * @param string $pagelayout
     * @return array
     */
    public function pagelayout_options($pagelayout) {
        $info = $this->layout_info_for_page($pagelayout);
        if (!empty($info['options'])) {
            return $info['options'];
        }
        return [];
    }

    /**
     * Inform a block_manager about the block regions this theme wants on this
     * page layout.
     *
     * @param string $pagelayout the general type of the page.
     * @param block_manager $blockmanager the block_manger to set up.
     */
    public function setup_blocks($pagelayout, $blockmanager) {
        $layoutinfo = $this->layout_info_for_page($pagelayout);
        if (!empty($layoutinfo['regions'])) {
            $blockmanager->add_regions($layoutinfo['regions'], false);
            $blockmanager->set_default_region($layoutinfo['defaultregion']);
        }
    }

    /**
     * Gets the visible name for the requested block region.
     *
     * @param string $region The region name to get
     * @param string $theme The theme the region belongs to (may come from the parent theme)
     * @return string
     */
    protected function get_region_name($region, $theme) {

        $stringman = get_string_manager();

        // Check if the name is defined in the theme.
        if ($stringman->string_exists('region-' . $region, 'theme_' . $theme)) {
            return get_string('region-' . $region, 'theme_' . $theme);
        }

        // Check the theme parents.
        foreach ($this->parents as $parentthemename) {
            if ($stringman->string_exists('region-' . $region, 'theme_' . $parentthemename)) {
                return get_string('region-' . $region, 'theme_' . $parentthemename);
            }
        }

        // Last resort, try the boost theme for names.
        return get_string('region-' . $region, 'theme_boost');
    }

    /**
     * Get the list of all block regions known to this theme in all templates.
     *
     * @return array internal region name => human readable name.
     */
    public function get_all_block_regions() {
        $regions = [];
        foreach ($this->layouts as $layoutinfo) {
            foreach ($layoutinfo['regions'] as $region) {
                $regions[$region] = $this->get_region_name($region, $this->name);
            }
        }
        return $regions;
    }

    /**
     * Returns the human readable name of the theme
     *
     * @return string
     */
    public function get_theme_name() {
        return get_string('pluginname', 'theme_' . $this->name);
    }

    /**
     * Returns the block render method.
     *
     * It is set by the theme via:
     *     $THEME->blockrendermethod = '...';
     *
     * It can be one of two values, blocks or blocks_for_region.
     * It should be set to the method being used by the theme layouts.
     *
     * @return string
     */
    public function get_block_render_method() {
        if ($this->blockrendermethod) {
            // Return the specified block render method.
            return $this->blockrendermethod;
        }
        // Its not explicitly set, check the parent theme configs.
        foreach ($this->parent_configs as $config) {
            if (isset($config->blockrendermethod)) {
                return $config->blockrendermethod;
            }
        }
        // Default it to blocks.
        return 'blocks';
    }

    /**
     * Get the callable for CSS tree post processing.
     *
     * @return string|null
     */
    public function get_css_tree_post_processor() {
        $configs = [$this] + $this->parent_configs;
        foreach ($configs as $config) {
            if (!empty($config->csstreepostprocessor) && is_callable($config->csstreepostprocessor)) {
                return $config->csstreepostprocessor;
            }
        }
        return null;
    }
}
// Alias this class to the old name.
// This file will be autoloaded by the legacyclasses autoload system.
// In future all uses of this class will be corrected and the legacy references will be removed.
class_alias(theme_config::class, \theme_config::class);
