Custom Grav theme to interact with UserFrosting

collegeparktutors.php

<?php
namespace Grav\Theme;

class CollegeParkTutors extends Antimatter {
    
    public function onTwigTemplatePaths() { 
        $grav_twig = $this->grav['twig'];
        $uf_dir = realpath(ROOT_DIR . '/..') . '/common/';
        $grav_twig->twig_paths[] = $uf_dir . "templates/collegeparktutors";
    }
    
    public function onTwigSiteVariables() {
        
        // Get Grav variables
        $grav_twig = $this->grav['twig'];
        $grav_site = $this->grav['config']['site'];
        
        // Load UF
        $uf_dir = realpath(ROOT_DIR . '/..') . '/common/';       
        require_once( $uf_dir . "config/config-collegeparktutors.php" );
        require_once( $uf_dir . "initialize.php" );
        
        $app = \Slim\Slim::getInstance();
        
        // Replace Grav's global Twig variables with our own
        unset($grav_twig->twig_vars['site']);
        $grav_twig->twig_vars['site'] = $app->site;
        
        $function_error_log = new \Twig_SimpleFunction('errorLog', function ($obj) {
            error_log(print_r($obj, true));
        });
        
        $grav_twig->twig->addFunction($function_error_log); 
        
        // Add Twig functions for including CSS and JS scripts from schema
        $function_include_css = new \Twig_SimpleFunction('includeCSS', function ($group_name = "common") {
            // Return array of CSS includes
            $app = \Slim\Slim::getInstance();
            return $app->schema->getCSSIncludes($group_name, $app->site['minify_css']);
            
        });
        
        $grav_twig->twig->addFunction($function_include_css);
        
        $function_include_bottom_js = new \Twig_SimpleFunction('includeJSBottom', function ($group_name = "common") {    
            // Return array of JS includes
            $app = \Slim\Slim::getInstance();
            return $app->schema->getJSBottomIncludes($group_name, $app->site['minify_js']);
        });
        
        $grav_twig->twig->addFunction($function_include_bottom_js);
        
        $function_include_top_js = new \Twig_SimpleFunction('includeJSTop', function ($group_name = "common") {    
            // Return array of JS includes
            $app = \Slim\Slim::getInstance();
            return $app->schema->getJSTopIncludes($group_name, $app->site['minify_js']);
        });
        
        $grav_twig->twig->addFunction($function_include_top_js);        
    }
}