functions.php

<?php
    /*
    TwigPress is a boilerplate Twig Engine for Wordpress.
    Copyright (c) 2013 Julian Xhokaxhiu

    Permission is hereby granted, free of charge, to any person obtaining a copy of
    this software and associated documentation files (the "Software"), to deal in
    the Software without restriction, including without limitation the rights to
    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
    the Software, and to permit persons to whom the Software is furnished to do so,
    subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
    FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
    COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Need help? Contact me at http://about.me/JulianXhokaxhiu
    */

    require_once __DIR__.'/core/lib/Twig/Autoloader.php';
    Twig_Autoloader::register();

    /* DEBUG ONLY */
    define('TwigPress_Debug', true);
    define('TwigPress_Template_URI', get_stylesheet_directory_uri().'/templates');

    class WP_API_Proxy{
        /*
            Description: Proxy Wordpress APIs so they could be available to Twig without mapping them.
            Based upon: Darko Goles (http://inchoo.net/wordpress/twig-wordpress-part2/)
        */
        public function __call($function,$arguments) {
            if (!function_exists($function)) {
                trigger_error('['.get_class(self).'] '.'function ['.$function.'] do not exist. Is it a Wordpress API?',E_USER_ERROR);
                return NULL;
            }
            return call_user_func_array($function,$arguments);
        }
    }

    class TwigPress_API_Proxy{
        public function __call($function,$arguments) {
            if (!function_exists($function)) {
                trigger_error('['.get_class(self).'] '.'function ['.$function.'] do not exist. Is it a Wordpress API?',E_USER_ERROR);
                return NULL;
            }
            return call_user_func_array($function,$arguments);
        }
        /* APIs */
        public function addCss($path){
            $hash = md5(TwigPress_Template_URI.$path);
            wp_register_style($hash,TwigPress_Template_URI.$path);
            wp_enqueue_style($hash);
        }
        public function addJs($path){
            $hash = md5(TwigPress_Template_URI.$path);
            wp_register_script($hash,TwigPress_Template_URI.$path);
            wp_enqueue_script($hash);
        }
    }

    class TwigPress{
        protected $apis;
        protected $twig;
        function __construct($args = array()){
            $loader = new Twig_Loader_Filesystem(get_stylesheet_directory().'/templates');
            $this->twig = new Twig_Environment($loader, array(
                'cache' => TwigPress_Debug ? false : get_stylesheet_directory().'/cache',
                'debug' => TwigPress_Debug
            ));
            if(TwigPress_Debug) $this->twig->addExtension(new Twig_Extension_Debug());
            $this->render(get_current_template(),$args['vars']);
        }
        protected function render($name,$tpl_vars = array()){
            if(isset($name)){
                $this->set_base_api('fn', new TwigPress_API_Proxy());
                $this->set_base_api('template_name',$name);

                $template = $this->twig->loadTemplate($name.'.twig');
                echo $template->render($this->init_apis($tpl_vars));
            }else $this->display_error('No template specified.');
        }
        protected function init_apis($tpl_vars = array()){
            $core_vars = array(
                "twpapi" => $this->get_base_api(),
                "wpapi" => new WP_API_Proxy(),
                "tplapi" => $tpl_vars
            );

            return $core_vars;
        }
        protected function get_base_api(){
            $this->set_base_api('base_uri',TwigPress_Template_URI);
            return $this->apis;
        }
        protected function set_base_api($key,$value){
            $this->apis[$key] = $value;
        }
        /* UTILITY */
        protected function display_error($error){
            trigger_error('['.get_class($this).'] '.$error,E_USER_ERROR);
        }
    }

    /*
        Description: get the current requested template
        URL: http://wordpress.stackexchange.com/questions/10537/get-name-of-the-current-template-file/10565#10565
    */
    add_filter('template_include','var_template_include');
    function var_template_include($t){
        $tpl_path = pathinfo($t);
        $GLOBALS['current_theme_template'] = $tpl_path['filename'];
        return $t;
    }
    function get_current_template(){
        if(!isset($GLOBALS['current_theme_template'])) return false;
        return $GLOBALS['current_theme_template'];
    }