<?php
/**
 * The Strangecode Codebase - a general application development framework for PHP
 * For details visit the project site: <http://trac.strangecode.com/codebase/>
 * Copyright 2001-2012 Strangecode, LLC
 *
 * This file is part of The Strangecode Codebase.
 *
 * The Strangecode Codebase 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.
 *
 * The Strangecode Codebase 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
 * The Strangecode Codebase. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * CSS.inc.css
 *
 * Dynamically outputs cached CSS data.
 *
 * @author  Quinn Comendant <quinn@strangecode.com>
 * @version 1.2
 */
class CSS
{

    // Include these style sheets.
    protected $_css_files = array('default' => array());

    // CSS object parameters.
    protected $_params = array(
        'character_set' => 'utf-8',
        'cache_enable' => false,
        'cache_css' => null, // Same as above; kept for backwards compatibility.
        'cache_seconds' => 7776000, // 90 days.
        'strip_whitespace' => false,
        'output_compression' => false,
    );

    /**
     * Set (or overwrite existing) parameters by passing an array of new parameters.
     *
     * @access public
     * @param  array    $params     Array of parameters (key => val pairs).
     */
    public function setParam($params)
    {
        $app =& App::getInstance();

        if (isset($params) && is_array($params)) {
            // Merge new parameters with old overriding only those passed.
            $this->_params = array_merge($this->_params, $params);
            // Maintaining backwards compatibility.
            if (isset($params['cache_css']) && !isset($params['cache_enable'])) {
                $this->_params['cache_enable'] = $params['cache_css'];
            }
        } else {
            $app->logMsg(sprintf('Parameters are not an array: %s', $params), LOG_ERR, __FILE__, __LINE__);
        }
    }

    /**
     * Return the value of a parameter, if it exists.
     *
     * @access public
     * @param string $param        Which parameter to return.
     * @return mixed               Configured parameter value.
     */
    public function getParam($param)
    {
        $app =& App::getInstance();

        if (array_key_exists($param, $this->_params)) {
            return $this->_params[$param];
        } else {
            $app->logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__);
            return null;
        }
    }

    /**
     * Add a file-path to the array of files to include as CSS.
     *
     * @access  public
     * @param   string  $file   Include path to css files.
     * @param   mixed   $realms   Realm name string or array of realm names.
     * @return  bool    True on success, false on failure.
     */
    public function setFile($file, $realms='')
    {
        $app =& App::getInstance();

        if (!is_array($realms)) {
            $realms = array($realms);
        }

        if ($fp = fopen($file, 'r', true)) {
            foreach ($realms as $realm) {
                $realm = '' == $realm ? 'default' : $realm;
                $this->_css_files[$realm][] = $file;
            }
            fclose($fp);
            return true;
        } else {
            $app->logMsg(sprintf('CSS file non-existent: %s', $file), LOG_ERR, __FILE__, __LINE__);
            return false;
        }
    }

    /**
     * Output headers for CSS.
     *
     * @access  public
     *
     * @return  bool    False if no files have been set.
     */
    public function headers($realm='')
    {
        $app =& App::getInstance();

        $realm = '' == $realm ? 'default' : $realm;

        if (empty($this->_css_files[$realm])) {
            $app->logMsg(sprintf('CSS::headers called without specifying any files.', null), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        // Get time of latest modified file, including this class file.
        $files_mtime = array();
        foreach (array_merge($this->_css_files[$realm], array(__FILE__)) as $file) {
            $files_mtime[] = statIncludePath($file, 'mtime');
        }
        sort($files_mtime, SORT_NUMERIC);
        $latest_mtime = array_pop($files_mtime);

        if ($this->getParam('output_compression') && extension_loaded('zlib')) {
            ob_start('ob_gzhandler');
        }

        header(sprintf('Content-Type: text/css; charset=%s', $this->getParam('character_set')));
        header(sprintf('Last-Modified: %s GMT', gmdate('D, d M Y H:i:s', $latest_mtime), null));
        if ($this->getParam('cache_enable')) {
            header(sprintf('Cache-Control: public, max-age=%s', $this->getParam('cache_seconds')));
            header(sprintf('Expires: %s GMT', gmdate('D, d M Y H:i:s', $latest_mtime + $this->getParam('cache_seconds'))));
            header('Pragma: public');
            header('Vary: Accept-Encoding');
        } else {
            // Disallow HTTP caching entirely. http://stackoverflow.com/a/2068407
            header('Cache-Control: no-cache, no-store, must-revalidate'); // HTTP 1.1.
            header('Pragma: no-cache'); // HTTP 1.0.
            header('Expires: 0'); // Proxies.
        }
    }

    /**
     * Include CSS files specified by setFile().
     *
     * @access  public
     *
     * @return  bool    False if no files have been set.
     */
    public function output($realm='')
    {
        $app =& App::getInstance();

        $realm = '' == $realm ? 'default' : $realm;

        if (empty($this->_css_files[$realm])) {
            $app->logMsg(sprintf('CSS::output called without specifying any files.', null), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

        foreach ($this->_css_files[$realm] as $file) {
            if ($this->getParam('strip_whitespace')) {
                // Strip whitespace and print file.
                echo preg_replace(
                    array('!/\*.*?\*/!s' . $app->getParam('preg_u'), '/[\n\r]+/' . $app->getParam('preg_u'), '/([;:])\s+/m' . $app->getParam('preg_u'), '/\s*}[ \t]*/' . $app->getParam('preg_u'), '/\s*{\s*/' . $app->getParam('preg_u'), '/[ \t\n\r]*,[ \t\n\r]*/' . $app->getParam('preg_u'), '/^\s+/' . $app->getParam('preg_u')),
                    array('', "\n", '$1', '}', '{', ',', ''), file_get_contents($file, true)
                );
            } else {
                // Include file as is.
                include $file;
            }
        }

        if ($this->getParam('output_compression') && extension_loaded('zlib')) {
            ob_end_flush();
        }
    }
}