<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         2.0.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Core\Configure\Engine;

use Cake\Core\Configure\ConfigEngineInterface;
use Cake\Core\Exception\Exception;
use Cake\Core\Plugin;

/**
 * PHP engine allows Configure to load configuration values from
 * files containing simple PHP arrays.
 *
 * Files compatible with PhpConfig should define a `$config` variable, that
 * contains all of the configuration data contained in the file.
 */
class PhpConfig implements ConfigEngineInterface {

/**
 * The path this engine finds files on.
 *
 * @var string
 */
	protected $_path = null;

/**
 * Constructor for PHP Config file reading.
 *
 * @param string|null $path The path to read config files from. Defaults to CONFIG.
 */
	public function __construct($path = null) {
		if ($path === null) {
			$path = CONFIG;
		}
		$this->_path = $path;
	}

/**
 * Read a config file and return its contents.
 *
 * Files with `.` in the name will be treated as values in plugins. Instead of
 * reading from the initialized path, plugin keys will be located using Plugin::path().
 *
 * @param string $key The identifier to read from. If the key has a . it will be treated
 *  as a plugin prefix.
 * @return array Parsed configuration values.
 * @throws \Cake\Core\Exception\Exception when files don't exist or they don't contain `$config`.
 *  Or when files contain '..' as this could lead to abusive reads.
 */
	public function read($key) {
		if (strpos($key, '..') !== false) {
			throw new Exception('Cannot load configuration files with ../ in them.');
		}

		$file = $this->_getFilePath($key);
		if (!is_file($file)) {
			throw new Exception(sprintf('Could not load configuration file: %s', $file));
		}

		include $file;
		if (!isset($config)) {
			throw new Exception(sprintf('No variable $config found in %s', $file));
		}
		return $config;
	}

/**
 * Converts the provided $data into a string of PHP code that can
 * be used saved into a file and loaded later.
 *
 * @param string $key The identifier to write to. If the key has a . it will be treated
 *  as a plugin prefix.
 * @param array $data Data to dump.
 * @return int Bytes saved.
 */
	public function dump($key, array $data) {
		$contents = '<?php' . "\n" . '$config = ' . var_export($data, true) . ';';

		$filename = $this->_getFilePath($key);
		return file_put_contents($filename, $contents);
	}

/**
 * Get file path
 *
 * @param string $key The identifier to write to. If the key has a . it will be treated
 *  as a plugin prefix.
 * @return string Full file path
 */
	protected function _getFilePath($key) {
		if (substr($key, -4) === '.php') {
			$key = substr($key, 0, -4);
		}
		list($plugin, $key) = pluginSplit($key);
		$key .= '.php';

		if ($plugin) {
			$file = Plugin::configPath($plugin) . $key;
		} else {
			$file = $this->_path . $key;
		}

		return $file;
	}

}
