<?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         3.0.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\I18n;

use Aura\Intl\Package;
use Cake\Core\App;
use Cake\Core\Plugin;
use Cake\Utility\Inflector;
use \Locale;

/**
 * A generic translations package factory that will load translations files
 * based on the file extension and the package name.
 *
 * This class is a callable, so it can be used as a package loader argument.
 */
class MessagesFileLoader {

/**
 * The package (domain) name.
 *
 * @var string
 */
	protected $_name;

/**
 * The locale to load for the given package.
 *
 * @var string
 */
	protected $_locale;

/**
 * The extension name.
 *
 * @var string
 */
	protected $_extension;

/**
 * Creates a translation file loader. The file to be loaded corresponds to
 * the following rules:
 *
 * - The locale is a folder under the `Locale` directory, a fallback will be
 *   used if the folder is not found.
 * - The $name corresponds to the file name to load
 * - If there is a loaded plugin with the underscored version of $name, the
 *   translation file will be loaded from such plugin.
 *
 * @param string $name The name (domain) of the translations package.
 * @param string $locale The locale to load, this will be mapped to a folder
 * in the system.
 * @param string $extension The file extension to use. This will also be mapped
 * to a messages parser class.
 */
	public function __construct($name, $locale, $extension = 'po') {
		$this->_name = $name;
		$this->_locale = $locale;
		$this->_extension = $extension;
	}

/**
 * Loads the translation file and parses it. Returns an instance of a translations
 * package containing the messages loaded from the file.
 *
 * @return Aura\Intl\Package
 * @throws \RuntimeException if no file parser class could be found for the specified
 * file extension.
 */
	public function __invoke() {
		$package = new Package;
		$folder = $this->translationsFolder();
		$ext = $this->_extension;

		if (!$folder || !is_file($folder . $this->_name . ".$ext")) {
			return $package;
		}

		$name = ucfirst($ext);
		$class = App::classname($name, 'I18n\Parser', 'FileParser');

		if (!$class) {
			throw new \RuntimeException(sprintf('Could not find class %s', "{$name}FileParser"));
		}

		$messages = (new $class)->parse($folder . $this->_name . ".$ext");
		$package->setMessages($messages);
		return $package;
	}

/**
 * Returns the folder where the file should be looked for according to the locale
 * and package name.
 *
 * @return string|boolean The folder where the file should be looked for or false
 * if it does not exists.
 */
	public function translationsFolder() {
		$locale = Locale::parseLocale($this->_locale) + ['region' => null];

		$folders = [
			implode('_', [$locale['language'], $locale['region']]),
			$locale['language']
		];

		$pluginName = Inflector::camelize($this->_name);
		$basePath = APP . 'Locale' . DS;

		if (Plugin::loaded($pluginName)) {
			$basePath = Plugin::path($pluginName) . 'src' . DS . 'Locale' . DS;
		}

		foreach ($folders as $folder) {
			$path = $basePath . $folder . DS;
			if (is_dir($path)) {
				return $path;
			}
		}

		return false;
	}

}