<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 */

namespace Zend\I18n\Translator\Loader;

/**
 * Abstract file loader implementation; provides facilities around resolving
 * files via the include_path.
 */
abstract class AbstractFileLoader implements FileLoaderInterface
{
    /**
     * Whether or not to consult the include_path when locating files
     *
     * @var bool
     */
    protected $useIncludePath = false;

    /**
     * Indicate whether or not to use the include_path to resolve translation files
     *
     * @param bool $flag
     * @return self
     */
    public function setUseIncludePath($flag = true)
    {
        $this->useIncludePath = (bool) $flag;
        return $this;
    }

    /**
     * Are we using the include_path to resolve translation files?
     *
     * @return bool
     */
    public function useIncludePath()
    {
        return $this->useIncludePath;
    }

    /**
     * Resolve a translation file
     *
     * Checks if the file exists and is readable, returning a boolean false if not; if the "useIncludePath"
     * flag is enabled, it will attempt to resolve the file from the
     * include_path if the file does not exist on the current working path.
     *
     * @param string $filename
     * @return string|false
     */
    protected function resolveFile($filename)
    {
        if (!is_file($filename) || !is_readable($filename)) {
            if (!$this->useIncludePath()) {
                return false;
            }
            return $this->resolveViaIncludePath($filename);
        }
        return $filename;
    }

    /**
     * Resolve a translation file via the include_path
     *
     * @param string $filename
     * @return string|false
     */
    protected function resolveViaIncludePath($filename)
    {
        $resolvedIncludePath = stream_resolve_include_path($filename);
        if (!$resolvedIncludePath || !is_file($resolvedIncludePath) || !is_readable($resolvedIncludePath)) {
            return false;
        }
        return $resolvedIncludePath;
    }
}