<?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\Session\Config;

use Zend\Session\Exception;

/**
 * Session configuration proxying to session INI options
 */
class SessionConfig extends StandardConfig
{
    /**
     * Used with {@link handleError()}; stores PHP error code
     * @var int
     */
    protected $phpErrorCode    = false;

    /**
     * Used with {@link handleError()}; stores PHP error message
     * @var string
     */
    protected $phpErrorMessage = false;

    /**
     * @var int Default number of seconds to make session sticky, when rememberMe() is called
     */
    protected $rememberMeSeconds = 1209600; // 2 weeks

    /**
     * @var string session.serialize_handler
     */
    protected $serializeHandler;

    /**
     * @var array Valid cache limiters (per session.cache_limiter)
     */
    protected $validCacheLimiters = [
        '',
        'nocache',
        'public',
        'private',
        'private_no_expire',
    ];

    /**
     * @var array Valid hash bits per character (per session.hash_bits_per_character)
     */
    protected $validHashBitsPerCharacters = [
        4,
        5,
        6,
    ];

    /**
     * @var array Valid hash functions (per session.hash_function)
     */
    protected $validHashFunctions;

    /**
     * Set storage option in backend configuration store
     *
     * @param  string $storageName
     * @param  mixed $storageValue
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setStorageOption($storageName, $storageValue)
    {
        switch ($storageName) {
            case 'remember_me_seconds':
                // do nothing; not an INI option
                return;
            case 'url_rewriter_tags':
                $key = 'url_rewriter.tags';
                break;
            default:
                $key = 'session.' . $storageName;
                break;
        }

        $result = ini_set($key, (string) $storageValue);
        if (false === $result) {
            throw new Exception\InvalidArgumentException(
                "'{$key}' is not a valid sessions-related ini setting."
            );
        }
        return $this;
    }

    /**
     * Retrieve a storage option from a backend configuration store
     *
     * Used to retrieve default values from a backend configuration store.
     *
     * @param  string $storageOption
     * @return mixed
     */
    public function getStorageOption($storageOption)
    {
        switch ($storageOption) {
            case 'remember_me_seconds':
                // No remote storage option; just return the current value
                return $this->rememberMeSeconds;
            case 'url_rewriter_tags':
                return ini_get('url_rewriter.tags');
            // The following all need a transformation on the retrieved value;
            // however they use the same key naming scheme
            case 'use_cookies':
            case 'use_only_cookies':
            case 'use_trans_sid':
            case 'cookie_httponly':
                return (bool) ini_get('session.' . $storageOption);
            default:
                return ini_get('session.' . $storageOption);
        }
    }

    /**
     * Set session.save_handler
     *
     * @param  string $phpSaveHandler
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setPhpSaveHandler($phpSaveHandler)
    {
        $phpSaveHandler = (string) $phpSaveHandler;
        set_error_handler([$this, 'handleError']);
        ini_set('session.save_handler', $phpSaveHandler);
        restore_error_handler();
        if ($this->phpErrorCode >= E_WARNING) {
            throw new Exception\InvalidArgumentException(
                'Invalid save handler specified: ' . $this->phpErrorMessage
            );
        }

        $this->setOption('save_handler', $phpSaveHandler);
        return $this;
    }

    /**
     * Set session.save_path
     *
     * @param  string $savePath
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException on invalid path
     */
    public function setSavePath($savePath)
    {
        if ($this->getOption('save_handler') == 'files') {
            parent::setSavePath($savePath);
        }
        $this->savePath = $savePath;
        $this->setOption('save_path', $savePath);
        return $this;
    }

    /**
     * Set session.serialize_handler
     *
     * @param  string $serializeHandler
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setSerializeHandler($serializeHandler)
    {
        $serializeHandler = (string) $serializeHandler;

        set_error_handler([$this, 'handleError']);
        ini_set('session.serialize_handler', $serializeHandler);
        restore_error_handler();
        if ($this->phpErrorCode >= E_WARNING) {
            throw new Exception\InvalidArgumentException('Invalid serialize handler specified');
        }

        $this->serializeHandler = (string) $serializeHandler;
        return $this;
    }

    // session.cache_limiter

    /**
     * Set cache limiter
     *
     * @param $cacheLimiter
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setCacheLimiter($cacheLimiter)
    {
        $cacheLimiter = (string) $cacheLimiter;
        if (!in_array($cacheLimiter, $this->validCacheLimiters)) {
            throw new Exception\InvalidArgumentException('Invalid cache limiter provided');
        }
        $this->setOption('cache_limiter', $cacheLimiter);
        ini_set('session.cache_limiter', $cacheLimiter);
        return $this;
    }

    /**
     * Set session.hash_function
     *
     * @param  string|int $hashFunction
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setHashFunction($hashFunction)
    {
        $hashFunction = (string) $hashFunction;
        $validHashFunctions = $this->getHashFunctions();
        if (!in_array($hashFunction, $validHashFunctions, true)) {
            throw new Exception\InvalidArgumentException('Invalid hash function provided');
        }

        $this->setOption('hash_function', $hashFunction);
        ini_set('session.hash_function', $hashFunction);
        return $this;
    }

    /**
     * Set session.hash_bits_per_character
     *
     * @param  int $hashBitsPerCharacter
     * @return SessionConfig
     * @throws Exception\InvalidArgumentException
     */
    public function setHashBitsPerCharacter($hashBitsPerCharacter)
    {
        if (!is_numeric($hashBitsPerCharacter)
            || !in_array($hashBitsPerCharacter, $this->validHashBitsPerCharacters)
        ) {
            throw new Exception\InvalidArgumentException('Invalid hash bits per character provided');
        }

        $hashBitsPerCharacter = (int) $hashBitsPerCharacter;
        $this->setOption('hash_bits_per_character', $hashBitsPerCharacter);
        ini_set('session.hash_bits_per_character', $hashBitsPerCharacter);
        return $this;
    }

    /**
     * Retrieve list of valid hash functions
     *
     * @return array
     */
    protected function getHashFunctions()
    {
        if (empty($this->validHashFunctions)) {
            /**
             * @link http://php.net/manual/en/session.configuration.php#ini.session.hash-function
             * "0" and "1" refer to MD5-128 and SHA1-160, respectively, and are
             * valid in addition to whatever is reported by hash_algos()
             */
            $this->validHashFunctions = ['0', '1'] + hash_algos();
        }
        return $this->validHashFunctions;
    }

    /**
     * Handle PHP errors
     *
     * @param  int $code
     * @param  string $message
     * @return void
     */
    protected function handleError($code, $message)
    {
        $this->phpErrorCode    = $code;
        $this->phpErrorMessage = $message;
    }
}
