<?php

namespace OAuth\Common\Storage;

use OAuth\Common\Token\TokenInterface;
use OAuth\Common\Storage\Exception\TokenNotFoundException;

/**
 * Stores a token in a PHP session.
 */
class Session implements TokenStorageInterface
{
    /**
     * @var string
     */
    protected $sessionVariableName;

    /**
     * @param bool   $startSession        Whether or not to start the session upon construction.
     * @param string $sessionVariableName the variable name to use within the _SESSION superglobal
     */
    public function __construct($startSession = true, $sessionVariableName = 'lusitanian_oauth_token')
    {
        if ($startSession && !isset($_SESSION)) {
            session_start();
        }

        $this->sessionVariableName = $sessionVariableName;
        if (!isset($_SESSION[$sessionVariableName])) {
            $_SESSION[$sessionVariableName] = array();
        }
    }

    /**
     * {@inheritDoc}
     */
    public function retrieveAccessToken($service)
    {
        if ($this->hasAccessToken($service)) {
            return unserialize($_SESSION[$this->sessionVariableName][$service]);
        }

        throw new TokenNotFoundException('Token not found in session, are you sure you stored it?');
    }

    /**
     * {@inheritDoc}
     */
    public function storeAccessToken($service, TokenInterface $token)
    {
        $serializedToken = serialize($token);

        if (isset($_SESSION[$this->sessionVariableName])
            && is_array($_SESSION[$this->sessionVariableName])
        ) {
            $_SESSION[$this->sessionVariableName][$service] = $serializedToken;
        } else {
            $_SESSION[$this->sessionVariableName] = array(
                $service => $serializedToken,
            );
        }

        // allow chaining
        return $this;
    }

    /**
     * {@inheritDoc}
     */
    public function hasAccessToken($service)
    {
        return isset($_SESSION[$this->sessionVariableName], $_SESSION[$this->sessionVariableName][$service]);
    }

    /**
     * {@inheritDoc}
     */
    public function clearToken($service)
    {
        if (array_key_exists($service, $_SESSION[$this->sessionVariableName])) {
            unset($_SESSION[$this->sessionVariableName][$service]);
        }

        // allow chaining
        return $this;
    }

    /**
     * {@inheritDoc}
     */
    public function clearAllTokens()
    {
        unset($_SESSION[$this->sessionVariableName]);

        // allow chaining
        return $this;
    }

    public function __destruct()
    {
        session_write_close();
    }
}