<?php
namespace sammo;

if(!defined('ROOT')){
    define('ROOT', '../..');
}

/**
 * Session Wrapper. 내부적으로 $_SESSION을 이용
 * 
 * @property int    $userID    유저코드
 * @property string $userName  유저명
 * @property int    $userGrade 유저등급
 * @property string $ip        IP
 */
class Session {

    const PROTECTED_NAMES = [
        'ip'=>true,
        'time'=>true, 
        'userID'=>true, 
        'userName'=>true, 
        'userGrade'=>true, 
        'writeClosed'=>true,
        'generalID'=>true,
        'generalName'=>true
    ];

    const GAME_KEY_DATE = '_g_loginDate';
    const GAME_KEY_GENERAL_ID = '_g_no';
    const GAME_KEY_GENERAL_NAME = '_g_name';
    const GAME_KEY_EXPECTED_DEADTIME = '_g_deadtime';
    

    private $writeClosed = false;
    private $sessionID = null;

    public static function Instance(): Session{
        static $inst = null;
        if($inst === null){
            $inst = new Session();
        }
        return $inst;
    }

    public function restart(): Session{
        //NOTE: logout 프로세스는 아예 세션을 날려버리기도 하므로, 항상 안전하게 session_restart가 가능함을 보장하지 않음.
        ini_set('session.use_only_cookies', false);
        ini_set('session.use_cookies', false);
        ini_set('session.use_trans_sid', false);
        ini_set('session.cache_limiter', null);
        session_start($this->sessionID); // second session_start
        $this->writeClosed = false;
        return $this;
    }

    public static function requireLogin($movePath = ROOT): Session{
        $session = Session::Instance();
        if($session->isLoggedIn()){
            return $session;
        }

        $session->setReadOnly();

        if(is_string($path)){
            header('Location:'.$path);
            die();
        }

        Json::die([
            'result'=>false,
            'reason'=>'로그인이 필요합니다.'
        ]);
    }

    public function __construct() {
        //session_cache_limiter('nocache, must_revalidate');

        // 세션 변수의 등록
        if (session_id() == ""){
            session_start();
            $this->sessionID = session_id();
        }

        //첫 등장

        if(!Util::array_get($_SESSION['ip'])) {
            $_SESSION['ip'] = Util::get_client_ip(true);
            $_SESSION['time'] = time();
        }
    }

    public function setReadOnly(): Session{
        if(!$this->writeClosed){
            session_write_close();
            $this->writeClosed = true;
        }        
        return $this;
    }

    public function __set(string $name, $value){
        if(key_exists($key, $this->PROTECED_NAMES)){
            trigger_error("{$name}은 외부에서 쓰기 금지된 Session 변수입니다.", E_USER_NOTICE);
            return;
        }

        $this->set($name, $value);        
    }

    private function set(string $name, $value){
        if($value === null){
            unset($_SESSION[$name]);
        }
        else{
            $_SESSION[$name] = $value;
        }
    }

    public function __get(string $name){
        if($name == 'generalID'){
            return $this->get(DB::prefix().static::GAME_KEY_GENERAL_ID);
        }
        if($name == 'generalName'){
            return $this->get(DB::prefix().static::GAME_KEY_GENERAL_NAME);
        }
        return $this->get($name);
    }

    private function get(string $name){
        return Util::array_get($_SESSION[$name]);
    }

    public function login(int $userID, string $userName, int $grade): Session {
        $this->set('userID', $userID);
        $this->set('userName', $userName);
        $this->set('ip', Util::get_client_ip(true));
        $this->set('time', time());
        $this->set('userGrade', $grade);
        $this->set('access_token', null);
        return $this;
    }


    public function logout(): Session {
        if($this->writeClosed){
            $this->restart();
        }
        if(class_exists('\\sammo\\UniqueConst')){
            $this->logoutGame();
        }
        
        $this->set('userID', null);
        $this->set('userName', null);
        $this->set('userGrade', null);
        $this->set('time', time());
        return $this;
    }

    public function loginGame(&$result = null): Session{
        $userID = $this->userID;
        if(!$userID){
            if($result !== null){
                $result = false;
            }
            return $this;
        }

        if(!class_exists('\\sammo\\DB') || !class_exists('\\sammo\\UniqueConst')){
            if($result !== null){
                $result = false;
            }
            return $this;
        }

        $serverID = UniqueConst::$serverID;
        $db = DB::db();

        $loginDate = $this->get($serverID.static::GAME_KEY_DATE);
        $generalID = $this->get($serverID.static::GAME_KEY_GENERAL_ID);
        $generalName = $this->get($serverID.static::GAME_KEY_GENERAL_NAME);
        $deadTime = $this->get($serverID.static::GAME_KEY_EXPECTED_DEADTIME);

        $now = time();
        if(
            $generalID && $generalName && $loginDate && $deadTime
            && $loginDate + 600 > $now && $deadTime > $now
        ){
            //로그인 정보는 10분간 유지한다.
            if($result !== null){
                $result = true;
            }
            return $this;
        }

        if($generalID || $generalName || $loginDate || $deadTime){
            $this->logoutGame();
        }

        $general = $db->queryFirstRow(
            'SELECT `no`, `name`, `killturn`, `turntime` from general where `owner` = %i', 
            $userID
        );
        if(!$general){
            if($result !== null){
                $result = false;
            }
            return $this;
        }

        $turnterm = $db->queryFirstField('SELECT turnterm from game limit 1');

        $generalID = $general['no'];
        $generalName = $general['name'];
        $nextTurn = new \DateTime($general['turntime']);
        $nextTurn = $nextTurn->getTimestamp();

        $deadTime = $nextTurn + $general['killturn'] * $turnterm;
        if($deadTime < $now){
            if($result !== null){
                $result = false;
            }
            return $this;
        }


        $this->set($serverID.static::GAME_KEY_DATE, $now);
        $this->set($serverID.static::GAME_KEY_GENERAL_ID, $generalID);
        $this->set($serverID.static::GAME_KEY_GENERAL_NAME, $generalName);
        $this->set($serverID.static::GAME_KEY_EXPECTED_DEADTIME, $deadTime);
        return $this;
    }

    public function logoutGame(): Session{
        if($this->writeClosed){
            $this->restart();
        }
        $serverID = UniqueConst::$serverID;
        $this->set($serverID.static::GAME_KEY_DATE, null);
        $this->set($serverID.static::GAME_KEY_GENERAL_ID, null);
        $this->set($serverID.static::GAME_KEY_GENERAL_NAME, null);
        $this->set($serverID.static::GAME_KEY_EXPECTED_DEADTIME, null);
        return $this;
    }


    /**
     * 로그인 유저의 전역 grade를 받아옴
     * @return int|null
     */
    public static function getUserGrade(bool $requireLogin = false, string $exitPath = ROOT){
        if($requireLogin){
            $obj = self::requireLogin($exitPath);
        }
        else{
            $obj = self::Instance();
        }
        
        return $obj->userGrade;
    }

    /** 
     * 로그인한 유저의 전역 id(숫자)를 받아옴 
     *
     * @return int|null 
     */
    public static function getUserID(bool $requireLogin = false, string $exitPath = ROOT){
        if($requireLogin){
            $obj = self::requireLogin($exitPath);
        }
        else{
            $obj = self::Instance();
        }
        
        return $obj->userID;
    }

    public function isLoggedIn() {
        if($this->userID){
            return true;
        }
        else{
            return false;
        }
    }

    public function __destruct() {
    }
}