<?php
declare(strict_types=1);

/**
 * Created by PhpStorm.
 * User: stanley-king
 * Date: 16/1/30
 * Time: 下午3:43
 */
class session
{
    static $stInstance = NULL;
    private $fdestroy = false;
    private $sessid = '';

    const prefix = 'MPHPSESSID';
    const session_name = 'MPHPSESSID';

    static public function instance()
    {
        if (self::$stInstance == NULL) {
            self::$stInstance = new session();
        }
        return self::$stInstance;
    }

    private function __construct()
    {

    }

    public function init()
    {
        session_set_save_handler(
            [$this, 'onOpen'],
            [$this, 'onClose'],
            [$this, 'onRead'],
            [$this, 'onWrite'],
            [$this, 'onDestroy'],
            [$this, 'onGc']);
    }

    public function start()
    {
        $this->fdestroy = false;
        session_start();
        $_SESSION['MPHPSESSID'] = $this->sessid;
    }

    public function end($need_close = true)
    {
        // 会触发write 和 close 函数
        if($need_close) {
            session_write_close();
        }

        foreach ($_SESSION as $key => $value) {
            unset($_SESSION[$key]);
        }
        foreach ($_COOKIE as $key => $value) {
            unset($_COOKIE[$key]);
        }
        foreach ($_POST as $key => $value) {
            unset($_POST[$key]);
        }
        foreach ($_GET as $key => $value) {
            unset($_GET[$key]);
        }
        request_helper::clear_server();
        $this->sessid = '';
    }

    public function destroy()
    {
        $this->fdestroy = true;
        $sid = $this->sessid;
        fcgi_setcookie("MPHPSESSID", "{$sid}", -3600, '/', COOKIE_DOMAIN);
    }

    public function onOpen()
    {
        return true;
    }

    public function onRead($rsid)
    {
        //这段代码为了确保内置H5，直接使用客户端的session 状态。
        $client = strtolower(trim($_SERVER['HTTP_CLIENT_TYPE']));

        if ($client == 'ios' || $client == 'android') {
            $sid = $_COOKIE[self::session_name];
            Log::record("MPHPSESSID = {$sid}", Log::DEBUG);
            return $this->from_certain($sid);
        } else {
            $sid = $_COOKIE[self::session_name];
            Log::record("MPHPSESSID = {$sid}", Log::DEBUG);

            if (isset($_POST['HPHPSESSID']) && !empty($_POST['HPHPSESSID'])) {
                $hsid = $_POST['HPHPSESSID'];
                $this->sessid = $hsid;
                if ($sid == $hsid) {
                    return $this->from_certain($sid);
                } else {
                    return $this->from_uncertain($hsid);
                }
            } else {
                return $this->from_certain($sid);
            }
        }
    }

    private function from_uncertain($sid)
    {
        $this->set_cookie($sid);
        if (empty($sid)) {
            return '';
        } else {
            $data = rcache($sid, self::prefix);
            if (empty($data)) {
                return '';
            } else {
                $this->sessid = $sid;
                return $data[self::session_name];
            }
        }
    }

    private function from_certain($sid)
    {
        if (empty($sid)) {
            $sid = session_create_id('');
            if (!empty($sid)) {
                $this->set_cookie($sid);
                $this->sessid = $sid;
            } else {
                Log::record("session_create_id error.", Log::ERR);
            }

            return '';
        } else {
            $data = rcache($sid, self::prefix);
            if (empty($data)) {
                dcache($sid, self::prefix);
                $sid = session_create_id('');
                if ($sid == true) {
                    $this->set_cookie($sid);
                    $this->sessid = $sid;
                } else {
                    Log::record("session_create_id error.", Log::ERR);
                }

                return '';
            } else {
                $this->sessid = $sid;
                return $data[self::session_name];
            }
        }
    }

    public function onClose()
    {
        return true;
    }

    public function onWrite($sid, $data)
    {
        if ($this->fdestroy) {
            dcache($this->sessid, self::prefix);
        } else {
            wcache($this->sessid, [self::session_name => $data], self::prefix, self::expire_min());
        }

        return true;
    }

    public function onDestroy($sid)
    {
        return dcache($this->sessid, self::prefix);
    }

    public function onGc($expire)
    {
        return true;
    }

    public function set_cookie($sid)
    {
        $expire_time = time() + self::expire_min() * 60;
        fcgi_setcookie("MPHPSESSID", "{$sid}", $expire_time, '/', COOKIE_DOMAIN);
        Log::record("set_cookie MPHPSESSID={$sid}", Log::DEBUG);
    }

    private static function expire_min()
    {
        if (is_debug()) {
            return 43200;
        } else {
            return 43200;
        }
    }

    static public function read_other_session($sid)
    {
        $data = rcache($sid, self::prefix);
        $org = $_SESSION;
        $_SESSION = [];
        if (session_decode($data[self::session_name]) == true) {
            $data = $_SESSION;
            $_SESSION = $org;
            return $data;
        } else {
            $_SESSION = $org;
            return false;
        }
    }

    static public function write_other_session($sid, $data)
    {
        $org = $_SESSION;
        $_SESSION = $data;
        $data = session_encode();
        wcache($sid, [self::session_name => $data], self::prefix, self::expire_min());
        $_SESSION = $org;
    }
}