<?php

/**
 * 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 expire_min = 6000;
    const prefix = 'PHPSESSID';
    const session_name = 'PHPSESSID';

    private $expire_time;

    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(
            array(&$this,'onOpen'),
            array(&$this,'onClose'),
            array(&$this,'onRead'),
            array(&$this,'onWrite'),
            array(&$this,'onDestroy'),
            array(&$this,'onGc'));
    }

    public function start()
    {
        $this->fdestroy = false;
        session_start();
        $_SESSION['PHPSESSID'] = $_COOKIE[self::session_name];
    }

    public function end()
    {
        // 会触发write 和 close 函数
        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;
        //session_destroy();//会触发destroy 和 close 函数
    }

    public function onOpen() {
        return true;
    }
    public function onRead($rsid)
    {
        $sid = $_COOKIE[self::session_name];
        if(empty($sid))
        {
            $ret = session_regenerate_id(false);
            if($ret == true) {
                $sid = session_id();
                $this->expire_time = time() + self::expire_min * 60;
                fcgi_setcookie("PHPSESSID","{$sid}",$this->expire_time);
                $_COOKIE[self::session_name] = $sid;
                $this->sessid = $sid;
            } else {
                Log::record("session_regenerate_id error.",Log::ERR);
            }

            return '';
        }
        else
        {
            $data = rcache($sid,self::prefix,self::session_name);
            if(empty($data))
            {
                dcache($sid,self::prefix);
                $ret = session_regenerate_id(false);
                if($ret == true) {
                    $sid = session_id();
                    $this->expire_time = time() + self::expire_min * 60;
                    fcgi_setcookie("PHPSESSID","{$sid}",$this->expire_time);
                    $this->sessid = $sid;
                    $_COOKIE[self::session_name] = $sid;
                } else {
                    Log::record("session_regenerate_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,array(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;
    }
}