<?php
/**
 * [WeEngine System] Copyright (c) 2014 WE7.CC
 * WeEngine is NOT a free software, it under the license terms, visited http://www.we7.cc/ for more details.
 */
defined('IN_IA') or exit('Access Denied');


class WeSession implements SessionHandlerInterface {
	
	public static $uniacid;
	
	public static $openid;
	
	public static $expire;

	
	public static function start($uniacid, $openid, $expire = 3600) {
		WeSession::$uniacid = $uniacid;
		WeSession::$openid = $openid;
		WeSession::$expire = $expire;

		$cache_setting = $GLOBALS['_W']['config']['setting'];
		if (extension_loaded('memcache') && !empty($cache_setting['memcache']['server']) && !empty($cache_setting['memcache']['session'])) {
			self::setHandler('memcache');
		} elseif (extension_loaded('redis') && !empty($cache_setting['redis']['server']) && !empty($cache_setting['redis']['session'])) {
			self::setHandler('redis');
		} else {
			self::setHandler('mysql');
		}
		register_shutdown_function('session_write_close');
		session_start();
	}

	public static function setHandler($type = 'mysql') {
		$classname = "WeSession{$type}";
		if (class_exists($classname)) {
			$sess = new $classname;
		}
		if (version_compare(PHP_VERSION, '5.5') >= 0) {
			session_set_save_handler($sess, true);
		} else {
			session_set_save_handler(
				array(&$sess, 'open'),
				array(&$sess, 'close'),
				array(&$sess, 'read'),
				array(&$sess, 'write'),
				array(&$sess, 'destroy'),
				array(&$sess, 'gc')
			);
		}
		return true;
	}

	public function open($save_path, $session_name) {
		return true;
	}

	public function close() {
		return true;
	}

	
	public function read($sessionid) {
		return '';
	}

	
	public function write($sessionid, $data) {
		return true;
	}

	
	public function destroy($sessionid) {
		return true;
	}

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

class WeSessionMemcache extends WeSession {
	protected $session_name;

	protected function key($sessionid) {
		return $this->session_name . ':' . $sessionid;
	}

	public function open($save_path, $session_name) {
		$this->session_name = $session_name;

		if (cache_type() != 'memcache') {
			trigger_error('Memcache 扩展不可用或是服务未开启，请将 \$config[\'setting\'][\'memcache\'][\'session\'] 设置为0 ');
			return false;
		}
		return true;
	}

	public function read($sessionid) {
		$row = cache_read($this->key($sessionid));
		if (empty($row) || $row['expiretime'] < TIMESTAMP) {
			return '';
		}
		if(is_array($row) && !empty($row['data'])) {
			return $row['data'];
		}
		return '';
	}

	public function write($sessionid, $data) {
		$row = array();
		$row['data'] = $data;
		$row['uniacid'] = WeSession::$uniacid;
		$row['openid'] = WeSession::$openid;
		$row['expiretime'] = TIMESTAMP + WeSession::$expire;

		return cache_write($this->key($sessionid), $row);
	}

	public function destroy($sessionid) {
		return cache_write($this->key($sessionid), '');
	}
}

class WeSessionRedis extends WeSessionMemcache {
	public function open($save_path, $session_name) {
		$this->session_name = $session_name;

		if (cache_type() != 'redis') {
			trigger_error('Redis 扩展不可用或是服务未开启，请将 \$config[\'setting\'][\'redis\'][\'session\'] 设置为0 ');
			return false;
		}
		return true;
	}
}

class WeSessionMysql extends WeSession {

	public function open($save_path, $session_name) {
		return true;
	}

	public function read($sessionid) {
		$sql = 'SELECT * FROM ' . tablename('core_sessions') . ' WHERE `sid`=:sessid AND `expiretime`>:time';
		$params = array();
		$params[':sessid'] = $sessionid;
		$params[':time'] = TIMESTAMP;
		$row = pdo_fetch($sql, $params);
		if(is_array($row) && !empty($row['data'])) {
			return $row['data'];
		}
		return '';
	}

	public function write($sessionid, $data) {
		$row = array();
		$row['sid'] = $sessionid;
		$row['uniacid'] = WeSession::$uniacid;
		$row['openid'] = WeSession::$openid;
		$row['data'] = $data;
		$row['expiretime'] = TIMESTAMP + WeSession::$expire;
		return pdo_insert('core_sessions', $row, true) >= 1;
	}

	public function destroy($sessionid) {
		$row = array();
		$row['sid'] = $sessionid;

		return pdo_delete('core_sessions', $row) == 1;
	}

	public function gc($expire) {
		$sql = 'DELETE FROM ' . tablename('core_sessions') . ' WHERE `expiretime`<:expire';

		return pdo_query($sql, array(':expire' => TIMESTAMP)) == 1;
	}
}