<?php

/**
 * @todo refactor storage backend out to an abstract driver interface
 * @todo implement/try a redis backend
 * @todo test memcached again, on 64bit Ubuntu laptop everything was ok, on 32 Ubuntu PC not.
 */

class Comet_Storage {

    protected $_channel = null;

    protected $_memcacheServer = '127.0.0.1';
    protected $_memcachePort = 11211;

    protected $_cacheBackend = null;
    protected $_cacheType = 'memcache';


    public function __construct() {
        $this->_loadBackend();
    }

    public function setChannel($channel) {
        //_log(' '.__FILE__.' '.__LINE__.' | set channel to '.$this->_normalizeName($channel));
        $this->_channel = $this->_normalizeName($channel);
    }

    /**
     *
     * @return string channel name
     */
    public function getChannel() {
        return $this->_channel;
    }

    /**
     *
     * @param string $clientid
     * @return array
     */
    public function getClientData($clientid) {

        $channel = $this->getChannel();
        $lastid = 0;
        switch ($this->_cacheType) {
            case 'file':
                $clientPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'client_'.$clientid;
                //_log(' '.__FILE__.' '.__LINE__.' | get client info from '.$clientPath);
                $clientinfo = unserialize(file_get_contents($clientPath));
                if (isset($clientinfo[$channel])) {
                    $lastid = $clientinfo[$channel];
                }
                break;
            case 'memcache':
                //_log(' '.__FILE__.' '.__LINE__.' | get client info from client_'.$clientid);
                $clientinfo = $this->_cacheBackend->get('client_'.$clientid);
                if (isset($clientinfo[$channel])) {
                    $lastid = $clientinfo[$channel];
                }
                break;
        }
        $data = $this->_getChannelData();
        //_log(' '.__FILE__.' '.__LINE__.' | channel data restored from storage '.print_r($data,1));
        //_log(' '.__FILE__.' '.__LINE__.' | checking for position '.$lastid);
        if (isset($data[$lastid])) {
            //_log(' '.__FILE__.' '.__LINE__.' | channel data found for client on position '.$lastid);
            $length = count($data) - $lastid;
            $result = array_slice($data,$lastid, $length, true);
            $keys = array_keys($result);
            $lastid = array_pop($keys);
            if ($lastid > 0) {
                $this->_setClientInfo($clientid, $lastid + 1);
            }
            return array_values($result);
        } else {
            //_log(' '.__FILE__.' '.__LINE__.' | no channel data found for client '.$lastid);
            return array();
        }
    }

    public function getClientChannels($clientid) {

        switch ($this->_cacheType) {
            case 'file':
                $clientPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'client_'.$clientid;
                //_log(' '.__FILE__.' '.__LINE__.' | get client info from '.$clientPath);
                if (file_exists($clientPath)) {
                    $clientinfo = unserialize(file_get_contents($clientPath));
                    return($clientinfo);
                }
                break;
            case 'memcache':
                //_log(' '.__FILE__.' '.__LINE__.' | get client info from client_'.$clientid);
                $clientinfo = $this->_cacheBackend->get('client_'.$clientid);
                if ($clientinfo) {
                    return $clientinfo;
                }
                break;
        }
        return false;
    }
    
    public function addClient($clientid) {
        //_log(' '.__FILE__.' '.__LINE__.' | add client '.$clientid);
        $data = $this->_getChannelData();
        $lastid = count($data);

        $this->_setClientInfo($clientid,$lastid);        
    }
    
    public function removeClient($clientid) {
        switch ($this->_cacheType) {
            case 'file':
                $clientPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'client_'.$clientid;
                $clientinfo = unserialize(file_get_contents($clientPath));
                foreach($clientinfo as $channel => $id) {
                    $this->setChannel($channel);
                    $this->_deleteChannelUser($clientId);
                }
                unlink($clientPath);
                break;
            case 'memcache':
                $clientinfo = $this->_cacheBackend->get('client_'.$clientid);
                foreach($clientinfo as $channel => $id) {
                    $this->setChannel($channel);
                    $this->_deleteChannelUser($clientid);
                }
                //_log(' '.__FILE__.' '.__LINE__.' | remove client .'.$clientid.' from channel '.$channel);
                $this->_cacheBackend->delete('client_'.$clientid);
                break;
        }
    }

    public function removeClientFromChannel($clientid) {
        //_log(' '.__FILE__.' '.__LINE__.' | add client '.$clientid);
        $data = $this->_getChannelData();
        $lastid = count($data);

        $this->_addChannelUser($clientid);
        $this->_setClientInfo($clientid,NULL);
    }
    public function addClientToChannel($clientid) {
        //_log(' '.__FILE__.' '.__LINE__.' | add client '.$clientid);
        $data = $this->_getChannelData();
        $lastid = count($data);

        $this->_addChannelUser($clientid);
        $this->_setClientInfo($clientid,$lastid);
    }

    public function addChannelData($data) {
        $channel = $this->getChannel();
        switch ($this->_cacheType) {
            case 'file':
                $channelPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'channel_'.$channel;
                $channelinfo = unserialize(file_get_contents($channelPath));
                if (is_array($channelinfo)) {
                    $channelinfo[] = $data;
                } else {
                    $channelinfo[0] = $data;
                }
                //_log(' '.__FILE__.' '.__LINE__.' | set channel info to '.$channelPath);
                file_put_contents($channelPath, serialize($channelinfo));
                break;
            case 'memcache':
                $channelinfo = $this->_cacheBackend->get('channel_'.$channel);
                if (is_array($channelinfo)) {
                    $channelinfo[] = $data;
                } else {
                    $channelinfo = array();
                    $channelinfo[0] = $data;
                }
                //_log(' '.__FILE__.' '.__LINE__.' | set channel info to channel_'.$channel);
                $this->_cacheBackend->set('channel_'.$channel,$channelinfo);
                break;
        }
    }

    protected function _getChannelData() {
        $channel = $this->getChannel();
        $channelinfo = array();
        switch ($this->_cacheType) {
            case 'file':
                $channelPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'channel_'.$channel;
                //_log(' '.__FILE__.' '.__LINE__.' | get channel info from '.$channelPath);
                $channelinfo = unserialize(file_get_contents($channelPath));
                break;
            case 'memcache':
                //_log(' '.__FILE__.' '.__LINE__.' | get channel info from channel_'.$channel);
                $channelinfo = $this->_cacheBackend->get('channel_'.$channel);
                break;
        }
        return $channelinfo;
    }

    protected function _getChannelUsers() {
        $channel = $this->getChannel();
        $channelinfo = array();
        switch ($this->_cacheType) {
            case 'file':
                $channelUsersPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'channelusers_'.$channel;
                //_log(' '.__FILE__.' '.__LINE__.' | get channel users from '.$channelPath);
                $channelusers = unserialize(file_get_contents($channelUsersPath));
                break;
            case 'memcache':
                //_log(' '.__FILE__.' '.__LINE__.' | get channel info from channel_'.$channel);
                $channelusers = $this->_cacheBackend->get('channelusers_'.$channel);
                break;
        }
        return $channelusers;
    }

    protected function _addChannelUser($clientid) {
        $users = $this->_getChannelUsers();
        if (!in_array($clientid,$users)) {
            $users[] = $clientid;
            $this->_saveChannelUsers($users);
        }
    }

    protected function _deleteChannelUser($clientid) {
        $users = $this->_getChannelUsers();
        if (in_array($clientid,$users)) {
            $users_flip = array_flip($users);
            unset($users_flip[$clientid]);
            $users = array_flip($users_flip);
            $this->_saveChannelUsers($users);
        }
    }

    protected function _saveChannelUsers($users) {
        $channel = $this->getChannel();
        switch ($this->_cacheType) {
            case 'file':
                $channelUsersPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'channelusers_'.$channel;
                //_log(' '.__FILE__.' '.__LINE__.' | saving channel users to '.$channelUsersPath);
                file_put_contents($channelUsersPath, serialize($users));
                break;
            case 'memcache':
                //_log(' '.__FILE__.' '.__LINE__.' | save channel users to channelusers_'.$channel);
                $this->_cacheBackend->set('channelusers_'.$channel,$users);
                break;
        }
    }

    protected function _setClientInfo($clientid,$lastid = NULL) {
        $channel = $this->getChannel();
         //_log(' '.__FILE__.' '.__LINE__.' | store clientid,channel,lastid: '.$clientid.' - '.$channel.' - '.$lastid);
        switch ($this->_cacheType) {
            case 'file':
                $clientPath = $this->_cacheBackend . DIRECTORY_SEPARATOR . 'client_'.$clientid;
                //_log(' '.__FILE__.' '.__LINE__.' | store client info to '.$clientPath);
                $clientinfo = unserialize(file_get_contents($clientPath));
                if (is_null($lastid)) {
                    unset($clientinfo[$channel]);
                } else {
                    $clientinfo[$channel] = $lastid;
                }
                //_log(' '.__FILE__.' '.__LINE__.' | store client info to '.$clientPath.' :'.print_r($clientinfo,1));
                file_put_contents($clientPath, serialize($clientinfo));
                break;
            case 'memcache':
                $clientinfo = $this->_cacheBackend->get('client_'.$clientid);
                if (!is_array($clientinfo)) {
                    $clientinfo = array();
                }

                if (isset($clientinfo[$channel])) {
                    if (is_null($lastid)) {
                        unset($clientinfo[$channel]);
                    } else {
                        $clientinfo[$channel] = $lastid;
                    }
                } else {
                    $clientinfo[$channel] = $lastid;
                }

                //_log(' '.__FILE__.' '.__LINE__.' | store client info to client_'.$clientid.' :'.print_r($clientinfo,1));
                $this->_cacheBackend->set('client_'.$clientid,$clientinfo);
                $val = $this->_cacheBackend->get('client_'.$clientid);
                //_log(' '.__FILE__.' '.__LINE__.' | client info stored :'.print_r($val,1));
                break;
        }
    }

    protected function _normalizeName($channel) {
        return str_replace(array('/'),array('_'),strtolower($channel));
    }
    
    protected function _loadBackend() {
        //_log(' '.__FILE__.' '.__LINE__.' | load storage backend');
        $memcache = false;
        if (class_exists('Memcache')) {
            $memcache = new Memcache;
            $memcache->connect($this->_memcacheServer, $this->_memcachePort);
            //_log(' '.__FILE__.' '.__LINE__.' | memcache version '.$memcache->getVersion());
        }

        //$memcache = false;
        if ($memcache) {
            //_log(' '.__FILE__.' '.__LINE__.' | storage backend = memcache ');
            $this->_cacheBackend = $memcache;
            $this->_cacheType = 'memcache';
        } else {
            //_log(' '.__FILE__.' '.__LINE__.' | storage backend = file based at '.sys_get_temp_dir());
            if (is_dir('/dev/shm')) {
                $this->_cacheBackend = '/dev/shm';
            } else {
                $this->_cacheBackend = sys_get_temp_dir();
            }
            $this->_cacheType = 'file';
        }
    }

}