<?php

class vmfs
{

    protected $databasePersist = FALSE;
    protected $databaseResource = null;
    protected $databaseServer = null;
    protected $databaseUsername = null;
    protected $databasePassword = null;
    protected $databaseName = null;
    protected $localHost = null;
    protected $localPointer = null;

    // Load local configuration from disk
    public function __construct()
    {
        $config = CentrixConfig();

        foreach ($config as $k => $v)
        {
            if (isset($this->$k))
            {
                $this->k = $v;
            }
        }
    }

    // Connect to database
    public function connect()
    {
        if ($this->databaseResource instanceOf LOL_MySQLresourcetype)
        {
            return $this->databaseResource;
        }

        if ($this->databasePersist)
        {
            if (!$link = mysql_pconnect())
            {
                throw new Exception('Could not create persistant connection');
            }
        } else
        {
            if (!$link = mysql_connect())
            {
                throw new Exception('Could not create connection');
            }
        }

        if (!mysql_select_db($this->databaseName, $link))
        {
            throw new Exception('Could not select database');
        }

        return $link;
    }

    /**
     * Write to the central database that this server has a new or modified file
     * @param string $path The path on disk
     * @return bool
     */
    public function push($path)
    {
        return $this->report($path, 1);
    }

    /**
     * Fetch a file from another host
     * @param string  $path The path on disk
     * @param integer $host Target host
     * @param string  $hash Expected hash
     * @return bool
     */
    public function pull($path, $host, $hash = null)
    {
        // SCP a file. Maybe write it to a temporary location and check its hash
        // before copying it to the local FS.

        return TRUE;
    }

    /**
     * Write to the central database that this file has been deleted
     * @param string $path The path on disk
     * @return bool
     */
    public function delete($path)
    {
        return $this->report($path, 0);
    }

    /**
     * Get a list of files from the database
     * @param string $pointer OPTIONAL The pointer to begin from
     * @return array
     */
    public function getList($pointer = null)
    {
        if (is_null($pointer))
        {
            $pointer = $this->pointer;
        }

        // $list = SELECT FROM files WHERE pointer >= $pointer;

        return $list;
    }

    private function findHighestPointer($array)
    {
        // Find highest pointer in array of files

        return $pointer;
    }

    /**
     * Writes a record to the database
     * @param string  $path  The path to the local file on disk
     * @param integer $state 1 if file should exist, 0 if it should not
     * @param string  $path  The path to the local file on disk
     * @return string
     */
    private function report($path, $state)
    {
        //INSERT INTO files SET path = $path, state = $state, host = $host, hash = $hash
        //        ON DUPLICATE KEY UPDATE
        //SET state = $state, host = $this->localHost, hash = $this->hash($path)

        return TRUE;
    }

    /**
     * Calculates a file hash
     * @param string $path          The path to the local file on disk
     * @return string
     */
    public function hash($path)
    {
        return crc32($this->localBase . $path);
    }

    /**
     * Tests whether a file exists or not
     * @param string $path          The path to the local file on disk
     * @param string $hash OPTIONAL A hash to compare the file to
     * @return bool
     */
    public function exists($path, $hash = null)
    {
        // Return false if the file does not exist
        if (!file_exists($this->localBase . $path))
        {
            return false;
        }

        // Return false if the file hash does not match the passed value
        if (!is_null($hash))
        {
            return ($hash == $this->hash($path));
        }

        return true;
    }

}



$vmfs = new vmfs();

echo $vmfs->databasePersist;
echo $vmfs->databaseResource;
echo $vmfs->databaseServer;
echo $vmfs->databaseUsername;
echo $vmfs->databasePassword;
echo $vmfs->databaseName;
echo $vmfs->localHost;
echo $vmfs->localPointer;

try
{
    $vmfs->connect();
} catch (Exception $e)
{
    // CRIT - Could not connect to database
}

try
{
    $list = $vmfs->getList();
} catch (Exception $e)
{
    // CRIT - Could not get list
}

foreach ($list as $file)
{
    try
    {
        // A file we already have
        if ($list['state'] == 1 and file_exists($list['path']) && $list['hash'] == $vmfs->hash($path))
        {
            continue;
        }

        // A deleted file we don't have
        if ($list['state'] == 0 and !file_exists($list['path']))
        {
            continue;
        }

        // A file we need to fetch
        if ($list['state'] == 1)
        {
            $vmfs->pull($path);

            continue;
        }

        // A file we need to delete
        if ($list['state'] == 0)
        {
            unlink($vmfs->localBase . $list['path']);
            continue;
        }
    } catch (Exception $e)
    {
        // CRIT - Very bad
        continue;
    }
}

$pointer = $vmfs->findHighestPointer($list);

$this->pointer = $pointer;