<?php

namespace FiberlinkBundle\SNMP;
use \Exception;
use \Cache;

class SNMP
{
    /**
     * The SNMP community to use when polling SNMP services. Defaults to 'public' by the constructor.
     *
     * @var string The SNMP community to use when polling SNMP services. Defaults to 'public' by the constructor.
     */
    protected $_community;

    /**
     * The SNMP host to query. Defaults to '127.0.0.1'
     * @var string The SNMP host to query. Defaults to '127.0.0.1' by the constructor.
     */
    protected $_host;

    /**
     * The SNMP query timeout value (microseconds). Default: 1000000
     * @var int The SNMP query timeout value (microseconds). Default: 1000000
     */
    protected $_timeout = 100000000;

    /**
     * The SNMP query retry count. Default: 5
     * @var int The SNMP query retry count. Default: 5
     */
    protected $_retry = 5;


    /**
     * A variable to hold the last unaltered result of an SNMP query
     * @var mixed The last unaltered result of an SNMP query
     */
    protected $_lastResult = null;

    /**
     * The cache object to use as the cache
     * @var \Cache The cache object to use
     */
    protected $_cache = null;

    /**
     * Set to true to disable local cache lookup and force SNMP queries
     *
     * Results are still stored. If you need to force a SNMP query, you can:
     *
     * $snmp = new OSS_SNMP( ... )'
     * ...
     * $snmp->disableCache();
     * $snmp->get( ... );
     * $snmp->enableCache();
     */
    protected $_disableCache = false;

    /**
     * SNMP output constants to mirror those of PHP
     * @var SNMP output constants to mirror those of PHP
     */
    const OID_OUTPUT_FULL    = SNMP_OID_OUTPUT_FULL;

    /**
     * SNMP output constants to mirror those of PHP
     * @var SNMP output constants to mirror those of PHP
     */
    const OID_OUTPUT_NUMERIC = SNMP_OID_OUTPUT_NUMERIC;


    /**
     * Definition of an SNMP return type 'TruthValue'
     * @var Definition of an SNMP return type 'TruthValue'
     */
    const SNMP_TRUTHVALUE_TRUE  = 1;

    /**
     * Definition of an SNMP return type 'TruthValue'
     * @var Definition of an SNMP return type 'TruthValue'
     */
    const SNMP_TRUTHVALUE_FALSE = 2;

    /**
     * PHP equivalents of SNMP return type TruthValue
     * @var array PHP equivalents of SNMP return type TruthValue
     */
    public static $SNMP_TRUTHVALUES = array(
        self::SNMP_TRUTHVALUE_TRUE  => true,
        self::SNMP_TRUTHVALUE_FALSE => false
    );

    /**
     * The constructor.
     *
     * @param string $host The target host for SNMP queries.
     * @param string $community The community to use for SNMP queries.
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function __construct( $host = '127.0.0.1', $community = 'public' )
    {
        return $this->setHost( $host )
                    ->setCommunity( $community )
                    ->setOidOutputFormat( self::OID_OUTPUT_NUMERIC );
    }


    /**
     * Proxy to the snmp2_real_walk command
     *
     * @param string $oid The OID to walk
     * @return array The results of the walk
     */
    public function realWalk( $oid )
    {
        return $this->_lastResult = @snmp2_real_walk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );
    }


    /**
     * Get a single SNMP value
     *
     * @throws \Exception On *any* SNMP error, warnings are supressed and a generic exception is thrown
     * @param string $oid The OID to get
     * @return mixed The resultant value
     */
    public function get( $oid )
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmp2_get( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        return $this->getCache()->save( $oid, $this->parseSnmpValue( $this->_lastResult ) );
    }

    /**
     * Get indexed SNMP values (first degree)
     *
     * Walks the SNMP tree returning an array of key => value pairs.
     *
     * This is a first degree walk and it will throw an exception if there is more that one degree of values.
     *
     * I.e. the following query with sample results:
     *
     * walk1d( '.1.0.8802.1.1.2.1.3.7.1.4' )
     *
     *       .1.0.8802.1.1.2.1.3.7.1.4.1 = STRING: "GigabitEthernet1/0/1"
     *       .1.0.8802.1.1.2.1.3.7.1.4.2 = STRING: "GigabitEthernet1/0/2"
     *       .1.0.8802.1.1.2.1.3.7.1.4.3 = STRING: "GigabitEthernet1/0/3"
     *       .....
     *
     * would yield an array:
     *
     *      1 => GigabitEthernet1/0/1
     *      2 => GigabitEthernet1/0/2
     *      3 => GigabitEthernet1/0/3
     *
     * @param string $oid The OID to walk
     * @return array The resultant values
     * @throws \Exception On *any* SNMP error, warnings are supressed and a generic exception is thrown
     */
    public function walk1d( $oid )
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmp2_real_walk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        $result = array();

        $oidPrefix = null;
        foreach( $this->_lastResult as $_oid => $value )
        {
            if( $oidPrefix !== null && $oidPrefix != substr( $_oid, 0, strrpos( $_oid, '.' ) ) )
                throw new Exception( 'Requested OID tree is not a first degree indexed SNMP value' );
            else
                $oidPrefix = substr( $_oid, 0, strrpos( $_oid, '.' ) );

            $result[ substr( $_oid, strrpos( $_oid, '.' ) + 1 ) ] = $this->parseSnmpValue( $value );
        }

        return $this->getCache()->save( $oid, $result );
    }

    /**
     * Get indexed SNMP values where the array key is the given position of the OID
     *
     * I.e. the following query with sample results:
     *
     * subOidWalk( '.1.3.6.1.4.1.9.9.23.1.2.1.1.9', 15 )
     *
     *
     *       .1.3.6.1.4.1.9.9.23.1.2.1.1.9.10101.5 = Hex-STRING: 00 00 00 01
     *       .1.3.6.1.4.1.9.9.23.1.2.1.1.9.10105.2 = Hex-STRING: 00 00 00 01
     *       .1.3.6.1.4.1.9.9.23.1.2.1.1.9.10108.4 = Hex-STRING: 00 00 00 01
     *
     * would yield an array:
     *
     *      10101 => Hex-STRING: 00 00 00 01
     *      10105 => Hex-STRING: 00 00 00 01
     *      10108 => Hex-STRING: 00 00 00 01
     *
     * @throws \Exception On *any* SNMP error, warnings are supressed and a generic exception is thrown
     * @param string $oid The OID to walk
     * @param int $position The position of the OID to use as the key
     * @return array The resultant values
     */
    public function subOidWalk( $oid, $position )
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmp2_real_walk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        $result = array();

        foreach( $this->_lastResult as $_oid => $value )
        {
            $oids = explode( '.', $_oid );

            $result[ $oids[ $position] ] = $this->parseSnmpValue( $value );
        }

        return $this->getCache()->save( $oid, $result );
    }


    /**
     * Get indexed SNMP values where they are indexed by IPv4 addresses
     *
     * I.e. the following query with sample results:
     *
     * subOidWalk( '.1.3.6.1.2.1.15.3.1.1. )
     *
     *
     *       .1.3.6.1.2.1.15.3.1.1.10.20.30.4 = IpAddress: 192.168.10.10
     *       ...
     *
     * would yield an array:
     *
     *      [10.20.30.4] => "192.168.10.10"
     *      ....
     *
     * @throws \Exception On *any* SNMP error, warnings are supressed and a generic exception is thrown
     * @param string $oid The OID to walk
     * @return array The resultant values
     */
    public function walkIPv4( $oid )
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmp2_real_walk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        $result = array();

        foreach( $this->_lastResult as $_oid => $value )
        {
            $oids = explode( '.', $_oid );

            $len = count( $oids );

            $result[ $oids[ $len - 4 ] . '.' . $oids[ $len - 3 ] . '.' . $oids[ $len - 2 ] . '.' . $oids[ $len - 1 ]  ] = $this->parseSnmpValue( $value );
        }

        return $this->getCache()->save( $oid, $result );
    }


    /**
     * Parse the result of an SNMP query into a PHP type
     *
     * For example, [STRING: "blah"] is parsed to a PHP string containing: blah
     *
     * @param string $v The value to parse
     * @return mixed The parsed value
     * @throws Exception
     */
    public function parseSnmpValue( $v )
    {
        // first, rule out an empty string
        if( $v == '""' || $v == '' )
            return "";

        $type = substr( $v, 0, strpos( $v, ':' ) );
        $value = trim( substr( $v, strpos( $v, ':' ) + 1 ) );

        switch( $type )
        {
            case 'STRING':
                if($value == '"-"') return "";
                    
                if( substr( $value, 0, 1 ) == '"' )
                    $rtn = (string)trim( substr( substr( $value, 1 ), 0, -1 ) );
                else
                    $rtn = (string)$value;
                break;

            case 'INTEGER': //case : INTEGER : someText(intValue) // INTEGER : -3.15 Unidad
                if( strpos( $value, '(' ) !== false and substr($value, 0,1) != '-'){
                    $rtn = (float)substr( substr( $value, strpos( $value, '(' ) + 1 ), 0);
                }else{
                    $rtn = (float)$value;
		}

		if($rtn == (int)$rtn) $rtn = (int) $rtn;
                break;

            case 'Counter32':
            case 'Counter64':
                $rtn = (int)$value;
                break;

            case 'Gauge32':
            case 'Gauge64':
                $rtn = (int)$value;
                break;

            case 'Hex-STRING':
                $rtn = (string)implode( '', explode( ' ', $value ) );
                break;

            case 'IpAddress':
                $rtn = (string)$value;
                break;

            case 'Timeticks':
                $rtn = (int)substr( $value, 1, strrpos( $value, ')' ) - 1 );
                break;

            default:
                throw new Exception( "ERR: Unhandled SNMP return type: $type\n" );
        }

        return $rtn;
    }

    /**
     * Utility function to convert TruthValue SNMP responses to true / false
     *
     * @param integer $value The TruthValue ( 1 => true, 2 => false) to convert
     * @return boolean
     */
    public static function ppTruthValue( $value )
    {
        if( is_array( $value ) )
            foreach( $value as $k => $v )
                $value[$k] = self::$SNMP_TRUTHVALUES[ $v ];
        else
            $value = self::$SNMP_TRUTHVALUES[ $value ];

        return $value;
    }

    /**
     * Utility function to translate one value(s) to another via an associated array
     *
     * I.e. all elements '$value' will be replaced with $translator( $value ) where
     * $translator is an associated array.
     *
     * Huh? Just read the code below!
     *
     * @param mixed $values A scalar or array or values to translate
     * @param array $translator An associated array to use to translate the values
     * @return mixed The translated scalar or array
     */
    public static function translate( $values, $translator )
    {
        if( !is_array( $values ) )
        {
            if( isset( $translator[ $values ] ) )
                return $translator[ $values ];
            else
                return "*** UNKNOWN ***";
        }

        foreach( $values as $k => $v )
        {
            if( isset( $translator[ $v ] ) )
                $values[$k] = $translator[ $v ];
            else
                $values[$k] = "*** UNKNOWN ***";
        }

        return $values;
    }

    /**
     * Sets the output format for SNMP queries.
     *
     * Should be one of the class OID_OUTPUT_* constants
     *
     * @param int $f The fomat to use
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function setOidOutputFormat( $f )
    {
        snmp_set_oid_output_format( $f );
        return $this;
    }


    /**
     * Sets the target host for SNMP queries.
     *
     * @param string $h The target host for SNMP queries.
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function setHost( $h )
    {
        $this->_host = $h;

        // clear the temporary result cache and last result
        $this->_lastResult = null;
        unset( $this->_resultCache );
        $this->_resultCache = array();

        return $this;
    }

    /**
     * Returns the target host as currently configured for SNMP queries
     *
     * @return string The target host as currently configured for SNMP queries
     */
    public function getHost()
    {
        return $this->_host;
    }

    /**
     * Sets the community string to use for SNMP queries.
     *
     * @param string $c The community to use for SNMP queries.
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function setCommunity( $c )
    {
        $this->_community = $c;
        return $this;
    }

    /**
     * Returns the community string currently in use.
     *
     * @return string The community string currently in use.
     */
    public function getCommunity()
    {
        return $this->_community;
    }

    /**
     * Sets the timeout to use for SNMP queries (microseconds).
     *
     * @param int $t The timeout to use for SNMP queries (microseconds).
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function setTimeout( $t )
    {
        $this->_timeout = $t;
        return $this;
    }

    /**
     * Returns the SNMP query timeout (microseconds).
     *
     * @return int The the SNMP query timeout (microseconds)
     */
    public function getTimeout()
    {
        return $this->_timeout;
    }

    /**
     * Sets the SNMP query retry count.
     *
     * @param int $r The SNMP query retry count
     * @return FiberlinkBundle\SNMP\SNMP An instance of $this (for fluent interfaces)
     */
    public function setRetry( $r )
    {
        $this->_retry = $r;
        return $this;
    }

    /**
     * Returns the SNMP query retry count
     *
     * @return string The SNMP query retry count
     */
    public function getRetry()
    {
        return $this->_retry;
    }

    /**
     * Returns the unaltered original last SNMP result
     *
     * @return mixed The unaltered original last SNMP result
     */
    public function getLastResult()
    {
        return $this->_lastResult;
    }

    /**
     * Returns the internal result cache
     *
     * @return array The internal result cache
     */
    public function getResultCache()
    {
        return $this->_resultCache;
    }


    /**
     * Disable lookups of the local cache
     *
     * @return SNMP An instance of this for fluent interfaces
     */
    public function disableCache()
    {
        $this->_disableCache = true;
        return $this;
    }


    /**
     * Enable lookups of the local cache
     *
     * @return SNMP An instance of this for fluent interfaces
     */
    public function enableCache()
    {
        $this->_disableCache = false;
        return $this;
    }

    /**
     * Query whether we are using the cache or not
     *
     * @return boolean True of the local lookup cache is enabled. Otherwise false.
     */
    public function cache()
    {
        return !$this->_disableCache;
    }

    /**
     * Set the cache to use
     *
     * @param \OSS_SNMP\Cache $c The cache to use
     * @return FiberlinkBundle\SNMP\SNMP For fluent interfaces
     */
    public function setCache( $c )
    {
        $this->_cache = $c;
        return $this;
    }

    /**
     * Get the cache in use (or create a Cache\Basic instance
     *
     * We kind of mandate the use of a cache as the code is written with a cache in mind.
     * You are free to disable it via disableCache() but your machines may be hammered!
     *
     * We would suggest disableCache() / enableCache() used in pairs only when really needed.
     *
     * @return \OSS_SNMP\Cache The cache object
     */
    public function getCache()
    {
        if( $this->_cache === null )
            $this->_cache = new \OSS_SNMP\Cache\Basic();

        return $this->_cache;
    }


    /**
     * Magic method for generic function calls
     *
     * @param string $method
     * @param array $args
     * @throws Exception
     */
    public function __call( $method, $args )
    {
        if( substr( $method, 0, 3 ) == 'use' )
            return $this->useExtension( substr( $method, 3 ), $args );

        throw new Exception( "ERR: Unknown method requested in magic __call(): $method\n" );
    }


    /**
     * This is the MIB Extension magic
     *
     * Calling $this->useXXX_YYY_ZZZ()->fn() will instantiate
     * an extension MIB class is the given name and this $this SNMP
     * instance and then call fn().
     *
     * See the examples for more information.
     *
     * @param string $mib The extension class to use
     * @param array $args
     * @return FiberlinkBundle\MIBS
     */
    public function useExtension( $mib, $args )
    {
        $mib = 'FiberlinkBundle\\SNMP\\MIBS\\' . str_replace( '_', '\\', $mib );
        $m = new $mib();
        $m->setSNMP( $this );
        return $m;
    }
    
    /**
     * Retorna la última parte del oid, iniciando desde $position
     *
     * I.e. the following query with sample results:
     *
     * lastOidWalk( '1.3.6.1.4.1.13464.1.11.3.1.1.2', 14 )
     *
     * tener en cuenta que retorna con . por delante y realiza explode por .
     * 
     *      .1.3.6.1.4.1.13464.1.11.3.1.1.2.0.1 2
     *      .1.3.6.1.4.1.13464.1.11.3.1.1.2.0.2 2
     *      .1.3.6.1.4.1.13464.1.11.3.1.1.2.0.3 2
     *      .1.3.6.1.4.1.13464.1.11.3.1.1.2.0.4 2
     *      
     * Posiciones:
     *        .  1  .  3  .  6  .  1  .  4  .  1  .  13464  .  1  .  11  .  3  .  1  .  1  .  2  .  0  .  4   2 
     *      0    1     2     3     4     5     6       7       8     9      10    11    12    13    14    15  value
     *
     * Would yield an array:
     *
     *      [0.1] => 2
     *      [0.2] => 2
     *      [0.3] => 2
     *      [0.4] => 2
     *
     *
     * @throws \Exception On *any* SNMP error, warnings are supressed and a generic exception is thrown
     * @param string $oid The OID to walk
     * @param int $position The position of the OID to use as the key
     * @return array The resultant values
     */
    public function lastOidWalk( $oid, $position)
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmp2_real_walk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        $result = array();

        foreach( $this->_lastResult as $_oid => $value )
        {
            $oids = explode( '.', $_oid );

            $_oids = array_slice($oids, $position);
            $oid = implode(".", $_oids);
            
            $result[ $oid ] = $this->parseSnmpValue( $value );
        }

        return $this->getCache()->save( $oid, $result );
    }
    
    /**
     * Proxy to the snmprealwalk command
     *
     * @param string $oid The OID to walk
     * @return array The results of the walk
     */
    public function realWalkV1( $oid )
    {
        return $this->_lastResult = @snmprealwalk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );
    }
    
    public function lastOidWalkV1( $oid, $position )
    {
        if( $this->cache() && ( $rtn = $this->getCache()->load( $oid ) ) !== null )
            return $rtn;

        $this->_lastResult = @snmprealwalk( $this->getHost(), $this->getCommunity(), $oid, $this->getTimeout(), $this->getRetry() );

        if( $this->_lastResult === false )
            throw new Exception( 'Cound not perform walk for OID ' . $oid );

        $result = array();

        foreach( $this->_lastResult as $_oid => $value )
        {
            $oids = explode( '.', $_oid );

            $_oids = array_slice($oids, $position);
            $oid = implode(".", $_oids);
            
            $result[ $oid ] = $this->parseSnmpValue( $value );
        }

        return $this->getCache()->save( $oid, $result );
        
    }
    
}