<?php
/*
 * Copyright (C) 2015 Daniel Preussker <f0o@devilcode.org>
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Device-Grouping
 * @author Daniel Preussker <f0o@devilcode.org>
 * @author Tony Murray <murrayotony@gmail.com>
 * @copyright 2016 f0o, murrant, LibreNMS
 * @license GPL
 * @package LibreNMS
 * @subpackage Devices
 */


/**
 * Add a new device group
 * @param $pattern
 * @param $name
 * @param $desc
 * @return int|string
 */
function AddDeviceGroup($name, $desc, $pattern)
{
    $group_id = dbInsert(array('name' => $name, 'desc' => $desc, 'pattern' => $pattern), 'device_groups');
    if ($group_id) {
        UpdateDeviceGroup($group_id);
    }
    return $group_id;
}

/**
 * Update a device group
 * @param $group_id
 * @param $pattern
 * @param $name
 * @param $desc
 * @return bool
 */
function EditDeviceGroup($group_id, $name = null, $desc = null, $pattern = null)
{
    $vars = array();
    if (!is_null($name)) {
        $vars['name'] = $name;
    }
    if (!is_null($desc)) {
        $vars['desc'] = $desc;
    }
    if (!is_null($pattern)) {
        $vars['pattern'] = $pattern;
    }

    $success = dbUpdate($vars, 'device_groups', 'id=?', array($group_id)) >= 0;

    if ($success) {
        UpdateDeviceGroup($group_id);
    }
    return $success;
}

/**
 * Generate SQL from Group-Pattern
 * @param string $pattern Pattern to generate SQL for
 * @param string $search  What to searchid for
 * @return string
 */
function GenGroupSQL($pattern, $search='',$extra=0) {
    $pattern = RunGroupMacros($pattern);
    if ($pattern === false) {
       return false;
    }
    $tmp    = explode(' ', $pattern);
    $tables = array();
    foreach ($tmp as $opt) {
        if (strstr($opt, '%') && strstr($opt, '.')) {
            $tmpp     = explode('.', $opt, 2);
            $tmpp[0]  = str_replace('%', '', $tmpp[0]);
            $tables[] = mres(str_replace('(', '', $tmpp[0]));
            $pattern  = str_replace($opt, $tmpp[0].'.'.$tmpp[1], $pattern);
        }
    }

    $pattern = rtrim($pattern, '&&');
    $pattern = rtrim($pattern, '||');

    $tables = array_keys(array_flip($tables));
    $x      = sizeof($tables);
    $i      = 0;
    $join   = '';
    while ($i < $x) {
        if (isset($tables[($i + 1)])) {
            $join .= $tables[$i].'.device_id = '.$tables[($i + 1)].'.device_id && ';
        }

        $i++;
    }

    if (!empty($search)) {
        $search .= ' &&';
    }

    $sql_extra = '';
    if ($extra === 1) {
        $sql_extra = ",`devices`.*";
    }
    $sql = 'SELECT DISTINCT('.str_replace('(', '', $tables[0]).'.device_id)'.$sql_extra.' FROM '.implode(',', $tables).' WHERE '.$search.' ('.str_replace(array('%', '@', '!~', '~'), array('', '.*', 'NOT REGEXP', 'REGEXP'), $pattern).')';
    return $sql;

}//end GenGroupSQL()


/**
 * Run the group queries again to get fresh list of devices for this group
 * @param integer $group_id Group-ID
 * @return string
 */
function QueryDevicesFromGroup($group_id)
{
    $pattern = dbFetchCell('SELECT pattern FROM device_groups WHERE id = ?', array($group_id));
    $pattern = rtrim($pattern, '&&');
    $pattern = rtrim($pattern, '||');
    if (!empty($pattern)) {
        return dbFetchColumn(GenGroupSQL($pattern));
    }

    return false;

}//end QueryDevicesFromGroup()

/**
 * Get an array of all the device ids belonging to this group_id
 * @param $group_id
 * @param bool $nested Return an array of arrays containing 'device_id'. (for API compatibility)
 * @return array
 */
function GetDevicesFromGroup($group_id, $nested = false)
{
    $query = 'SELECT `device_id` FROM `device_group_device` WHERE `device_group_id`=?';
    if ($nested) {
        return dbFetchRows($query, array($group_id));
    } else {
        return dbFetchColumn($query, array($group_id));
    }
}//end GetDevicesFromGroup()

/**
 * Get all Device-Groups
 * @return array
 */
function GetDeviceGroups() {
    return dbFetchRows('SELECT * FROM device_groups ORDER BY name');

}//end GetDeviceGroups()

/**
 * Run the group queries again to get fresh list of groups for this device
 * @param integer $device_id Device-ID
 * @param int $extra Return extra info about the groups (name, desc, pattern)
 * @return array
 */
function QueryGroupsFromDevice($device_id,$extra=0) {
    $ret = array();
    foreach (GetDeviceGroups() as $group) {
        if (dbFetchCell(GenGroupSQL($group['pattern'], 'device_id=?',$extra).' LIMIT 1', array($device_id)) == $device_id) {
            if ($extra === 0) {
                $ret[] = $group['id'];
            }
            else {
                $ret[] = $group;
            }
        }
    }

    return $ret;

}//end QueryGroupsFromDevice()

/**
 * Get the Device Group IDs of a Device from the database
 * @param $device_id
 * @param int $extra Return extra info about the groups (name, desc, pattern)
 * @return array
 */
function GetGroupsFromDevice($device_id, $extra = 0)
{
    $ret = array();
    if ($extra === 0) {
        $ret = dbFetchColumn('SELECT `device_group_id` FROM `device_group_device` WHERE `device_id`=?', array($device_id));
    } else {
        $ret = dbFetchRows('SELECT `device_groups`.* FROM `device_group_device` LEFT JOIN `device_groups` ON `device_group_device`.`device_group_id`=`device_groups`.`id` WHERE `device_group_device`.`device_id`=?', array($device_id));
    }
    return $ret;
}//end GetGroupsFromDeviceDB()

/**
 * Process Macros
 * @param string $rule Rule to process
 * @param int $x Recursion-Anchor
 * @return string|boolean
 */
function RunGroupMacros($rule,$x=1) {
    global $config;
    krsort($config['alert']['macros']['group']);
    foreach( $config['alert']['macros']['group'] as $macro=>$value ) {
        if( !strstr($macro," ") ) {
            $rule = str_replace('%macros.'.$macro,'('.$value.')',$rule);
        }
    }
    if( strstr($rule,"%macros") ) {
        if( ++$x < 30 ) {
            $rule = RunGroupMacros($rule,$x);
        } else {
            return false;
        }
    }
    return $rule;
}//end RunGroupMacros()


/**
 * Update device-group relationship for the given device id
 * @param $device_id
 */
function UpdateGroupsForDevice($device_id)
{
    $queried_groups = QueryGroupsFromDevice($device_id);
    $db_groups = GetGroupsFromDevice($device_id);

    // compare the arrays to get the added and removed groups
    $added_groups = array_diff($queried_groups, $db_groups);
    $removed_groups = array_diff($db_groups, $queried_groups);

    // insert new groups
    $insert = array();
    foreach ($added_groups as $group_id) {
        $insert[] = array('device_id' => $device_id, 'device_group_id' => $group_id);
    }
    if (!empty($insert)) {
        dbBulkInsert($insert, 'device_group_device');
    }

    // remove old groups
    if (!empty($removed_groups)) {
        dbDelete('device_group_device', '`device_id`=? AND `device_group_id` IN (?)', array($device_id, array(implode(',', $removed_groups))));
    }

}

/**
 * Update the device-group relationship for the given group id
 * @param $group_id
 */
function UpdateDeviceGroup($group_id)
{
    $queried_devices = QueryDevicesFromGroup($group_id);
    $db_devices = GetDevicesFromGroup($group_id);

    // compare the arrays to get the added and removed devices
    $added_devices = array_diff($queried_devices, $db_devices);
    $removed_devices = array_diff($db_devices, $queried_devices);

    // insert new devices
    $insert = array();
    foreach ($added_devices as $device_id) {
        $insert[] = array('device_id' => $device_id, 'device_group_id' => $group_id);
    }
    if (!empty($insert)) {
        dbBulkInsert($insert, 'device_group_device');
    }

    // remove old devices
    if (!empty($removed_devices)) {
        dbDelete('device_group_device', '`device_group_id`=? AND `device_id` IN (?)', array($group_id, array(implode(',', $removed_devices))));
    }
}