<?php
/**
 * adminSyslogBroker.php -- the syslog broker client
 *
 *
 * @author  mike@givingassistant.org
 * @version 1.0
 *
 *
 * HISTORY:
 * ========
 * 09-16-19     mks     DB-113: original coding
 * 07-28-20     mks     DB-156: broker self-registration installed
 *
 */
//use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Channel\AMQPChannel;
use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Exception\AMQPRuntimeException;

//use PhpAmqpLib\Message\AMQPMessage;
//use PhpAmqpLib\Exception\AMQPTimeoutException;

pcntl_async_signals(true);                                      // enable asynchronous signal handling (PHP 7.1)
$_REDIRECT = true;
$topDir = dirname(__DIR__);
// load the lite version of the framework
@require_once($topDir . '/config/sneakerstrap.inc');                  // can't be constants b/c this loads the constants
$res = 'SYSL: ';

// event management for children
$syslogServiceConfig = gasConfig::$settings[CONFIG_BROKER_SERVICES][CONFIG_ADMIN];
$numberChildren = $syslogServiceConfig[CONFIG_BROKER_INSTANCES][CONFIG_SYSLOG_BROKER];
$requestsPerInstance = (empty($syslogServiceConfig[CONFIG_BROKER_REQUEST_LIMIT])) ? NUMBER_C : $syslogServiceConfig[CONFIG_BROKER_REQUEST_LIMIT];
$numberChildren = ($numberChildren < 1) ? 1 : $numberChildren;  // todo -- should this be = 2??
$runningBrokers = $numberChildren;
$requestCounter = 0;
$myRequestsPerInstance = 0;
$startingMemory = 0;
$groot = rtrim($res, COLON) . UDASH . guid();                 // root guid
consoleLog($res, CON_SUCCESS, sprintf(INFO_BROKER_STARTUP, substr(basename(__FILE__), 0, -4), $groot));
$parentLog = new gacErrorLogger();
$errors = null;
$file = rtrim(basename(__FILE__), DOT . FILE_TYPE_PHP);
$service = ENV_ADMIN;

if (!validateService($service, $errors)) {
    $hdr = sprintf(INFO_LOC, $file, __LINE__);
    $msg = sprintf(ERROR_SERVICE_REG, $file, $service);
    $parentLog->fatal($hdr . $msg);
    $parentLog->__destruct();
    unset($parentLog);
    exit(1);
}

//////////////////////////////////////////////////////////////////////////////////
// set-up the replacement signal handler that will be called on a child's death //
//////////////////////////////////////////////////////////////////////////////////
//declare( ticks = 1);
function sigHandler($_sig) {
    global $numberChildren;
    switch ($_sig) {
        case SIGCHLD :
            $numberChildren--;
            while (($pid = pcntl_wait($_sig, WNOHANG)) > 0) {
                @pcntl_wexitstatus($_sig);
            }
            break;
    }
}
pcntl_signal(SIGCLD, 'sigHandler');

/////////////////////////////////////////////////////////////////////////////////////////
// set-up the forking function so that it can be called initially or on a SIGCLD event //
/////////////////////////////////////////////////////////////////////////////////////////
function forkMe()
{
    global $thisWatcher, $eos, $res, $parentLog, $requestsPerInstance, $myRequestsPerInstance, $startingMemory, $groot;
    $myRequestsPerInstance = $requestsPerInstance + (mt_rand(0, 2) * 10) + mt_rand(0, 9);
    $startingMemory = memory_get_usage(true);

    $thisPid = pcntl_fork();

    switch ($thisPid) {
        case -1 :   // error
            $cmsg = ERROR_FORK_FAILED . $thisWatcher;
            $parentLog->fatal($cmsg);
            die(getDateTime() . CON_ERROR . $res . $cmsg . $eos);
            break;
        case 0 :    // child (broker daemon)
            // replace the sigcld signal handler
            pcntl_signal(SIGCLD, SIG_DFL);
            $thisPid = getmypid();

            $childGUID = rtrim($res, COLON) . UDASH . guid();

            try {
                // toss the childGUID unto cache because it does not propagate down to the callback method
                gasCache::sysAdd(($groot . UDASH . $thisPid), $childGUID);

                // create the child logger object
                /** @var gacErrorLogger $childLog */
                $childLog = new gacErrorLogger();

                $queueTag = gasConfig::$settings[CONFIG_BROKER_SERVICES][CONFIG_BROKER_QUEUE_TAG];

                $queue = $queueTag . BROKER_QUEUE_SYSLOG;
                /** @var AMQPStreamConnection $brokerConnection */
                $brokerConnection = gasResourceManager::fetchResource(RESOURCE_ADMIN);
                if (is_null($brokerConnection)) {
                    $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                    $childLog->fatal($hdr . ERROR_RESOURCE_404 . RESOURCE_ADMIN . COLON . BROKER_QUEUE_SYSLOG);
                    consoleLog($res, CON_ERROR,$hdr . ERROR_RESOURCE_404 . RESOURCE_ADMIN . COLON . BROKER_QUEUE_SYSLOG);
                    exit(SHELL_FAILURE);                                                 // shell-script exit value for fail
                }

                // declare the channel...
                $brokerChannel = $brokerConnection->channel();
                // declare the topic exchange for topic-logging
                $brokerChannel->exchange_declare(EXCHANGE_NAME_TOPIC_LOGS, EXCHANGE_TYPE_TOPIC, false, false, false);
                // declare the channel queue and create the queue name
                list($queueName, ,) = $brokerChannel->queue_declare($queue);
                // this broker handles all messages passed to the topic_logs exchange
                $brokerChannel->queue_bind($queueName, EXCHANGE_NAME_TOPIC_LOGS, EXCHANGE_QUEUE_BINDING_LOGS);
            } catch (AMQPRuntimeException | Throwable $t) {
                $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                @handleExceptionMessaging($hdr, $t->getMessage(), $foo, true);
                exit(SHELL_FAILURE);
            }

            // register the broker child start-up as a system-event
            $data = [
                SYSTEM_EVENT_NAME => SYSEV_NAME_CHILD_REG,
                SYSTEM_EVENT_TYPE => SYSEV_TYPE_BROKER,
                SYSTEM_EVENT_BROKER_ROOT_GUID => $groot,
                SYSTEM_EVENT_BROKER_GUID => $childGUID,
                SYSTEM_EVENT_KEY => SYSEV_CHILD_RPI,
                SYSTEM_EVENT_VAL => $myRequestsPerInstance,
                SYSTEM_EVENT_CODE_LOC => basename(__FILE__) . COLON . __LINE__
            ];
            @postSystemEvent($data, $childGUID, $childLog);

            register_shutdown_function(BROKER_SHUTDOWN_FUNCTION, $brokerChannel, $brokerConnection, $res);
            $callback = function($_request) {
                $startTime = gasStatic::doingTime();
                global $requestCounter, $res, $eos, $myRequestsPerInstance, $startingMemory, $groot, $service;
                /** @var AMQPChannel $brokerChannel */
                global $brokerChannel;
                /** @var PhpAmqpLib\Connection\AMQPStreamConnection $brokerConnection */
                global $brokerConnection;

                $childGUID = gasCache::sysGet(($groot . UDASH . getmypid()));
                if (gasConfig::$settings[CONFIG_DEBUG]) {
                    consoleLog($res, CON_DEBUG, 'Child GUID: ' . $childGUID);
                    consoleLog($res,CON_DEBUG, 'root GUID: ' . $groot);
                }

                $requestCounter++;
                $returnData = null;
                $eventTimer = false;
                $request = null;
                $eventSuccess = false;
                $conMsg = '';
                $errorList = array();
                $thisPid = getmypid();
                $eventGUID = guid();
                $ogGUID = '';

                // set-up the call-back logger
                $callBackLog = new gacErrorLogger($eventGUID, false);

                if (!firstPassPayloadValidation($_request, $service,$msg, $request, $eventGUID)) {
                    $conMsg = $msg;
                    $callBackLog->info($msg);
                    $event = BROKER_QUEUE_SYSLOG . '(' . ERROR_DATA_VALIDATION_FIRST_PASS . ')';
                } elseif (!validateMetaData($request, $errorList)) {
                    for ($index = 0, $last = count($errorList); $index < $last; $index++) {
                        $conMsg .= $errorList[$index] . $eos;
                        $callBackLog->error($errorList[$index]);
                    }
                    $conMsg = rtrim($conMsg, $eos);
                    $event = BROKER_QUEUE_SYSLOG . '(' . ERROR_META_VALIDATION_SECOND_PASS . ')';
                } else {
                    $event = BROKER_QUEUE_SYSLOG . '(' . $request[BROKER_REQUEST] . ')';
                    switch ($request[BROKER_REQUEST]) {
                        case BROKER_REQUEST_SHUTDOWN :
//                            $_request->delivery_info[BROKER_CHANNEL]->basic_cancel($_request->delivery_info[BROKER_DELIVERY_TAG]);
                            $conMsg = SUCCESS_SHUTDOWN;
                            $eventSuccess = true;
                        break;

                        case BROKER_REQUEST_PING :
                            $conMsg = SUCCESS_PING . BROKER_QUEUE_SYSLOG;
                            $eventSuccess = true;
                        break;

                        // syslog processing happens here
                        case BROKER_REQUEST_LOG :
                            try {
                                $namaste = '[' . CONFIG_ID_NODE_NAMASTE . '] ';
                                $sysLogError = gasStatic::getSysLogError($request[BROKER_DATA][0][(LOG_VALUE . COLLECTION_MONGO_LOGS_EXT)]);
                                if (!syslog($sysLogError, $namaste . $request[BROKER_DATA][0][ERROR_MESSAGE . COLLECTION_MONGO_LOGS_EXT])) {
                                    consoleLog($res, CON_ERROR, ERROR_SYSLOG);
                                    $conMsg = FAIL_EVENT . ERROR_SYSLOG;
                                } else {
                                    $conMsg = SUCCESS_EVENT . BROKER_REQUEST_SYSLOG;
                                    $eventSuccess = true;
                                }
                            } catch (Throwable | TypeError $t) {
                                $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                                consoleLog($res, CON_ERROR, $hdr . $t->getMessage());
                            }
                        break;

                        default :
                            $conMsg = ERROR_BROKER_EVENT_UNKNOWN . $request[BROKER_REQUEST];
                            $callBackLog->warn(ERROR_BROKER_EVENT_UNKNOWN . $request[BROKER_REQUEST]);
                            // todo - not a supported event so log something dire
                        break;
                    }
                }
                if (!$eventSuccess and empty($conMsg)) {
                    $conMsg = ERROR_FINE_PICKLE;
                }
                if (!empty($conMsg)) {
                    consoleLog($res, (($eventSuccess) ? CON_SUCCESS : CON_ERROR), $conMsg . sprintf(ERROR_EVENT_COUNT, $requestCounter, $myRequestsPerInstance));
                }
//                $_request->delivery_info[BROKER_CHANNEL]->basic_ack($_request->delivery_info[BROKER_DELIVERY_TAG]);

                // get the broker-event processing time
                $eventTime = gasStatic::doingTime($startTime);

                // log a system-event for the event -- unlike the other system events, we're not going to submit
                // this one via a broker - which is standard but, instead, we're going to write the record out
                // directly since doing otherwise would cause an infinite loop in processing.
                if ($eventTime and $eventTimer) {
                    $data = [
                        SYSTEM_EVENT_NAME => SYSEV_NAME_EVENT_TIMER,
                        SYSTEM_EVENT_TYPE => SYSEV_TYPE_BROKER,
                        SYSTEM_EVENT_BROKER_ROOT_GUID => $groot,
                        SYSTEM_EVENT_BROKER_GUID => $childGUID,
                        DB_EVENT_GUID => $eventGUID,
                        SYSTEM_EVENT_COUNT => $requestCounter,
                        SYSTEM_EVENT_COUNT_TOTAL => $myRequestsPerInstance,
                        SYSTEM_EVENT_TIMER => $eventTime,
                        SYSTEM_EVENT_BROKER_EVENT => $event,
                        SYSTEM_EVENT_META_DATA => $request[BROKER_META_DATA],
                        SYSTEM_EVENT_CODE_LOC => basename(__FILE__) . COLON . __LINE__
                    ];
                    if (!empty($ogGUID)) $data[SYSTEM_EVENT_OGUID] = $ogGUID;
                    @postSystemEvent($data, $eventGUID, $callBackLog);
                }

                // exit the child if we've reached the request limit
                if ($requestCounter >= $myRequestsPerInstance) {
                    if (getmypid() == $thisPid) {
                        $meta = [
                            META_SESSION_IP => STRING_SESSION_HOME,
                            META_SESSION_DAEMON => 1,
                            META_SESSION_MISC => INFO_BROKER_RECYCLE,
                            META_EVENT_GUID => $eventGUID
                        ];
                        $data = [
                            SYSTEM_EVENT_NAME => SYSEV_NAME_BROKER_RECYCLE,
                            SYSTEM_EVENT_TYPE => SYSEV_TYPE_BROKER,
                            SYSTEM_EVENT_BROKER_ROOT_GUID => $groot,
                            SYSTEM_EVENT_BROKER_GUID => $childGUID,
                            DB_EVENT_GUID => $eventGUID,
                            SYSTEM_EVENT_START =>  $startingMemory,
                            SYSTEM_EVENT_PEAK =>  memory_get_peak_usage(true),
                            SYSTEM_EVENT_END =>  memory_get_usage(true),
                            SYSTEM_EVENT_BROKER_EVENT => $event,
                            SYSTEM_EVENT_COUNT => $requestCounter,
                            SYSTEM_EVENT_COUNT_TOTAL => $myRequestsPerInstance,
                            SYSTEM_EVENT_META_DATA => $meta,
                            SYSTEM_EVENT_CODE_LOC => basename(__FILE__) . COLON . __LINE__
                        ];
                        @postSystemEvent($data, $eventGUID, $callBackLog);
                        gasCache::sysDel(($groot . UDASH . $thisPid));
                    }
                    consoleLog($res, CON_SYSTEM, INFO_BROKER_REQ_COUNT);
                    if (is_object($brokerChannel)) $brokerChannel->close();
                    if (is_object($brokerConnection)) $brokerConnection->close();
                    exit(0);
                }
            };
            consoleLog($res, CON_SYSTEM, sprintf(INFO_BROKER_QUEUE_ESTABLISHED, BROKER_QUEUE_SYSLOG, $thisPid, $myRequestsPerInstance));
            $brokerChannel->basic_consume($queue, '', false, true, false, false, $callback);
            while (count($brokerChannel->callbacks)) {
                try {
                    $brokerChannel->wait();
                } catch (Throwable $t) {
                    $hdr = sprintf(INFO_LOC, basename(__FILE__), __LINE__);
                    @handleExceptionMessaging($hdr, $t->getMessage(), $foo, true);
                }
            }
            break;

        case 1 :    // parent
                    // does nothing
            break;
    }
    return($thisPid);
}

for ($numBrokers = 0; $numBrokers < $runningBrokers; $numBrokers++) {
    $childrenPidList[] = forkMe();
}
consoleLog($res, CON_SUCCESS, sprintf(INFO_BROKER_PARENT_STARTED, count($childrenPidList), BROKER_QUEUE_SYSLOG));

// "register" the broker instantiation event
$data = [
    SYSTEM_EVENT_NAME => SYSEV_NAME_GROOT_REG,
    SYSTEM_EVENT_TYPE => SYSEV_TYPE_BROKER,
    SYSTEM_EVENT_BROKER_ROOT_GUID => $groot,
    SYSTEM_EVENT_KEY => STRING_NUMBER_CHILDREN,
    SYSTEM_EVENT_VAL => $numberChildren,
    SYSTEM_EVENT_CODE_LOC => basename(__FILE__) . COLON . __LINE__,
    SYSTEM_EVENT_NOTES => BROKER_SYSEV_REG . rtrim($res, ": ")
];
@postSystemEvent($data, $groot, $parentLog);

// the parent process continues to run, waking-up every second to monitor it's children...
// when a child dies, it's death-rattle is caught and the child is replaced with a new process.
while (count($childrenPidList)) {
    $lastPid = 0;
    $newPidList = null;
    $result = pcntl_waitpid(0, $status);        // detect any sigchld from the parent-group
    if (in_array($result, $childrenPidList)) {
        $key = array_search($result, $childrenPidList);
        array_splice($childrenPidList, $key, 1);
        // process has already exited -- restart it
        $childrenPidList[] = forkMe();
    }
}