<?php
/**
 * sBroker.php -- the tercero session (one-way) broker
 *
 * The session broker is a "system" broker designed to basically do one thing - handle requests to expire existing
 * sessions on tercero from the admin service.
 *
 * This broker was created so as to not overly-burden the user-broker with administrative requests.  The broker is
 * a "fire-n-forget" broker meaning that no response is published (returned) to the calling client.
 *
 * If there is an error in processing, then we'll communicate that error back to admin by publishing a system event.
 *
 *
 * @author  mike@givingassistant.org
 * @version 1.0
 *
 *
 * HISTORY:
 * ========
 * 10-02-20     mks     DB-168: original coding
 *
 *
 */
use PhpAmqpLib\Channel\AMQPChannel;
use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Exception\AMQPChannelClosedException;
use PhpAmqpLib\Exception\AMQPRuntimeException;
use PhpAmqpLib\Exception\AMQPTimeoutException;

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

// event management for children
$appServerConfig = gasConfig::$settings[CONFIG_BROKER_SERVICES][CONFIG_BROKER_TERCERO];
$numberChildren = $appServerConfig[CONFIG_BROKER_INSTANCES][CONFIG_SESSION_BROKER];
$requestsPerInstance = (empty($appServerConfig[CONFIG_BROKER_REQUEST_LIMIT])) ? NUMBER_C : $appServerConfig[CONFIG_BROKER_REQUEST_LIMIT];
$numberChildren = ($numberChildren < 1) ? 1 : $numberChildren;  // todo -- should this be = 2??  (Yes, but only if prod)
$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_TERCERO;

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_S;
                /** @var AMQPStreamConnection $brokerConnection */
                $brokerConnection = gasResourceManager::fetchResource(RESOURCE_TERCERO);
                if (is_null($brokerConnection)) {
                    $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                    $childLog->fatal($hdr . ERROR_RESOURCE_404 . RESOURCE_TERCERO . COLON . BROKER_QUEUE_S);
                    consoleLog($res, CON_ERROR,$hdr . ERROR_RESOURCE_404 . RESOURCE_TERCERO . COLON . BROKER_QUEUE_S);
                    exit(1);                                                    // shell-script exit value for fail
                }
                $brokerChannel = $brokerConnection->channel();
//                $brokerChannel->queue_declare($queue, BROKER_QUEUE_DECLARE_PASSIVE, false, false, true);
                $brokerChannel->queue_declare($queue);
            } catch (AMQPRuntimeException | AMQPTimeoutException | Throwable $t) {
                $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                @handleExceptionMessaging($hdr, $t->getMessage(), $foo, true);
                exit(1);
            }

            // 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;
                $file = basename(__FILE__);

                $childGUID = gasCache::sysGet(($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 = '';
                /** @var gacMongoDB $obj */
                $obj = null;

                // set-up the call-back logger
                $callBackLog = new gacErrorLogger($eventGUID, false);
                if (!firstPassPayloadValidation($_request, $service, $msg, $request, $eventGUID)) {
                    $conMsg = $msg;
                    $callBackLog->info($msg);
                    $event = BROKER_QUEUE_S . '(' . ERROR_DATA_VALIDATION_FIRST_PASS . ')';
                } elseif (!validateMetaData($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_S . '(' . ERROR_META_VALIDATION_SECOND_PASS . ')';
                } else {
                    $event = BROKER_QUEUE_S . '(' . $request[BROKER_REQUEST] . ')';
                    switch ($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_S;
                            $eventSuccess = true;
                        break;

                        case BROKER_REQUEST_EXPIRE_SESSION :
                            $errors = [];
                            /** var gacMongoDB $obj */
                            if (!is_null($obj = grabWidget($request[BROKER_META_DATA], '', $errors))) {
                                // we have widget - update the session record
                                /** @var gatSessions $template */
                                $template = $obj->template;
                                $bc = new gacWorkQueueClient($file . AT . __LINE__, BROKER_QUEUE_AI);
                                if (!$bc->status) {
                                    $hdr = sprintf(INFO_LOC, $file, __LINE__);
                                    @handleExceptionMessaging($hdr, ERROR_BROKER_CLIENT_DECLARE . BROKER_QUEUE_AI, $foo, true);
                                    $conMsg = FAIL_EVENT . $request[BROKER_REQUEST];
                                } elseif (!is_null($payload = $template->buildExpireSessionPayload($request[BROKER_DATA], $errors))) {
                                    $obj->_updateRecord($payload);
                                    if ($obj->status) {
                                        // publish a request back to admin to expire the system-event record indicating success in closing the session
                                        // (because both of these queues are type f-n-f...)
                                        $bc->call($template->buildCloseSysEventPayload($request[BROKER_DATA][STRING_GUID_KEY]));
                                        // successful session update - console log message and done (no return to client)
                                        $conMsg = SUCCESS_EVENT . $request[BROKER_REQUEST];
                                        $eventSuccess = true;
                                    } else {
                                        // create failed-session record for failure to update session record
                                        if (count($errors))
                                            foreach ($errors as $error)
                                                $callBackLog->error($error);
                                        $conMsg = FAIL_EVENT . $request[BROKER_REQUEST];
                                        $data = [
                                            MONGO_FAILED_EVENT_GUID => $request[BROKER_DATA][STRING_GUID_KEY],
                                            MONGO_FAILED_EVENT_NAME => $request[BROKER_REQUEST],
                                            MONGO_FAILED_EVENT_DESC => basename(__FILE__) . AT . __LINE__,
                                            MONGO_FAILED_EVENT_SEV => ERROR_WARN
                                        ];
                                        $meta = [
                                            META_TEMPLATE => TEMPLATE_CLASS_FAILED_SESSIONS,
                                            META_CLIENT => CLIENT_SYSTEM,
                                            META_DO_CACHE => 0,
                                            META_SESSION_ID => $request[BROKER_DATA][STRING_GUID_KEY],
                                        ];
                                        $request = [
                                            BROKER_REQUEST => BROKER_REQUEST_CREATE,
                                            BROKER_DATA => [$data],
                                            BROKER_META_DATA => $meta
                                        ];
                                        $bc->call(gzcompress(json_encode($request)));
                                        if (is_object($bc)) $bc->__destruct();
                                        unset($bd);
                                    }
                                } else {
                                    // we somehow failed to build the data payload based on the request data
                                    if (count($errors))
                                        foreach ($errors as $error)
                                            $callBackLog->error($error);
                                    $conMsg = FAIL_EVENT . $request[BROKER_REQUEST];
                                }
                            } else {
                                $hdr = sprintf(INFO_LOC, $file, __LINE__);
                                $conMsg = ERROR_TEMPLATE_INSTANTIATE . $request[BROKER_META_DATA][META_TEMPLATE];
                                $obj->eventMessages[] = $conMsg;
                                $callBackLog->warn($hdr . $conMsg);
                            }
                        break;

                        default :
                            $conMsg = ERROR_BROKER_EVENT_UNKNOWN . $request[BROKER_REQUEST];
                            $callBackLog->warn(ERROR_BROKER_EVENT_UNKNOWN . $request[BROKER_REQUEST]);
                        break;
                    }
                }
                if (!$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_S, $thisPid, $myRequestsPerInstance));
            $brokerChannel->basic_consume($queue, '', false, true, false, false, $callback);
            while (count($brokerChannel->callbacks)) {
                try {
                    $brokerChannel->wait();
                } catch (AMQPChannelClosedException | Throwable $t) {
                    $hdr = basename(__FILE__) . AT . __LINE__ . COLON;
                    @handleExceptionMessaging($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_S));

// "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();
    }
}