<?php

namespace Alchemy\Phrasea\Model\Repositories;

use Alchemy\Phrasea\Model\Entities\WorkerRunningJob;
use Alchemy\Phrasea\WorkerManager\Queue\MessagePublisher;
use DateTime;
use Doctrine\DBAL\Driver\Connection;
use Doctrine\ORM\EntityRepository;
use Exception;
use PDO;

class WorkerRunningJobRepository extends EntityRepository
{

    /**
     * Check and declare that we want to create a subdef from a document
     *
     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
     * - if not (needed resource(s) already in use by other job(s)) : return null
     *
     * rules :
     * - if someone else is already writing the document, we can't create a subdef from it
     * - if someone else is already writing this subdef, we can't re-create it
     *
     * @param array $payload
     * @return int | null           workerRunningJobId
     */
    public function canCreateSubdef(array $payload)
    {
        $this->reconnect();
        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();

        $sqlclause = "(`work_on` = " . $cnx->quote('document') . " OR `work_on` = " . $cnx->quote($payload['subdefName']) . ")";

        return $this->canDoJob($payload, MessagePublisher::SUBDEF_CREATION_TYPE, $sqlclause);
    }


    /**
     * Check and declare that we want to write meta into a subdef
     *
     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
     * - if not (needed resource(s) already in use by other job(s)) : return null
     *
     * rule :
     * - if someone is already working on the file, we can't write
     *
     * @param array $payload
     * @return int | null       workerRunningJobId
     */
    public function canWriteMetadata(array $payload)
    {
        $this->reconnect();
        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();

        $sqlclause = "(`work_on` = " . $cnx->quote($payload['subdefName']) . ")";

        return $this->canDoJob($payload, MessagePublisher::WRITE_METADATAS_TYPE, $sqlclause);
    }

    /**
     * Check and declare that we want to do jon for a subdef
     *
     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
     * - if not (needed resource(s) already in use by other job(s)) : return null
     *
     * The rule depends on caller / jobType (canCreateSubdef or canWriteMetadata)
     *
     * @param array $payload
     * @param string $jobType           // MessagePublisher::WRITE_METADATAS_TYPE | MessagePublisher::SUBDEF_CREATION_TYPE
     * @param string $sqlClause
     * @return int | null       workerRunningJobId
     */
    private function canDoJob(array $payload, string $jobType, string $sqlClause)
    {
        $workerRunningJobId = null;     // returned

        $databoxId      = $payload['databoxId'];
        $recordId       = $payload['recordId'];
        $subdefName     = $payload['subdefName'];

        file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
            sprintf('canDoJob("%s") for %s.%s.%s ?', $jobType, $databoxId, $recordId, $subdefName)
        ), FILE_APPEND | LOCK_EX);

        // first protect sql by a critical section
        if( !( $recordMutexId = $this->getRecordMutex($databoxId, $recordId)) ) {
            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                'getRecordMutex() failed'
            ), FILE_APPEND | LOCK_EX);

            return null;
        }

        // here we can do sql atomically

        $this->reconnect();
        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();

        if($cnx->beginTransaction() === true) {

            try {
                $row = null;
                $sql = "SELECT * FROM `WorkerRunningJob` WHERE\n"
                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING) . " AND\n"
                    . " `databox_id` = " . $cnx->quote($databoxId, PDO::PARAM_INT) . " AND\n"
                    . " `record_id` = " . $cnx->quote($recordId, PDO::PARAM_INT) . " AND\n"
                    . " " . $sqlClause . " AND\n"
                    . " (`work` = " . $cnx->quote(MessagePublisher::WRITE_METADATAS_TYPE) . " OR `work` = " . $cnx->quote(MessagePublisher::SUBDEF_CREATION_TYPE) . ")\n"
                    . " LIMIT 1";

                $stmt = $cnx->prepare($sql);
                if ($stmt->execute() === true) {
                    $row = $stmt->fetch(PDO::FETCH_ASSOC);
                }
                else {
                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("!!! FAILED select on %s.%s.%s because (%s)", $databoxId, $recordId, $subdefName, $stmt->errorCode())
                    ), FILE_APPEND | LOCK_EX);
                }
                $stmt->closeCursor();

                if(!$row) {
                    // no job running : create or update (may return false) if error
                    $workerRunningJobId = $this->creteOrUpdateJob($cnx, $payload, $jobType);
                }
                else {
                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("job %s (id=%s) already running on %s.%s.%s", $row['work'], $row['id'], $databoxId, $recordId, $subdefName)
                    ), FILE_APPEND | LOCK_EX);
                }

                $cnx->commit();
            }
            catch (Exception $e) {
                $cnx->rollBack();

                file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                    sprintf("!!! FAILED in transaction to select/create on %s.%s.%s because (%s)", $databoxId, $recordId, $subdefName, $e->getMessage())
                ), FILE_APPEND | LOCK_EX);
            }
        }
        else {
            file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                sprintf("!!! FAILED to create transaction to select/create on %s.%s.%s", $databoxId, $recordId, $subdefName)
            ), FILE_APPEND | LOCK_EX);
        }

        // end of critical section
        $this->releaseMutex($recordMutexId);

        return $workerRunningJobId;
    }

    /**
     * @param Connection $cnx
     * @param array $payload
     * @param string $type
     * @return int|null     // workerJobId
     */
    private function creteOrUpdateJob(Connection $cnx, array $payload, string $type)
    {
        // for unpredicted sql errors we can still ignore and return null (lock failed),
        // because anyway the worker/rabbit retry system will stop itself after n failures.

        $workerJobId = null;

        try {
            if (!isset($payload['workerJobId'])) {

                // new job

                $datePublished = new DateTime();
                $datePublished->setTimestamp($payload['published']);
                $datePublished->format('Y-m-d H:i:s');

                $pl = json_encode([
                    'message_type' => $type,
                    'payload'      => $payload
                ]);

                $sql = "INSERT INTO `WorkerRunningJob` SET \n"
                    . " `databox_id` = " . $cnx->quote($payload['databoxId'], PDO::PARAM_INT) . ",\n"
                    . " `record_id` = " . $cnx->quote($payload['recordId'], PDO::PARAM_INT) . ",\n"
                    . " `work` = " . $cnx->quote($type) . ",\n"
                    . " `work_on` = " . $cnx->quote($payload['subdefName']) . ",\n"
                    . " `payload` = " . $cnx->quote($pl) . ",\n"
                    . " `published` = " . $cnx->quote($datePublished->format('Y-m-d H:i:s')) . ",\n"
                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING);

                if ($cnx->exec($sql) === 1) {
                    // went well, the row is inserted
                    $workerJobId = $cnx->lastInsertId();
                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("created job %s (id=%s) for %s.%s.%s", $type, $workerJobId, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
                    ), FILE_APPEND | LOCK_EX);
                }
                else {
                    // row not inserted ?
                    throw new Exception("Failed to insert into WorkerRunningJob");
                }
            }
            else {
                // retry from delayed : update retry count (value is already incremented in payload)
                $sql = "UPDATE `WorkerRunningJob` SET \n"
                    . " `info` = " . $cnx->quote(WorkerRunningJob::ATTEMPT . $payload['count']) . ",\n"
                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING)
                    . " WHERE `id` = " . $cnx->quote($payload['workerJobId'], PDO::PARAM_INT);

                if ($cnx->exec($sql) === 1) {
                    // went well, the row is updated
                    $workerJobId = $payload['workerJobId'];

                    file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("updated job %s (id=%s) for %s.%s.%s", $type, $workerJobId, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
                    ), FILE_APPEND | LOCK_EX);
                }
                else {
                    // row not inserted ?
                    throw new Exception(sprintf("Failed to update WorkerRunningJob with id=%s", $payload['workerJobId']));
                }
            }
        }
        catch (Exception $e) {
            // bad case : we return null anyway

            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                sprintf("!!! FAILED creating/updating job %s for %s.%s.%s because (%s)", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'], $e->getMessage())
            ), FILE_APPEND | LOCK_EX);
        }

        return $workerJobId;
    }

    /**
     * Acquire a "mutex" to protect critical section on a (sbid + rid) by trying to insert a row in WorkerRunningJob table.
     * If it fails that means that another critical section is already running on this record.
     *
     * when many q-messages are consumed at the same time, many process may ask the same mutex immediatly, many fails.
     * so we retry after a short random delay which gives a good chance to ok, and avoids unnecessary "delayed" q-messages.
     *
     *
     * !!! IMPORTANT !!!
     * we CAN'T use the entity manager to insert, because if this fails with exception (possible case),
     * the EM will be closed and we will have no other chance for anothe tryout.
     * So we play plain sql everywhere here.
     *
     * @param int $databoxId
     * @param int $recordId
     * @return bool
     */
    private function getRecordMutex(int $databoxId, int $recordId)
    {
        // First we delete old unreleased mutex (which should never happen).
        // A mutex is supposed to last only for a very short time (select + insert-or-update).
        // 60s is considered as a dead mutex
        //
        try {
            $this->reconnect();
            $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();

            $sql = "DELETE FROM `WorkerRunningJob` WHERE\n"
                . " `databox_id` = " . $cnx->quote($databoxId) . " AND\n"
                . " `record_id` = " . $cnx->quote($recordId) . " AND\n"
                . " `flock` = " . $cnx->quote('_mutex_') . " AND\n"
                . " TIMESTAMPDIFF(SECOND, `published`, NOW()) > 60";

            if ($cnx->exec($sql) > 0) {
                // affected rows is 1 since by definition this key is unique
                file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                    sprintf("!!! old mutex for %s.%s deleted (!!! SHOULD NOT HAPPEN !!!)", $databoxId, $recordId)
                ), FILE_APPEND | LOCK_EX);
            }
        }
        catch(Exception $e) {
            // here something went very wrong, like sql death
            file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                sprintf("!!! FAILED while trying to delete old mutex for %s.%s (!!! SHOULD NOT HAPPEN !!!)", $databoxId, $recordId)
            ), FILE_APPEND | LOCK_EX);

            return false; // we could choose to continue, but if we end up here... better to stop
        }

        // here we create a mutex, which CAN fail if another process did the same right before us
        //
        $e = null;  // last exception if failed

        for($tryout=1; $tryout<=3; $tryout++) {
            try {
                $this->reconnect();

                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();

                $sql = "INSERT INTO WorkerRunningJob (`databox_id`, `record_id`, `published`, `status`, `flock`) VALUES (\n"
                    . $cnx->quote($databoxId) . ",\n"
                    . $cnx->quote($recordId) . ",\n"
                    . "NOW(),\n"
                    . $cnx->quote('_') . ",\n"
                    . $cnx->quote('_mutex_') . "\n"
                    . ")";

                if(($a = $cnx->exec($sql)) === 1) {

                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("getMutex tryout %s for %s.%s OK", $tryout, $databoxId, $recordId)
                    ), FILE_APPEND | LOCK_EX);

                    return $cnx->lastInsertId();
                }

                throw new Exception(sprintf("inserting mutex should return 1 row affected, got %s", $a));
            }
            catch (Exception $e) {
                /**
                 * with plain sql, EM should still be opened here
                 */

                // duplicate key is possible, we retry on any kind of error
                if($tryout < 3) {
                    $rnd = rand(10, 50) * 10;   // 100 ms ... 500 ms with 10 ms steps

                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("getMutex retry in %d msec", $rnd)
                    ), FILE_APPEND | LOCK_EX);

                    usleep($rnd * 1000);
                }
            }
        }

        file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
            sprintf("!!! FAILED getMutex for %s.%s because (%s)", $databoxId, $recordId, $e->getMessage())
        ), FILE_APPEND | LOCK_EX);

        return false;
    }

    /**
     * Release a mutex by deleting it.
     * This should not fail, but -as for creation-, we will try N times
     *
     * @param int $recordMutexId
     */
    private function releaseMutex(int $recordMutexId)
    {
        $e = null;  // last exception if failed
        for($tryout=1; $tryout<=3; $tryout++) {
            try {
                $this->reconnect();

                /**
                 * because we did not create an entity for mutex row,
                 * we must use plain sql also to delete it
                 */
                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
                $sql = "DELETE FROM WorkerRunningJob WHERE `id` = " . $cnx->quote($recordMutexId);

                $cnx->exec($sql);

                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                    sprintf("releaseMutex (id=%s) DONE", $recordMutexId)
                ), FILE_APPEND | LOCK_EX);

                return;
            }
            catch (Exception $e) {
                if($tryout < 3) {
                    $rnd = rand(10, 50) * 10;   // 100 ms ... 500 ms with 10 ms steps

                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("releaseMutex (id=%s) retry in %d msec", $recordMutexId, $rnd)
                    ), FILE_APPEND | LOCK_EX);

                    usleep($rnd * 1000);
                }
            }
        }

        // Here we were not able to release a mutex (bad)
        // The last chance will be later, when old mutex (60s) is deleted
        file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
            sprintf("!!! FAILED release mutex (id=%s) because (%s)", $recordMutexId, $e->getMessage())
        ), FILE_APPEND | LOCK_EX);
    }

    /**
     * mark a job a "finished"
     * nb : after a long job, connection may be lost so we reconnect.
     *      But sometimes (?) a first commit fails (due to reconnect ?), while the second one is ok.
     *      So here we try 2 times, just in case...
     *
     * @param int $workerRunningJobId
     * @param null $info
     */
    public function markFinished(int $workerRunningJobId, $info = null)
    {
        for($tryout=1; $tryout<=2; $tryout++) {
            try {
                $this->reconnect();
                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
                $sql = "UPDATE `WorkerRunningJob` SET \n"
                    . " `finished` = NOW(),\n"
                    . " `status` = " . $cnx->quote(WorkerRunningJob::FINISHED);
                if(!is_null($info)) {
                    $sql .= ",\n `info` = " . $cnx->quote(WorkerRunningJob::FINISHED);
                }
                $sql .= "\n WHERE `id` = " . $cnx->quote($workerRunningJobId, PDO::PARAM_INT);

                if(($a = $cnx->exec($sql) )=== 1) {
                    // ok
                    file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                        sprintf("job (id=%d) marked as finished", $workerRunningJobId)
                    ), FILE_APPEND | LOCK_EX);

                    return;
                }
                // not ok ? retry
                throw new Exception(sprintf("updating WorkerRunningJob should return 1 row affected, got %s", $a));
            }
            catch (Exception $e) {
                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                    sprintf("failed to mark job (id=%d) as finished (tryout %s, retry in 1 sec) because (%s)", $workerRunningJobId, $tryout, $e->getMessage())
                ), FILE_APPEND | LOCK_EX);
                if($tryout < 2) {
                    sleep(1);   // retry in 1 sec
                }
            }
        }
        file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
            sprintf("!!! FAILED to mark job (id=%d) as finished", $workerRunningJobId)
        ), FILE_APPEND | LOCK_EX);
    }

    /**
     * @param array $databoxIds
     * @return int
     */
    public function checkPopulateStatusByDataboxIds(array $databoxIds)
    {
        $qb = $this->createQueryBuilder('w');
        $qb->where($qb->expr()->in('w.databoxId', $databoxIds))
            ->andWhere('w.work = :work')
            ->andWhere('w.status = :status')
            ->setParameters([ 'work' => MessagePublisher::POPULATE_INDEX_TYPE, 'status' => WorkerRunningJob::RUNNING])
        ;

        return count($qb->getQuery()->getResult());
    }

    public function findByStatus(array $status, $start = 0, $limit = WorkerRunningJob::MAX_RESULT)
    {
        $qb = $this->createQueryBuilder('w');
        $qb
            ->where($qb->expr()->in('w.status', $status))
            ->setFirstResult($start)
            ->setMaxResults($limit)
            ->orderBy('w.id', 'DESC')
        ;

        return $qb->getQuery()->getResult();
    }

    /**
     * @param $commitId
     * @return bool
     */
    public function canAckUploader($commitId)
    {
        $qb = $this->createQueryBuilder('w');
        $res = $qb
            ->where('w.commitId = :commitId')
            ->andWhere('w.work = :work')
            ->andWhere('w.status != :status')
            ->setParameters([
                'commitId' => $commitId,
                'work'     => MessagePublisher::ASSETS_INGEST_TYPE,
                'status'   => WorkerRunningJob::FINISHED
            ])
            ->getQuery()
            ->getResult()
        ;

        return count($res) == 0;
    }

    public function truncateWorkerTable()
    {
        $connection = $this->_em->getConnection();
        $platform = $connection->getDatabasePlatform();
        $this->_em->beginTransaction();
        try {
            $connection->executeUpdate($platform->getTruncateTableSQL('WorkerRunningJob'));
        }
        catch (Exception $e) {
            $this->_em->rollback();
        }
    }

    public function deleteFinishedWorks()
    {
        $this->_em->beginTransaction();
        try {
            $this->_em->getConnection()->delete('WorkerRunningJob', ['status' => WorkerRunningJob::FINISHED]);
            $this->_em->commit();
        }
        catch (Exception $e) {
            $this->_em->rollback();
        }
    }

    public function getEntityManager()
    {
        return parent::getEntityManager();
    }

    public function reconnect()
    {
//        if(!$this->getEntityManager()->isOpen()) {
//            file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
//                sprintf("recreate _em")
//            ), FILE_APPEND | LOCK_EX);
//            $this->_em = $this->_em->create(
//                $this->_em->getConnection(),
//                $this->_em->getConfiguration(),
//                $this->_em->getEventManager()
//            );
//        }
        if($this->_em->getConnection()->ping() === false) {
            $this->_em->getConnection()->close();
            $this->_em->getConnection()->connect();
        }
    }
}