/**
 *  Main algorithm to handle the visit.
 *
 *  Once we have the visitor information, we have to determine if the visit is a new or a known visit.
 *
 * 1) When the last action was done more than 30min ago,
 *      or if the visitor is new, then this is a new visit.
 *
 * 2) If the last action is less than 30min ago, then the same visit is going on.
 *    Because the visit goes on, we can get the time spent during the last action.
 *
 * NB:
 *  - In the case of a new visit, then the time spent
 *    during the last action of the previous visit is unknown.
 *
 *    - In the case of a new visit but with a known visitor,
 *    we can set the 'returning visitor' flag.
 *
 * In all the cases we set a cookie to the visitor with the new information.
 */
public function handle() {
    foreach ($this->requestProcessors as $processor) {
        Common::printDebug("Executing " . get_class($processor) . "::manipulateRequest()...");
        $processor->manipulateRequest($this->request);
    }
    $this->visitProperties = new VisitProperties();
    foreach ($this->requestProcessors as $processor) {
        Common::printDebug("Executing " . get_class($processor) . "::processRequestParams()...");
        $abort = $processor->processRequestParams($this->visitProperties, $this->request);
        if ($abort) {
            Common::printDebug("-> aborting due to processRequestParams method");
            return;
        }
    }
    $isNewVisit = $this->request->getMetadata('CoreHome', 'isNewVisit');
    if (!$isNewVisit) {
        $isNewVisit = $this->triggerPredicateHookOnDimensions($this->getAllVisitDimensions() , 'shouldForceNewVisit');
        $this->request->setMetadata('CoreHome', 'isNewVisit', $isNewVisit);
    }
    foreach ($this->requestProcessors as $processor) {
        Common::printDebug("Executing " . get_class($processor) . "::afterRequestProcessed()...");
        $abort = $processor->afterRequestProcessed($this->visitProperties, $this->request);
        if ($abort) {
            Common::printDebug("-> aborting due to afterRequestProcessed method");
            return;
        }
    }
    $isNewVisit = $this->request->getMetadata('CoreHome', 'isNewVisit');
    // Known visit when:
    // ( - the visitor has the Piwik cookie with the idcookie ID used by Piwik to match the visitor
    //   OR
    //   - the visitor doesn't have the Piwik cookie but could be match using heuristics @see recognizeTheVisitor()
    // )
    // AND
    // - the last page view for this visitor was less than 30 minutes ago @see isLastActionInTheSameVisit()
    if (!$isNewVisit) {
        try {
            $this->handleExistingVisit($this->request->getMetadata('Goals', 'visitIsConverted'));
        }
        catch(VisitorNotFoundInDb $e) {
            $this->request->setMetadata('CoreHome', 'visitorNotFoundInDb', true); // TODO: perhaps we should just abort here?
            
        }
    }
    // New visit when:
    // - the visitor has the Piwik cookie but the last action was performed more than 30 min ago @see isLastActionInTheSameVisit()
    // - the visitor doesn't have the Piwik cookie, and couldn't be matched in @see recognizeTheVisitor()
    // - the visitor does have the Piwik cookie but the idcookie and idvisit found in the cookie didn't match to any existing visit in the DB
    if ($isNewVisit) {
        $this->handleNewVisit($this->request->getMetadata('Goals', 'visitIsConverted'));
    }
    // update the cookie with the new visit information
    $this->request->setThirdPartyCookie($this->request->getVisitorIdForThirdPartyCookie());
    foreach ($this->requestProcessors as $processor) {
        Common::printDebug("Executing " . get_class($processor) . "::recordLogs()...");
        $processor->recordLogs($this->visitProperties, $this->request);
    }
    $this->markArchivedReportsAsInvalidIfArchiveAlreadyFinished();
}