diff --git a/src/applications/calendar/controller/PhabricatorCalendarController.php b/src/applications/calendar/controller/PhabricatorCalendarController.php
index 36a9bfbbe9..88ffba9380 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarController.php
@@ -1,21 +1,40 @@
 <?php
 
 abstract class PhabricatorCalendarController extends PhabricatorController {
 
   protected function newICSResponse(
     PhabricatorUser $viewer,
     $file_name,
     array $events) {
 
     $ics_data = id(new PhabricatorCalendarICSWriter())
       ->setViewer($viewer)
       ->setEvents($events)
       ->writeICSDocument();
 
     return id(new AphrontFileResponse())
       ->setDownload($file_name)
       ->setMimeType('text/calendar')
       ->setContent($ics_data);
   }
 
+  protected function newImportedEventResponse(PhabricatorCalendarEvent $event) {
+    if (!$event->isImportedEvent()) {
+      return null;
+    }
+
+    // Give the user a specific, detailed message if they try to edit an
+    // imported event via common web paths. Other edits (including those via
+    // the API) are blocked by the normal policy system, but this makes it more
+    // clear exactly why the event can't be edited.
+
+    return $this->newDialog()
+      ->setTitle(pht('Can Not Edit Imported Event'))
+      ->appendParagraph(
+        pht(
+          'This event has been imported from an external source and '.
+          'can not be edited.'))
+      ->addCancelButton($event->getURI(), pht('Done'));
+  }
+
 }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php b/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
index 63ce289970..fbf7f9d45e 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventCancelController.php
@@ -1,111 +1,119 @@
 <?php
 
 final class PhabricatorCalendarEventCancelController
   extends PhabricatorCalendarController {
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getViewer();
     $id = $request->getURIData('id');
 
+    // Just check CAN_VIEW first. Then we'll check if this is an import so
+    // we can raise a better error.
     $event = id(new PhabricatorCalendarEventQuery())
       ->setViewer($viewer)
       ->withIDs(array($id))
-      ->requireCapabilities(
-        array(
-          PhabricatorPolicyCapability::CAN_VIEW,
-          PhabricatorPolicyCapability::CAN_EDIT,
-        ))
       ->executeOne();
     if (!$event) {
       return new Aphront404Response();
     }
 
+    $response = $this->newImportedEventResponse($event);
+    if ($response) {
+      return $response;
+    }
+
+    // Now that we've done the import check, check for CAN_EDIT.
+    PhabricatorPolicyFilter::requireCapability(
+      $viewer,
+      $event,
+      PhabricatorPolicyCapability::CAN_EDIT);
+
     $cancel_uri = $event->getURI();
 
     $is_parent = $event->isParentEvent();
     $is_child = $event->isChildEvent();
     $is_cancelled = $event->getIsCancelled();
 
     if ($is_child) {
       $is_parent_cancelled = $event->getParentEvent()->getIsCancelled();
     } else {
       $is_parent_cancelled = false;
     }
 
     $validation_exception = null;
     if ($request->isFormPost()) {
       $xactions = array();
 
       $xaction = id(new PhabricatorCalendarEventTransaction())
         ->setTransactionType(
           PhabricatorCalendarEventCancelTransaction::TRANSACTIONTYPE)
         ->setNewValue(!$is_cancelled);
 
       $editor = id(new PhabricatorCalendarEventEditor())
         ->setActor($viewer)
         ->setContentSourceFromRequest($request)
         ->setContinueOnNoEffect(true)
         ->setContinueOnMissingFields(true);
 
       try {
         $editor->applyTransactions($event, array($xaction));
         return id(new AphrontRedirectResponse())->setURI($cancel_uri);
       } catch (PhabricatorApplicationTransactionValidationException $ex) {
         $validation_exception = $ex;
       }
     }
 
     if ($is_cancelled) {
       if ($is_parent_cancelled) {
         $title = pht('Cannot Reinstate Instance');
         $paragraph = pht(
           'You cannot reinstate an instance of a cancelled recurring event.');
         $cancel = pht('Back');
         $submit = null;
       } else if ($is_child) {
         $title = pht('Reinstate Instance');
         $paragraph = pht(
           'Reinstate this instance of this recurring event?');
         $cancel = pht('Back');
         $submit = pht('Reinstate Instance');
       } else if ($is_parent) {
         $title = pht('Reinstate Recurring Event');
         $paragraph = pht(
           'Reinstate all instances of this recurring event which have not '.
           'been individually cancelled?');
         $cancel = pht('Back');
         $submit = pht('Reinstate Recurring Event');
       } else {
         $title = pht('Reinstate Event');
         $paragraph = pht('Reinstate this event?');
         $cancel = pht('Back');
         $submit = pht('Reinstate Event');
       }
     } else {
       if ($is_child) {
         $title = pht('Cancel Instance');
         $paragraph = pht('Cancel this instance of this recurring event?');
         $cancel = pht('Back');
         $submit = pht('Cancel Instance');
       } else if ($is_parent) {
         $title = pht('Cancel Recurrin Event');
         $paragraph = pht('Cancel this entire series of recurring events?');
         $cancel = pht('Back');
         $submit = pht('Cancel Recurring Event');
       } else {
         $title = pht('Cancel Event');
         $paragraph = pht(
           'Cancel this event? You can always reinstate the event later.');
         $cancel = pht('Back');
         $submit = pht('Cancel Event');
       }
     }
 
     return $this->newDialog()
       ->setTitle($title)
       ->setValidationException($validation_exception)
       ->appendParagraph($paragraph)
       ->addCancelButton($cancel_uri, $cancel)
       ->addSubmitButton($submit);
   }
 }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
index b5beea9019..7c01e795b7 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
@@ -1,12 +1,26 @@
 <?php
 
 final class PhabricatorCalendarEventEditController
   extends PhabricatorCalendarController {
 
   public function handleRequest(AphrontRequest $request) {
+    $viewer = $this->getViewer();
+
+    $id = $request->getURIData('id');
+    if ($id) {
+      $event = id(new PhabricatorCalendarEventQuery())
+        ->setViewer($viewer)
+        ->withIDs(array($id))
+        ->executeOne();
+      $response = $this->newImportedEventResponse($event);
+      if ($response) {
+        return $response;
+      }
+    }
+
     return id(new PhabricatorCalendarEventEditEngine())
       ->setController($this)
       ->buildResponse();
   }
 
 }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php b/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
index 9b58d39dec..52ad8cb133 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventJoinController.php
@@ -1,78 +1,83 @@
 <?php
 
 final class PhabricatorCalendarEventJoinController
   extends PhabricatorCalendarController {
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $this->getViewer();
     $id = $request->getURIData('id');
 
     $event = id(new PhabricatorCalendarEventQuery())
       ->setViewer($viewer)
       ->withIDs(array($id))
       ->executeOne();
     if (!$event) {
       return new Aphront404Response();
     }
 
+    $response = $this->newImportedEventResponse($event);
+    if ($response) {
+      return $response;
+    }
+
     $cancel_uri = $event->getURI();
 
     $action = $request->getURIData('action');
     switch ($action) {
       case 'accept':
         $is_join = true;
         break;
       case 'decline':
         $is_join = false;
         break;
       default:
         $is_join = !$event->getIsUserAttending($viewer->getPHID());
         break;
     }
 
     $validation_exception = null;
     if ($request->isFormPost()) {
       if ($is_join) {
         $xaction_type =
           PhabricatorCalendarEventAcceptTransaction::TRANSACTIONTYPE;
       } else {
         $xaction_type =
           PhabricatorCalendarEventDeclineTransaction::TRANSACTIONTYPE;
       }
 
       $xaction = id(new PhabricatorCalendarEventTransaction())
         ->setTransactionType($xaction_type)
         ->setNewValue(true);
 
       $editor = id(new PhabricatorCalendarEventEditor())
         ->setActor($viewer)
         ->setContentSourceFromRequest($request)
         ->setContinueOnNoEffect(true)
         ->setContinueOnMissingFields(true);
 
       try {
         $editor->applyTransactions($event, array($xaction));
         return id(new AphrontRedirectResponse())->setURI($cancel_uri);
       } catch (PhabricatorApplicationTransactionValidationException $ex) {
         $validation_exception = $ex;
       }
     }
 
     if ($is_join) {
       $title = pht('Join Event');
       $paragraph = pht('Would you like to join this event?');
       $submit = pht('Join');
     } else {
       $title = pht('Decline Event');
       $paragraph = pht('Would you like to decline this event?');
       $submit = pht('Decline');
     }
 
     return $this->newDialog()
       ->setTitle($title)
       ->setValidationException($validation_exception)
       ->appendParagraph($paragraph)
       ->addCancelButton($cancel_uri)
       ->addSubmitButton($submit);
   }
 }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
index 89e8109a4c..c8bc9b5593 100644
--- a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
@@ -1,537 +1,573 @@
 <?php
 
 final class PhabricatorCalendarEventViewController
   extends PhabricatorCalendarController {
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getViewer();
 
     $event = $this->loadEvent();
     if (!$event) {
       return new Aphront404Response();
     }
 
     // If we looked up or generated a stub event, redirect to that event's
     // canonical URI.
     $id = $request->getURIData('id');
     if ($event->getID() != $id) {
       $uri = $event->getURI();
       return id(new AphrontRedirectResponse())->setURI($uri);
     }
 
     $monogram = $event->getMonogram();
     $page_title = $monogram.' '.$event->getName();
     $crumbs = $this->buildApplicationCrumbs();
 
     $start = $event->newStartDateTime()
       ->newPHPDateTime();
 
     $crumbs->addTextCrumb(
       $start->format('F Y'),
       '/calendar/query/month/'.$start->format('Y/m/'));
 
     $crumbs->addTextCrumb(
       $start->format('D jS'),
       '/calendar/query/month/'.$start->format('Y/m/d/'));
 
     $crumbs->addTextCrumb($monogram);
     $crumbs->setBorder(true);
 
     $timeline = $this->buildTransactionTimeline(
       $event,
       new PhabricatorCalendarEventTransactionQuery());
 
     $header = $this->buildHeaderView($event);
     $subheader = $this->buildSubheaderView($event);
     $curtain = $this->buildCurtain($event);
     $details = $this->buildPropertySection($event);
     $recurring = $this->buildRecurringSection($event);
     $description = $this->buildDescriptionView($event);
 
     $comment_view = id(new PhabricatorCalendarEventEditEngine())
       ->setViewer($viewer)
       ->buildEditEngineCommentView($event);
 
     $timeline->setQuoteRef($monogram);
     $comment_view->setTransactionTimeline($timeline);
 
     $details_header = id(new PHUIHeaderView())
       ->setHeader(pht('Details'));
     $recurring_header = $this->buildRecurringHeader($event);
 
+    // NOTE: This is a bit hacky: for imported events, we're just hiding the
+    // comment form without actually preventing comments. Users could still
+    // submit a request to add comments to these events. This isn't really a
+    // major problem since they can't do anything truly bad and there isn't an
+    // easy way to selectively disable this or some other similar behaviors
+    // today, but it would probably be nice to fully disable these
+    // "pseudo-edits" (like commenting and probably subscribing and awarding
+    // tokens) at some point.
+    if ($event->isImportedEvent()) {
+      $comment_view = null;
+      $timeline->setShouldTerminate(true);
+    }
+
     $view = id(new PHUITwoColumnView())
       ->setHeader($header)
       ->setSubheader($subheader)
       ->setMainColumn(
         array(
           $timeline,
           $comment_view,
         ))
       ->setCurtain($curtain)
       ->addPropertySection(pht('Description'), $description)
       ->addPropertySection($recurring_header, $recurring)
       ->addPropertySection($details_header, $details);
 
     return $this->newPage()
       ->setTitle($page_title)
       ->setCrumbs($crumbs)
       ->setPageObjectPHIDs(array($event->getPHID()))
       ->appendChild($view);
   }
 
   private function buildHeaderView(
     PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
     $id = $event->getID();
 
     if ($event->isCancelledEvent()) {
       $icon = 'fa-ban';
       $color = 'red';
       $status = pht('Cancelled');
     } else {
       $icon = 'fa-check';
       $color = 'bluegrey';
       $status = pht('Active');
     }
 
     $header = id(new PHUIHeaderView())
       ->setUser($viewer)
       ->setHeader($event->getName())
       ->setStatus($icon, $color, $status)
       ->setPolicyObject($event)
       ->setHeaderIcon($event->getIcon());
 
+    if ($event->isImportedEvent()) {
+      $header->addTag(
+        id(new PHUITagView())
+          ->setType(PHUITagView::TYPE_SHADE)
+          ->setName(pht('Imported'))
+          ->setIcon('fa-download')
+          ->setHref($event->getImportSource()->getURI())
+          ->setShade('orange'));
+    }
+
     foreach ($this->buildRSVPActions($event) as $action) {
       $header->addActionLink($action);
     }
 
     return $header;
   }
 
   private function buildCurtain(PhabricatorCalendarEvent $event) {
     $viewer = $this->getRequest()->getUser();
     $id = $event->getID();
     $is_attending = $event->getIsUserAttending($viewer->getPHID());
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $event,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $edit_uri = "event/edit/{$id}/";
     if ($event->isChildEvent()) {
       $edit_label = pht('Edit This Instance');
     } else {
       $edit_label = pht('Edit Event');
     }
 
     $curtain = $this->newCurtainView($event);
 
     if ($edit_label && $edit_uri) {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName($edit_label)
           ->setIcon('fa-pencil')
           ->setHref($this->getApplicationURI($edit_uri))
           ->setDisabled(!$can_edit)
           ->setWorkflow(!$can_edit));
     }
 
+    $can_attend = !$event->isImportedEvent();
+
     if ($is_attending) {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName(pht('Decline Event'))
           ->setIcon('fa-user-times')
           ->setHref($this->getApplicationURI("event/join/{$id}/"))
+          ->setDisabled(!$can_attend)
           ->setWorkflow(true));
     } else {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName(pht('Join Event'))
           ->setIcon('fa-user-plus')
           ->setHref($this->getApplicationURI("event/join/{$id}/"))
+          ->setDisabled(!$can_attend)
           ->setWorkflow(true));
     }
 
     $cancel_uri = $this->getApplicationURI("event/cancel/{$id}/");
     $cancel_disabled = !$can_edit;
 
     if ($event->isChildEvent()) {
       $cancel_label = pht('Cancel This Instance');
       $reinstate_label = pht('Reinstate This Instance');
 
       if ($event->getParentEvent()->getIsCancelled()) {
         $cancel_disabled = true;
       }
     } else if ($event->isParentEvent()) {
       $cancel_label = pht('Cancel All');
       $reinstate_label = pht('Reinstate All');
     } else {
       $cancel_label = pht('Cancel Event');
       $reinstate_label = pht('Reinstate Event');
     }
 
     if ($event->isCancelledEvent()) {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName($reinstate_label)
           ->setIcon('fa-plus')
           ->setHref($cancel_uri)
           ->setDisabled($cancel_disabled)
           ->setWorkflow(true));
     } else {
       $curtain->addAction(
         id(new PhabricatorActionView())
           ->setName($cancel_label)
           ->setIcon('fa-times')
           ->setHref($cancel_uri)
           ->setDisabled($cancel_disabled)
           ->setWorkflow(true));
     }
 
     $ics_name = $event->getICSFilename();
     $export_uri = $this->getApplicationURI("event/export/{$id}/{$ics_name}");
 
     $curtain->addAction(
       id(new PhabricatorActionView())
         ->setName(pht('Export as .ics'))
         ->setIcon('fa-download')
         ->setHref($export_uri));
 
     return $curtain;
   }
 
   private function buildPropertySection(
     PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
 
     $properties = id(new PHUIPropertyListView())
       ->setUser($viewer);
 
     $invitees = $event->getInvitees();
     foreach ($invitees as $key => $invitee) {
       if ($invitee->isUninvited()) {
         unset($invitees[$key]);
       }
     }
 
     if ($invitees) {
       $invitee_list = new PHUIStatusListView();
 
       $icon_invited = PHUIStatusItemView::ICON_OPEN;
       $icon_attending = PHUIStatusItemView::ICON_ACCEPT;
       $icon_declined = PHUIStatusItemView::ICON_REJECT;
 
       $status_invited = PhabricatorCalendarEventInvitee::STATUS_INVITED;
       $status_attending = PhabricatorCalendarEventInvitee::STATUS_ATTENDING;
       $status_declined = PhabricatorCalendarEventInvitee::STATUS_DECLINED;
 
       $icon_map = array(
         $status_invited => $icon_invited,
         $status_attending => $icon_attending,
         $status_declined => $icon_declined,
       );
 
       $icon_color_map = array(
         $status_invited => null,
         $status_attending => 'green',
         $status_declined => 'red',
       );
 
       foreach ($invitees as $invitee) {
         $item = new PHUIStatusItemView();
         $invitee_phid = $invitee->getInviteePHID();
         $status = $invitee->getStatus();
         $target = $viewer->renderHandle($invitee_phid);
         $icon = $icon_map[$status];
         $icon_color = $icon_color_map[$status];
 
         $item->setIcon($icon, $icon_color)
           ->setTarget($target);
         $invitee_list->addItem($item);
       }
     } else {
       $invitee_list = phutil_tag(
         'em',
         array(),
         pht('None'));
     }
 
+    if ($event->isImportedEvent()) {
+      $properties->addProperty(
+        pht('Imported By'),
+        pht(
+          '%s from %s',
+          $viewer->renderHandle($event->getImportAuthorPHID()),
+          $viewer->renderHandle($event->getImportSourcePHID())));
+    }
+
     $properties->addProperty(
       pht('Invitees'),
       $invitee_list);
 
     $properties->invokeWillRenderEvent();
 
     return $properties;
   }
 
   private function buildRecurringHeader(PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
 
     if (!$event->getIsRecurring()) {
       return null;
     }
 
     $header = id(new PHUIHeaderView())
       ->setHeader(pht('Recurring Event'));
 
     $sequence = $event->getSequenceIndex();
     if ($event->isParentEvent()) {
       $parent = $event;
     } else {
       $parent = $event->getParentEvent();
     }
 
     if ($parent->isValidSequenceIndex($viewer, $sequence + 1)) {
       $next_uri = $parent->getURI().'/'.($sequence + 1);
       $has_next = true;
     } else {
       $next_uri = null;
       $has_next = false;
     }
 
     if ($sequence) {
       if ($sequence > 1) {
         $previous_uri = $parent->getURI().'/'.($sequence - 1);
       } else {
         $previous_uri = $parent->getURI();
       }
       $has_previous = true;
     } else {
       $has_previous = false;
       $previous_uri = null;
     }
 
     $prev_button = id(new PHUIButtonView())
       ->setTag('a')
       ->setIcon('fa-chevron-left')
       ->setHref($previous_uri)
       ->setDisabled(!$has_previous)
       ->setText(pht('Previous'));
 
     $next_button = id(new PHUIButtonView())
       ->setTag('a')
       ->setIcon('fa-chevron-right')
       ->setHref($next_uri)
       ->setDisabled(!$has_next)
       ->setText(pht('Next'));
 
     $header
       ->addActionLink($next_button)
       ->addActionLink($prev_button);
 
     return $header;
   }
 
   private function buildRecurringSection(PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
 
     if (!$event->getIsRecurring()) {
       return null;
     }
 
     $properties = id(new PHUIPropertyListView())
       ->setUser($viewer);
 
     $is_parent = $event->isParentEvent();
     if ($is_parent) {
       $parent_link = null;
     } else {
       $parent = $event->getParentEvent();
       $parent_link = $viewer
         ->renderHandle($parent->getPHID())
         ->render();
     }
 
     $rrule = $event->newRecurrenceRule();
 
     if ($rrule) {
       $frequency = $rrule->getFrequency();
     } else {
       $frequency = null;
     }
 
     switch ($frequency) {
       case PhutilCalendarRecurrenceRule::FREQUENCY_DAILY:
         if ($is_parent) {
           $message = pht('This event repeats every day.');
         } else {
           $message = pht(
             'This event is an instance of %s, and repeats every day.',
             $parent_link);
         }
         break;
       case PhutilCalendarRecurrenceRule::FREQUENCY_WEEKLY:
         if ($is_parent) {
           $message = pht('This event repeats every week.');
         } else {
           $message = pht(
             'This event is an instance of %s, and repeats every week.',
             $parent_link);
         }
         break;
       case PhutilCalendarRecurrenceRule::FREQUENCY_MONTHLY:
         if ($is_parent) {
           $message = pht('This event repeats every month.');
         } else {
           $message = pht(
             'This event is an instance of %s, and repeats every month.',
             $parent_link);
         }
         break;
       case PhutilCalendarRecurrenceRule::FREQUENCY_YEARLY:
         if ($is_parent) {
           $message = pht('This event repeats every year.');
         } else {
           $message = pht(
             'This event is an instance of %s, and repeats every year.',
             $parent_link);
         }
         break;
     }
 
     $properties->addProperty(pht('Event Series'), $message);
 
     return $properties;
   }
 
   private function buildDescriptionView(
     PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
 
     $properties = id(new PHUIPropertyListView())
       ->setUser($viewer);
 
     if (strlen($event->getDescription())) {
       $description = new PHUIRemarkupView($viewer, $event->getDescription());
       $properties->addTextContent($description);
       return $properties;
     }
 
     return null;
   }
 
   private function loadEvent() {
     $request = $this->getRequest();
     $viewer = $this->getViewer();
 
     $id = $request->getURIData('id');
     $sequence = $request->getURIData('sequence');
 
     // We're going to figure out which event you're trying to look at. Most of
     // the time this is simple, but you may be looking at an instance of a
     // recurring event which we haven't generated an object for.
 
     // If you are, we're going to generate a "stub" event so we have a real
     // ID and PHID to work with, since the rest of the infrastructure relies
     // on these identifiers existing.
 
     // Load the event identified by ID first.
     $event = id(new PhabricatorCalendarEventQuery())
       ->setViewer($viewer)
       ->withIDs(array($id))
       ->executeOne();
     if (!$event) {
       return null;
     }
 
     // If we aren't looking at an instance of this event, this is a completely
     // normal request and we can just return this event.
     if (!$sequence) {
       return $event;
     }
 
     // When you view "E123/999", E123 is normally the parent event. However,
     // you might visit a different instance first instead and then fiddle
     // with the URI. If the event we're looking at is a child, we are going
     // to act on the parent instead.
     if ($event->isChildEvent()) {
       $event = $event->getParentEvent();
     }
 
     // Try to load the instance. If it already exists, we're all done and
     // can just return it.
     $instance = id(new PhabricatorCalendarEventQuery())
       ->setViewer($viewer)
       ->withInstanceSequencePairs(
         array(
           array($event->getPHID(), $sequence),
         ))
       ->executeOne();
     if ($instance) {
       return $instance;
     }
 
     if (!$viewer->isLoggedIn()) {
       throw new Exception(
         pht(
           'This event instance has not been created yet. Log in to create '.
           'it.'));
     }
 
     if (!$event->isValidSequenceIndex($viewer, $sequence)) {
       return null;
     }
 
     return $event->newStub($viewer, $sequence);
   }
 
   private function buildSubheaderView(PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
 
     $host_phid = $event->getHostPHID();
 
     $handles = $viewer->loadHandles(array($host_phid));
     $handle = $handles[$host_phid];
 
     $host = $viewer->renderHandle($host_phid);
     $host = phutil_tag('strong', array(), $host);
 
     $image_uri = $handles[$host_phid]->getImageURI();
     $image_href = $handles[$host_phid]->getURI();
 
     $date = $event->renderEventDate($viewer, true);
 
     $content = pht('Hosted by %s on %s.', $host, $date);
 
     return id(new PHUIHeadThingView())
       ->setImage($image_uri)
       ->setImageHref($image_href)
       ->setContent($content);
   }
 
 
   private function buildRSVPActions(PhabricatorCalendarEvent $event) {
     $viewer = $this->getViewer();
     $id = $event->getID();
 
     $invite_status = $event->getUserInviteStatus($viewer->getPHID());
     $status_invited = PhabricatorCalendarEventInvitee::STATUS_INVITED;
     $is_invite_pending = ($invite_status == $status_invited);
     if (!$is_invite_pending) {
       return array();
     }
 
     $decline_button = id(new PHUIButtonView())
       ->setTag('a')
       ->setIcon('fa-times grey')
       ->setHref($this->getApplicationURI("/event/decline/{$id}/"))
       ->setWorkflow(true)
       ->setText(pht('Decline'));
 
     $accept_button = id(new PHUIButtonView())
       ->setTag('a')
       ->setIcon('fa-check green')
       ->setHref($this->getApplicationURI("/event/accept/{$id}/"))
       ->setWorkflow(true)
       ->setText(pht('Accept'));
 
     return array($decline_button, $accept_button);
   }
 
 }
diff --git a/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php b/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
index 05d1cc0bb9..876ec7acf7 100644
--- a/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
+++ b/src/applications/calendar/phid/PhabricatorCalendarImportPHIDType.php
@@ -1,50 +1,50 @@
 <?php
 
 final class PhabricatorCalendarImportPHIDType extends PhabricatorPHIDType {
 
   const TYPECONST = 'CIMP';
 
   public function getTypeName() {
     return pht('Calendar Import');
   }
 
   public function newObject() {
     return new PhabricatorCalendarImport();
   }
 
   public function getPHIDTypeApplicationClass() {
     return 'PhabricatorCalendarApplication';
   }
 
   protected function buildQueryForObjects(
     PhabricatorObjectQuery $query,
     array $phids) {
 
     return id(new PhabricatorCalendarImportQuery())
       ->withPHIDs($phids);
   }
 
   public function loadHandles(
     PhabricatorHandleQuery $query,
     array $handles,
     array $objects) {
 
     foreach ($handles as $phid => $handle) {
       $import = $objects[$phid];
 
       $id = $import->getID();
-      $name = $import->getName();
+      $name = $import->getDisplayName();
       $uri = $import->getURI();
 
       $handle
         ->setName($name)
         ->setFullName(pht('Calendar Import %s: %s', $id, $name))
         ->setURI($uri);
 
       if ($import->getIsDisabled()) {
         $handle->setStatus(PhabricatorObjectHandle::STATUS_CLOSED);
       }
     }
   }
 
 }
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
index 7ad6d85881..6baa54e008 100644
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -1,1186 +1,1194 @@
 <?php
 
 final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
   implements
     PhabricatorPolicyInterface,
     PhabricatorExtendedPolicyInterface,
     PhabricatorProjectInterface,
     PhabricatorMarkupInterface,
     PhabricatorApplicationTransactionInterface,
     PhabricatorSubscribableInterface,
     PhabricatorTokenReceiverInterface,
     PhabricatorDestructibleInterface,
     PhabricatorMentionableInterface,
     PhabricatorFlaggableInterface,
     PhabricatorSpacesInterface,
     PhabricatorFulltextInterface,
     PhabricatorConduitResultInterface {
 
   protected $name;
   protected $hostPHID;
   protected $description;
   protected $isCancelled;
   protected $isAllDay;
   protected $icon;
   protected $mailKey;
   protected $isStub;
 
   protected $isRecurring = 0;
 
   private $isGhostEvent = false;
   protected $instanceOfEventPHID;
   protected $sequenceIndex;
 
   protected $viewPolicy;
   protected $editPolicy;
 
   protected $spacePHID;
 
   protected $utcInitialEpoch;
   protected $utcUntilEpoch;
   protected $utcInstanceEpoch;
   protected $parameters = array();
 
   protected $importAuthorPHID;
   protected $importSourcePHID;
   protected $importUIDIndex;
   protected $importUID;
 
   private $parentEvent = self::ATTACHABLE;
   private $invitees = self::ATTACHABLE;
   private $importSource = self::ATTACHABLE;
 
   private $viewerTimezone;
 
   // TODO: DEPRECATED. Remove once we're sure the migrations worked.
   protected $allDayDateFrom;
   protected $allDayDateTo;
   protected $dateFrom;
   protected $dateTo;
   protected $recurrenceEndDate;
   protected $recurrenceFrequency = array();
 
   public static function initializeNewCalendarEvent(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
       ->withClasses(array('PhabricatorCalendarApplication'))
       ->executeOne();
 
     $view_default = PhabricatorCalendarEventDefaultViewCapability::CAPABILITY;
     $edit_default = PhabricatorCalendarEventDefaultEditCapability::CAPABILITY;
     $view_policy = $app->getPolicy($view_default);
     $edit_policy = $app->getPolicy($edit_default);
 
     $now = PhabricatorTime::getNow();
 
     $default_icon = 'fa-calendar';
 
     $datetime_start = PhutilCalendarAbsoluteDateTime::newFromEpoch(
       $now,
       $actor->getTimezoneIdentifier());
     $datetime_end = $datetime_start->newRelativeDateTime('PT1H');
 
     return id(new PhabricatorCalendarEvent())
       ->setDescription('')
       ->setHostPHID($actor->getPHID())
       ->setIsCancelled(0)
       ->setIsAllDay(0)
       ->setIsStub(0)
       ->setIsRecurring(0)
       ->setIcon($default_icon)
       ->setViewPolicy($view_policy)
       ->setEditPolicy($edit_policy)
       ->setSpacePHID($actor->getDefaultSpacePHID())
       ->attachInvitees(array())
       ->setDateFrom(0)
       ->setDateTo(0)
       ->setAllDayDateFrom(0)
       ->setAllDayDateTo(0)
       ->setStartDateTime($datetime_start)
       ->setEndDateTime($datetime_end)
       ->attachImportSource(null)
       ->applyViewerTimezone($actor);
   }
 
   private function newChild(
     PhabricatorUser $actor,
     $sequence,
     PhutilCalendarDateTime $start = null) {
     if (!$this->isParentEvent()) {
       throw new Exception(
         pht(
           'Unable to generate a new child event for an event which is not '.
           'a recurring parent event!'));
     }
 
     $child = id(new self())
       ->setIsCancelled(0)
       ->setIsStub(0)
       ->setInstanceOfEventPHID($this->getPHID())
       ->setSequenceIndex($sequence)
       ->setIsRecurring(true)
       ->attachParentEvent($this)
       ->setAllDayDateFrom(0)
       ->setAllDayDateTo(0)
       ->setDateFrom(0)
       ->setDateTo(0);
 
     return $child->copyFromParent($actor, $start);
   }
 
   protected function readField($field) {
     static $inherit = array(
       'hostPHID' => true,
       'isAllDay' => true,
       'icon' => true,
       'spacePHID' => true,
       'viewPolicy' => true,
       'editPolicy' => true,
       'name' => true,
       'description' => true,
     );
 
     // Read these fields from the parent event instead of this event. For
     // example, we want any changes to the parent event's name to apply to
     // the child.
     if (isset($inherit[$field])) {
       if ($this->getIsStub()) {
         // TODO: This should be unconditional, but the execution order of
         // CalendarEventQuery and applyViewerTimezone() are currently odd.
         if ($this->parentEvent !== self::ATTACHABLE) {
           return $this->getParentEvent()->readField($field);
         }
       }
     }
 
     return parent::readField($field);
   }
 
 
   public function copyFromParent(
     PhabricatorUser $actor,
     PhutilCalendarDateTime $start = null) {
 
     if (!$this->isChildEvent()) {
       throw new Exception(
         pht(
           'Unable to copy from parent event: this is not a child event.'));
     }
 
     $parent = $this->getParentEvent();
 
     $this
       ->setHostPHID($parent->getHostPHID())
       ->setIsAllDay($parent->getIsAllDay())
       ->setIcon($parent->getIcon())
       ->setSpacePHID($parent->getSpacePHID())
       ->setViewPolicy($parent->getViewPolicy())
       ->setEditPolicy($parent->getEditPolicy())
       ->setName($parent->getName())
       ->setDescription($parent->getDescription());
 
     $sequence = $this->getSequenceIndex();
 
     if ($start) {
       $start_datetime = $start;
     } else {
       $start_datetime = $parent->newSequenceIndexDateTime($sequence);
 
       if (!$start_datetime) {
         throw new Exception(
           pht(
             'Sequence "%s" is not valid for event!',
             $sequence));
       }
     }
 
     $duration = $parent->newDuration();
     $end_datetime = $start_datetime->newRelativeDateTime($duration);
 
     $this
       ->setStartDateTime($start_datetime)
       ->setEndDateTime($end_datetime);
 
     return $this;
   }
 
   public function isValidSequenceIndex(PhabricatorUser $viewer, $sequence) {
     return (bool)$this->newSequenceIndexDateTime($sequence);
   }
 
   public function newSequenceIndexDateTime($sequence) {
     $set = $this->newRecurrenceSet();
     if (!$set) {
       return null;
     }
 
     $instances = $set->getEventsBetween(
       null,
       $this->newUntilDateTime(),
       $sequence + 1);
 
     return idx($instances, $sequence, null);
   }
 
   public function newStub(PhabricatorUser $actor, $sequence) {
     $stub = $this->newChild($actor, $sequence);
 
     $stub->setIsStub(1);
 
     $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
       $stub->save();
     unset($unguarded);
 
     $stub->applyViewerTimezone($actor);
 
     return $stub;
   }
 
   public function newGhost(
     PhabricatorUser $actor,
     $sequence,
     PhutilCalendarDateTime $start = null) {
 
     $ghost = $this->newChild($actor, $sequence, $start);
 
     $ghost
       ->setIsGhostEvent(true)
       ->makeEphemeral();
 
     $ghost->applyViewerTimezone($actor);
 
     return $ghost;
   }
 
   public function applyViewerTimezone(PhabricatorUser $viewer) {
     $this->viewerTimezone = $viewer->getTimezoneIdentifier();
     return $this;
   }
 
   public function getDuration() {
     return ($this->getEndDateTimeEpoch() - $this->getStartDateTimeEpoch());
   }
 
   public function updateUTCEpochs() {
     // The "intitial" epoch is the start time of the event, in UTC.
     $start_date = $this->newStartDateTime()
       ->setViewerTimezone('UTC');
     $start_epoch = $start_date->getEpoch();
     $this->setUTCInitialEpoch($start_epoch);
 
     // The "until" epoch is the last UTC epoch on which any instance of this
     // event occurs. For infinitely recurring events, it is `null`.
 
     if (!$this->getIsRecurring()) {
       $end_date = $this->newEndDateTime()
         ->setViewerTimezone('UTC');
       $until_epoch = $end_date->getEpoch();
     } else {
       $until_epoch = null;
       $until_date = $this->newUntilDateTime();
       if ($until_date) {
         $until_date->setViewerTimezone('UTC');
         $duration = $this->newDuration();
         $until_epoch = id(new PhutilCalendarRelativeDateTime())
           ->setOrigin($until_date)
           ->setDuration($duration)
           ->getEpoch();
       }
     }
     $this->setUTCUntilEpoch($until_epoch);
 
     // The "instance" epoch is a property of instances of recurring events.
     // It's the original UTC epoch on which the instance started. Usually that
     // is the same as the start date, but they may be different if the instance
     // has been edited.
 
     // The ICS format uses this value (original start time) to identify event
     // instances, and must do so because it allows additional arbitrary
     // instances to be added (with "RDATE").
 
     $instance_epoch = null;
     $instance_date = $this->newInstanceDateTime();
     if ($instance_date) {
       $instance_epoch = $instance_date
         ->setViewerTimezone('UTC')
         ->getEpoch();
     }
     $this->setUTCInstanceEpoch($instance_epoch);
 
     return $this;
   }
 
   public function save() {
     if (!$this->mailKey) {
       $this->mailKey = Filesystem::readRandomCharacters(20);
     }
 
     $import_uid = $this->getImportUID();
     if ($import_uid !== null) {
       $index = PhabricatorHash::digestForIndex($import_uid);
     } else {
       $index = null;
     }
     $this->setImportUIDIndex($index);
 
     $this->updateUTCEpochs();
 
     return parent::save();
   }
 
   /**
    * Get the event start epoch for evaluating invitee availability.
    *
    * When assessing availability, we pretend events start earlier than they
    * really do. This allows us to mark users away for the entire duration of a
    * series of back-to-back meetings, even if they don't strictly overlap.
    *
    * @return int Event start date for availability caches.
    */
   public function getStartDateTimeEpochForCache() {
     $epoch = $this->getStartDateTimeEpoch();
     $window = phutil_units('15 minutes in seconds');
     return ($epoch - $window);
   }
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_COLUMN_SCHEMA => array(
         'name' => 'text',
         'description' => 'text',
         'isCancelled' => 'bool',
         'isAllDay' => 'bool',
         'icon' => 'text32',
         'mailKey' => 'bytes20',
         'isRecurring' => 'bool',
         'instanceOfEventPHID' => 'phid?',
         'sequenceIndex' => 'uint32?',
         'isStub' => 'bool',
         'utcInitialEpoch' => 'epoch',
         'utcUntilEpoch' => 'epoch?',
         'utcInstanceEpoch' => 'epoch?',
 
         'importAuthorPHID' => 'phid?',
         'importSourcePHID' => 'phid?',
         'importUIDIndex' => 'bytes12?',
         'importUID' => 'text?',
 
         // TODO: DEPRECATED.
         'allDayDateFrom' => 'epoch',
         'allDayDateTo' => 'epoch',
         'dateFrom' => 'epoch',
         'dateTo' => 'epoch',
         'recurrenceEndDate' => 'epoch?',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_date' => array(
           'columns' => array('dateFrom', 'dateTo'),
         ),
         'key_instance' => array(
           'columns' => array('instanceOfEventPHID', 'sequenceIndex'),
           'unique' => true,
         ),
         'key_epoch' => array(
           'columns' => array('utcInitialEpoch', 'utcUntilEpoch'),
         ),
         'key_rdate' => array(
           'columns' => array('instanceOfEventPHID', 'utcInstanceEpoch'),
           'unique' => true,
         ),
       ),
       self::CONFIG_SERIALIZATION => array(
         'recurrenceFrequency' => self::SERIALIZATION_JSON,
         'parameters' => self::SERIALIZATION_JSON,
       ),
     ) + parent::getConfiguration();
   }
 
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(
       PhabricatorCalendarEventPHIDType::TYPECONST);
   }
 
   public function getMonogram() {
     return 'E'.$this->getID();
   }
 
   public function getInvitees() {
     return $this->assertAttached($this->invitees);
   }
 
   public function attachInvitees(array $invitees) {
     $this->invitees = $invitees;
     return $this;
   }
 
   public function getInviteePHIDsForEdit() {
     $invitees = array();
 
     foreach ($this->getInvitees() as $invitee) {
       if ($invitee->isUninvited()) {
         continue;
       }
       $invitees[] = $invitee->getInviteePHID();
     }
 
     return $invitees;
   }
 
   public function getUserInviteStatus($phid) {
     $invitees = $this->getInvitees();
     $invitees = mpull($invitees, null, 'getInviteePHID');
 
     $invited = idx($invitees, $phid);
     if (!$invited) {
       return PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
     }
     $invited = $invited->getStatus();
     return $invited;
   }
 
   public function getIsUserAttending($phid) {
     $attending_status = PhabricatorCalendarEventInvitee::STATUS_ATTENDING;
 
     $old_status = $this->getUserInviteStatus($phid);
     $is_attending = ($old_status == $attending_status);
 
     return $is_attending;
   }
 
   public function getIsUserInvited($phid) {
     $uninvited_status = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
     $declined_status = PhabricatorCalendarEventInvitee::STATUS_DECLINED;
     $status = $this->getUserInviteStatus($phid);
     if ($status == $uninvited_status || $status == $declined_status) {
       return false;
     }
     return true;
   }
 
   public function getIsGhostEvent() {
     return $this->isGhostEvent;
   }
 
   public function setIsGhostEvent($is_ghost_event) {
     $this->isGhostEvent = $is_ghost_event;
     return $this;
   }
 
   public function getURI() {
     if ($this->getIsGhostEvent()) {
       $base = $this->getParentEvent()->getURI();
       $sequence = $this->getSequenceIndex();
       return "{$base}/{$sequence}/";
     }
 
     return '/'.$this->getMonogram();
   }
 
   public function getParentEvent() {
     return $this->assertAttached($this->parentEvent);
   }
 
   public function attachParentEvent($event) {
     $this->parentEvent = $event;
     return $this;
   }
 
   public function isParentEvent() {
     return ($this->getIsRecurring() && !$this->getInstanceOfEventPHID());
   }
 
   public function isChildEvent() {
     return ($this->instanceOfEventPHID !== null);
   }
 
   public function isCancelledEvent() {
     if ($this->getIsCancelled()) {
       return true;
     }
 
     if ($this->isChildEvent()) {
       if ($this->getParentEvent()->getIsCancelled()) {
         return true;
       }
     }
 
     return false;
   }
 
   public function renderEventDate(
     PhabricatorUser $viewer,
     $show_end) {
 
     $start = $this->newStartDateTime();
     $end = $this->newEndDateTime();
 
     if ($show_end) {
       $min_date = $start->newPHPDateTime();
       $max_date = $end->newPHPDateTime();
 
       $min_day = $min_date->format('Y m d');
       $max_day = $max_date->format('Y m d');
 
       $show_end_date = ($min_day != $max_day);
     } else {
       $show_end_date = false;
     }
 
     $min_epoch = $start->getEpoch();
     $max_epoch = $end->getEpoch();
 
     if ($this->getIsAllDay()) {
       if ($show_end_date) {
         return pht(
           '%s - %s, All Day',
           phabricator_date($min_epoch, $viewer),
           phabricator_date($max_epoch, $viewer));
       } else {
         return pht(
           '%s, All Day',
           phabricator_date($min_epoch, $viewer));
       }
     } else if ($show_end_date) {
       return pht(
         '%s - %s',
         phabricator_datetime($min_epoch, $viewer),
         phabricator_datetime($max_epoch, $viewer));
     } else if ($show_end) {
       return pht(
         '%s - %s',
         phabricator_datetime($min_epoch, $viewer),
         phabricator_time($max_epoch, $viewer));
     } else {
       return pht(
         '%s',
         phabricator_datetime($min_epoch, $viewer));
     }
   }
 
 
   public function getDisplayIcon(PhabricatorUser $viewer) {
     if ($this->isCancelledEvent()) {
       return 'fa-times';
     }
 
     if ($viewer->isLoggedIn()) {
       $status = $this->getUserInviteStatus($viewer->getPHID());
       switch ($status) {
         case PhabricatorCalendarEventInvitee::STATUS_ATTENDING:
           return 'fa-check-circle';
         case PhabricatorCalendarEventInvitee::STATUS_INVITED:
           return 'fa-user-plus';
         case PhabricatorCalendarEventInvitee::STATUS_DECLINED:
           return 'fa-times';
       }
     }
 
+    if ($this->isImportedEvent()) {
+      return 'fa-download';
+    }
+
     return $this->getIcon();
   }
 
   public function getDisplayIconColor(PhabricatorUser $viewer) {
     if ($this->isCancelledEvent()) {
       return 'red';
     }
 
+    if ($this->isImportedEvent()) {
+      return 'orange';
+    }
+
     if ($viewer->isLoggedIn()) {
       $status = $this->getUserInviteStatus($viewer->getPHID());
       switch ($status) {
         case PhabricatorCalendarEventInvitee::STATUS_ATTENDING:
           return 'green';
         case PhabricatorCalendarEventInvitee::STATUS_INVITED:
           return 'green';
         case PhabricatorCalendarEventInvitee::STATUS_DECLINED:
           return 'grey';
       }
     }
 
     return 'bluegrey';
   }
 
   public function getDisplayIconLabel(PhabricatorUser $viewer) {
     if ($this->isCancelledEvent()) {
       return pht('Cancelled');
     }
 
     if ($viewer->isLoggedIn()) {
       $status = $this->getUserInviteStatus($viewer->getPHID());
       switch ($status) {
         case PhabricatorCalendarEventInvitee::STATUS_ATTENDING:
           return pht('Attending');
         case PhabricatorCalendarEventInvitee::STATUS_INVITED:
           return pht('Invited');
         case PhabricatorCalendarEventInvitee::STATUS_DECLINED:
           return pht('Declined');
       }
     }
 
     return null;
   }
 
   public function getICSFilename() {
     return $this->getMonogram().'.ics';
   }
 
   public function newIntermediateEventNode(
     PhabricatorUser $viewer,
     array $children) {
 
     $base_uri = new PhutilURI(PhabricatorEnv::getProductionURI('/'));
     $domain = $base_uri->getDomain();
 
     // NOTE: For recurring events, all of the events in the series have the
     // same UID (the UID of the parent). The child event instances are
     // differentiated by the "RECURRENCE-ID" field.
     if ($this->isChildEvent()) {
       $parent = $this->getParentEvent();
       $instance_datetime = PhutilCalendarAbsoluteDateTime::newFromEpoch(
         $this->getUTCInstanceEpoch());
       $recurrence_id = $instance_datetime->getISO8601();
       $rrule = null;
     } else {
       $parent = $this;
       $recurrence_id = null;
       $rrule = $this->newRecurrenceRule();
     }
     $uid = $parent->getPHID().'@'.$domain;
 
     $created = $this->getDateCreated();
     $created = PhutilCalendarAbsoluteDateTime::newFromEpoch($created);
 
     $modified = $this->getDateModified();
     $modified = PhutilCalendarAbsoluteDateTime::newFromEpoch($modified);
 
     $date_start = $this->newStartDateTime();
     $date_end = $this->newEndDateTime();
 
     if ($this->getIsAllDay()) {
       $date_start->setIsAllDay(true);
       $date_end->setIsAllDay(true);
     }
 
     $host_phid = $this->getHostPHID();
 
     $invitees = $this->getInvitees();
     foreach ($invitees as $key => $invitee) {
       if ($invitee->isUninvited()) {
         unset($invitees[$key]);
       }
     }
 
     $phids = array();
     $phids[] = $host_phid;
     foreach ($invitees as $invitee) {
       $phids[] = $invitee->getInviteePHID();
     }
 
     $handles = $viewer->loadHandles($phids);
 
     $host_handle = $handles[$host_phid];
     $host_name = $host_handle->getFullName();
     $host_uri = $host_handle->getURI();
     $host_uri = PhabricatorEnv::getURI($host_uri);
 
     $organizer = id(new PhutilCalendarUserNode())
       ->setName($host_name)
       ->setURI($host_uri);
 
     $attendees = array();
     foreach ($invitees as $invitee) {
       $invitee_phid = $invitee->getInviteePHID();
       $invitee_handle = $handles[$invitee_phid];
       $invitee_name = $invitee_handle->getFullName();
       $invitee_uri = $invitee_handle->getURI();
       $invitee_uri = PhabricatorEnv::getURI($invitee_uri);
 
       switch ($invitee->getStatus()) {
         case PhabricatorCalendarEventInvitee::STATUS_ATTENDING:
           $status = PhutilCalendarUserNode::STATUS_ACCEPTED;
           break;
         case PhabricatorCalendarEventInvitee::STATUS_DECLINED:
           $status = PhutilCalendarUserNode::STATUS_DECLINED;
           break;
         case PhabricatorCalendarEventInvitee::STATUS_INVITED:
         default:
           $status = PhutilCalendarUserNode::STATUS_INVITED;
           break;
       }
 
       $attendees[] = id(new PhutilCalendarUserNode())
         ->setName($invitee_name)
         ->setURI($invitee_uri)
         ->setStatus($status);
     }
 
     // TODO: Use $children to generate EXDATE/RDATE information.
 
     $node = id(new PhutilCalendarEventNode())
       ->setUID($uid)
       ->setName($this->getName())
       ->setDescription($this->getDescription())
       ->setCreatedDateTime($created)
       ->setModifiedDateTime($modified)
       ->setStartDateTime($date_start)
       ->setEndDateTime($date_end)
       ->setOrganizer($organizer)
       ->setAttendees($attendees);
 
     if ($rrule) {
       $node->setRecurrenceRule($rrule);
     }
 
     if ($recurrence_id) {
       $node->setRecurrenceID($recurrence_id);
     }
 
     return $node;
   }
 
   public function newStartDateTime() {
     $datetime = $this->getParameter('startDateTime');
     if ($datetime) {
       return $this->newDateTimeFromDictionary($datetime);
     }
 
     $epoch = $this->getDateFrom();
     return $this->newDateTimeFromEpoch($epoch);
   }
 
   public function getStartDateTimeEpoch() {
     return $this->newStartDateTime()->getEpoch();
   }
 
   public function newEndDateTime() {
     $datetime = $this->getParameter('endDateTime');
     if ($datetime) {
       return $this->newDateTimeFromDictionary($datetime);
     }
 
     $epoch = $this->getDateTo();
     return $this->newDateTimeFromEpoch($epoch);
   }
 
   public function getEndDateTimeEpoch() {
     return $this->newEndDateTime()->getEpoch();
   }
 
   public function newUntilDateTime() {
     $datetime = $this->getParameter('untilDateTime');
     if ($datetime) {
       return $this->newDateTimeFromDictionary($datetime);
     }
 
     $epoch = $this->getRecurrenceEndDate();
     if (!$epoch) {
       return null;
     }
     return $this->newDateTimeFromEpoch($epoch);
   }
 
   public function getUntilDateTimeEpoch() {
     $datetime = $this->newUntilDateTime();
 
     if (!$datetime) {
       return null;
     }
 
     return $datetime->getEpoch();
   }
 
   public function newDuration() {
     return id(new PhutilCalendarDuration())
       ->setSeconds($this->getDuration());
   }
 
   public function newInstanceDateTime() {
     if (!$this->getIsRecurring()) {
       return null;
     }
 
     $index = $this->getSequenceIndex();
     if (!$index) {
       return null;
     }
 
     return $this->newSequenceIndexDateTime($index);
   }
 
   private function newDateTimeFromEpoch($epoch) {
     $datetime = PhutilCalendarAbsoluteDateTime::newFromEpoch($epoch);
 
     if ($this->getIsAllDay()) {
       $datetime->setIsAllDay(true);
     }
 
     return $this->newDateTimeFromDateTime($datetime);
   }
 
   private function newDateTimeFromDictionary(array $dict) {
     $datetime = PhutilCalendarAbsoluteDateTime::newFromDictionary($dict);
     return $this->newDateTimeFromDateTime($datetime);
   }
 
   private function newDateTimeFromDateTime(PhutilCalendarDateTime $datetime) {
     $viewer_timezone = $this->viewerTimezone;
     if ($viewer_timezone) {
       $datetime->setViewerTimezone($viewer_timezone);
     }
 
     return $datetime;
   }
 
   public function getParameter($key, $default = null) {
     return idx($this->parameters, $key, $default);
   }
 
   public function setParameter($key, $value) {
     $this->parameters[$key] = $value;
     return $this;
   }
 
   public function setStartDateTime(PhutilCalendarDateTime $datetime) {
     return $this->setParameter(
       'startDateTime',
       $datetime->newAbsoluteDateTime()->toDictionary());
   }
 
   public function setEndDateTime(PhutilCalendarDateTime $datetime) {
     return $this->setParameter(
       'endDateTime',
       $datetime->newAbsoluteDateTime()->toDictionary());
   }
 
   public function setUntilDateTime(PhutilCalendarDateTime $datetime) {
     return $this->setParameter(
       'untilDateTime',
       $datetime->newAbsoluteDateTime()->toDictionary());
   }
 
   public function setRecurrenceRule(PhutilCalendarRecurrenceRule $rrule) {
     return $this->setParameter(
       'recurrenceRule',
       $rrule->toDictionary());
   }
 
   public function newRecurrenceRule() {
     if ($this->isChildEvent()) {
       return $this->getParentEvent()->newRecurrenceRule();
     }
 
     if (!$this->getIsRecurring()) {
       return null;
     }
 
     $dict = $this->getParameter('recurrenceRule');
     if (!$dict) {
       return null;
     }
 
     $rrule = PhutilCalendarRecurrenceRule::newFromDictionary($dict);
 
     $start = $this->newStartDateTime();
     $rrule->setStartDateTime($start);
 
     $until = $this->newUntilDateTime();
     if ($until) {
       $rrule->setUntil($until);
     }
 
     return $rrule;
   }
 
   public function newRecurrenceSet() {
     if ($this->isChildEvent()) {
       return $this->getParentEvent()->newRecurrenceSet();
     }
 
     $set = new PhutilCalendarRecurrenceSet();
 
     $rrule = $this->newRecurrenceRule();
     if (!$rrule) {
       return null;
     }
 
     $set->addSource($rrule);
 
     return $set;
   }
 
   public function isImportedEvent() {
     return (bool)$this->getImportSourcePHID();
   }
 
   public function getImportSource() {
     return $this->assertAttached($this->importSource);
   }
 
   public function attachImportSource(
     PhabricatorCalendarImport $import = null) {
     $this->importSource = $import;
     return $this;
   }
 
 
 /* -(  Markup Interface  )--------------------------------------------------- */
 
 
   /**
    * @task markup
    */
   public function getMarkupFieldKey($field) {
     $hash = PhabricatorHash::digest($this->getMarkupText($field));
     $id = $this->getID();
     return "calendar:T{$id}:{$field}:{$hash}";
   }
 
 
   /**
    * @task markup
    */
   public function getMarkupText($field) {
     return $this->getDescription();
   }
 
 
   /**
    * @task markup
    */
   public function newMarkupEngine($field) {
     return PhabricatorMarkupEngine::newCalendarMarkupEngine();
   }
 
 
   /**
    * @task markup
    */
   public function didMarkupText(
     $field,
     $output,
     PhutilMarkupEngine $engine) {
     return $output;
   }
 
 
   /**
    * @task markup
    */
   public function shouldUseMarkupCache($field) {
     return (bool)$this->getID();
   }
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
       PhabricatorPolicyCapability::CAN_EDIT,
     );
   }
 
   public function getPolicy($capability) {
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
         if ($this->getImportSource()) {
           return PhabricatorPolicies::POLICY_NOONE;
         } else {
           return $this->getEditPolicy();
         }
     }
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     if ($this->getImportSource()) {
       return false;
     }
 
     // The host of an event can always view and edit it.
     $user_phid = $this->getHostPHID();
     if ($user_phid) {
       $viewer_phid = $viewer->getPHID();
       if ($viewer_phid == $user_phid) {
         return true;
       }
     }
 
     if ($capability == PhabricatorPolicyCapability::CAN_VIEW) {
       $status = $this->getUserInviteStatus($viewer->getPHID());
       if ($status == PhabricatorCalendarEventInvitee::STATUS_INVITED ||
         $status == PhabricatorCalendarEventInvitee::STATUS_ATTENDING ||
         $status == PhabricatorCalendarEventInvitee::STATUS_DECLINED) {
         return true;
       }
     }
 
     return false;
   }
 
   public function describeAutomaticCapability($capability) {
     if ($this->getImportSource()) {
       return pht(
         'Events imported from external sources can not be edited in '.
         'Phabricator.');
     }
 
     return pht(
       'The host of an event can always view and edit it. Users who are '.
       'invited to an event can always view it.');
   }
 
 
 /* -(  PhabricatorExtendedPolicyInterface  )--------------------------------- */
 
 
   public function getExtendedPolicy($capability, PhabricatorUser $viewer) {
     $extended = array();
 
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         $import_source = $this->getImportSource();
         if ($import_source) {
           $extended[] = array(
             $import_source,
             PhabricatorPolicyCapability::CAN_VIEW,
           );
         }
         break;
     }
 
     return $extended;
   }
 
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */
 
 
   public function getApplicationTransactionEditor() {
     return new PhabricatorCalendarEventEditor();
   }
 
   public function getApplicationTransactionObject() {
     return $this;
   }
 
   public function getApplicationTransactionTemplate() {
     return new PhabricatorCalendarEventTransaction();
   }
 
   public function willRenderTimeline(
     PhabricatorApplicationTransactionView $timeline,
     AphrontRequest $request) {
 
     return $timeline;
   }
 
 /* -(  PhabricatorSubscribableInterface  )----------------------------------- */
 
 
   public function isAutomaticallySubscribed($phid) {
     return ($phid == $this->getHostPHID());
   }
 
 /* -(  PhabricatorTokenReceiverInterface  )---------------------------------- */
 
 
   public function getUsersToNotifyOfTokenGiven() {
     return array($this->getHostPHID());
   }
 
 /* -(  PhabricatorDestructibleInterface  )----------------------------------- */
 
 
   public function destroyObjectPermanently(
     PhabricatorDestructionEngine $engine) {
 
     $this->openTransaction();
     $this->delete();
     $this->saveTransaction();
   }
 
 /* -(  PhabricatorSpacesInterface  )----------------------------------------- */
 
 
   public function getSpacePHID() {
     return $this->spacePHID;
   }
 
 
 /* -(  PhabricatorFulltextInterface  )--------------------------------------- */
 
 
   public function newFulltextEngine() {
     return new PhabricatorCalendarEventFulltextEngine();
   }
 
 
 /* -(  PhabricatorConduitResultInterface  )---------------------------------- */
 
 
   public function getFieldSpecificationsForConduit() {
     return array(
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('name')
         ->setType('string')
         ->setDescription(pht('The name of the event.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('description')
         ->setType('string')
         ->setDescription(pht('The event description.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('isAllDay')
         ->setType('bool')
         ->setDescription(pht('True if the event is an all day event.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('startDateTime')
         ->setType('datetime')
         ->setDescription(pht('Start date and time of the event.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('endDateTime')
         ->setType('datetime')
         ->setDescription(pht('End date and time of the event.')),
     );
   }
 
   public function getFieldValuesForConduit() {
     $start_datetime = $this->newStartDateTime();
     $end_datetime = $this->newEndDateTime();
 
     return array(
       'name' => $this->getName(),
       'description' => $this->getDescription(),
       'isAllDay' => (bool)$this->getIsAllDay(),
       'startDateTime' => $this->getConduitDateTime($start_datetime),
       'endDateTime' => $this->getConduitDateTime($end_datetime),
     );
   }
 
   public function getConduitSearchAttachments() {
     return array();
   }
 
   private function getConduitDateTime($datetime) {
     if (!$datetime) {
       return null;
     }
 
     $epoch = $datetime->getEpoch();
 
     // TODO: Possibly pass the actual viewer in from the Conduit stuff, or
     // retain it when setting the viewer timezone?
     $viewer = id(new PhabricatorUser())
       ->overrideTimezoneIdentifier($this->viewerTimezone);
 
     return array(
       'epoch' => (int)$epoch,
       'display' => array(
         'default' => phabricator_datetime($epoch, $viewer),
       ),
       'iso8601' => $datetime->getISO8601(),
       'timezone' => $this->viewerTimezone,
     );
   }
 
 }