Suggest better start/end datetimes for Calendar events

Summary:
Fixes T11638.

  - Fix a regression: I broke this "round to the nearest hour" code a while ago while fiddling with datetimes.
  - Improve a beahvior: from the day view, make the menu-bar "Create Event" button default to creating an event on the day you were viewing.

Test Plan: Created events from month and day views, got nice round numbers and proper day suggestions.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11638

Differential Revision: https://secure.phabricator.com/D16754

src/applications/calendar/controller/PhabricatorCalendarEventListController.php

@@ -3,6 +3,10 @@
 final class PhabricatorCalendarEventListController
   extends PhabricatorCalendarController {
 
+  private $viewYear;
+  private $viewMonth;
+  private $viewDay;
+
   public function shouldAllowPublic() {
     return true;
   }
@@ -16,6 +20,10 @@ final class PhabricatorCalendarEventListController
     $month = $request->getURIData('month');
     $day = $request->getURIData('day');
 
+    $this->viewYear = $year;
+    $this->viewMonth = $month;
+    $this->viewDay = $day;
+
     $engine = new PhabricatorCalendarEventSearchEngine();
 
     if ($month && $year) {
@@ -33,9 +41,36 @@ final class PhabricatorCalendarEventListController
   protected function buildApplicationCrumbs() {
     $crumbs = parent::buildApplicationCrumbs();
 
+    $viewer = $this->getViewer();
+
+    $year = $this->viewYear;
+    $month = $this->viewMonth;
+    $day = $this->viewDay;
+
+    $parameters = array();
+
+    // If the viewer clicks "Create Event" while on a particular day view,
+    // default the times to that day.
+    if ($year && $month && $day) {
+      $datetimes = PhabricatorCalendarEvent::newDefaultEventDateTimes(
+        $viewer,
+        PhabricatorTime::getNow());
+
+      foreach ($datetimes as $datetime) {
+        $datetime
+          ->setYear($year)
+          ->setMonth($month)
+          ->setDay($day);
+      }
+
+      list($start, $end) = $datetimes;
+      $parameters['start'] = $start->getEpoch();
+      $parameters['end'] = $end->getEpoch();
+    }
+
     id(new PhabricatorCalendarEventEditEngine())
       ->setViewer($this->getViewer())
-      ->addActionToCrumbs($crumbs);
+      ->addActionToCrumbs($crumbs, $parameters);
 
     return $crumbs;
   }

src/applications/calendar/storage/PhabricatorCalendarEvent.php

@@ -75,10 +75,10 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
 
     $default_icon = 'fa-calendar';
 
-    $datetime_start = PhutilCalendarAbsoluteDateTime::newFromEpoch(
-      $now,
-      $actor->getTimezoneIdentifier());
-    $datetime_end = $datetime_start->newRelativeDateTime('PT1H');
+    $datetime_defaults = self::newDefaultEventDateTimes(
+      $actor,
+      $now);
+    list($datetime_start, $datetime_end) = $datetime_defaults;
 
     return id(new PhabricatorCalendarEvent())
       ->setDescription('')
@@ -102,6 +102,31 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
       ->applyViewerTimezone($actor);
   }
 
+  public static function newDefaultEventDateTimes(
+    PhabricatorUser $viewer,
+    $now) {
+
+    $datetime_start = PhutilCalendarAbsoluteDateTime::newFromEpoch(
+      $now,
+      $viewer->getTimezoneIdentifier());
+
+    // Advance the time by an hour, then round downwards to the nearest hour.
+    // For example, if it is currently 3:25 PM, we suggest a default start time
+    // of 4 PM.
+    $datetime_start = $datetime_start
+      ->newRelativeDateTime('PT1H')
+      ->newAbsoluteDateTime();
+    $datetime_start->setMinute(0);
+    $datetime_start->setSecond(0);
+
+    // Default the end time to an hour after the start time.
+    $datetime_end = $datetime_start
+      ->newRelativeDateTime('PT1H')
+      ->newAbsoluteDateTime();
+
+    return array($datetime_start, $datetime_end);
+  }
+
   private function newChild(
     PhabricatorUser $actor,
     $sequence,

src/applications/transactions/editengine/PhabricatorEditEngine.php

@@ -1349,7 +1349,9 @@ abstract class PhabricatorEditEngine
   }
 
 
-  final public function addActionToCrumbs(PHUICrumbsView $crumbs) {
+  final public function addActionToCrumbs(
+    PHUICrumbsView $crumbs,
+    array $parameters = array()) {
     $viewer = $this->getViewer();
 
     $can_create = $this->hasCreateCapability();
@@ -1385,6 +1387,11 @@ abstract class PhabricatorEditEngine
       $form_key = $config->getIdentifier();
       $create_uri = $this->getEditURI(null, "form/{$form_key}/");
 
+      if ($parameters) {
+        $create_uri = (string)id(new PhutilURI($create_uri))
+          ->setQueryParams($parameters);
+      }
+
       if (count($configs) > 1) {
         $menu_icon = 'fa-caret-square-o-down';
 
@@ -1395,6 +1402,11 @@ abstract class PhabricatorEditEngine
           $form_key = $config->getIdentifier();
           $config_uri = $this->getEditURI(null, "form/{$form_key}/");
 
+          if ($parameters) {
+            $config_uri = (string)id(new PhutilURI($config_uri))
+              ->setQueryParams($parameters);
+          }
+
           $item_icon = 'fa-plus';
 
           $dropdown->addAction(