Support basic notification aggregation

Summary: This is both only partially complete (supports Maniphest only) and somewhat overcomplicated (includes support for applying similar algorithms to Feed), but provides runtime aggregation of notifications.

Test Plan: {F13502}

Reviewers: btrahan, jungejason

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D2884

src/__phutil_library_map__.php

@@ -638,11 +638,13 @@ phutil_register_library_map(array(
     'PhabricatorFeedPublicStreamController' => 'applications/feed/controller/PhabricatorFeedPublicStreamController.php',
     'PhabricatorFeedQuery' => 'applications/feed/PhabricatorFeedQuery.php',
     'PhabricatorFeedStory' => 'applications/feed/story/PhabricatorFeedStory.php',
+    'PhabricatorFeedStoryAggregate' => 'applications/feed/story/PhabricatorFeedStoryAggregate.php',
     'PhabricatorFeedStoryAudit' => 'applications/feed/story/PhabricatorFeedStoryAudit.php',
     'PhabricatorFeedStoryCommit' => 'applications/feed/story/PhabricatorFeedStoryCommit.php',
     'PhabricatorFeedStoryData' => 'applications/feed/storage/PhabricatorFeedStoryData.php',
     'PhabricatorFeedStoryDifferential' => 'applications/feed/story/PhabricatorFeedStoryDifferential.php',
     'PhabricatorFeedStoryManiphest' => 'applications/feed/story/PhabricatorFeedStoryManiphest.php',
+    'PhabricatorFeedStoryManiphestAggregate' => 'applications/feed/story/PhabricatorFeedStoryManiphestAggregate.php',
     'PhabricatorFeedStoryNotification' => 'applications/notification/storage/PhabricatorFeedStoryNotification.php',
     'PhabricatorFeedStoryPhriction' => 'applications/feed/story/PhabricatorFeedStoryPhriction.php',
     'PhabricatorFeedStoryProject' => 'applications/feed/story/PhabricatorFeedStoryProject.php',
@@ -1646,11 +1648,13 @@ phutil_register_library_map(array(
     'PhabricatorFeedController' => 'PhabricatorController',
     'PhabricatorFeedDAO' => 'PhabricatorLiskDAO',
     'PhabricatorFeedPublicStreamController' => 'PhabricatorFeedController',
+    'PhabricatorFeedStoryAggregate' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryAudit' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryCommit' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryData' => 'PhabricatorFeedDAO',
     'PhabricatorFeedStoryDifferential' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryManiphest' => 'PhabricatorFeedStory',
+    'PhabricatorFeedStoryManiphestAggregate' => 'PhabricatorFeedStoryAggregate',
     'PhabricatorFeedStoryNotification' => 'PhabricatorFeedDAO',
     'PhabricatorFeedStoryPhriction' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryProject' => 'PhabricatorFeedStory',

src/applications/feed/story/PhabricatorFeedStory.php

@@ -139,4 +139,8 @@ abstract class PhabricatorFeedStory {
     return $text;
   }
 
+  public function getNotificationAggregations() {
+    return array();
+  }
+
 }

src/applications/feed/story/PhabricatorFeedStoryAggregate.php

@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+abstract class PhabricatorFeedStoryAggregate extends PhabricatorFeedStory {
+
+  private $aggregateStories = array();
+
+  public function getHasViewed() {
+    return head($this->getAggregateStories())->getHasViewed();
+  }
+
+  public function getRequiredHandlePHIDs() {
+    $phids = array();
+    foreach ($this->getAggregateStories() as $story) {
+      $phids[] = $story->getRequiredHandlePHIDs();
+    }
+    return array_mergev($phids);
+  }
+
+  public function getRequiredObjectPHIDs() {
+    $phids = array();
+    foreach ($this->getAggregateStories() as $story) {
+      $phids[] = $story->getRequiredObjectPHIDs();
+    }
+    return array_mergev($phids);
+  }
+
+  protected function getAuthorPHIDs() {
+    $authors = array();
+    foreach ($this->getAggregateStories() as $story) {
+      $authors[] = $story->getStoryData()->getAuthorPHID();
+    }
+    return array_unique(array_filter($authors));
+  }
+
+  protected function getDataValues($key, $default) {
+    $result = array();
+    foreach ($this->getAggregateStories() as $key => $story) {
+      $result[$key] = $story->getStoryData()->getValue($key, $default);
+    }
+    return $result;
+  }
+
+  final public function setAggregateStories(array $aggregate_stories) {
+    assert_instances_of($aggregate_stories, 'PhabricatorFeedStory');
+    $this->aggregateStories = $aggregate_stories;
+    return $this;
+  }
+
+  final public function getAggregateStories() {
+    return $this->aggregateStories;
+  }
+
+  final public function getNotificationAggregations() {
+    throw new Exception(
+      "You can not get aggregations for an aggregate story.");
+  }
+
+}

src/applications/feed/story/PhabricatorFeedStoryManiphest.php

@@ -111,4 +111,19 @@ final class PhabricatorFeedStoryManiphest
 
     return $one_line;
   }
+
+  public function getNotificationAggregations() {
+    $class = get_class($this);
+    $phid  = $this->getStoryData()->getValue('taskPHID');
+    $read  = (int)$this->getHasViewed();
+
+    // Don't aggregate updates separated by more than 2 hours.
+    $block = (int)($this->getEpoch() / (60 * 60 * 2));
+
+    return array(
+      "{$class}:{$phid}:{$read}:{$block}"
+        => 'PhabricatorFeedStoryManiphestAggregate',
+    );
+  }
+
 }

src/applications/feed/story/PhabricatorFeedStoryManiphestAggregate.php

@@ -0,0 +1,86 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+final class PhabricatorFeedStoryManiphestAggregate
+  extends PhabricatorFeedStoryAggregate {
+
+  public function renderView() {
+    return null;
+  }
+
+
+  public function renderNotificationView() {
+    $data = $this->getStoryData();
+
+    $task_link = $this->linkTo($data->getValue('taskPHID'));
+
+    $authors = $this->getAuthorPHIDs();
+
+    // TODO: These aren't really translatable because linkTo() returns a
+    // string, not an object with a gender.
+
+    switch (count($authors)) {
+      case 1:
+        $author = $this->linkTo(array_shift($authors));
+        $title = pht(
+          '%s made multiple updates to %s',
+          $author,
+          $task_link);
+        break;
+      case 2:
+        $author1 = $this->linkTo(array_shift($authors));
+        $author2 = $this->linkTo(array_shift($authors));
+        $title = pht(
+          '%s and %s made multiple updates to %s',
+          $author1,
+          $author2,
+          $task_link);
+        break;
+      case 3:
+        $author1 = $this->linkTo(array_shift($authors));
+        $author2 = $this->linkTo(array_shift($authors));
+        $author3 = $this->linkTo(array_shift($authors));
+        $title = pht(
+          '%s, %s, and %s made multiple updates to %s',
+          $author1,
+          $author2,
+          $author3,
+          $task_link);
+        break;
+      default:
+        $author1 = $this->linkTo(array_shift($authors));
+        $author2 = $this->linkTo(array_shift($authors));
+        $others  = count($authors);
+        $title = pht(
+          '%s, %s, and %d others made multiple updates to %s',
+          $author1,
+          $author2,
+          $others,
+          $task_link);
+        break;
+    }
+
+    $view = new PhabricatorNotificationStoryView();
+    $view->setEpoch($this->getEpoch());
+    $view->setViewed($this->getHasViewed());
+    $view->setTitle($title);
+
+    return $view;
+  }
+
+}

src/applications/notification/builder/PhabricatorNotificationBuilder.php

@@ -27,6 +27,114 @@ final class PhabricatorNotificationBuilder {
   public function buildView() {
 
     $stories = $this->stories;
+    $stories = mpull($stories, null, 'getChronologicalKey');
+
+    // Aggregate notifications. Generally, we can aggregate notifications only
+    // by object, e.g. "a updated T123" and "b updated T123" can become
+    // "a and b updated T123", but we can't combine "a updated T123" and
+    // "a updated T234" into "a updated T123 and T234" because there would be
+    // nowhere sensible for the notification to link to, and no reasonable way
+    // to unambiguously clear it.
+
+    // Each notification emits keys it can aggregate on. For instance, if this
+    // story is "a updated T123", it might emit a key like this:
+    //
+    //   task:phid123:unread => PhabricatorFeedStoryManiphestAggregate
+    //
+    // All the unread notifications about the task with PHID "phid123" will
+    // emit the same key, telling us we can aggregate them into a single
+    // story of type "PhabricatorFeedStoryManiphestAggregate", which could
+    // read like "a and b updated T123".
+    //
+    // A story might be able to aggregate in multiple ways. Although this is
+    // unlikely for stories in a notification context, stories in a feed context
+    // can also aggregate by actor:
+    //
+    //   task:phid123   => PhabricatorFeedStoryManiphestAggregate
+    //   actor:user123  => PhabricatorFeedStoryActorAggregate
+    //
+    // This means the story can either become "a and b updated T123" or
+    // "a updated T123 and T456". When faced with multiple possibilities, it's
+    // our job to choose the best aggregation.
+    //
+    // For now, we use a simple greedy algorithm and repeatedly select the
+    // aggregate story which consumes the largest number of individual stories
+    // until no aggregate story exists that consumes more than one story.
+
+
+    // Build up a map of all the possible aggregations.
+
+    $chronokey_map = array();
+    $aggregation_map = array();
+    $agg_types = array();
+    foreach ($stories as $chronokey => $story) {
+      $chronokey_map[$chronokey] = $story->getNotificationAggregations();
+      foreach ($chronokey_map[$chronokey] as $key => $type) {
+        $agg_types[$key] = $type;
+        $aggregation_map[$key]['keys'][$chronokey] = true;
+      }
+    }
+
+    // Repeatedly select the largest available aggregation until none remain.
+
+    $aggregated_stories = array();
+    while ($aggregation_map) {
+
+      // Count the size of each aggregation, removing any which will consume
+      // fewer than 2 stories.
+
+      foreach ($aggregation_map as $key => $dict) {
+        $size = count($dict['keys']);
+        if ($size > 1) {
+          $aggregation_map[$key]['size'] = $size;
+        } else {
+          unset($aggregation_map[$key]);
+        }
+      }
+
+      // If we're out of aggregations, break out.
+
+      if (!$aggregation_map) {
+        break;
+      }
+
+      // Select the aggregation we're going to make, and remove it from the
+      // map.
+
+      $aggregation_map = isort($aggregation_map, 'size');
+      $agg_info = idx(last($aggregation_map), 'keys');
+      $agg_key  = last_key($aggregation_map);
+      unset($aggregation_map[$agg_key]);
+
+      // Select all the stories it aggregates, and remove them from the master
+      // list of stories and from all other possible aggregations.
+
+      $sub_stories = array();
+      foreach ($agg_info as $chronokey => $ignored) {
+        $sub_stories[$chronokey] = $stories[$chronokey];
+        unset($stories[$chronokey]);
+        foreach ($chronokey_map[$chronokey] as $key => $type) {
+          unset($aggregation_map[$key]['keys'][$chronokey]);
+        }
+        unset($chronokey_map[$chronokey]);
+      }
+
+      // Build the aggregate story.
+
+      krsort($sub_stories);
+      $story_class = $agg_types[$agg_key];
+      $conv = array(head($sub_stories)->getStoryData());
+
+      $new_story = newv($story_class, $conv);
+      $new_story->setAggregateStories($sub_stories);
+      $aggregated_stories[] = $new_story;
+    }
+
+    // Combine the aggregate stories back into the list of stories.
+
+    $stories = array_merge($stories, $aggregated_stories);
+    $stories = mpull($stories, null, 'getChronologicalKey');
+    krsort($stories);
 
     $handles = array();
     $objects = array();
@@ -39,7 +147,6 @@ final class PhabricatorNotificationBuilder {
 
     $null_view = new AphrontNullView();
 
-    //TODO ADD NOTIFICATIONS HEADER
     foreach ($stories as $story) {
       $story->setHandles($handles);
       $view = $story->renderNotificationView();