Sorting Views result rows based on an array of node IDs

Question

I have a View of song nodes, and each node has a programmatically calculated total number of points associated with it. (For background: song nodes are referenced in a custom field_chart_items field on a chart node, hence the $chartHistory node query seen in the hook below. The custom field includes a numeric Position that's entered on the chart node, and a numeric Points total that's hidden from view and calculated based on Position in a chart_field_entity_presave() hook.) I'm trying to sort the View's results by points, with highest points totals listed first.

In a views_pre_render() hook, I calculate the points total for each row and place it into an array, $songAndPoints, that contains the song's nid and points total. The array is sorted so that the song with the highest points total comes first – therefore, the order of the nids in the array is the order in which I want my results to appear.

Can I programmatically reorder the $view->result array based on the array of nids I'm getting? My attempt below, using a uasort() callback, doesn't work, but I'm not sure if or how I can do what I'm looking for (or if, perhaps, it needs to happen in a different hook).

<?php
/**
 * Implements hook_views_pre_render().
 */
function MODULE_views_pre_render(&$view) {
  if ($view->current_display === 'DISPLAYID'
    && $view->id() === 'VIEWID') {
      $entity_type_manager = \Drupal::entityTypeManager();
      $node_storage = $entity_type_manager->getStorage('node');  

      foreach ($view->result as $key => $song) {
        $node_type = 'chart';
        $songNID = $song->nid;
        
        $chartHistory = $node_storage->getQuery()
          ->condition('type', $node_type)
          ->condition('field_chart_items', $songNID, 'IN')
          ->condition('status', 1)
          ->execute();

        if ($chartHistory) {
          foreach ($chartHistory as $chartNID) {
            // ...
            // Various calculations to get points total, $songPoints, for each song.
            // ...
          }
          $songAndPoints[$key] = ['points' => $songPoints, 'nid' => $songNID];

          // Sort based on point values.
          arsort($songAndPoints);

        } else {
          $songAndPoints[] = ['points' => 0, 'nid' => $songNID];
        }
      }

      kint($songAndPoints); // Array with original row number as key and two values, points and NID, sorted with highest points first. This is how I want to sort the results.

      uasort($view->result, "MODULE_sort_by_points_total");
  }
}

/**
 * Custom uasort() callback to sort view results by points totals.
 */
function MODULE_sort_by_points_total($left, $right) {
    $order = ['704', '712', '707', '713', '711', '709', '708', '883', '882', '715', '714', '710', '705']; // TEMPORARY: Hardcoded list of node IDs in order; should be replaced by something like array_column($songAndPoints, 'nid'), but hardcoded values don't work either.

    $flipped = array_flip($order);
    $leftPos = $flipped[$left]->nid;
    $rightPos = $flipped[$right]->nid;
    return $leftPos >= $rightPos;
    // via https://stackoverflow.com/questions/17324708/php-array-multisort-not-sorting-my-multidimensional-array-as-expected/17325584#17325584
}

Answer 1

I got my answer via the Drupal Slack, but reposting it here for anyone who might come across this later, since that's not publicly searchable. It was more of a PHP issue than anything Drupal-specific.

Within the uasort() callback, the $left and $right arguments are objects of the ResultRow class, with nid available from them, so switching $leftPos and $rightPos to $flipped[$left->nid] and $flipped[$right->nid], respectively, gets me access to the results' nids.

/**
 * Custom uasort() callback to sort view results by points totals.
 */
function MODULE_sort_by_points_total($left, $right) {
    $order = ['704', '712', '707', '713', '711', '709', '708', '883', '882', '715', '714', '710', '705'];

    $flipped = array_flip($order);
    $leftPos = $flipped[$left->nid];
    $rightPos = $flipped[$right->nid];
    return $leftPos >= $rightPos;
}

Continuing on, I figured out that switching it to an anonymous function was what I needed to pass $songAndPoints to the uasort() function, as follows, instead of separating it:

$sortByPointsTotal = function($left, $right) use ($songAndPoints) {
    $order = array_column($songAndPoints, 'nid');
    
    $flipped = array_flip($order);
    $leftPos = $flipped[$left->nid];
    $rightPos = $flipped[$right->nid];
    return $leftPos >= $rightPos;
};

uasort($view->result, $sortByPointsTotal);