Rolling up Data in a collection

collections.php

The purpose of this is we pull a SQL query, and then by grouping together we will get sets of two and we want to see if the most
recent item in the set has increased or decreased relative to the other items. The final form of the result needs to take the form
[
  'decreased' => $count,
  'no-change' => $count,
  'increased' => $count,
]

What I have is below. I especially don't like the last three lines where I'm forced to move out of the functional style and use
null coalescing three times. I think it could look better.


$rollup = collect($query->get())
              ->groupBy(function ($results_data) {
                  // The query restricts two only two days, so this will return pairings of a engine-keyword-location
                  // that we can compare for ranking changes.
                  return "$results_data->engine|$results_data->keyword_id|$results_data->location_id";
              })
              ->map(function (Collection $collection) {
                  $collection = $collection->sortByDesc('created_at_date');
                  if ($collection->count() > 2) {
                      // There was an error with the query, we're missing a dispatch. Assume the missing dispatch is unranked
                      return (int)$collection->first()->rank <=> 0;
                  }
            
                  return (int)$collection->first()->rank <=> (int)$collection->last()->rank;
              })->groupBy(function ($item, $key) {
                  return $item;
              })->map(function (Collection $groups) {
                  return $groups->count();
              });

$rollup['decreased'] = $rollup->get(-1) ?? 0;
$rollup['no-change'] = $rollup->get(0) ?? 0;
$rollup['increased'] = $rollup->get(1) ?? 0;