Feature Request: Create protected method for query generation in Trend metrics

[bkuhl]

Scenario

I have a large application with a sizeable data set and calculating metrics in runtime isn't possible. As a new Nova User, I'm also bringing a large data set of pre-calculated metrics in an already established table. We have queue jobs that run daily in the background creating daily "snapshots" of what the counts are at that time, creating DB records like:

This makes it much less expensive to calculate metrics over large periods of time.

The Ask

I'd like to show these as a Trend using the pre-calculated table for weekly, monthly and daily timeframes. This is doable, but the challenge is around the Laravel\Nova\Metrics\Trend::aggregate(...) method. It'd be great if instead of the query being built in this method, it could be built in another protected method so that it's easier to supply my own query that provides the same database results.

My Workaround

At the moment, to meet my needs I've had to mostly duplicate Laravel\Nova\Metrics\Trend::aggregate(...) so I can still get the benefits of formatAggregateResultDate() and formatPossibleAggregateResultDate() which handle generating the date ranges and ensuring zeroes for records which aren't in the db result set.

The result looks something like below (this is all still WIP):

    protected function valueByDays(NovaRequest $request): TrendResult
    {
        $unit = Trend::BY_DAYS;

        $timezone = Nova::resolveUserTimezone($request) ?? $request->timezone;
        $possibleDateResults = $this->getAllPossibleDateResults(
            $startingDate = $this->getAggregateStartingDate($request, $unit, $timezone),
            $endingDate = CarbonImmutable::now($timezone),
            Trend::BY_DAYS,
            $request->twelveHourTime === 'true'
        );

        // Most code here is reused from parent class, but we needed a custom query
        $results = DailyStat::where('stat', $this->forDailyStat())
            ->where('date', '>=', $startingDate)
            ->where('date', '<=', $endingDate)
            ->orderByDesc('date')
            ->select(
                DB::raw("`date` as date_result, `value` as aggregate")
            )
            ->get()
            ->keyBy('date_result');

        $results = array_merge($possibleDateResults, $results->mapWithKeys(function ($result) use ($request, $unit) {
            return [$this->formatAggregateResultDate(
                $result->date_result, $unit, $request->twelveHourTime === 'true'
            ) => round($result->aggregate, $this->roundingPrecision, $this->roundingMode)];
        })->all());

        if (count($results) > $request->range) {
            array_shift($results);
        }

        return (new TrendResult())
            ->trend($results);
    }

    protected function formatAggregateResultDate($result, $unit, $twelveHourTime)
    {
        switch ($unit) {
            case Trend::BY_DAYS:
                return $result;
        }

        parent::formatAggregateResultDate($result, $unit, $twelveHourTime);
    }

    protected function formatPossibleAggregateResultDate(CarbonInterface $date, $unit, $twelveHourTime)
    {
        switch ($unit) {
            case Trend::BY_DAYS:
                return $date->format(DailyStat::DATE_FORMAT);
        }

        parent::formatAggregateResultDate($date, $unit, $twelveHourTime);
    }