Uptime check job with alert debouncing

<?php

namespace App\Jobs;

use App\Models\Monitor;
use App\Notifications\MonitorDown;
use App\Notifications\MonitorRecovered;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\Middleware\WithoutOverlapping;
use Illuminate\Support\Facades\Http;
use Throwable;

class CheckMonitor implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable;

    public int $tries = 1;

    public function __construct(public int $monitorId) {}

    /** One check per monitor at a time, even if the scheduler fires twice. */
    public function middleware(): array
    {
        return [(new WithoutOverlapping((string) $this->monitorId))->dontRelease()->expireAfter(120)];
    }

    public function handle(): void
    {
        $monitor = Monitor::findOrFail($this->monitorId);
        $started = hrtime(true);

        try {
            $res = Http::timeout(10)->withoutRedirecting()->get($monitor->url);
            $up = $res->status() < 400;
            $note = 'HTTP '.$res->status();
        } catch (Throwable $e) {
            $up = false;
            $note = class_basename($e);
        }

        $monitor->checks()->create([
            'up' => $up,
            'note' => $note,
            'ms' => (int) ((hrtime(true) - $started) / 1e6),
        ]);

        $up ? $this->onSuccess($monitor) : $this->onFailure($monitor);
    }

    private function onFailure(Monitor $m): void
    {
        $m->increment('consecutive_failures');
        $m->refresh();

        // Debounce: alert once, when the streak first reaches the threshold.
        if ($m->consecutive_failures >= $m->alert_after && ! $m->alerted_at) {
            $m->forceFill(['alerted_at' => now()])->save();
            $m->owner->notify(new MonitorDown($m));
        }
    }

    private function onSuccess(Monitor $m): void
    {
        $wasAlerted = $m->alerted_at !== null;
        $m->forceFill(['consecutive_failures' => 0, 'alerted_at' => null])->save();

        if ($wasAlerted) {
            $m->owner->notify(new MonitorRecovered($m));
        }
    }
}