<?php

namespace App\Console\Commands;

use App\Models\MetricSample;
use App\Models\Server;
use Illuminate\Console\Command;
use Illuminate\Support\Facades\Cache;

/**
 * Persist a once-a-minute resource sample per server — the long history the Server-Details graph
 * plots. The source of truth is the `servers` DB ROW the 15s poller forceFills every tick (cpu/mem/
 * disk + last_seen_at), NOT a cache: the poller and this command run in SEPARATE containers in prod,
 * so a cache-backed read only worked when the cache store happened to be shared. Reading the row
 * means history is collected whenever the live gauges have data (they read the same row), regardless
 * of the cache driver. A server not freshly polled (never polled / offline — last_seen_at stale)
 * simply gets no sample (an honest gap). `load` is not on the row, so it is taken from the live cache
 * best-effort when present (stored but not plotted). Prunes beyond the retention window. Scheduled
 * everyMinute in routes/console.php.
 */
class SampleMetrics extends Command
{
    protected $signature = 'clusev:sample-metrics {--retention=30 : Days of history to keep}';

    protected $description = 'Persist a one-per-minute metric history sample per server (and prune old samples)';

    public function handle(): int
    {
        $now = now();
        // Only servers the 15s poller updated recently — a stale row means offline / no credential,
        // and sampling it would plot a flatline of its last-known values. 90s tolerates a missed tick.
        $fresh = $now->copy()->subSeconds(90);
        $rows = [];

        foreach (Server::query()->get(['id', 'cpu', 'mem', 'disk', 'last_seen_at']) as $server) {
            if ($server->last_seen_at === null || $server->last_seen_at->lt($fresh)) {
                continue;
            }
            // load is not persisted on the row; best-effort from the live cache when the store is shared.
            $cached = Cache::get("metrics:latest:{$server->id}");
            $rows[] = [
                'server_id' => $server->id,
                // Percentages — clamp to 0..100 so a stray reading can never plot outside the chart.
                'cpu' => min(100, max(0, (int) $server->cpu)),
                'mem' => min(100, max(0, (int) $server->mem)),
                'disk' => min(100, max(0, (int) $server->disk)),
                'load' => is_array($cached) ? round((float) ($cached['load'] ?? 0), 2) : 0.0,
                'sampled_at' => $now,
            ];
        }

        if ($rows !== []) {
            MetricSample::insert($rows);
        }

        $retention = max(1, (int) $this->option('retention'));
        MetricSample::where('sampled_at', '<', now()->subDays($retention))->delete();

        return self::SUCCESS;
    }
}