<?php

namespace App\Livewire;

use App\Livewire\Concerns\WithFleetContext;
use App\Models\AuditEvent;
use App\Models\Server;
use App\Services\FleetService;
use Illuminate\Support\Facades\Cache;
use Livewire\Attributes\Layout;
use Livewire\Attributes\Title;
use Livewire\Component;
use Throwable;

#[Layout('layouts.app')]
#[Title('Clusev — Dashboard')]
class Dashboard extends Component
{
    use WithFleetContext;

    public bool $ready = false;

    /** @var array<int, array> notable systemd units (lazy-loaded over SSH) */
    public array $svcRows = [];

    /** Lazy: the SSH services read runs after the shell renders (wire:init). */
    public function load(FleetService $fleet): void
    {
        $this->svcRows = $this->liveServices($fleet, $this->activeServer());
        $this->ready = true;
    }

    /** Deterministic wavy series — fallback sparkline for metrics without history. */
    private function series(float $base, int $n = 40, float $amp = 9): array
    {
        $out = [];
        for ($i = 0; $i < $n; $i++) {
            $v = $base + sin($i / 3.0) * $amp + sin($i / 6.5) * ($amp * 0.55) + cos($i / 2.0) * 2;
            $out[] = (int) max(2, min(98, round($v)));
        }

        return $out;
    }

    /** Pad a real history series to a minimum length for a stable sparkline. */
    private function pad(array $values, int $current, int $min = 16): array
    {
        $values = array_map('intval', $values);
        if ($values === []) {
            $values = [$current];
        }
        while (count($values) < $min) {
            array_unshift($values, $values[0]);
        }

        return $values;
    }

    /** @param  array<int,int>  $series */
    private function trend(array $series, string $suffix = '%'): array
    {
        $cur = (int) (end($series) ?: 0);
        $prev = (int) ($series[max(0, count($series) - 8)] ?? $cur);
        $d = $cur - $prev;

        return [
            'dir' => $d > 1 ? 'up' : ($d < -1 ? 'down' : 'flat'),
            'text' => ($d >= 0 ? '+' : '').$d.$suffix,
        ];
    }

    /** A handful of notable systemd units (failed + running first), cached. */
    private function liveServices(FleetService $fleet, ?Server $active): array
    {
        if (! $active || ! $active->credential_exists) {
            return [];
        }

        try {
            $svc = Cache::remember("svc:{$active->id}", 30, fn () => $fleet->systemd($active, 1)['services']);
        } catch (Throwable) {
            return [];
        }

        $rank = fn (array $s): int => match ($s['sub']) {
            'failed' => 0,
            'running' => 1,
            default => 2,
        };
        usort($svc, fn ($a, $b) => [$rank($a), $a['name']] <=> [$rank($b), $b['name']]);

        return array_slice($svc, 0, 8);
    }

    public function render(FleetService $fleet)
    {
        $active = $this->activeServer();

        // Metrics come from the poller (DB + cache) — no SSH on web render.
        $latest = $active ? $fleet->latest($active) : null;
        $cpu = (int) ($latest['cpu'] ?? $active?->cpu ?? 0);
        $mem = (int) ($latest['mem'] ?? $active?->mem ?? 0);
        $disk = (int) ($latest['disk'] ?? $active?->disk ?? 0);
        $load = (float) ($latest['load'] ?? 0);

        $hist = $active ? $fleet->history($active) : ['cpu' => [], 'mem' => []];
        $cpuSeries = $this->pad($hist['cpu'], $cpu);
        $memSeries = $this->pad($hist['mem'], $mem);
        $diskSeries = $this->series(max(4, $disk), 40, 2);
        $loadSeries = $this->series(max(8, (int) round($load * 18)), 40, 6);

        return view('livewire.dashboard', [
            'active' => $active,
            'cpu' => $cpu,
            'mem' => $mem,
            'disk' => $disk,
            'load' => round($load, 2),
            'cpuSeries' => $cpuSeries,
            'memSeries' => $memSeries,
            'diskSeries' => $diskSeries,
            'loadSeries' => $loadSeries,
            'cpuTrend' => $this->trend($cpuSeries),
            'memTrend' => $this->trend($memSeries),
            'diskTrend' => $this->trend($diskSeries),
            'loadTrend' => $this->trend($loadSeries, ''),
            'services' => $this->svcRows,
            'events' => AuditEvent::with('server')->latest()->limit(6)->get(),
        ]);
    }
}