<?php

declare(strict_types=1);

namespace App\Services\Hosting;

use App\Models\DnsServer;
use App\Models\ServicePlan;
use App\Services\Plesk\PleskService;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Cache;
use Throwable;

class HostingServerSelector
{
    private const HEALTH_TTL_SECONDS = 60;

    private const PROBE_TIMEOUT_SECONDS = 5;

    public function __construct(private readonly PleskService $plesk)
    {
    }

    public function candidates(ServicePlan $plan): Collection
    {
        return $plan->servers()->get()
            ->filter(fn (DnsServer $server) => $server->status === 'activated' && $server->servesHosting())
            ->values();
    }

    public function pick(ServicePlan $plan, array $excludeIds = []): ?DnsServer
    {
        return $this->candidates($plan)->first(
            fn (DnsServer $server) => ! in_array($server->id, $excludeIds, true) && $this->isHealthy($server)
        );
    }

    public function hasHealthyServer(ServicePlan $plan): bool
    {
        return $this->pick($plan) !== null;
    }

    public function isHealthy(DnsServer $server): bool
    {
        return Cache::remember($this->cacheKey($server), self::HEALTH_TTL_SECONDS, fn () => $this->probe($server));
    }

    public function forget(DnsServer $server): void
    {
        Cache::forget($this->cacheKey($server));
    }

    private function probe(DnsServer $server): bool
    {
        try {
            return $this->plesk
                ->client($server, self::PROBE_TIMEOUT_SECONDS)
                ->get($this->plesk->url($server, 'server'))
                ->successful();
        } catch (Throwable) {
            return false;
        }
    }

    private function cacheKey(DnsServer $server): string
    {
        return 'hosting-server-health:' . $server->id;
    }
}