<?php

declare(strict_types=1);

namespace App\Infrastructure\Reputation;

use App\Domain\Policy\Policy;
use App\Domain\Reputation\Blocklist;
use App\Domain\Reputation\BlocklistBuilder;
use App\Domain\Time\Clock;

/**
 * Per-policy in-process cache of `Blocklist` results.
 *
 * SPEC §M07.3: 30-second TTL by default, keyed on `policy_id`. Cache stores
 * the domain `Blocklist` object — text and JSON renderings happen
 * downstream and share the same cached build (the build is the expensive
 * part).
 *
 * Invalidation: mutation paths call `invalidate($policyId)` for policy-
 * scoped changes and `invalidateAll()` for global changes (manual blocks,
 * allowlist, "rebuild scores"). Tests can pass `ttlSeconds=0` to disable
 * caching entirely.
 *
 * Multi-replica caveat: the cache is per-process. The cidr-evaluator
 * factory has the same caveat (see PROGRESS.md M06).
 */
class BlocklistCache
{
    /**
     * @var array<int, array{blocklist: Blocklist, expires_at: float}>
     */
    private array $cache = [];

    public function __construct(
        private readonly BlocklistBuilder $builder,
        private readonly Clock $clock,
        private readonly int $ttlSeconds = 30,
    ) {
    }

    public function getOrBuild(Policy $policy): Blocklist
    {
        $now = (float) $this->clock->now()->getTimestamp();
        $entry = $this->cache[$policy->id] ?? null;
        if ($entry !== null && $now < $entry['expires_at']) {
            return $entry['blocklist'];
        }

        $blocklist = $this->builder->build($policy);
        if ($this->ttlSeconds > 0) {
            $this->cache[$policy->id] = [
                'blocklist' => $blocklist,
                'expires_at' => $now + $this->ttlSeconds,
            ];
        }

        return $blocklist;
    }

    public function invalidate(int $policyId): void
    {
        unset($this->cache[$policyId]);
    }

    public function invalidateAll(): void
    {
        $this->cache = [];
    }
}