<?php

declare(strict_types=1);

namespace App\Support\Health\Checks;

use App\Filament\Resources\MissingUrls\MissingUrlResource;
use App\Models\MissingUrl;
use App\Support\Health\Check;
use App\Support\Health\Finding;
use App\Support\Health\Severity;

/**
 * Addresses the frontend keeps being asked for and cannot answer.
 *
 * Every other check here reasons about what is stored; this one is the only
 * one that knows what visitors actually did. A 404 is the one fault on the
 * public site that nobody on this side can discover by looking — it happens to
 * somebody else, on another machine, and then they leave.
 *
 * Counted from two hits upward. A single request is as likely to be a scanner
 * as a person, and a number that never reaches zero stops being read.
 */
class UnresolvedMissingUrls implements Check
{
    /**
     * Below this, an address is a stray request rather than a broken link.
     */
    protected const THRESHOLD = 2;

    public function key(): string
    {
        return 'missing-urls';
    }

    public function permission(): ?string
    {
        // The same permission that governs doing something about it.
        return 'redirects.view_any';
    }

    public function run(): Finding
    {
        $missing = MissingUrl::query()
            ->pending()
            ->where('hits', '>=', self::THRESHOLD)
            ->orderByDesc('hits')
            ->get(['path', 'hits', 'referrer']);

        return Finding::problem(
            $this->key(),
            $missing->count(),

            // An address our own site links to is a fault in what we publish,
            // not somebody else's stale bookmark, and it will keep producing
            // 404s until it is fixed here.
            $missing->contains(fn (MissingUrl $url) => $url->isInternalReferrer())
                ? Severity::Error
                : Severity::Warning,

            url: MissingUrlResource::getUrl('index'),
            samples: $missing->map(fn (MissingUrl $url) => "{$url->path} ({$url->hits})")->all(),
        );
    }
}