<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\Storage;
use LogicException;

/** Global technical inspection, with aggregate output only. Never repairs or removes files. */
class ReceiptDocumentHealth
{
    /** @return array<string,mixed> */
    public function inspect(int $limit = 1000): array
    {
        abort_unless(app()->runningInConsole() && ! auth()->check(), 403, 'Verificação reservada à operação técnica.');
        if ($limit < 1 || $limit > 10000) {
            throw new LogicException('Limite fora do intervalo permitido.');
        }
        $result = ['checked_at' => now()->toIso8601String(), 'ok' => false, 'complete' => false, 'reasons' => [],
            'documents_checked' => 0, 'files_checked' => 0, 'missing' => 0, 'invalid_reference' => 0, 'altered' => 0,
            'unreferenced_recent' => 0, 'unreferenced_older' => 0];
        if (! Schema::hasTable('receipt_documents')) {
            return [...$result, 'reasons' => ['not_installed']];
        }

        return DB::transaction(function () use ($limit, $result) {
            if (DB::getDriverName() === 'pgsql' && DB::transactionLevel() === 1) {
                DB::statement('SET TRANSACTION ISOLATION LEVEL REPEATABLE READ READ ONLY');
            }
            $disk = Storage::disk('receipt_documents');
            $root = realpath($disk->path(''));
            if ($root === false) {
                return [...$result, 'reasons' => ['storage_unavailable']];
            }
            $records = DB::table('receipt_documents')->orderBy('id')->limit($limit + 1)->get();
            $limited = $records->count() > $limit;
            foreach ($records->take($limit) as $document) {
                $result['documents_checked']++;
                $prefix = $document->tenant_id.'/'.$document->goods_receipt_id.'/';
                $name = substr($document->path, strlen($prefix));
                if (! str_starts_with($document->path, $prefix) || ! preg_match('/\A[A-Za-z0-9_-]+\.[A-Za-z0-9]+\z/D', $name)
                    || ! DB::table('goods_receipts')->where('id', $document->goods_receipt_id)->where('tenant_id', $document->tenant_id)->exists()) {
                    $result['invalid_reference']++;

                    continue;
                }
                $path = realpath($disk->path($document->path));
                if ($path === false || ! is_file($path)) {
                    $result['missing']++;

                    continue;
                }
                $normalizedPath = str_replace('\\', '/', $path);
                $normalizedRoot = str_replace('\\', '/', $root).'/';
                $withinRoot = PHP_OS_FAMILY === 'Windows'
                    ? str_starts_with(strtolower($normalizedPath), strtolower($normalizedRoot))
                    : str_starts_with($normalizedPath, $normalizedRoot);
                if (! $withinRoot) {
                    $result['invalid_reference']++;

                    continue;
                }
                $size = filesize($path);
                if ($size !== (int) $document->size || $size < 1 || $size > 2097152 || hash_file('sha256', $path) !== $document->sha256) {
                    $result['altered']++;
                }
            }
            // Lazy listing and an independent ceiling also bound unreferenced-file inspection.
            foreach ($disk->getDriver()->listContents('', true) as $entry) {
                if (! $entry->isFile()) {
                    continue;
                }
                if ($result['files_checked'] >= $limit) {
                    $limited = true;
                    break;
                }
                $result['files_checked']++;
                if (! DB::table('receipt_documents')->where('path', $entry->path())->exists()) {
                    $age = now()->getTimestamp() - $disk->lastModified($entry->path());
                    $result[$age >= 3600 ? 'unreferenced_older' : 'unreferenced_recent']++;
                }
            }
            $result['complete'] = ! $limited;
            foreach (['missing', 'invalid_reference', 'altered', 'unreferenced_recent', 'unreferenced_older'] as $reason) {
                if ($result[$reason] > 0) {
                    $result['reasons'][] = $reason;
                }
            }
            if ($limited) {
                $result['reasons'][] = 'limit_reached';
            }
            $result['ok'] = $result['reasons'] === [];

            return $result;
        });
    }
}