<?php

declare(strict_types=1);

namespace App\Services;

use Illuminate\Support\Facades\Cache;
use Throwable;

class DiskSpaceMonitor
{
    private const CACHE_KEY = 'disk_space_monitor.status';

    /**
     * @return array{warning: bool, free_bytes: int|null, threshold_bytes: int, path: string, checked_at: string|null}
     */
    public function status(): array
    {
        try {
            return Cache::remember(
                self::CACHE_KEY,
                now()->addSeconds($this->cacheSeconds()),
                fn (): array => $this->freshStatus()
            );
        } catch (Throwable) {
            return $this->freshStatus();
        }
    }

    public function formatBytes(?int $bytes): string
    {
        if ($bytes === null) {
            return 'неизвестно';
        }

        $units = ['Б', 'КБ', 'МБ', 'ГБ', 'ТБ'];
        $value = (float) $bytes;
        $unitIndex = 0;

        while ($value >= 1024 && $unitIndex < count($units) - 1) {
            $value /= 1024;
            $unitIndex++;
        }

        return sprintf('%s %s', round($value, $unitIndex === 0 ? 0 : 2), $units[$unitIndex]);
    }

    /**
     * @return array{warning: bool, free_bytes: int|null, threshold_bytes: int, path: string, checked_at: string|null}
     */
    private function freshStatus(): array
    {
        $path = $this->path();
        $thresholdBytes = $this->thresholdBytes();
        $freeBytes = @disk_free_space($path);
        $freeBytes = $freeBytes === false ? null : (int) $freeBytes;

        return [
            'warning' => $freeBytes !== null && $freeBytes < $thresholdBytes,
            'free_bytes' => $freeBytes,
            'threshold_bytes' => $thresholdBytes,
            'path' => $path,
            'checked_at' => now()->toDateTimeString(),
        ];
    }

    private function path(): string
    {
        return (string) config('app.disk_space_warning.path', storage_path());
    }

    private function thresholdBytes(): int
    {
        return max(0, (int) config('app.disk_space_warning.threshold_bytes', 1024 * 1024 * 1024));
    }

    private function cacheSeconds(): int
    {
        return max(1, (int) config('app.disk_space_warning.cache_seconds', 300));
    }
}