<?php

namespace App\Services;

use Illuminate\Http\Request;

class CompressionService
{
    /**
     * Check compression capabilities of the client
     */
    public static function getClientCapabilities(Request $request): array
    {
        $acceptEncoding = $request->header('Accept-Encoding', '');
        
        return [
            'supports_gzip' => str_contains($acceptEncoding, 'gzip'),
            'supports_deflate' => str_contains($acceptEncoding, 'deflate'),
            'supports_brotli' => str_contains($acceptEncoding, 'br'),
            'raw_header' => $acceptEncoding,
        ];
    }

    /**
     * Get compression info for debugging
     */
    public static function getCompressionInfo(string $content): array
    {
        $originalSize = strlen($content);
        $info = ['original_size' => $originalSize];

        if (function_exists('gzencode')) {
            $gzipped = gzencode($content, 6);
            if ($gzipped !== false) {
                $gzippedSize = strlen($gzipped);
                $info['gzip'] = [
                    'compressed_size' => $gzippedSize,
                    'ratio' => round(($gzippedSize / $originalSize) * 100, 2) . '%',
                    'savings' => round((1 - $gzippedSize / $originalSize) * 100, 2) . '%'
                ];
            }
        }

        if (function_exists('gzdeflate')) {
            $deflated = gzdeflate($content, 6);
            if ($deflated !== false) {
                $deflatedSize = strlen($deflated);
                $info['deflate'] = [
                    'compressed_size' => $deflatedSize,
                    'ratio' => round(($deflatedSize / $originalSize) * 100, 2) . '%',
                    'savings' => round((1 - $deflatedSize / $originalSize) * 100, 2) . '%'
                ];
            }
        }

        if (function_exists('brotli_compress')) {
            $brotlied = brotli_compress($content, 6);
            if ($brotlied !== false) {
                $brotliedSize = strlen($brotlied);
                $info['brotli'] = [
                    'compressed_size' => $brotliedSize,
                    'ratio' => round(($brotliedSize / $originalSize) * 100, 2) . '%',
                    'savings' => round((1 - $brotliedSize / $originalSize) * 100, 2) . '%'
                ];
            }
        }

        return $info;
    }

    /**
     * Format bytes to human readable format
     */
    public static function formatBytes(int $bytes, int $precision = 2): string
    {
        $units = ['B', 'KB', 'MB', 'GB', 'TB'];
        
        for ($i = 0; $bytes > 1024 && $i < count($units) - 1; $i++) {
            $bytes /= 1024;
        }
        
        return round($bytes, $precision) . ' ' . $units[$i];
    }
}