<?php namespace App\Services;

use Carbon\Carbon;
use Illuminate\Support\Arr;
use SplFileObject;

class LogsService
{
    private array $sources = [
        'repuve' => 'logs/repuve-nacional.log',
        'padron-estatal' => 'logs/padron-estatal.log',
    ];

    public function readRepuve(array $filters): array
    {
        return $this->read('repuve', $filters);
    }

    public function readPadronEstatal(array $filters): array
    {
        return $this->read('padron-estatal', $filters);
    }

    private function read(string $source, array $filters): array
    {
        $path = storage_path($this->sources[$source]);

        if (!is_file($path) || !is_readable($path)) {
            return [];
        }

        $entries = $this->parseFile($path);
        
        return $this->applyFilters($entries, $filters);
    }

    private function parseFile(string $path): array
    {
        $file = new SplFileObject($path, 'r');
        $entries = [];
        $current = null;

        while (!$file->eof()) {
            $line = rtrim((string) $file->fgets(), "\r\n");
            if ($line === '') {
                continue;
            }

            $header = $this->parseHeader($line);

            if ($header) {
                if ($current) {
                    $entries[] = $this->sanitize($current);
                }
                $current = $header;
                continue;
            }

            if ($current) {
                $current['message'] .= "\n" . $line;
            }
        }

        if ($current) {
            $entries[] = $this->sanitize($current);
        }

        usort($entries, fn($a, $b) => strcmp($b['timestamp'], $a['timestamp']));

        return $entries;
    }

    private function parseHeader(string $line): ?array
    {
        $pattern = '/^\[(?<dt>[^\]]+)\]\s[^\.\s]+\.(?<level>[A-Z]+):\s(?<message>.*)$/';

        if (!preg_match($pattern, $line, $m)) {
            return null;
        }

        try {
            $date = Carbon::parse($m['dt']);
        } catch (\Throwable $e) {
            return null;
        }

        return [
            'timestamp' => $date->toDateTimeString(),
            'level' => strtolower($m['level']),
            'message' => $m['message'],
        ];
    }

    private function applyFilters(array $entries, array $filters): array
    {
        $start = !empty($filters['start_date']) ? Carbon::parse($filters['start_date'])->startOfDay() : null;
        $end = !empty($filters['end_date']) ? Carbon::parse($filters['end_date'])->endOfDay() : null;
        $level = $filters['level'] ?? null;

        return array_values(array_filter($entries, function (array $entry) use ($start, $end, $level) {
            $dt = Carbon::parse($entry['timestamp']);

            if ($start && $dt->lt($start)) {
                return false;
            }

            if ($end && $dt->gt($end)) {
                return false;
            }

            if ($level && $entry['level'] !== strtolower($level)) {
                return false;
            }

            return true;
        }));
    }

    private function sanitize(array $entry): array
    {
        $text = $entry['message'];

        $patterns = [
            '/("password"\s*:\s*")[^"]*(")/i' => '$1***$2',
            '/("token"\s*:\s*")[^"]*(")/i' => '$1***$2',
            '/(authorization)\s*[:=]\s*([^,\s]+)/i' => '$1=***',
            '/(<arg0>)(.*?)(<\/arg0>)/i' => '$1***$3',
            '/(<arg1>)(.*?)(<\/arg1>)/i' => '$1***$3',
        ];

        foreach ($patterns as $pattern => $replacement) {
            $text = preg_replace($pattern, $replacement, $text);
        }

        $entry['message'] = $text;

        return $entry;
    }
}