vb_book/app/Controllers/LogViewer.php

<?php

namespace App\Controllers;

class LogViewer extends BaseController
{
    protected $logsPath;

    public function __construct()
    {
        $this->logsPath = WRITEPATH . 'logs/';
    }

    public function index()
    {
        $files = [];

        if (is_dir($this->logsPath)) {
            $items = scandir($this->logsPath);

            foreach ($items as $item) {
                if ($item === '.' || $item === '..') {
                    continue;
                }

                $fullPath = $this->logsPath . $item;

                if (is_file($fullPath)) {
                    $files[] = [
                        'name'     => $item,
                        'size'     => $this->formatSize(filesize($fullPath)),
                        'modified' => date('Y-m-d H:i:s', filemtime($fullPath)),
                    ];
                }
            }
        }

        usort($files, function ($a, $b) {
            return strcmp($b['modified'], $a['modified']);
        });

        $showPayment = $this->request->getGet('payment') === '1';
        $entries     = [];
        $lineCount   = 0;

        if ($showPayment) {
            foreach ($files as $file) {
                $fullPath = $this->logsPath . $file['name'];
                $lines    = $this->extractPaymentLogLines($fullPath);

                if (!empty($lines)) {
                    $entries[] = [
                        'file'  => $file['name'],
                        'lines' => $lines,
                    ];
                    $lineCount += count($lines);
                }
            }
        }

        $data['files']        = $files;
        $data['showPayment']  = $showPayment;
        $data['entries']      = $entries;
        $data['lineCount']    = $lineCount;
        $data['page_name']    = $showPayment ? 'Payment Logs' : 'Log Files';

        $this->render_page('logviewer/index', $data);
    }

    public function view($filename = null)
    {
        $filename = $this->sanitizeFilename($filename);

        if (!$filename) {
            return redirect()->to('/logs')->with('error', 'Invalid file name.');
        }

        $fullPath = $this->logsPath . $filename;

        if (!is_file($fullPath)) {
            return redirect()->to('/logs')->with('error', 'File not found.');
        }

        $showPayment = $this->request->getGet('payment') === '1';
        $content     = file_get_contents($fullPath);

        if ($showPayment) {
            $lines = $this->extractPaymentLogLines($fullPath);
            $content = !empty($lines) ? implode("\n", $lines) : '';
        }

        $data['filename']    = $filename;
        $data['content']     = $content;
        $data['showPayment'] = $showPayment;
        $data['page_name']   = $showPayment ? 'Payment Logs' : 'View Log';

        $this->render_page('logviewer/view', $data);
    }

    public function download($filename = null)
    {
        $filename = $this->sanitizeFilename($filename);

        if (!$filename) {
            return redirect()->to('/logs')->with('error', 'Invalid file name.');
        }

        $fullPath = $this->logsPath . $filename;

        if (!is_file($fullPath)) {
            return redirect()->to('/logs')->with('error', 'File not found.');
        }

        return $this->response->download($fullPath, null);
    }

    private function extractPaymentLogLines(string $fullPath): array
    {
        if (!is_readable($fullPath)) {
            return [];
        }

        $lines   = [];
        $handle  = fopen($fullPath, 'r');

        if ($handle === false) {
            return [];
        }

        while (($line = fgets($handle)) !== false) {
            if (strpos($line, '[PAYMENT]') !== false) {
                $lines[] = rtrim($line, "\r\n");
            }
        }

        fclose($handle);

        return $lines;
    }

    private function sanitizeFilename($filename)
    {
        if (!$filename) {
            return false;
        }

        $filename = basename($filename);

        if (!preg_match('/^[A-Za-z0-9_\-\.]+\.(log|php|txt|html)$/', $filename)) {
            return false;
        }

        return $filename;
    }

    private function formatSize($bytes)
    {
        if ($bytes >= 1073741824) {
            return number_format($bytes / 1073741824, 2) . ' GB';
        } elseif ($bytes >= 1048576) {
            return number_format($bytes / 1048576, 2) . ' MB';
        } elseif ($bytes >= 1024) {
            return number_format($bytes / 1024, 2) . ' KB';
        }
        return $bytes . ' bytes';
    }
}