<?php

declare(strict_types=1);

namespace MageSail\Magesail\Controller\Adminhtml\Tunnel;

use Magento\Backend\App\Action;
use Magento\Backend\App\Action\Context;
use Magento\Framework\Controller\ResultFactory;
use MageSail\Magesail\Model\TunnelStatus;

class Logtail extends Action
{
    private const BYTES = 8192;
    private const LINES = 40;

    public function __construct(
        Context $context,
        private readonly TunnelStatus $tunnelStatus
    ) {
        parent::__construct($context);
    }

    public function execute()
    {
        $tunnelId = trim((string) $this->getRequest()->getParam('tunnel_id', ''));
        if ($tunnelId === '') {
            $json = $this->resultFactory->create(ResultFactory::TYPE_JSON);
            $json->setData(['lines' => [], 'error' => 'missing_tunnel_id']);
            return $json;
        }
        $path = $this->tunnelStatus->getLogFilePath($tunnelId);
        $lines = [];
        if (\is_readable($path)) {
            $size = filesize($path);
            if ($size !== false && $size > 0) {
                $fp = fopen($path, 'rb');
                if ($fp) {
                    $start = max(0, $size - self::BYTES);
                    fseek($fp, $start);
                    if ($start > 0) {
                        fgets($fp);
                    }
                    $chunk = stream_get_contents($fp) ?: '';
                    fclose($fp);
                    $lines = preg_split('/\R/', $chunk) ?: [];
                    $lines = array_values(array_filter($lines, static fn ($l) => $l !== ''));
                    if (\count($lines) > self::LINES) {
                        $lines = \array_slice($lines, -self::LINES);
                    }
                }
            }
        }
        $json = $this->resultFactory->create(ResultFactory::TYPE_JSON);
        $json->setData(['lines' => $lines]);
        return $json;
    }

    protected function _isAllowed()
    {
        return $this->_authorization->isAllowed('MageSail_Magesail::tunnel')
            || $this->_authorization->isAllowed('MageSail_Magesail::tunnel_view')
            || $this->_authorization->isAllowed('MageSail_Magesail::tunnel_manage');
    }
}