<?php

if (!defined('ABSPATH')) {
    exit;
}

// phpcs:disable WordPress.WP.AlternativeFunctions -- Backups stream multi-gigabyte files with seek/append/resume, which WP_Filesystem does not support. All paths are inside the plugin's protected backup folder or files being backed up.

/**
 * Append-only plain-text log for one backup job.
 */
final class SWPB_Log
{
    private string $path;

    public function __construct(string $path)
    {
        $this->path = $path;
    }

    public function path(): string
    {
        return $this->path;
    }

    public function line(string $message): void
    {
        $stamp = gmdate('Y-m-d H:i:s');
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- streaming log file inside the protected backup folder.
        @file_put_contents($this->path, '[' . $stamp . ' UTC] ' . $message . "\n", FILE_APPEND | LOCK_EX);
    }

    public function tail(int $lines = 200): string
    {
        if (!is_readable($this->path)) {
            return '';
        }
        $size = (int)filesize($this->path);
        $handle = fopen($this->path, 'rb');
        if (!$handle) {
            return '';
        }
        $read = min($size, 64 * 1024);
        fseek($handle, -$read, SEEK_END);
        $data = (string)fread($handle, $read);
        fclose($handle);
        $rows = explode("\n", rtrim($data, "\n"));
        return implode("\n", array_slice($rows, -$lines));
    }
}