<?php
/**
 * 回归：f_check nt.txt 畸形行跳过 + fp 索引合法
 */
$config_name = 'index';
$all_fp_url  = ['https://example.com/fp1'];
$num         = count($all_fp_url);
$now_url     = 0;
$lines       = ["index\n", "index||||||2\n"];

foreach ($lines as $buffer) {
    $bb = explode('||||||', $buffer);
    if (trim($bb[0] ?? '') !== $config_name) {
        continue;
    }
    if (!isset($bb[1]) || trim($bb[1]) === '') {
        continue;
    }
    $now_url = max(1, (int) trim($bb[1]));
    break;
}

if (!$now_url) {
    $now_url = 1;
}

$idx    = max(0, min(max(1, (int) $now_url) - 1, $num - 1));
$fp_url = $all_fp_url[$idx];

echo json_encode([
    'ok'      => $fp_url === 'https://example.com/fp1' && $idx === 0,
    'fp_url'  => $fp_url,
    'idx'     => $idx,
    'now_url' => $now_url,
], JSON_UNESCAPED_UNICODE) . "\n";