function getModels(int $limit = 10000): array {
    $cacheFile = __DIR__ . '/../cache/models.json';

    // 1) start with whatever we already have on disk (or an empty array)
    $existing = [];
    if (file_exists($cacheFile)) {
        $data     = json_decode(file_get_contents($cacheFile), true);
        $existing = $data['data']['models'] ?? [];
    }
    // re-index by uniqueModelId for easy merging
    $byId = [];
    foreach ($existing as $m) {
        if (!empty($m['uniqueModelId'])) {
            $byId[$m['uniqueModelId']] = $m;
        }
    }

    // 2) fetch each category feed and merge new models
    $categories = ['girl','lesbian','fetish','mature','hot_flirt','soul_mate'];
    foreach ($categories as $cat) {
        $url = 'https://ptcdw.com/api/model/feed'
             . '?siteId=261964'
             . "&category={$cat}"
             . "&limit={$limit}"
             . '&extendedDetails=1'
             . '&responseFormat=json'
             // … your other params …
             ;
        $json = @file_get_contents($url);
        if (! $json) continue;
        $feed = json_decode($json, true);
        if (! empty($feed['data']['models']) && is_array($feed['data']['models'])) {
            foreach ($feed['data']['models'] as $m) {
                if (! empty($m['uniqueModelId'])) {
                    // overwrite or insert
                    $byId[$m['uniqueModelId']] = $m;
                }
            }
        }
    }

    // 3) rebuild the indexed array
    $models = array_values($byId);

    // 4) regenerate slug & fullSlug on every run
    foreach ($models as &$m) {
        $base = strtolower(preg_replace('/[^a-z0-9]+/','-',$m['displayName']));
        $m['slug'] = trim($base,'-');
        $parts = [];
        if (!empty($m['persons'][0]['age'])) {
            $parts[] = intval($m['persons'][0]['age']) . 'y';
        }
        if (!empty($m['ethnicity'])) {
            $parts[] = strtolower($m['ethnicity']);
        }
        if (!empty($m['persons'][0]['body']['eyeColor'])) {
            $parts[] = strtolower($m['persons'][0]['body']['eyeColor']) . '-eyes';
        }
        $parts[] = 'live-cam';
        $suffix   = preg_replace('/[^a-z0-9]+/','-',implode('-',$parts));
        $m['fullSlug'] = trim(strtolower($suffix),'-');
    }
    unset($m);

    // 5) write back your merged cache
    file_put_contents($cacheFile,
        json_encode(['data'=>['models'=>$models]], JSON_PRETTY_PRINT)
    );

    return $models;
}