const PIPER_MODEL_ORIGIN = 'https://huggingface.co/diffusionstudio/piper-voices/resolve/main/';
const localPathPrefix = '/static/piper-wasm-v1/voices/';

export function localPiperModelUrl(requestedUrl, origin) {
  if (!requestedUrl.startsWith(PIPER_MODEL_ORIGIN)) return null;
  const relativePath = requestedUrl.slice(PIPER_MODEL_ORIGIN.length);
  if (!/^[\w./-]+$/.test(relativePath) || relativePath.split('/').includes('..')) return null;
  return new URL(`${localPathPrefix}${relativePath}`, origin).href;
}