/** The extensions the backend's parser knows; anything else is refused here
 *  rather than read as "pasted text" with a nonsense title. */
const PLAYLIST_EXT = /\.(m3u8?|pls|xspf|csv|json|txt)$/i;
/** The playlist-FILE door picks FIRST, like the folder door — the phone's
 *  own document picker (the storage plugin's `pick_file`). Every type is
 *  offered on purpose: Android's providers report m3u and pls under half a
 *  dozen types and often as plain bytes, so a filter that names one greys
 *  out the very file being looked for; the extension is checked here
 *  instead. A document with no path on this phone is copied into the app's
 *  cache under its own name, up to the size the parser itself refuses.
 *  Returns { path, name } — or null when the picker was dismissed. */
export async function pickImportFile() {
    let picked;
    try { picked = await api.pickFile("*/*", 8 * 1024 * 1024); }
    catch (e) { if (/cancelled/.test(String(e))) return null; throw e; }
    if (!picked?.path) throw new Error("That file isn't on this phone's storage — copy it here first, then import it.");
    const name = picked.name || "";
    if (!PLAYLIST_EXT.test(name)) throw new Error("“" + (name || "That file") + "” isn't a playlist file — M3U, M3U8, PLS, XSPF, CSV, JSON or TXT.");
    return { path: picked.path, name };
}