/**
 * NFC tag writing.
 *
 * Two paths, one purpose — write ONLY the verify URL (the same pointer the QR
 * carries). A tag is passive and clonable, exactly like copying a QR; the trust
 * still comes from the signature on the relay.
 *
 *  • Native (Capacitor APK): the local `SkateSpotsNfc` Android plugin, registered
 *    by name — Web NFC isn't exposed in the WebView.
 *  • Web (Chrome on Android over HTTPS): Web NFC (`NDEFReader`).
 *
 * iOS can't write tags either way; reading works everywhere by tapping.
 */
import { Capacitor, registerPlugin } from '@capacitor/core';

interface NativeNfc {
  isSupported(): Promise<{ supported: boolean }>;
  writeUrl(options: { url: string }): Promise<void>;
  cancel(): Promise<void>;
}
const NativeNfc = registerPlugin<NativeNfc>('SkateSpotsNfc');

interface NdefWriter {
  write(message: { records: Array<{ recordType: string; data: string }> }): Promise<void>;
}
type NdefCtor = new () => NdefWriter;

function ndefCtor(): NdefCtor | undefined {
  if (typeof window === 'undefined') return undefined;
  return (window as unknown as { NDEFReader?: NdefCtor }).NDEFReader;
}

/** Whether we can attempt a write here. On native the plugin validates the adapter. */
export function isNfcSupported(): boolean {
  if (Capacitor.isNativePlatform()) return true;
  return !!ndefCtor();
}

/** Write a URL record to an NFC tag. Rejects if unsupported or the write fails. */
export async function writeNfcUrl(url: string): Promise<void> {
  if (Capacitor.isNativePlatform()) {
    await NativeNfc.writeUrl({ url });
    return;
  }
  const Ctor = ndefCtor();
  if (!Ctor) throw new Error('NFC writing is not supported on this device/browser.');
  const writer = new Ctor();
  await writer.write({ records: [{ recordType: 'url', data: url }] });
}