import '../security/secret_store.dart';

/// A suggested community server the user can join with one tap.
class RelayPreset {
  const RelayPreset(this.name, this.url);
  final String name;
  final String url;
}

/// User choices for the (Block 2) social layer: the coarse area to publish/
/// browse offers in, and which community relays to talk to. Backed by the OS
/// keystore (via [SecretStore]) to honour "no plaintext at rest" — no
/// shared_preferences.
///
/// Relays default to a small set of well-known public servers so the market
/// works out of the box; the exposure is minimal (offers are opt-in and carry
/// only a coarse geohash) and the user can swap them for a community server.
/// The area stays unset until the user picks one (it's inherently personal).
class SocialSettings {
  SocialSettings(this._store);

  final SecretStore _store;

  static const _areaKey = 'tane.social.area_geohash';
  static const _relaysKey = 'tane.social.relays';

  /// Suggested servers shown as one-tap options in the sharing setup.
  static const List<RelayPreset> presets = [
    RelayPreset('nos.lol', 'wss://nos.lol'),
    RelayPreset('Damus', 'wss://relay.damus.io'),
    RelayPreset('Primal', 'wss://relay.primal.net'),
  ];

  /// Applied automatically for new users (a subset of [presets]) so sharing
  /// works from the first launch, until the user changes it.
  static const List<String> defaultRelays = ['wss://nos.lol', 'wss://relay.damus.io'];

  /// The user's coarse area as a low-precision geohash (may be empty). Set
  /// manually or from device location; the transport coarsens it further.
  Future<String> areaGeohash() async => (await _store.read(_areaKey)) ?? '';

  Future<void> setAreaGeohash(String geohash) =>
      _store.write(_areaKey, geohash.trim().toLowerCase());

  /// The relays to talk to. When the user has never configured any, falls back
  /// to [defaultRelays]. Once they save a choice (even an empty one), that wins
  /// — so a privacy-minded user can turn the network off entirely.
  Future<List<String>> relayUrls() async {
    final raw = await _store.read(_relaysKey);
    if (raw == null) return const [...defaultRelays]; // never configured
    return raw.split('\n').where((s) => s.trim().isNotEmpty).toList();
  }

  Future<void> setRelayUrls(List<String> urls) => _store.write(
        _relaysKey,
        urls.map((u) => u.trim()).where((u) => u.isNotEmpty).join('\n'),
      );

  /// Whether the social layer has enough config to attempt going online.
  Future<bool> get isConfigured async =>
      (await relayUrls()).isNotEmpty && (await areaGeohash()).isNotEmpty;
}