import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import '../../core/data/backend.dart';
import 'galaxy_data.dart';
import '../../core/i18n/app_locale.dart';

/// HOME과 Galaxy의 동일한 기여 거래: 연타 합산, 확정 결과, 동일 키 재확인.
class ZapController extends ChangeNotifier {
  ZapController(this.repository, {required this.onFailure});
  final GalaxyRepository repository;
  final ValueChanged<String> onFailure;
  int? balance;
  int pending = 0;
  bool sending = false;
  int touchSerial = 0;
  ZapResult? result;
  Timer? _burst;
  bool _disposed = false;
  ({String fandomId, int count, String key})? _batch;
  bool get needsRetry => _batch != null && !sending;

  void tap(String fandomId) {
    if (_disposed || sending || _batch != null || fandomId.isEmpty) return;
    if (pending == 0) HapticFeedback.lightImpact();
    pending++;
    touchSerial++;
    notifyListeners();
    _burst ??= Timer(const Duration(milliseconds: 450), () => _flush(fandomId));
  }

  void retry() {
    if (_batch case final batch?) _flush(batch.fandomId);
  }

  Future<void> _flush(String fandomId) async {
    if (_disposed || sending) return;
    final batch =
        _batch ??
        (
          fandomId: fandomId,
          count: pending,
          key: 'z${DateTime.now().microsecondsSinceEpoch}',
        );
    if (batch.count == 0) return;
    _burst?.cancel();
    _burst = null;
    _batch = batch;
    sending = true;
    pending = 0;
    notifyListeners();
    try {
      final receipt = await repository.zap(
        fandomId: batch.fandomId,
        count: batch.count,
        clientSeq: batch.key,
      );
      if (_disposed) return;
      if (receipt.txId.isEmpty) throw StateError('Missing ZAP receipt');
      if (receipt.balanceAfter >= 0) balance = receipt.balanceAfter;
      result = receipt;
      _batch = null;
    } catch (error) {
      if (_disposed) return;
      onFailure(switch (error) {
        BackendException(code: 'E-POP-01') => appL10n.zapFailNoPop,
        BackendException(code: 'E-POP-02') => appL10n.zapFailLedger,
        BackendException(code: 'E-AUTH-03') => appL10n.authLoginRequired,
        _ => appL10n.zapFailRetry,
      });
    } finally {
      if (!_disposed) {
        sending = false;
        notifyListeners();
      }
    }
  }

  @override
  void dispose() {
    _disposed = true;
    _burst?.cancel();
    super.dispose();
  }
}