import '../entities/shift_report.dart';
import '../entities/sync_event.dart';
import '../entities/transaction.dart';

/// Result of one end-of-day upload.
class SyncOutcome {
  const SyncOutcome({
    required this.attempted,
    required this.uploaded,
    this.error,
  });

  final int attempted;
  final int uploaded;
  final String? error;

  bool get isSuccess => error == null;
  bool get hadNothingToDo => attempted == 0;
  int get remaining => attempted - uploaded;
}

/// One row of the order sync log.
class OrderSyncRow {
  const OrderSyncRow({
    required this.orderId,
    required this.invoiceNumber,
    required this.total,
    required this.createdAt,
    required this.isSynced,
    this.syncedAt,
    this.attempts = 0,
    this.error,
  });

  final String orderId;
  final String invoiceNumber;
  final double total;
  final DateTime createdAt;
  final bool isSynced;
  final DateTime? syncedAt;
  final int attempts;
  final String? error;
}

/// The terminal's two network touchpoints.
///
/// Morning: pull the catalogue. End of day: upload every order still at
/// `sync_status = 0`. Nothing else leaves the device.
abstract class SyncRepository {
  bool get hasCatalogue;
  DateTime? get lastImportAt;
  String? get catalogueRevision;

  /// Morning step — downloads products and writes them to SQLite.
  Future<SyncEvent> importCatalogue({
    void Function(double progress, String stage)? onProgress,
  });

  /// How many bills are still held locally.
  Future<int> unsyncedCount();

  Future<List<SaleTransaction>> unsyncedOrders();

  /// Today's trading totals, read back from SQLite.
  ///
  /// Terminal-wide by default. Set [scopeToCashier] to cover only the bills
  /// [cashierName] rang — what a till is actually settled against.
  Future<ShiftReport> todayReport({
    required String terminalId,
    required String cashierName,
    bool scopeToCashier = false,
  });

  /// End-of-day step — uploads pending orders and flips the accepted ones to
  /// `sync_status = 1`. Failures leave every row untouched at 0.
  Future<SyncOutcome> syncOrders({
    void Function(double progress, String stage)? onProgress,
  });

  Future<List<OrderSyncRow>> orderSyncRows({int limit = 200});

  List<SyncEvent> get events;
}