smooth-app/packages/smooth_app/lib/background/background_task_offline.dart

import 'package:flutter/material.dart';
import 'package:openfoodfacts/openfoodfacts.dart';
import 'package:provider/provider.dart';
import 'package:smooth_app/background/background_task.dart';
import 'package:smooth_app/background/background_task_progressing.dart';
import 'package:smooth_app/background/background_task_queue.dart';
import 'package:smooth_app/background/background_task_top_barcodes.dart';
import 'package:smooth_app/background/operation_type.dart';
import 'package:smooth_app/background/work_type.dart';
import 'package:smooth_app/database/dao_work_barcode.dart';
import 'package:smooth_app/database/local_database.dart';
import 'package:smooth_app/l10n/app_localizations.dart';

/// Main background task about pre-downloading top n products for offline usage.
class BackgroundTaskOffline extends BackgroundTaskProgressing {
  BackgroundTaskOffline._({
    required super.processName,
    required super.uniqueId,
    required super.stamp,
    required super.work,
    required super.pageSize,
    required super.totalSize,
    required super.productType,
  });

  BackgroundTaskOffline.fromJson(super.json) : super.fromJson();

  static const OperationType _operationType = OperationType.offline;

  static Future<void> addTask({
    required final BuildContext context,
    required final int pageSize,
    required final int totalSize,
    required final ProductType productType,
  }) async {
    final LocalDatabase localDatabase = context.read<LocalDatabase>();
    final String uniqueId = await _operationType.getNewKey(
      localDatabase,
      totalSize: totalSize,
      soFarSize: 0,
    );
    final BackgroundTask task = _getNewTask(
      uniqueId,
      WorkType.offline.getWorkTag(productType),
      pageSize,
      totalSize,
      productType,
    );
    if (!context.mounted) {
      return;
    }
    await task.addToManager(
      localDatabase,
      context: context,
      queue: BackgroundTaskQueue.longHaul,
    );
  }

  @override
  (String, AlignmentGeometry)? getFloatingMessage(
    final AppLocalizations appLocalizations,
  ) => (
    appLocalizations.background_task_title_top_n,
    AlignmentDirectional.bottomCenter,
  );

  static BackgroundTaskOffline _getNewTask(
    final String uniqueId,
    final String work,
    final int pageSize,
    final int totalSize,
    final ProductType productType,
  ) => BackgroundTaskOffline._(
    processName: _operationType.processName,
    uniqueId: uniqueId,
    stamp: ';offline',
    work: work,
    pageSize: pageSize,
    totalSize: totalSize,
    productType: productType,
  );

  @override
  Future<void> preExecute(final LocalDatabase localDatabase) async {}

  @override
  bool get hasImmediateNextTask => true;

  @override
  Future<void> execute(final LocalDatabase localDatabase) async {
    final DaoWorkBarcode daoWorkBarcode = DaoWorkBarcode(localDatabase);
    await daoWorkBarcode.deleteWork(work);
    await BackgroundTaskTopBarcodes.addTask(
      localDatabase: localDatabase,
      work: work,
      pageSize: pageSize,
      totalSize: totalSize,
      soFarSize: 0,
      productType: productType,
    );
  }
}