cake_wallet/lib/reactions/on_current_fiat_change.dart

import 'package:cake_wallet/entities/fiat_api_mode.dart';
import 'package:cake_wallet/entities/transaction_description.dart';
import 'package:hive/hive.dart';
import 'package:mobx/mobx.dart';
import 'package:cake_wallet/core/fiat_conversion_service.dart';
import 'package:cake_wallet/store/dashboard/fiat_conversion_store.dart';
import 'package:cake_wallet/store/settings_store.dart';
import 'package:cake_wallet/store/app_store.dart';
import 'package:cake_wallet/entities/fiat_currency.dart';

import 'fiat_historical_rate_update.dart';

ReactionDisposer? _onCurrentFiatCurrencyChangeDisposer;

void startCurrentFiatChangeReaction(AppStore appStore, SettingsStore settingsStore,
    FiatConversionStore fiatConversionStore, Box<TransactionDescription> transactionDescription) {
  _onCurrentFiatCurrencyChangeDisposer?.reaction.dispose();
  _onCurrentFiatCurrencyChangeDisposer =
      reaction((_) => settingsStore.fiatCurrency, (FiatCurrency fiatCurrency) async {
    if (appStore.wallet == null || settingsStore.fiatApiMode == FiatApiMode.disabled) {
      return;
    }


    final cryptoCurrency = appStore.wallet!.currency;
    fiatConversionStore.prices[cryptoCurrency] = await FiatConversionService.fetchPrice(
        crypto: cryptoCurrency,
        fiat: fiatCurrency,
        torOnly: settingsStore.fiatApiMode == FiatApiMode.torOnly);

    if (settingsStore.showHistoricalFiatAmount) {
      await historicalRateUpdate(
          appStore.wallet!, settingsStore, fiatConversionStore, transactionDescription);
    }


      });
}