WIP wallet state management improvements

lib/providers/wallet_provider.dart

@@ -0,0 +1,60 @@
+import 'package:equatable/equatable.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:stackwallet/providers/db/main_db_provider.dart';
+import 'package:stackwallet/providers/global/secure_store_provider.dart';
+import 'package:stackwallet/services/coins/ethereum/ethereum_wallet.dart';
+import 'package:stackwallet/services/coins/manager.dart';
+import 'package:stackwallet/services/ethereum/ethereum_token_service.dart';
+import 'package:stackwallet/services/transaction_notification_tracker.dart';
+import 'package:stackwallet/utilities/logger.dart';
+
+class ContractWalletId implements Equatable {
+  final String walletId;
+  final String tokenContractAddress;
+
+  ContractWalletId({
+    required this.walletId,
+    required this.tokenContractAddress,
+  });
+
+  @override
+  List<Object?> get props => [walletId, tokenContractAddress];
+
+  @override
+  bool? get stringify => true;
+}
+
+/// provide the wallet for a given wallet id
+final walletProvider =
+    ChangeNotifierProvider.family<Manager?, String>((ref, arg) => null);
+
+/// provide the token wallet given a contract address and eth wallet id
+final tokenWalletProvider =
+    ChangeNotifierProvider.family<EthTokenWallet?, ContractWalletId>(
+        (ref, arg) {
+  final ethWallet =
+      ref.watch(walletProvider(arg.walletId).select((value) => value?.wallet))
+          as EthereumWallet?;
+  final contract =
+      ref.read(mainDBProvider).getEthContractSync(arg.tokenContractAddress);
+
+  if (ethWallet == null || contract == null) {
+    Logging.instance.log(
+      "Attempted to access a token wallet with walletId=${arg.walletId} where"
+      " contractAddress=${arg.tokenContractAddress}",
+      level: LogLevel.Warning,
+    );
+    return null;
+  }
+
+  final secureStore = ref.watch(secureStoreProvider);
+
+  return EthTokenWallet(
+    token: contract,
+    ethWallet: ethWallet,
+    secureStore: secureStore,
+    tracker: TransactionNotificationTracker(
+      walletId: arg.walletId,
+    ),
+  );
+});