token wallet info cache refactor from hive to isar

lib/db/isar/main_db.dart

@@ -22,6 +22,7 @@ import 'package:stackwallet/utilities/amount/amount.dart';
 import 'package:stackwallet/utilities/enums/coin_enum.dart';
 import 'package:stackwallet/utilities/stack_file_system.dart';
 import 'package:stackwallet/wallets/isar/models/spark_coin.dart';
+import 'package:stackwallet/wallets/isar/models/token_wallet_info.dart';
 import 'package:stackwallet/wallets/isar/models/wallet_info.dart';
 import 'package:stackwallet/wallets/isar/models/wallet_info_meta.dart';
 import 'package:tuple/tuple.dart';
@@ -65,6 +66,7 @@ class MainDB {
         TransactionV2Schema,
         SparkCoinSchema,
         WalletInfoMetaSchema,
+        TokenWalletInfoSchema,
       ],
       directory: (await StackFileSystem.applicationIsarDirectory()).path,
       // inspector: kDebugMode,

lib/wallets/isar/models/token_wallet_info.dart

@@ -0,0 +1,93 @@
+import 'package:isar/isar.dart';
+import 'package:stackwallet/models/balance.dart';
+import 'package:stackwallet/models/isar/models/isar_models.dart';
+import 'package:stackwallet/utilities/amount/amount.dart';
+import 'package:stackwallet/wallets/isar/isar_id_interface.dart';
+
+part 'token_wallet_info.g.dart';
+
+@Collection(accessor: "tokenWalletInfo", inheritance: false)
+class TokenWalletInfo implements IsarId {
+  @override
+  Id id = Isar.autoIncrement;
+
+  @Index(
+    unique: true,
+    replace: false,
+    composite: [
+      CompositeIndex("tokenAddress"),
+    ],
+  )
+  final String walletId;
+
+  final String tokenAddress;
+
+  final int tokenFractionDigits;
+
+  final String? cachedBalanceJsonString;
+
+  TokenWalletInfo({
+    required this.walletId,
+    required this.tokenAddress,
+    required this.tokenFractionDigits,
+    this.cachedBalanceJsonString,
+  });
+
+  EthContract getContract(Isar isar) =>
+      isar.ethContracts.where().addressEqualTo(tokenAddress).findFirstSync()!;
+
+  // token balance cache
+  Balance getCachedBalance() {
+    if (cachedBalanceJsonString == null) {
+      return Balance(
+        total: Amount.zeroWith(
+          fractionDigits: tokenFractionDigits,
+        ),
+        spendable: Amount.zeroWith(
+          fractionDigits: tokenFractionDigits,
+        ),
+        blockedTotal: Amount.zeroWith(
+          fractionDigits: tokenFractionDigits,
+        ),
+        pendingSpendable: Amount.zeroWith(
+          fractionDigits: tokenFractionDigits,
+        ),
+      );
+    }
+    return Balance.fromJson(
+      cachedBalanceJsonString!,
+      tokenFractionDigits,
+    );
+  }
+
+  Future<void> updateCachedBalance(
+    Balance balance, {
+    required Isar isar,
+  }) async {
+    // // ensure we are updating using the latest entry of this in the db
+    final thisEntry = await isar.tokenWalletInfo
+        .where()
+        .walletIdEqualToTokenAddressNotEqualTo(walletId, tokenAddress)
+        .findFirst();
+    if (thisEntry == null) {
+      throw Exception(
+        "Attempted to update cached token balance before object was saved in db",
+      );
+    } else {
+      await isar.writeTxn(() async {
+        await isar.tokenWalletInfo.deleteByWalletIdTokenAddress(
+          walletId,
+          tokenAddress,
+        );
+        await isar.tokenWalletInfo.put(
+          TokenWalletInfo(
+            walletId: walletId,
+            tokenAddress: tokenAddress,
+            tokenFractionDigits: tokenFractionDigits,
+            cachedBalanceJsonString: balance.toJsonIgnoreCoin(),
+          ),
+        );
+      });
+    }
+  }
+}