feat(consolidation): Liquid UTXO consolidation with decoy outputs

integration_test/coins_test.dart

@@ -4,12 +4,11 @@ import 'package:bb_mobile/core/fees/domain/fees_entity.dart';
 import 'package:bb_mobile/core/seed/data/models/seed_model.dart';
 import 'package:bb_mobile/core/settings/domain/settings_entity.dart';
 import 'package:bb_mobile/core/storage/sqlite_database.dart';
-import 'package:bb_mobile/core/wallet/data/datasources/bdk_wallet_datasource.dart'
-    show NoSpendableUtxoException;
 import 'package:bb_mobile/core/wallet/data/datasources/frozen_wallet_utxo_datasource.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/wallet_repository.dart';
 import 'package:bb_mobile/core/wallet/domain/entities/wallet.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/wallet_address_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/wallet_build_tx_exceptions.dart';
 import 'package:bb_mobile/core/wallet/domain/repositories/wallet_utxo_repository.dart';
 import 'package:bb_mobile/core/wallet/domain/usecases/prepare_bitcoin_send_usecase.dart';
 import 'package:bb_mobile/features/settings/domain/usecases/set_environment_usecase.dart';

lib/core/swaps/domain/usecases/auto_swap_execution_usecase.dart

@@ -6,15 +6,21 @@ import 'package:bb_mobile/core/swaps/domain/entity/swap.dart';
 import 'package:bb_mobile/core/swaps/domain/ports/blockchain_port.dart';
 import 'package:bb_mobile/core/utils/constants.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/liquid_wallet_repository.dart';
+import 'package:bb_mobile/core/wallet/data/repositories/wallet_address_repository.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/wallet_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/entities/liquid_tx_output.dart';
 import 'package:bb_mobile/core/wallet/domain/repositories/wallet_transaction_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/repositories/wallet_utxo_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/wallet_build_tx_exceptions.dart';
 import 'package:bb_mobile/features/labels/labels_facade.dart';
 import 'package:bb_mobile/core/utils/logger.dart';
 
 class AutoSwapExecutionUsecase {
   final BoltzSwapRepository _repository;
   final WalletRepository _walletRepository;
   final LiquidWalletRepository _liquidWalletRepository;
+  final WalletUtxoRepository _walletUtxoRepository;
+  final WalletAddressRepository _walletAddressRepository;
   final BlockchainPort _blockchainPort;
   final WalletTransactionRepository _walletTxRepository;
   final LabelsFacade _labelsFacade;
@@ -23,6 +29,8 @@ class AutoSwapExecutionUsecase {
     required this._repository,
     required this._walletRepository,
     required this._liquidWalletRepository,
+    required this._walletUtxoRepository,
+    required this._walletAddressRepository,
     required this._blockchainPort,
     required this._walletTxRepository,
     required this._labelsFacade,
@@ -130,10 +138,44 @@ class AutoSwapExecutionUsecase {
     );
 
     log.fine('Building PSET...');
-    final pset = await _liquidWalletRepository.buildPset(
+    // Built via buildCustomTx (an explicit UTXO list), not buildPset (LWK's
+    // own coin selection, which is known to add every L-BTC UTXO regardless
+    // of amount — see PrepareLiquidSendUsecase) — this is a background,
+    // unattended payment, so a frozen UTXO (e.g. a consolidation decoy,
+    // which must never be re-spent) must never be able to slip in here
+    // either, same as an ordinary user-initiated send.
+    final confirmed = await _liquidWalletRepository.getConfirmedLbtcOutpoints(
       walletId: defaultLiquidWallet.id,
-      address: swap.paymentAddress,
-      amountSat: swap.paymentAmount,
+    );
+    final frozen = (await _walletUtxoRepository.getAllFrozenOutpoints())
+        .toSet();
+    final usable = confirmed.where((o) => !frozen.contains(o)).toList();
+
+    if (usable.isEmpty) {
+      throw NoSpendableUtxoException(
+        'Wallet ${defaultLiquidWallet.id} has no spendable (confirmed, '
+        'unfrozen) L-BTC UTXOs',
+      );
+    }
+    if (_liquidWalletRepository.exceedsLiquidInputLimit(usable.length)) {
+      throw LiquidInputLimitExceededException(
+        'Wallet ${defaultLiquidWallet.id} exceeds the Liquid confidential-tx '
+        'input limit',
+      );
+    }
+
+    final changeAddress = await _walletAddressRepository
+        .generateNewReceiveAddress(walletId: defaultLiquidWallet.id);
+    final pset = await _liquidWalletRepository.buildCustomTx(
+      walletId: defaultLiquidWallet.id,
+      utxos: usable,
+      outputs: [
+        LiquidTxOutput(
+          address: swap.paymentAddress,
+          satoshi: swap.paymentAmount,
+        ),
+      ],
+      drainToAddress: changeAddress.address,
       // 0.1 sat/vByte = 25 sat/kwu — Liquid's network minrelayfee default.
       feeRate: const RelativeFee(25),
     );

lib/core/swaps/swaps_locator.dart

@@ -34,8 +34,10 @@ import 'package:bb_mobile/core/swaps/interface_adapters/blockchain_adapter.dart'
 import 'package:bb_mobile/core/utils/constants.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/liquid_wallet_repository.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/wallet_address_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/repositories/wallet_utxo_repository.dart';
 import 'package:bb_mobile/core/wallet/data/repositories/wallet_repository.dart';
 import 'package:bb_mobile/core/wallet/domain/repositories/wallet_transaction_repository.dart';
+import 'package:bb_mobile/core/wallet/domain/repositories/wallet_utxo_repository.dart';
 import 'package:bb_mobile/features/labels/labels_facade.dart';
 import 'package:get_it/get_it.dart';
 
@@ -240,6 +242,8 @@ class SwapsLocator {
         ),
         walletRepository: locator<WalletRepository>(),
         liquidWalletRepository: locator<LiquidWalletRepository>(),
+        walletUtxoRepository: locator<WalletUtxoRepository>(),
+        walletAddressRepository: locator<WalletAddressRepository>(),
         blockchainPort: locator<BlockchainPort>(),
         walletTxRepository: locator<WalletTransactionRepository>(),
         labelsFacade: locator<LabelsFacade>(),

lib/core/wallet/data/datasources/bdk_wallet_datasource.dart

@@ -15,6 +15,7 @@ import 'package:bb_mobile/core/wallet/data/models/wallet_transaction_model.dart'
 import 'package:bb_mobile/core/wallet/data/models/wallet_utxo_model.dart';
 import 'package:bb_mobile/core/electrum/domain/value_objects/electrum_connection.dart';
 import 'package:bb_mobile/core/wallet/domain/entities/wallet.dart';
+import 'package:bb_mobile/core/wallet/domain/wallet_build_tx_exceptions.dart';
 import 'package:bull_sdk/bdk.dart' as bdk;
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
@@ -826,10 +827,6 @@ class UnsupportedBdkNetworkException extends BullException {
   UnsupportedBdkNetworkException(super.message);
 }
 
-class NoSpendableUtxoException extends BullException {
-  NoSpendableUtxoException(super.message);
-}
-
 /// Confirmation count for an output confirmed at [height], given the current
 /// chain [tip]. A `null` height (unconfirmed) returns 0; the result is clamped
 /// to 0 to guard a reorg / mid-sync window where `tip < height` (D2).

lib/core/wallet/data/datasources/liquid_receive_address_index_datasource.dart

@@ -0,0 +1,63 @@
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// Persists, per Liquid wallet, the highest receive-address index this app
+/// has ever handed out to the UI — independent of LWK's own sync state.
+///
+/// LWK's "last unused address" is derived purely from what the wallet has
+/// synced as used; two receive requests issued before an intervening sync
+/// would otherwise return the identical address (there's no LWK-side
+/// reservation mechanism, unlike BDK's persisted, sync-independent
+/// reveal-index — see `BdkWalletDatasource.getNewAddress` /
+/// `BdkFacade.saveWallet`). This datasource is that missing reservation for
+/// Liquid, so the same class of address reuse can't happen there either.
+class LiquidReceiveAddressIndexDatasource {
+  static String _key(String walletId) =>
+      'liquid_last_receive_address_index_$walletId';
+
+  // Per-wallet async mutex: each call for a given walletId waits for the
+  // previous one (for that same wallet) to finish before reading, so a
+  // concurrent reservation race can't have two callers read the same
+  // "current" value before either writes back. Different wallets never
+  // block each other.
+  final Map<String, Future<void>> _locks = {};
+
+  /// The persisted index, or null if nothing has ever been reserved for
+  /// this wallet yet.
+  Future<int?> read(String walletId) async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.getInt(_key(walletId));
+  }
+
+  /// Atomically reserves and persists a new "last issued" index for
+  /// [walletId]: `max(persisted, atLeast) + 1`. [atLeast] should be LWK's
+  /// own sync-derived next-unused index, so a wallet restored on a new
+  /// device (where the local persisted counter starts at 0) still advances
+  /// correctly. Concurrent calls for the same wallet are serialized, so
+  /// each one is guaranteed a distinct reserved index.
+  Future<int> reserveNext(String walletId, {required int atLeast}) {
+    final previous = _locks[walletId] ?? Future.value();
+    final chained = previous.then((_) async {
+      final prefs = await SharedPreferences.getInstance();
+      final current = prefs.getInt(_key(walletId)) ?? 0;
+      final next = (current > atLeast ? current : atLeast) + 1;
+      await prefs.setInt(_key(walletId), next);
+      return next;
+    });
+    // Release the lock once this reservation settles, whatever the outcome,
+    // so a failure here can't deadlock every later call for this wallet.
+    _locks[walletId] = chained.then((_) {}, onError: (_) {});
+    return chained;
+  }
+
+  /// Self-heals the persisted index up to [atLeast] without reserving a new
+  /// one — used when the address actually returned to the UI (after any
+  /// system-label skip-forward) ended up higher than what's currently
+  /// persisted, so the next reservation still starts from the right place.
+  Future<void> ensureAtLeast(String walletId, int atLeast) async {
+    final prefs = await SharedPreferences.getInstance();
+    final current = prefs.getInt(_key(walletId)) ?? 0;
+    if (atLeast > current) {
+      await prefs.setInt(_key(walletId), atLeast);
+    }
+  }
+}