non lelantus firo sends

lib/pages/send_view/confirm_transaction_view.dart

@@ -9,6 +9,7 @@ import 'package:stackwallet/pages/wallet_view/wallet_view.dart';
 import 'package:stackwallet/providers/providers.dart';
 import 'package:stackwallet/route_generator.dart';
 import 'package:stackwallet/services/coins/epiccash/epiccash_wallet.dart';
+import 'package:stackwallet/services/coins/firo/firo_wallet.dart';
 import 'package:stackwallet/utilities/cfcolors.dart';
 import 'package:stackwallet/utilities/enums/coin_enum.dart';
 import 'package:stackwallet/utilities/enums/flush_bar_type.dart';
@@ -19,6 +20,8 @@ import 'package:stackwallet/widgets/rounded_container.dart';
 import 'package:stackwallet/widgets/rounded_white_container.dart';
 import 'package:stackwallet/widgets/stack_dialog.dart';
 
+import '../../providers/wallet/public_private_balance_state_provider.dart';
+
 class ConfirmTransactionView extends ConsumerStatefulWidget {
   const ConfirmTransactionView({
     Key? key,
@@ -56,10 +59,20 @@ class _ConfirmTransactionViewState
 
     final note = transactionInfo["note"] as String? ?? "";
     final manager =
-    ref.read(walletsChangeNotifierProvider).getManager(walletId);
+        ref.read(walletsChangeNotifierProvider).getManager(walletId);
 
     try {
-      final txid = await manager.confirmSend(txData: transactionInfo);
+      String txid;
+      final coin = manager.coin;
+      if ((coin == Coin.firo || coin == Coin.firoTestNet) &&
+          ref.read(publicPrivateBalanceStateProvider.state).state !=
+              "Private") {
+        txid = await (manager.wallet as FiroWallet)
+            .confirmSendPublic(txData: transactionInfo);
+      } else {
+        txid = await manager.confirmSend(txData: transactionInfo);
+      }
+
       unawaited(manager.refresh());
 
       // save note
@@ -79,7 +92,7 @@ class _ConfirmTransactionViewState
           showFloatingFlushBar(
             type: FlushBarType.warning,
             message:
-            "Connection failed. Please check the address and try again.",
+                "Connection failed. Please check the address and try again.",
             context: context,
           ),
         );
@@ -100,10 +113,10 @@ class _ConfirmTransactionViewState
             message: e.toString(),
             rightButton: TextButton(
               style: Theme.of(context).textButtonTheme.style?.copyWith(
-                backgroundColor: MaterialStateProperty.all<Color>(
-                  CFColors.buttonGray,
-                ),
-              ),
+                    backgroundColor: MaterialStateProperty.all<Color>(
+                      CFColors.buttonGray,
+                    ),
+                  ),
               child: Text(
                 "Ok",
                 style: STextStyles.button.copyWith(
@@ -212,9 +225,9 @@ class _ConfirmTransactionViewState
                                         .select((value) => value.locale),
                                   ),
                                 )} ${ref.watch(
-                                  managerProvider
-                                      .select((value) => value.coin),
-                                ).ticker}",
+                                      managerProvider
+                                          .select((value) => value.coin),
+                                    ).ticker}",
                                 style: STextStyles.itemSubtitle12,
                                 textAlign: TextAlign.right,
                               ),
@@ -240,9 +253,9 @@ class _ConfirmTransactionViewState
                                         .select((value) => value.locale),
                                   ),
                                 )} ${ref.watch(
-                                  managerProvider
-                                      .select((value) => value.coin),
-                                ).ticker}",
+                                      managerProvider
+                                          .select((value) => value.coin),
+                                    ).ticker}",
                                 style: STextStyles.itemSubtitle12,
                                 textAlign: TextAlign.right,
                               ),
@@ -292,9 +305,9 @@ class _ConfirmTransactionViewState
                                         .select((value) => value.locale),
                                   ),
                                 )} ${ref.watch(
-                                  managerProvider
-                                      .select((value) => value.coin),
-                                ).ticker}",
+                                      managerProvider
+                                          .select((value) => value.coin),
+                                    ).ticker}",
                                 style: STextStyles.itemSubtitle12,
                                 textAlign: TextAlign.right,
                               ),
@@ -306,18 +319,18 @@ class _ConfirmTransactionViewState
                         ),
                         TextButton(
                           style:
-                          Theme.of(context).textButtonTheme.style?.copyWith(
-                            backgroundColor:
-                            MaterialStateProperty.all<Color>(
-                              CFColors.stackAccent,
-                            ),
-                          ),
+                              Theme.of(context).textButtonTheme.style?.copyWith(
+                                    backgroundColor:
+                                        MaterialStateProperty.all<Color>(
+                                      CFColors.stackAccent,
+                                    ),
+                                  ),
                           onPressed: () async {
                             final unlocked = await Navigator.push(
                               context,
                               RouteGenerator.getRoute(
                                 shouldUseMaterialRoute:
-                                RouteGenerator.useMaterialPageRoute,
+                                    RouteGenerator.useMaterialPageRoute,
                                 builder: (_) => const LockscreenView(
                                   showBackButton: true,
                                   popOnSuccess: true,
@@ -325,9 +338,9 @@ class _ConfirmTransactionViewState
                                   routeOnSuccess: "",
                                   biometricsCancelButtonString: "CANCEL",
                                   biometricsLocalizedReason:
-                                  "Authenticate to send transaction",
+                                      "Authenticate to send transaction",
                                   biometricsAuthenticationTitle:
-                                  "Confirm Transaction",
+                                      "Confirm Transaction",
                                 ),
                                 settings: const RouteSettings(
                                     name: "/confirmsendlockscreen"),

lib/pages/send_view/send_view.dart

@@ -1333,9 +1333,28 @@ class _SendViewState extends ConsumerState<SendView> {
 
                                   final amount = Format.decimalAmountToSatoshis(
                                       _amountToSend!);
-                                  final availableBalance =
-                                      Format.decimalAmountToSatoshis(
-                                          await manager.availableBalance);
+                                  int availableBalance;
+                                  if ((coin == Coin.firo ||
+                                      coin == Coin.firoTestNet)
+                                      ) {
+                                    if (ref
+                                        .read(
+                                        publicPrivateBalanceStateProvider
+                                            .state)
+                                        .state ==
+                                        "Private") {
+                                      availableBalance = Format.decimalAmountToSatoshis(
+                                          await (manager.wallet as FiroWallet).availablePrivateBalance());
+                                    } else {
+                                      availableBalance = Format.decimalAmountToSatoshis(
+                                          await (manager.wallet as FiroWallet).availablePublicBalance());
+                                    }
+
+                                  } else {
+                                    availableBalance =
+                                        Format.decimalAmountToSatoshis(
+                                            await manager.availableBalance);
+                                  }
 
                                   // confirm send all
                                   if (amount == availableBalance) {
@@ -1419,14 +1438,36 @@ class _SendViewState extends ConsumerState<SendView> {
                                       },
                                     ));
 
-                                    final txData = await manager.prepareSend(
-                                      address: _address!,
-                                      satoshiAmount: amount,
-                                      args: {
-                                        "feeRate":
-                                            ref.read(feeRateTypeStateProvider)
-                                      },
-                                    );
+                                    Map<String, dynamic> txData;
+
+                                    if ((coin == Coin.firo ||
+                                            coin == Coin.firoTestNet) &&
+                                        ref
+                                                .read(
+                                                    publicPrivateBalanceStateProvider
+                                                        .state)
+                                                .state !=
+                                            "Private") {
+                                      txData =
+                                          await (manager.wallet as FiroWallet)
+                                              .prepareSendPublic(
+                                        address: _address!,
+                                        satoshiAmount: amount,
+                                        args: {
+                                          "feeRate":
+                                              ref.read(feeRateTypeStateProvider)
+                                        },
+                                      );
+                                    } else {
+                                      txData = await manager.prepareSend(
+                                        address: _address!,
+                                        satoshiAmount: amount,
+                                        args: {
+                                          "feeRate":
+                                              ref.read(feeRateTypeStateProvider)
+                                        },
+                                      );
+                                    }
 
                                     if (!wasCancelled && mounted) {
                                       // pop building dialog

lib/pages/wallet_view/sub_widgets/tx_icon.dart

@@ -10,7 +10,7 @@ class TxIcon extends StatelessWidget {
   static const Size size = Size(32, 32);
 
   String _getAssetName(bool isCancelled, bool isReceived, bool isPending) {
-    if (transaction.subType == "mint") {
+    if (!isReceived && transaction.subType == "mint") {
       if (isCancelled) {
         return Assets.svg.anonymizeFailed;
       }

lib/services/coins/firo/firo_wallet.dart

@@ -37,12 +37,14 @@ import 'package:stackwallet/utilities/assets.dart';
 import 'package:stackwallet/utilities/constants.dart';
 import 'package:stackwallet/utilities/default_nodes.dart';
 import 'package:stackwallet/utilities/enums/coin_enum.dart';
+import 'package:stackwallet/utilities/enums/fee_rate_type_enum.dart';
 import 'package:stackwallet/utilities/flutter_secure_storage_interface.dart';
 import 'package:stackwallet/utilities/format.dart';
 import 'package:stackwallet/utilities/logger.dart';
 import 'package:stackwallet/utilities/prefs.dart';
 import 'package:tuple/tuple.dart';
 
+const DUST_LIMIT = 1000;
 const MINIMUM_CONFIRMATIONS = 1;
 const MINT_LIMIT = 100100000000;
 const int LELANTUS_VALUE_SPEND_LIMIT_PER_TRANSACTION = 5001 * 100000000;
@@ -973,11 +975,117 @@ class FiroWallet extends CoinServiceAPI {
   @override
   bool get isConnected => _isConnected;
 
+  Future<Map<String, dynamic>> prepareSendPublic({
+    required String address,
+    required int satoshiAmount,
+    Map<String, dynamic>? args,
+  }) async {
+    try {
+      final feeRateType = args?["feeRate"];
+      final feeRateAmount = args?["feeRateAmount"];
+      if (feeRateType is FeeRateType || feeRateAmount is int) {
+        late final int rate;
+        if (feeRateType is FeeRateType) {
+          int fee = 0;
+          final feeObject = await fees;
+          switch (feeRateType) {
+            case FeeRateType.fast:
+              fee = feeObject.fast;
+              break;
+            case FeeRateType.average:
+              fee = feeObject.medium;
+              break;
+            case FeeRateType.slow:
+              fee = feeObject.slow;
+              break;
+          }
+          rate = fee;
+        } else {
+          rate = feeRateAmount as int;
+        }
+
+        // check for send all
+        bool isSendAll = false;
+        final balance =
+            Format.decimalAmountToSatoshis(await availablePublicBalance());
+        if (satoshiAmount == balance) {
+          isSendAll = true;
+        }
+
+        final txData =
+            await coinSelection(satoshiAmount, rate, address, isSendAll);
+
+        Logging.instance.log("prepare send: $txData", level: LogLevel.Info);
+        try {
+          if (txData is int) {
+            switch (txData) {
+              case 1:
+                throw Exception("Insufficient balance!");
+              case 2:
+                throw Exception(
+                    "Insufficient funds to pay for transaction fee!");
+              default:
+                throw Exception("Transaction failed with error code $txData");
+            }
+          } else {
+            final hex = txData["hex"];
+
+            if (hex is String) {
+              final fee = txData["fee"] as int;
+              final vSize = txData["vSize"] as int;
+
+              Logging.instance
+                  .log("prepared txHex: $hex", level: LogLevel.Info);
+              Logging.instance.log("prepared fee: $fee", level: LogLevel.Info);
+              Logging.instance
+                  .log("prepared vSize: $vSize", level: LogLevel.Info);
+
+              // fee should never be less than vSize sanity check
+              if (fee < vSize) {
+                throw Exception(
+                    "Error in fee calculation: Transaction fee cannot be less than vSize");
+              }
+
+              return txData as Map<String, dynamic>;
+            } else {
+              throw Exception("prepared hex is not a String!!!");
+            }
+          }
+        } catch (e, s) {
+          Logging.instance.log("Exception rethrown from prepareSend(): $e\n$s",
+              level: LogLevel.Error);
+          rethrow;
+        }
+      } else {
+        throw ArgumentError("Invalid fee rate argument provided!");
+      }
+    } catch (e, s) {
+      Logging.instance.log("Exception rethrown from prepareSend(): $e\n$s",
+          level: LogLevel.Error);
+      rethrow;
+    }
+  }
+
+  Future<String> confirmSendPublic({dynamic txData}) async {
+    try {
+      Logging.instance.log("confirmSend txData: $txData", level: LogLevel.Info);
+      final txHash = await _electrumXClient.broadcastTransaction(
+          rawTx: txData["hex"] as String);
+      Logging.instance.log("Sent txHash: $txHash", level: LogLevel.Info);
+      return txHash;
+    } catch (e, s) {
+      Logging.instance.log("Exception rethrown from confirmSend(): $e\n$s",
+          level: LogLevel.Error);
+      rethrow;
+    }
+  }
+
   @override
-  Future<Map<String, dynamic>> prepareSend(
-      {required String address,
-      required int satoshiAmount,
-      Map<String, dynamic>? args}) async {
+  Future<Map<String, dynamic>> prepareSend({
+    required String address,
+    required int satoshiAmount,
+    Map<String, dynamic>? args,
+  }) async {
     try {
       dynamic txHexOrError =
           await _createJoinSplitTransaction(satoshiAmount, address, false);
@@ -1129,6 +1237,531 @@ class FiroWallet extends CoinServiceAPI {
     isolates.clear();
   }
 
+  int estimateTxFee({required int vSize, required int feeRatePerKB}) {
+    return vSize * (feeRatePerKB / 1000).ceil();
+  }
+
+  /// The coinselection algorithm decides whether or not the user is eligible to make the transaction
+  /// with [satoshiAmountToSend] and [selectedTxFeeRate]. If so, it will call buildTrasaction() and return
+  /// a map containing the tx hex along with other important information. If not, then it will return
+  /// an integer (1 or 2)
+  dynamic coinSelection(
+    int satoshiAmountToSend,
+    int selectedTxFeeRate,
+    String _recipientAddress,
+    bool isSendAll, {
+    int additionalOutputs = 0,
+    List<UtxoObject>? utxos,
+  }) async {
+    Logging.instance
+        .log("Starting coinSelection ----------", level: LogLevel.Info);
+    final List<UtxoObject> availableOutputs = utxos ?? _outputsList;
+    final List<UtxoObject> spendableOutputs = [];
+    int spendableSatoshiValue = 0;
+
+    // Build list of spendable outputs and totaling their satoshi amount
+    for (var i = 0; i < availableOutputs.length; i++) {
+      if (availableOutputs[i].blocked == false &&
+          availableOutputs[i].status.confirmed == true) {
+        spendableOutputs.add(availableOutputs[i]);
+        spendableSatoshiValue += availableOutputs[i].value;
+      }
+    }
+
+    // sort spendable by age (oldest first)
+    spendableOutputs.sort(
+        (a, b) => b.status.confirmations.compareTo(a.status.confirmations));
+
+    Logging.instance.log("spendableOutputs.length: ${spendableOutputs.length}",
+        level: LogLevel.Info);
+    Logging.instance
+        .log("spendableOutputs: $spendableOutputs", level: LogLevel.Info);
+    Logging.instance.log("spendableSatoshiValue: $spendableSatoshiValue",
+        level: LogLevel.Info);
+    Logging.instance
+        .log("satoshiAmountToSend: $satoshiAmountToSend", level: LogLevel.Info);
+    // If the amount the user is trying to send is smaller than the amount that they have spendable,
+    // then return 1, which indicates that they have an insufficient balance.
+    if (spendableSatoshiValue < satoshiAmountToSend) {
+      return 1;
+      // If the amount the user wants to send is exactly equal to the amount they can spend, then return
+      // 2, which indicates that they are not leaving enough over to pay the transaction fee
+    } else if (spendableSatoshiValue == satoshiAmountToSend && !isSendAll) {
+      return 2;
+    }
+    // If neither of these statements pass, we assume that the user has a spendable balance greater
+    // than the amount they're attempting to send. Note that this value still does not account for
+    // the added transaction fee, which may require an extra input and will need to be checked for
+    // later on.
+
+    // Possible situation right here
+    int satoshisBeingUsed = 0;
+    int inputsBeingConsumed = 0;
+    List<UtxoObject> utxoObjectsToUse = [];
+
+    for (var i = 0;
+        satoshisBeingUsed < satoshiAmountToSend && i < spendableOutputs.length;
+        i++) {
+      utxoObjectsToUse.add(spendableOutputs[i]);
+      satoshisBeingUsed += spendableOutputs[i].value;
+      inputsBeingConsumed += 1;
+    }
+    for (int i = 0;
+        i < additionalOutputs && inputsBeingConsumed < spendableOutputs.length;
+        i++) {
+      utxoObjectsToUse.add(spendableOutputs[inputsBeingConsumed]);
+      satoshisBeingUsed += spendableOutputs[inputsBeingConsumed].value;
+      inputsBeingConsumed += 1;
+    }
+
+    Logging.instance
+        .log("satoshisBeingUsed: $satoshisBeingUsed", level: LogLevel.Info);
+    Logging.instance
+        .log("inputsBeingConsumed: $inputsBeingConsumed", level: LogLevel.Info);
+    Logging.instance
+        .log('utxoObjectsToUse: $utxoObjectsToUse', level: LogLevel.Info);
+
+    // numberOfOutputs' length must always be equal to that of recipientsArray and recipientsAmtArray
+    List<String> recipientsArray = [_recipientAddress];
+    List<int> recipientsAmtArray = [satoshiAmountToSend];
+
+    // gather required signing data
+    final utxoSigningData = await fetchBuildTxData(utxoObjectsToUse);
+
+    if (isSendAll) {
+      Logging.instance
+          .log("Attempting to send all $coin", level: LogLevel.Info);
+
+      final int vSizeForOneOutput = (await buildTransaction(
+        utxosToUse: utxoObjectsToUse,
+        utxoSigningData: utxoSigningData,
+        recipients: [_recipientAddress],
+        satoshiAmounts: [satoshisBeingUsed - 1],
+      ))["vSize"] as int;
+      int feeForOneOutput = estimateTxFee(
+        vSize: vSizeForOneOutput,
+        feeRatePerKB: selectedTxFeeRate,
+      );
+
+      if (feeForOneOutput < vSizeForOneOutput + 1) {
+        feeForOneOutput = vSizeForOneOutput + 1;
+      }
+
+      final int amount = satoshiAmountToSend - feeForOneOutput;
+      dynamic txn = await buildTransaction(
+        utxosToUse: utxoObjectsToUse,
+        utxoSigningData: utxoSigningData,
+        recipients: recipientsArray,
+        satoshiAmounts: [amount],
+      );
+      Map<String, dynamic> transactionObject = {
+        "hex": txn["hex"],
+        "recipient": recipientsArray[0],
+        "recipientAmt": amount,
+        "fee": feeForOneOutput,
+        "vSize": txn["vSize"],
+      };
+      return transactionObject;
+    }
+
+    final int vSizeForOneOutput = (await buildTransaction(
+      utxosToUse: utxoObjectsToUse,
+      utxoSigningData: utxoSigningData,
+      recipients: [_recipientAddress],
+      satoshiAmounts: [satoshisBeingUsed - 1],
+    ))["vSize"] as int;
+    final int vSizeForTwoOutPuts = (await buildTransaction(
+      utxosToUse: utxoObjectsToUse,
+      utxoSigningData: utxoSigningData,
+      recipients: [
+        _recipientAddress,
+        await _getCurrentAddressForChain(1),
+      ],
+      satoshiAmounts: [
+        satoshiAmountToSend,
+        satoshisBeingUsed - satoshiAmountToSend - 1,
+      ], // dust limit is the minimum amount a change output should be
+    ))["vSize"] as int;
+    debugPrint("vSizeForOneOutput $vSizeForOneOutput");
+    debugPrint("vSizeForTwoOutPuts $vSizeForTwoOutPuts");
+
+    // Assume 1 output, only for recipient and no change
+    var feeForOneOutput = estimateTxFee(
+      vSize: vSizeForOneOutput,
+      feeRatePerKB: selectedTxFeeRate,
+    );
+    // Assume 2 outputs, one for recipient and one for change
+    var feeForTwoOutputs = estimateTxFee(
+      vSize: vSizeForTwoOutPuts,
+      feeRatePerKB: selectedTxFeeRate,
+    );
+
+    Logging.instance
+        .log("feeForTwoOutputs: $feeForTwoOutputs", level: LogLevel.Info);
+    Logging.instance
+        .log("feeForOneOutput: $feeForOneOutput", level: LogLevel.Info);
+    if (feeForOneOutput < (vSizeForOneOutput + 1)) {
+      feeForOneOutput = (vSizeForOneOutput + 1);
+    }
+    if (feeForTwoOutputs < ((vSizeForTwoOutPuts + 1))) {
+      feeForTwoOutputs = ((vSizeForTwoOutPuts + 1));
+    }
+
+    Logging.instance
+        .log("feeForTwoOutputs: $feeForTwoOutputs", level: LogLevel.Info);
+    Logging.instance
+        .log("feeForOneOutput: $feeForOneOutput", level: LogLevel.Info);
+
+    if (satoshisBeingUsed - satoshiAmountToSend > feeForOneOutput) {
+      if (satoshisBeingUsed - satoshiAmountToSend >
+          feeForOneOutput + DUST_LIMIT) {
+        // Here, we know that theoretically, we may be able to include another output(change) but we first need to
+        // factor in the value of this output in satoshis.
+        int changeOutputSize =
+            satoshisBeingUsed - satoshiAmountToSend - feeForTwoOutputs;
+        // We check to see if the user can pay for the new transaction with 2 outputs instead of one. If they can and
+        // the second output's size > DUST_LIMIT satoshis, we perform the mechanics required to properly generate and use a new
+        // change address.
+        if (changeOutputSize > DUST_LIMIT &&
+            satoshisBeingUsed - satoshiAmountToSend - changeOutputSize ==
+                feeForTwoOutputs) {
+          // generate new change address if current change address has been used
+          await checkChangeAddressForTransactions();
+          final String newChangeAddress = await _getCurrentAddressForChain(1);
+
+          int feeBeingPaid =
+              satoshisBeingUsed - satoshiAmountToSend - changeOutputSize;
+
+          recipientsArray.add(newChangeAddress);
+          recipientsAmtArray.add(changeOutputSize);
+          // At this point, we have the outputs we're going to use, the amounts to send along with which addresses
+          // we intend to send these amounts to. We have enough to send instructions to build the transaction.
+          Logging.instance.log('2 outputs in tx', level: LogLevel.Info);
+          Logging.instance
+              .log('Input size: $satoshisBeingUsed', level: LogLevel.Info);
+          Logging.instance.log('Recipient output size: $satoshiAmountToSend',
+              level: LogLevel.Info);
+          Logging.instance.log('Change Output Size: $changeOutputSize',
+              level: LogLevel.Info);
+          Logging.instance.log(
+              'Difference (fee being paid): $feeBeingPaid sats',
+              level: LogLevel.Info);
+          Logging.instance
+              .log('Estimated fee: $feeForTwoOutputs', level: LogLevel.Info);
+          dynamic txn = await buildTransaction(
+            utxosToUse: utxoObjectsToUse,
+            utxoSigningData: utxoSigningData,
+            recipients: recipientsArray,
+            satoshiAmounts: recipientsAmtArray,
+          );
+
+          // make sure minimum fee is accurate if that is being used
+          if (txn["vSize"] - feeBeingPaid == 1) {
+            int changeOutputSize =
+                satoshisBeingUsed - satoshiAmountToSend - (txn["vSize"] as int);
+            feeBeingPaid =
+                satoshisBeingUsed - satoshiAmountToSend - changeOutputSize;
+            recipientsAmtArray.removeLast();
+            recipientsAmtArray.add(changeOutputSize);
+            Logging.instance.log('Adjusted Input size: $satoshisBeingUsed',
+                level: LogLevel.Info);
+            Logging.instance.log(
+                'Adjusted Recipient output size: $satoshiAmountToSend',
+                level: LogLevel.Info);
+            Logging.instance.log(
+                'Adjusted Change Output Size: $changeOutputSize',
+                level: LogLevel.Info);
+            Logging.instance.log(
+                'Adjusted Difference (fee being paid): $feeBeingPaid sats',
+                level: LogLevel.Info);
+            Logging.instance.log('Adjusted Estimated fee: $feeForTwoOutputs',
+                level: LogLevel.Info);
+            txn = await buildTransaction(
+              utxosToUse: utxoObjectsToUse,
+              utxoSigningData: utxoSigningData,
+              recipients: recipientsArray,
+              satoshiAmounts: recipientsAmtArray,
+            );
+          }
+
+          Map<String, dynamic> transactionObject = {
+            "hex": txn["hex"],
+            "recipient": recipientsArray[0],
+            "recipientAmt": recipientsAmtArray[0],
+            "fee": feeBeingPaid,
+            "vSize": txn["vSize"],
+          };
+          return transactionObject;
+        } else {
+          // Something went wrong here. It either overshot or undershot the estimated fee amount or the changeOutputSize
+          // is smaller than or equal to [DUST_LIMIT]. Revert to single output transaction.
+          Logging.instance.log('1 output in tx', level: LogLevel.Info);
+          Logging.instance
+              .log('Input size: $satoshisBeingUsed', level: LogLevel.Info);
+          Logging.instance.log('Recipient output size: $satoshiAmountToSend',
+              level: LogLevel.Info);
+          Logging.instance.log(
+              'Difference (fee being paid): ${satoshisBeingUsed - satoshiAmountToSend} sats',
+              level: LogLevel.Info);
+          Logging.instance
+              .log('Estimated fee: $feeForOneOutput', level: LogLevel.Info);
+          dynamic txn = await buildTransaction(
+            utxosToUse: utxoObjectsToUse,
+            utxoSigningData: utxoSigningData,
+            recipients: recipientsArray,
+            satoshiAmounts: recipientsAmtArray,
+          );
+          Map<String, dynamic> transactionObject = {
+            "hex": txn["hex"],
+            "recipient": recipientsArray[0],
+            "recipientAmt": recipientsAmtArray[0],
+            "fee": satoshisBeingUsed - satoshiAmountToSend,
+            "vSize": txn["vSize"],
+          };
+          return transactionObject;
+        }
+      } else {
+        // No additional outputs needed since adding one would mean that it'd be smaller than 546 sats
+        // which makes it uneconomical to add to the transaction. Here, we pass data directly to instruct
+        // the wallet to begin crafting the transaction that the user requested.
+        Logging.instance.log('1 output in tx', level: LogLevel.Info);
+        Logging.instance
+            .log('Input size: $satoshisBeingUsed', level: LogLevel.Info);
+        Logging.instance.log('Recipient output size: $satoshiAmountToSend',
+            level: LogLevel.Info);
+        Logging.instance.log(
+            'Difference (fee being paid): ${satoshisBeingUsed - satoshiAmountToSend} sats',
+            level: LogLevel.Info);
+        Logging.instance
+            .log('Estimated fee: $feeForOneOutput', level: LogLevel.Info);
+        dynamic txn = await buildTransaction(
+          utxosToUse: utxoObjectsToUse,
+          utxoSigningData: utxoSigningData,
+          recipients: recipientsArray,
+          satoshiAmounts: recipientsAmtArray,
+        );
+        Map<String, dynamic> transactionObject = {
+          "hex": txn["hex"],
+          "recipient": recipientsArray[0],
+          "recipientAmt": recipientsAmtArray[0],
+          "fee": satoshisBeingUsed - satoshiAmountToSend,
+          "vSize": txn["vSize"],
+        };
+        return transactionObject;
+      }
+    } else if (satoshisBeingUsed - satoshiAmountToSend == feeForOneOutput) {
+      // In this scenario, no additional change output is needed since inputs - outputs equal exactly
+      // what we need to pay for fees. Here, we pass data directly to instruct the wallet to begin
+      // crafting the transaction that the user requested.
+      Logging.instance.log('1 output in tx', level: LogLevel.Info);
+      Logging.instance
+          .log('Input size: $satoshisBeingUsed', level: LogLevel.Info);
+      Logging.instance.log('Recipient output size: $satoshiAmountToSend',
+          level: LogLevel.Info);
+      Logging.instance.log(
+          'Fee being paid: ${satoshisBeingUsed - satoshiAmountToSend} sats',
+          level: LogLevel.Info);
+      Logging.instance
+          .log('Estimated fee: $feeForOneOutput', level: LogLevel.Info);
+      dynamic txn = await buildTransaction(
+        utxosToUse: utxoObjectsToUse,
+        utxoSigningData: utxoSigningData,
+        recipients: recipientsArray,
+        satoshiAmounts: recipientsAmtArray,
+      );
+      Map<String, dynamic> transactionObject = {
+        "hex": txn["hex"],
+        "recipient": recipientsArray[0],
+        "recipientAmt": recipientsAmtArray[0],
+        "fee": feeForOneOutput,
+        "vSize": txn["vSize"],
+      };
+      return transactionObject;
+    } else {
+      // Remember that returning 2 indicates that the user does not have a sufficient balance to
+      // pay for the transaction fee. Ideally, at this stage, we should check if the user has any
+      // additional outputs they're able to spend and then recalculate fees.
+      Logging.instance.log(
+          'Cannot pay tx fee - checking for more outputs and trying again',
+          level: LogLevel.Warning);
+      // try adding more outputs
+      if (spendableOutputs.length > inputsBeingConsumed) {
+        return coinSelection(satoshiAmountToSend, selectedTxFeeRate,
+            _recipientAddress, isSendAll,
+            additionalOutputs: additionalOutputs + 1, utxos: utxos);
+      }
+      return 2;
+    }
+  }
+
+  Future<Map<String, dynamic>> fetchBuildTxData(
+    List<UtxoObject> utxosToUse,
+  ) async {
+    // return data
+    Map<String, dynamic> results = {};
+    Map<String, List<String>> addressTxid = {};
+
+    // addresses to check
+    List<String> addresses = [];
+
+    try {
+      // Populating the addresses to check
+      for (var i = 0; i < utxosToUse.length; i++) {
+        final txid = utxosToUse[i].txid;
+        final tx = await _cachedElectrumXClient.getTransaction(
+          txHash: txid,
+          coin: coin,
+        );
+
+        for (final output in tx["vout"] as List) {
+          final n = output["n"];
+          if (n != null && n == utxosToUse[i].vout) {
+            final address = output["scriptPubKey"]["addresses"][0] as String;
+
+            if (!addressTxid.containsKey(address)) {
+              addressTxid[address] = <String>[];
+            }
+            (addressTxid[address] as List).add(txid);
+
+            addresses.add(address);
+          }
+        }
+      }
+
+      // p2pkh / bip44
+      final addressesLength = addresses.length;
+      if (addressesLength > 0) {
+        final receiveDerivationsString =
+            await _secureStore.read(key: "${walletId}_receiveDerivations");
+        final receiveDerivations = Map<String, dynamic>.from(
+            jsonDecode(receiveDerivationsString ?? "{}") as Map);
+
+        final changeDerivationsString =
+            await _secureStore.read(key: "${walletId}_changeDerivations");
+        final changeDerivations = Map<String, dynamic>.from(
+            jsonDecode(changeDerivationsString ?? "{}") as Map);
+
+        for (int i = 0; i < addressesLength; i++) {
+          // receives
+
+          dynamic receiveDerivation;
+
+          for (int j = 0; j < receiveDerivations.length; j++) {
+            if (receiveDerivations["$j"]["address"] == addresses[i]) {
+              receiveDerivation = receiveDerivations["$j"];
+            }
+          }
+
+          // receiveDerivation = receiveDerivations[addresses[i]];
+          // if a match exists it will not be null
+          if (receiveDerivation != null) {
+            final data = P2PKH(
+              data: PaymentData(
+                  pubkey: Format.stringToUint8List(
+                      receiveDerivation["publicKey"] as String)),
+              network: _network,
+            ).data;
+
+            for (String tx in addressTxid[addresses[i]]!) {
+              results[tx] = {
+                "output": data.output,
+                "keyPair": ECPair.fromWIF(
+                  receiveDerivation["wif"] as String,
+                  network: _network,
+                ),
+              };
+            }
+          } else {
+            // if its not a receive, check change
+
+            dynamic changeDerivation;
+
+            for (int j = 0; j < changeDerivations.length; j++) {
+              if (changeDerivations["$j"]["address"] == addresses[i]) {
+                changeDerivation = changeDerivations["$j"];
+              }
+            }
+
+            // final changeDerivation = changeDerivations[addresses[i]];
+            // if a match exists it will not be null
+            if (changeDerivation != null) {
+              final data = P2PKH(
+                data: PaymentData(
+                    pubkey: Format.stringToUint8List(
+                        changeDerivation["publicKey"] as String)),
+                network: _network,
+              ).data;
+
+              for (String tx in addressTxid[addresses[i]]!) {
+                results[tx] = {
+                  "output": data.output,
+                  "keyPair": ECPair.fromWIF(
+                    changeDerivation["wif"] as String,
+                    network: _network,
+                  ),
+                };
+              }
+            }
+          }
+        }
+      }
+
+      return results;
+    } catch (e, s) {
+      Logging.instance
+          .log("fetchBuildTxData() threw: $e,\n$s", level: LogLevel.Error);
+      rethrow;
+    }
+  }
+
+  /// Builds and signs a transaction
+  Future<Map<String, dynamic>> buildTransaction({
+    required List<UtxoObject> utxosToUse,
+    required Map<String, dynamic> utxoSigningData,
+    required List<String> recipients,
+    required List<int> satoshiAmounts,
+  }) async {
+    Logging.instance
+        .log("Starting buildTransaction ----------", level: LogLevel.Info);
+
+    final txb = TransactionBuilder(network: _network);
+    txb.setVersion(1);
+
+    // Add transaction inputs
+    for (var i = 0; i < utxosToUse.length; i++) {
+      final txid = utxosToUse[i].txid;
+      txb.addInput(txid, utxosToUse[i].vout, null,
+          utxoSigningData[txid]["output"] as Uint8List);
+    }
+
+    // Add transaction output
+    for (var i = 0; i < recipients.length; i++) {
+      txb.addOutput(recipients[i], satoshiAmounts[i]);
+    }
+
+    try {
+      // Sign the transaction accordingly
+      for (var i = 0; i < utxosToUse.length; i++) {
+        final txid = utxosToUse[i].txid;
+        txb.sign(
+          vin: i,
+          keyPair: utxoSigningData[txid]["keyPair"] as ECPair,
+          witnessValue: utxosToUse[i].value,
+          redeemScript: utxoSigningData[txid]["redeemScript"] as Uint8List?,
+        );
+      }
+    } catch (e, s) {
+      Logging.instance.log("Caught exception while signing transaction: $e\n$s",
+          level: LogLevel.Error);
+      rethrow;
+    }
+
+    final builtTx = txb.build();
+    final vSize = builtTx.virtualSize();
+
+    return {"hex": builtTx.toHex(), "vSize": vSize};
+  }
+
   @override
   Future<void> updateNode(bool shouldRefresh) async {
     final failovers = NodeService()
@@ -2140,9 +2773,11 @@ class FiroWallet extends CoinServiceAPI {
           !listLelantusTxData.containsKey(value.txid)) {
         // Every receive should be listed whether minted or not.
         listLelantusTxData[value.txid] = value;
-      } else if (value.txType == "Sent" &&
-          hasAtLeastOneReceive &&
-          value.subType == "mint") {
+      } else if (value.txType == "Sent"
+          // &&
+          // hasAtLeastOneReceive &&
+          // value.subType == "mint"
+          ) {
         listLelantusTxData[value.txid] = value;
 
         // use mint sends to update receives with user readable values.
@@ -2402,12 +3037,45 @@ class FiroWallet extends CoinServiceAPI {
       }
     } on SocketException catch (se, s) {
       Logging.instance.log(
-          "SocketException caught in _checkReceivingAddressForTransactions(): $se\n$s",
+          "SocketException caught in checkReceivingAddressForTransactions(): $se\n$s",
           level: LogLevel.Error);
       return;
     } catch (e, s) {
       Logging.instance.log(
-          "Exception rethrown from _checkReceivingAddressForTransactions(): $e\n$s",
+          "Exception rethrown from checkReceivingAddressForTransactions(): $e\n$s",
+          level: LogLevel.Error);
+      rethrow;
+    }
+  }
+
+  Future<void> checkChangeAddressForTransactions() async {
+    try {
+      final String currentExternalAddr = await _getCurrentAddressForChain(1);
+      final int numtxs =
+          await _getReceivedTxCount(address: currentExternalAddr);
+      Logging.instance.log(
+          'Number of txs for current change address: $currentExternalAddr: $numtxs',
+          level: LogLevel.Info);
+
+      if (numtxs >= 1) {
+        await incrementAddressIndexForChain(
+            0); // First increment the change index
+        final newReceivingIndex =
+            DB.instance.get<dynamic>(boxName: walletId, key: 'changeIndex')
+                as int; // Check the new change index
+        final newReceivingAddress = await _generateAddressForChain(0,
+            newReceivingIndex); // Use new index to derive a new change address
+        await addToAddressesArrayForChain(newReceivingAddress,
+            0); // Add that new receiving address to the array of change addresses
+      }
+    } on SocketException catch (se, s) {
+      Logging.instance.log(
+          "SocketException caught in checkChangeAddressForTransactions(): $se\n$s",
+          level: LogLevel.Error);
+      return;
+    } catch (e, s) {
+      Logging.instance.log(
+          "Exception rethrown from checkChangeAddressForTransactions(): $e\n$s",
           level: LogLevel.Error);
       rethrow;
     }