From b0f2235c98529f579fdae122b4ffe4c5129900e8 Mon Sep 17 00:00:00 2001
From: Ademar Alves de Oliveira <ademar111190@gmail.com>
Date: Wed, 23 Aug 2023 10:37:47 -0300
Subject: [PATCH] Plug prepare withdraw method

---
 lib/bloc/withdraw/withdraw_funds_bloc.dart    | 34 ++++++++++++-------
 .../withdraw_funds_confirmation_page.dart     |  8 +++--
 2 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/lib/bloc/withdraw/withdraw_funds_bloc.dart b/lib/bloc/withdraw/withdraw_funds_bloc.dart
index 66bf1e2ff..1f3f91fd3 100644
--- a/lib/bloc/withdraw/withdraw_funds_bloc.dart
+++ b/lib/bloc/withdraw/withdraw_funds_bloc.dart
@@ -23,12 +23,16 @@ class WithdrawFundsBloc extends Cubit<WithdrawFundsState> {
   }) async {
     _log.v("Sweep to address $toAddress using $feeRateSatsPerVbyte fee vByte");
     await _breezLib.sweep(
-      toAddress: toAddress,
-      feeRateSatsPerVbyte: feeRateSatsPerVbyte,
+      req: SweepRequest(
+        toAddress: toAddress,
+        fee: SweepFee_Perkw(
+          satPerKw: feeRateSatsPerVbyte,
+        ),
+      ),
     );
   }
 
-  Future<List<FeeOption>> fetchFeeOptions() async {
+  Future<List<FeeOption>> fetchFeeOptions(String address) async {
     RecommendedFees recommendedFees;
     try {
       recommendedFees = await _breezLib.recommendedFees();
@@ -36,8 +40,7 @@ class WithdrawFundsBloc extends Cubit<WithdrawFundsState> {
         "fetchFeeOptions recommendedFees:\nfastestFee: ${recommendedFees.fastestFee},"
         "\nhalfHourFee: ${recommendedFees.halfHourFee},\nhourFee: ${recommendedFees.hourFee}.",
       );
-      final utxos = await _retrieveUTXOS();
-      return _constructFeeOptionList(utxos, recommendedFees);
+      return await _constructFeeOptionList(address, recommendedFees);
     } catch (e) {
       _log.e("fetchFeeOptions error", ex: e);
       emit(WithdrawFundsState(errorMessage: extractExceptionMessage(e, getSystemAppLocalizations())));
@@ -56,24 +59,27 @@ class WithdrawFundsBloc extends Cubit<WithdrawFundsState> {
     return utxos;
   }
 
-  List<FeeOption> _constructFeeOptionList(int utxos, RecommendedFees recommendedFees) {
+  Future<List<FeeOption>> _constructFeeOptionList(
+    String address,
+    RecommendedFees recommendedFees,
+  ) async {
     final List<FeeOption> feeOptions = [
       FeeOption(
         processingSpeed: ProcessingSpeed.economy,
         waitingTime: const Duration(minutes: 60),
-        fee: _calculateTransactionFee(utxos, recommendedFees.hourFee),
+        fee: await _calculateTransactionFee(address, recommendedFees.hourFee),
         feeVByte: recommendedFees.hourFee,
       ),
       FeeOption(
         processingSpeed: ProcessingSpeed.regular,
         waitingTime: const Duration(minutes: 30),
-        fee: _calculateTransactionFee(utxos, recommendedFees.halfHourFee),
+        fee: await _calculateTransactionFee(address, recommendedFees.halfHourFee),
         feeVByte: recommendedFees.halfHourFee,
       ),
       FeeOption(
         processingSpeed: ProcessingSpeed.priority,
         waitingTime: const Duration(minutes: 10),
-        fee: _calculateTransactionFee(utxos, recommendedFees.fastestFee),
+        fee: await _calculateTransactionFee(address, recommendedFees.fastestFee),
         feeVByte: recommendedFees.fastestFee,
       ),
     ];
@@ -81,9 +87,11 @@ class WithdrawFundsBloc extends Cubit<WithdrawFundsState> {
     return feeOptions;
   }
 
-  int _calculateTransactionFee(int inputs, int feeRateSatsPerVbyte) {
-    // based on https://bitcoin.stackexchange.com/a/3011
-    final transactionSize = (inputs * 148) + (2 * 34) + 10;
-    return transactionSize * feeRateSatsPerVbyte;
+  Future<int> _calculateTransactionFee(String address, int feeRateSatsPerVbyte) async {
+    final response = await _breezLib.prepareWithdraw(
+      address: address,
+      feeRateSatsPerVbyte: feeRateSatsPerVbyte,
+    );
+    return response.feeSat;
   }
 }
diff --git a/lib/routes/withdraw_funds/confirmation_page/withdraw_funds_confirmation_page.dart b/lib/routes/withdraw_funds/confirmation_page/withdraw_funds_confirmation_page.dart
index 90625301d..51d932abd 100644
--- a/lib/routes/withdraw_funds/confirmation_page/withdraw_funds_confirmation_page.dart
+++ b/lib/routes/withdraw_funds/confirmation_page/withdraw_funds_confirmation_page.dart
@@ -31,7 +31,7 @@ class _WithdrawFundsConfirmationPageState extends State<WithdrawFundsConfirmatio
   @override
   void initState() {
     super.initState();
-    _fetchFeeOptionsFuture = context.read<WithdrawFundsBloc>().fetchFeeOptions();
+    _fetchFeeOptionsFuture = context.read<WithdrawFundsBloc>().fetchFeeOptions(widget.toAddress);
     _fetchFeeOptionsFuture.then((feeOptions) {
       setState(() {
         affordableFees = feeOptions.where((f) => f.isAffordable(widget.amount)).toList();
@@ -57,7 +57,11 @@ class _WithdrawFundsConfirmationPageState extends State<WithdrawFundsConfirmatio
             );
           }
           if (snapshot.connectionState != ConnectionState.done) {
-            return const Center(child: Loader());
+            return const Center(
+              child: Loader(
+                color: Colors.white,
+              ),
+            );
           }
 
           if (affordableFees.isNotEmpty) {