From 5d500d0b2494f83930a8a06f1455767482faf507 Mon Sep 17 00:00:00 2001
From: joshuakrueger-dfx <joshua@dfxai.local>
Date: Thu, 4 Jun 2026 09:11:35 +0200
Subject: [PATCH] fix(sell): re-quote via the sell price endpoint on currency
 change
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onCurrencyChanged called getBuyPrice and rendered totalCost as the sell
"You receive" amount — a buy-side quote on the Sell screen, inconsistent with
onSharesChanged (which quotes via getSellPrice/estimatedAmount). Switch to the
sell endpoint so the displayed amount matches what the user actually receives.

The previous unit test pinned the getBuyPrice call as "likely on purpose"; that
assumption was wrong (it contradicts the sell-conversion path) and is rewritten
to assert the sell endpoint.

Regression: test/screens/sell/cubits/sell_converter_cubit_test.dart

Issue #657 — Part 4, finding S1 (HIGH).
---
 .../sell_converter/sell_converter_cubit.dart  |  8 ++++--
 .../cubits/sell_converter_cubit_test.dart     | 28 +++++++++++++------
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart b/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
index 93660b47..4cd89c90 100644
--- a/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
+++ b/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
@@ -87,11 +87,15 @@ class SellConverterCubit extends Cubit<SellConverterState> {
     // the seq guard.
     emit(state.copyWith(loading: true, currency: currency));
     try {
-      final result = await _brokerbotService.getBuyPrice(state.sharesText, currency);
+      // Sell flow: a currency switch must re-quote via the SELL price endpoint
+      // (estimatedAmount = what the user receives), mirroring _convertShares.
+      // It previously called getBuyPrice/totalCost, showing a buy-side quote
+      // as the "You receive" amount (issue #657 P4 S1).
+      final result = await _brokerbotService.getSellPrice(state.sharesText, currency);
       if (isClosed || mySeq != _seq) return;
       emit(
         state.copyWith(
-          fiatText: result.totalCost.toStringAsFixed(_fractionDigits(state.sharesText)),
+          fiatText: result.estimatedAmount.toStringAsFixed(_fractionDigits(state.sharesText)),
           loading: false,
         ),
       );
diff --git a/test/screens/sell/cubits/sell_converter_cubit_test.dart b/test/screens/sell/cubits/sell_converter_cubit_test.dart
index 15ac9c0f..68c64b3a 100644
--- a/test/screens/sell/cubits/sell_converter_cubit_test.dart
+++ b/test/screens/sell/cubits/sell_converter_cubit_test.dart
@@ -157,10 +157,12 @@ void main() {
       expect(cubit.state.fiatText, '125.50');
     });
 
-    test('onCurrencyChanged calls getBuyPrice (not getSellPrice) with current shares', () async {
-      // Note: the cubit uses BUY price for currency switch (likely on purpose
-      // to convert the displayed share count to a fiat estimate without the
-      // sell-side fee deduction). This test pins that contract.
+    test(
+        'onCurrencyChanged re-quotes via the SELL price endpoint '
+        '(issue #657 P4 S1 regression — used to call getBuyPrice)', () async {
+      // The previous behaviour called getBuyPrice/totalCost on a currency
+      // switch, rendering a buy-side quote as the sell "You receive" amount —
+      // inconsistent with onSharesChanged, which quotes via getSellPrice.
       when(() => service.getBuyPrice(any(), any())).thenAnswer(
         (_) async => BrokerbotBuyPriceDto(
           totalCost: 50.0,
@@ -182,16 +184,26 @@ void main() {
       await cubit.onSharesChanged('10');
       await Future<void>.delayed(const Duration(milliseconds: 250));
 
+      when(() => service.getSellPrice(any(), any())).thenAnswer(
+        (_) async => BrokerbotSellPriceDto(
+          shares: 10,
+          estimatedAmount: 95.5,
+          pricePerShare: 9.55,
+          currency: 'EUR',
+        ),
+      );
       await cubit.onCurrencyChanged(Currency.eur);
 
       expect(cubit.state.currency, Currency.eur);
-      expect(cubit.state.fiatText, '50.00');
-      verify(() => service.getBuyPrice('10', Currency.eur)).called(1);
+      // Sell-side estimate, NOT the buy-side totalCost (50.00).
+      expect(cubit.state.fiatText, '95.50');
+      verify(() => service.getSellPrice('10', Currency.eur)).called(1);
+      verifyNever(() => service.getBuyPrice(any(), any()));
     });
 
-    test('onCurrencyChanged flips currency even when getBuyPrice throws', () async {
+    test('onCurrencyChanged flips currency even when the sell quote throws', () async {
       when(
-        () => service.getBuyPrice(any(), any()),
+        () => service.getSellPrice(any(), any()),
       ).thenAnswer((_) async => throw Exception('throttle'));
 
       final cubit = SellConverterCubit(service);