qt: format send review amounts with display unit

WalletQmlModelTransaction previously returned raw satoshi integers from
amount(), fee(), and total(), so the review page showed unformatted
numbers with no unit label.

Add display unit awareness to WalletQmlModelTransaction: a
setDisplayUnit() method stores the active unit and re-emits the
relevant changed signals, and a formatWithUnit() helper formats values
using QmlBitcoinUnits with the correct "sat"/"sats"/"₿" suffix.
WalletQmlModel cascades the display unit to the current transaction
both when the transaction is created and when the unit changes.

Also append the unit label to per-recipient amounts in MultipleSendReview.

Author: epicleafies

qml/models/walletqmlmodel.cpp

@@ -283,6 +283,7 @@ bool WalletQmlModel::prepareTransaction()
         m_current_transaction = new WalletQmlModelTransaction(m_send_recipients, this);
         m_current_transaction->setWtx(newTx);
         m_current_transaction->setTransactionFee(nFeeRequired);
+        m_current_transaction->setDisplayUnit(m_display_unit);
         Q_EMIT currentTransactionChanged();
         return true;
     } else {
@@ -386,6 +387,9 @@ void WalletQmlModel::setDisplayUnit(int unit)
         if (m_activity_list_model) {
             m_activity_list_model->setDisplayUnit(unit);
         }
+        if (m_current_transaction) {
+            m_current_transaction->setDisplayUnit(unit);
+        }
         Q_EMIT balanceChanged();
         Q_EMIT displayUnitChanged(unit);
     }

qml/models/walletqmlmodeltransaction.cpp

@@ -4,6 +4,7 @@
 
 #include <qml/models/walletqmlmodeltransaction.h>
 
+#include <qml/bitcoinunits.h>
 #include <qml/models/sendrecipient.h>
 #include <qml/models/sendrecipientslistmodel.h>
 
@@ -14,9 +15,19 @@ WalletQmlModelTransaction::WalletQmlModelTransaction(const SendRecipientsListMod
 {
 }
 
+QString WalletQmlModelTransaction::formatWithUnit(CAmount value, int display_unit)
+{
+    auto unit = (display_unit == 1) ? QmlBitcoinUnits::Unit::SAT : QmlBitcoinUnits::Unit::BTC;
+    QString num = QmlBitcoinUnits::format(unit, value, false, QmlBitcoinUnits::SeparatorStyle::STANDARD);
+    if (display_unit == 1) {
+        return num + " " + ((qAbs(value) == 1) ? QStringLiteral("sat") : QStringLiteral("sats"));
+    }
+    return num + " ₿";
+}
+
 QString WalletQmlModelTransaction::amount() const
 {
-    return QString::number(m_amount);
+    return formatWithUnit(m_amount, m_display_unit);
 }
 
 QString WalletQmlModelTransaction::address() const
@@ -26,19 +37,29 @@ QString WalletQmlModelTransaction::address() const
 
 QString WalletQmlModelTransaction::fee() const
 {
-    return QString::number(m_fee);
+    return formatWithUnit(m_fee, m_display_unit);
 }
 
 QString WalletQmlModelTransaction::total() const
 {
-    return QString::number(m_amount + m_fee);
+    return formatWithUnit(m_amount + m_fee, m_display_unit);
 }
 
 QString WalletQmlModelTransaction::label() const
 {
     return m_label;
 }
 
+void WalletQmlModelTransaction::setDisplayUnit(int unit)
+{
+    if (unit != m_display_unit) {
+        m_display_unit = unit;
+        Q_EMIT amountChanged();
+        Q_EMIT feeChanged();
+        Q_EMIT totalChanged();
+    }
+}
+
 CTransactionRef& WalletQmlModelTransaction::getWtx()
 {
     return m_wtx;

qml/models/walletqmlmodeltransaction.h

@@ -38,6 +38,8 @@ class WalletQmlModelTransaction : public QObject
 
     CAmount getTotalTransactionAmount() const;
 
+    void setDisplayUnit(int unit);
+
     void reassignAmounts(int nChangePosRet); // needed for the subtract-fee-from-amount feature
 
 Q_SIGNALS:
@@ -48,11 +50,14 @@ class WalletQmlModelTransaction : public QObject
     void totalChanged();
 
 private:
+    static QString formatWithUnit(CAmount value, int display_unit);
+
     QString m_address;
     CAmount m_amount;
     CAmount m_fee;
     QString m_label;
     CTransactionRef m_wtx;
+    int m_display_unit{0};
 };
 
 #endif // BITCOIN_QML_MODELS_WALLETQMLMODELTRANSACTION_H

qml/pages/wallet/MultipleSendReview.qml

@@ -82,7 +82,7 @@ Page {
 
                         CoreText {
                             Layout.alignment: Qt.AlignVCenter | Qt.AlignRight
-                            text: amount
+                            text: amount + (optionsModel.displayUnit === 1 ? " sats" : " ₿")
                             font.pixelSize: 18
                         }
                     }