From b5fafb55c9ba3e3e1c8122b066202784f1339691 Mon Sep 17 00:00:00 2001
From: xiphon <xiphon@protonmail.com>
Date: Wed, 22 Jan 2020 16:32:19 +0000
Subject: [PATCH] Transfer: display estimated transaction fee, requires #6302

---
 js/Utils.js                |  4 +++
 pages/Transfer.qml         | 59 ++++++++++++++++++++++++++++++++++----
 src/libwalletqt/Wallet.cpp | 13 +++++++++
 src/libwalletqt/Wallet.h   |  5 ++++
 4 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/js/Utils.js b/js/Utils.js
index f32f80a9..51395dce 100644
--- a/js/Utils.js
+++ b/js/Utils.js
@@ -133,3 +133,7 @@ function capitalize(s){
     if (typeof s !== 'string') return ''
     return s.charAt(0).toUpperCase() + s.slice(1)
 }
+
+function removeTrailingZeros(value) {
+    return (value + '').replace(/(\.\d*[1-9])0+$/, '$1');
+}
diff --git a/pages/Transfer.qml b/pages/Transfer.qml
index 21d44ed9..bdda4019 100644
--- a/pages/Transfer.qml
+++ b/pages/Transfer.qml
@@ -27,6 +27,7 @@
 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import QtQuick 2.9
+import QtQuick.Controls 1.4
 import QtQuick.Layouts 1.1
 import QtQuick.Dialogs 1.2
 import moneroComponents.Clipboard 1.0
@@ -38,6 +39,7 @@ import "../components"
 import "../components" as MoneroComponents
 import "." 1.0
 import "../js/TxUtils.js" as TxUtils
+import "../js/Utils.js" as Utils
 
 
 Rectangle {
@@ -155,7 +157,7 @@ Rectangle {
                                    Amount <font size='2'>  ( </font> <a href='#'>Change account</a><font size='2'> )</font>")
                              + translationManager.emptyString
                   copyButton: !isNaN(amountLine.text) && persistentSettings.fiatPriceEnabled
-                  copyButtonText: fiatApiCurrencySymbol() + " ~" + fiatApiConvertToFiat(amountLine.text)
+                  copyButtonText: "~%1 %2".arg(fiatApiConvertToFiat(amountLine.text)).arg(fiatApiCurrencySymbol())
                   copyButtonEnabled: false
 
                   onLabelLinkActivated: {
@@ -186,14 +188,61 @@ Rectangle {
                       regExp: /^(\d{1,8})?([\.]\d{1,12})?$/
                   }
               }
+
+                MoneroComponents.TextPlain {
+                    id: feeLabel
+                    Layout.alignment: Qt.AlignRight
+                    Layout.topMargin: 12
+                    font.family: MoneroComponents.Style.fontRegular.name
+                    font.pixelSize: 14
+                    color: MoneroComponents.Style.defaultFontColor
+                    property bool estimating: false
+                    property var estimatedFee: null
+                    property string estimatedFeeFiat: {
+                        if (!persistentSettings.fiatPriceEnabled || estimatedFee == null) {
+                            return "";
+                        }
+                        const fiatFee = fiatApiConvertToFiat(estimatedFee);
+                        return " (%1 %3)".arg(fiatFee < 0.01 ? "<0.01" : "~" + fiatFee).arg(fiatApiCurrencySymbol());
+                    }
+                    property var fee: {
+                        estimatedFee = null;
+                        estimating = sendButton.enabled;
+                        if (!sendButton.enabled) {
+                            return;
+                        }
+                        currentWallet.estimateTransactionFeeAsync(
+                            addressLine.text,
+                            walletManager.amountFromString(amountLine.text),
+                            priorityModelV5.get(priorityDropdown.currentIndex).priority,
+                            function (amount) {
+                                estimatedFee = Utils.removeTrailingZeros(amount);
+                                estimating = false;
+                            });
+                    }
+                    text: {
+                        if (!sendButton.enabled || estimatedFee == null) {
+                            return ""
+                        }
+                        return "%1: ~%2 XMR".arg(qsTr("Fee")).arg(estimatedFee) +
+                            estimatedFeeFiat +
+                            translationManager.emptyString;
+                    }
+
+                    BusyIndicator {
+                        anchors.right: parent.right
+                        running: feeLabel.estimating
+                        height: parent.height
+                    }
+                }
           }
 
           ColumnLayout {
               visible: appWindow.walletMode >= 2
-              Layout.fillWidth: true
+              Layout.alignment: Qt.AlignTop
               Label {
                   id: transactionPriority
-                  Layout.topMargin: 12
+                  Layout.topMargin: 0
                   text: qsTr("Transaction priority") + translationManager.emptyString
                   fontBold: false
                   fontSize: 16
@@ -217,14 +266,12 @@ Rectangle {
                }
 
               StandardDropdown {
-                  Layout.fillWidth: true
+                  Layout.preferredWidth: 200
                   id: priorityDropdown
                   Layout.topMargin: 5
                   currentIndex: 0
               }
           }
-          // Make sure dropdown is on top
-          z: parent.z + 1
       }
 
       // recipient address input
diff --git a/src/libwalletqt/Wallet.cpp b/src/libwalletqt/Wallet.cpp
index c32026f8..5f632725 100644
--- a/src/libwalletqt/Wallet.cpp
+++ b/src/libwalletqt/Wallet.cpp
@@ -575,6 +575,19 @@ void Wallet::disposeTransaction(UnsignedTransaction *t)
     delete t;
 }
 
+void Wallet::estimateTransactionFeeAsync(const QString &destination,
+                                         quint64 amount,
+                                         PendingTransaction::Priority priority,
+                                         const QJSValue &callback)
+{
+    m_scheduler.run([this, destination, amount, priority] {
+        const uint64_t fee = m_walletImpl->estimateTransactionFee(
+            {std::make_pair(destination.toStdString(), amount)},
+            static_cast<Monero::PendingTransaction::Priority>(priority));
+        return QJSValueList({QString::fromStdString(Monero::Wallet::displayAmount(fee))});
+    }, callback);
+}
+
 TransactionHistory *Wallet::history() const
 {
     return m_history;
diff --git a/src/libwalletqt/Wallet.h b/src/libwalletqt/Wallet.h
index a6add1da..e43bd59d 100644
--- a/src/libwalletqt/Wallet.h
+++ b/src/libwalletqt/Wallet.h
@@ -248,6 +248,11 @@ public:
     //! deletes unsigned transaction and frees memory
     Q_INVOKABLE void disposeTransaction(UnsignedTransaction * t);
 
+    Q_INVOKABLE void estimateTransactionFeeAsync(const QString &destination,
+                                                 quint64 amount,
+                                                 PendingTransaction::Priority priority,
+                                                 const QJSValue &callback);
+
     //! returns transaction history
     TransactionHistory * history() const;