Merge #11316: [qt] Add use available balance in send coins dialog (CryptAxe, promag)

d052e3847 [qt] Add use available balance in send coins dialog (CryptAxe)

Pull request description:

  This is an alternative to #11098 to handle #11033 where a new button `Use available balance` is added to each entry. When activated, the available balance is calculated by using the coin control (if any) and then it's subtracted the remaining recipient amounts. If this amount is positive then the `Subtract fee from amount` is automatically selected.

  Comparing to #11098, this has the advantage to avoid the fair amount division over the recipients and allows to fine adjust the amounts in multiple iterations.

  Started from @CryptAxe commit 89e9eda to credit some code.

  <img width="965" alt="screen shot 2017-09-13 at 01 32 44" src="https://user-images.githubusercontent.com/3534524/30354518-e1bee31c-9824-11e7-9354-300aa63cdfd0.png">
  <img width="964" alt="screen shot 2017-09-13 at 01 44 57" src="https://user-images.githubusercontent.com/3534524/30354598-5731ac9c-9825-11e7-9d5f-8781988ed219.png">

Tree-SHA512: 01d20c13fd8b6c2a0ca1d74d3a9027c6922e6dccd3b08e59d5a72636be7072ed5eca7ebc5d431299497dd3374e83753220ad4174d8bc46dadb4b2f54973036a5

5 files changed, 55 insertions, 1 deletions

diff --git a/src/qt/forms/sendcoinsentry.ui b/src/qt/forms/sendcoinsentry.ui
index df06f36833..d0748c2edb 100644
--- a/src/qt/forms/sendcoinsentry.ui
+++ b/src/qt/forms/sendcoinsentry.ui
@@ -163,7 +163,7 @@
      </widget>
     </item>
     <item row="2" column="1">
-     <layout class="QHBoxLayout" name="horizontalLayoutAmount" stretch="0,1">
+     <layout class="QHBoxLayout" name="horizontalLayoutAmount" stretch="0,1,0">
       <item>
        <widget class="BitcoinAmountField" name="payAmount"/>
       </item>
@@ -177,6 +177,13 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="QPushButton" name="useAvailableBalanceButton">
+        <property name="text">
+         <string>Use available balance</string>
+        </property>
+       </widget>
+      </item>
      </layout>
     </item>
     <item row="3" column="0">
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 6309070fef..0d4cab2091 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -402,6 +402,7 @@ SendCoinsEntry *SendCoinsDialog::addEntry()
     entry->setModel(model);
     ui->entries->addWidget(entry);
     connect(entry, SIGNAL(removeEntry(SendCoinsEntry*)), this, SLOT(removeEntry(SendCoinsEntry*)));
+    connect(entry, SIGNAL(useAvailableBalance(SendCoinsEntry*)), this, SLOT(useAvailableBalance(SendCoinsEntry*)));
     connect(entry, SIGNAL(payAmountChanged()), this, SLOT(coinControlUpdateLabels()));
     connect(entry, SIGNAL(subtractFeeFromAmountChanged()), this, SLOT(coinControlUpdateLabels()));
 
@@ -599,6 +600,31 @@ void SendCoinsDialog::on_buttonMinimizeFee_clicked()
     minimizeFeeSection(true);
 }
 
+void SendCoinsDialog::useAvailableBalance(SendCoinsEntry* entry)
+{
+    // Get CCoinControl instance if CoinControl is enabled or create a new one.
+    CCoinControl coin_control;
+    if (model->getOptionsModel()->getCoinControlFeatures()) {
+        coin_control = *CoinControlDialog::coinControl;
+    }
+
+    // Calculate available amount to send.
+    CAmount amount = model->getBalance(&coin_control);
+    for (int i = 0; i < ui->entries->count(); ++i) {
+        SendCoinsEntry* e = qobject_cast<SendCoinsEntry*>(ui->entries->itemAt(i)->widget());
+        if (e && !e->isHidden() && e != entry) {
+            amount -= e->getValue().amount;
+        }
+    }
+
+    if (amount > 0) {
+      entry->checkSubtractFeeFromAmount();
+      entry->setAmount(amount);
+    } else {
+      entry->setAmount(0);
+    }
+}
+
 void SendCoinsDialog::setMinimumFee()
 {
     ui->customFee->setValue(GetRequiredFee(1000));
diff --git a/src/qt/sendcoinsdialog.h b/src/qt/sendcoinsdialog.h
index 70b4aa5a03..2ae6ccfa64 100644
--- a/src/qt/sendcoinsdialog.h
+++ b/src/qt/sendcoinsdialog.h
@@ -76,6 +76,7 @@ private Q_SLOTS:
     void on_buttonChooseFee_clicked();
     void on_buttonMinimizeFee_clicked();
     void removeEntry(SendCoinsEntry* entry);
+    void useAvailableBalance(SendCoinsEntry* entry);
     void updateDisplayUnit();
     void coinControlFeatureChanged(bool);
     void coinControlButtonClicked();
diff --git a/src/qt/sendcoinsentry.cpp b/src/qt/sendcoinsentry.cpp
index bb0f47b21c..8cf8db8030 100644
--- a/src/qt/sendcoinsentry.cpp
+++ b/src/qt/sendcoinsentry.cpp
@@ -48,6 +48,7 @@ SendCoinsEntry::SendCoinsEntry(const PlatformStyle *_platformStyle, QWidget *par
     connect(ui->deleteButton, SIGNAL(clicked()), this, SLOT(deleteClicked()));
     connect(ui->deleteButton_is, SIGNAL(clicked()), this, SLOT(deleteClicked()));
     connect(ui->deleteButton_s, SIGNAL(clicked()), this, SLOT(deleteClicked()));
+    connect(ui->useAvailableBalanceButton, SIGNAL(clicked()), this, SLOT(useAvailableBalanceClicked()));
 }
 
 SendCoinsEntry::~SendCoinsEntry()
@@ -112,11 +113,21 @@ void SendCoinsEntry::clear()
     updateDisplayUnit();
 }
 
+void SendCoinsEntry::checkSubtractFeeFromAmount()
+{
+    ui->checkboxSubtractFeeFromAmount->setChecked(true);
+}
+
 void SendCoinsEntry::deleteClicked()
 {
     Q_EMIT removeEntry(this);
 }
 
+void SendCoinsEntry::useAvailableBalanceClicked()
+{
+    Q_EMIT useAvailableBalance(this);
+}
+
 bool SendCoinsEntry::validate()
 {
     if (!model)
@@ -228,6 +239,11 @@ void SendCoinsEntry::setAddress(const QString &address)
     ui->payAmount->setFocus();
 }
 
+void SendCoinsEntry::setAmount(const CAmount &amount)
+{
+    ui->payAmount->setValue(amount);
+}
+
 bool SendCoinsEntry::isClear()
 {
     return ui->payTo->text().isEmpty() && ui->payTo_is->text().isEmpty() && ui->payTo_s->text().isEmpty();
diff --git a/src/qt/sendcoinsentry.h b/src/qt/sendcoinsentry.h
index a8be670c2a..557fea4e54 100644
--- a/src/qt/sendcoinsentry.h
+++ b/src/qt/sendcoinsentry.h
@@ -38,6 +38,7 @@ public:
 
     void setValue(const SendCoinsRecipient &value);
     void setAddress(const QString &address);
+    void setAmount(const CAmount &amount);
 
     /** Set up the tab chain manually, as Qt messes up the tab chain by default in some cases
      *  (issue https://bugreports.qt-project.org/browse/QTBUG-10907).
@@ -48,14 +49,17 @@ public:
 
 public Q_SLOTS:
     void clear();
+    void checkSubtractFeeFromAmount();
 
 Q_SIGNALS:
     void removeEntry(SendCoinsEntry *entry);
+    void useAvailableBalance(SendCoinsEntry* entry);
     void payAmountChanged();
     void subtractFeeFromAmountChanged();
 
 private Q_SLOTS:
     void deleteClicked();
+    void useAvailableBalanceClicked();
     void on_payTo_textChanged(const QString &address);
     void on_addressBookButton_clicked();
     void on_pasteButton_clicked();