[Qt] coin control change address handling update

- re-work change address handling so that default is CNoDestination(),
  until a verified and known change address was entered (easier code flow)
- add a missing NULL pointer check for adresstablemodel
- add a missing text when opening coin control address selection for
  priority and ensure the label is black
- add a missing . at the end of a sentence

1 files changed, 29 insertions, 28 deletions

diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 4bf5c3c479..92be835c56 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -546,44 +546,45 @@ void SendCoinsDialog::coinControlChangeChecked(int state)
 // Coin Control: custom change address changed
 void SendCoinsDialog::coinControlChangeEdited(const QString& text)
 {
-    if (model)
+    if (model && model->getAddressTableModel())
     {
-        CoinControlDialog::coinControl->destChange = CBitcoinAddress(text.toStdString()).Get();
+        // Default to no change address until verified
+        CoinControlDialog::coinControl->destChange = CNoDestination();
+        ui->labelCoinControlChangeLabel->setStyleSheet("QLabel{color:red;}");
+
+        CBitcoinAddress addr = CBitcoinAddress(text.toStdString());
 
-        // label for the change address
-        ui->labelCoinControlChangeLabel->setStyleSheet("QLabel{color:black;}");
-        if (text.isEmpty())
+        if (text.isEmpty()) // Nothing entered
+        {
             ui->labelCoinControlChangeLabel->setText("");
-        else if (!CBitcoinAddress(text.toStdString()).IsValid())
+        }
+        else if (!addr.IsValid()) // Invalid address
         {
-            // invalid change address
-            CoinControlDialog::coinControl->destChange = CNoDestination();
-
             ui->lineEditCoinControlChange->setValid(false);
-            ui->labelCoinControlChangeLabel->setStyleSheet("QLabel{color:red;}");
             ui->labelCoinControlChangeLabel->setText(tr("Warning: Invalid Bitcoin address"));
         }
-        else
+        else // Valid address
         {
-            QString associatedLabel = model->getAddressTableModel()->labelForAddress(text);
-            if (!associatedLabel.isEmpty())
-                ui->labelCoinControlChangeLabel->setText(associatedLabel);
-            else
+            CPubKey pubkey;
+            CKeyID keyid;
+            addr.GetKeyID(keyid);
+            if (!model->getPubKey(keyid, pubkey)) // Unknown change address
             {
-                CPubKey pubkey;
-                CKeyID keyid;
-                CBitcoinAddress(text.toStdString()).GetKeyID(keyid);
-                if (model->getPubKey(keyid, pubkey))
-                    ui->labelCoinControlChangeLabel->setText(tr("(no label)"));
+                ui->lineEditCoinControlChange->setValid(false);
+                ui->labelCoinControlChangeLabel->setText(tr("Warning: Unknown change address"));
+            }
+            else // Known change address
+            {
+                ui->labelCoinControlChangeLabel->setStyleSheet("QLabel{color:black;}");
+
+                // Query label
+                QString associatedLabel = model->getAddressTableModel()->labelForAddress(text);
+                if (!associatedLabel.isEmpty())
+                    ui->labelCoinControlChangeLabel->setText(associatedLabel);
                 else
-                {
-                    // unknown change address
-                    CoinControlDialog::coinControl->destChange = CNoDestination();
-
-                    ui->lineEditCoinControlChange->setValid(false);
-                    ui->labelCoinControlChangeLabel->setStyleSheet("QLabel{color:red;}");
-                    ui->labelCoinControlChangeLabel->setText(tr("Warning: Unknown change address"));
-                }
+                    ui->labelCoinControlChangeLabel->setText(tr("(no label)"));
+
+                CoinControlDialog::coinControl->destChange = addr.Get();
             }
         }
     }