Merge #1470: [GUI] Mark delegated UTXOs in CoinControl

1ef737b [GUI] coin control: add icon and tooltip for delegated UTXOs (random-zebra)

Pull request description:

  Implemented on top of:
  - [x] #1469

  (only last commit is new)

  **Problem**: As outlined in the description of #1391, delegated outputs are not clearly distinguishable in the coin control dialog.

  **Proposed Solution**: Add a "cold staking icon" (purple snow flake) at the end of delegated utxo rows. Hovering on this icon shows a tooltip with the staker address which has received the delegation.

  ![ccontrol1](https://user-images.githubusercontent.com/18186894/77853074-650b2c00-71e2-11ea-8908-926b39f9e230.png)

  <br>

  ![ccontrol2](https://user-images.githubusercontent.com/18186894/77853078-69374980-71e2-11ea-839a-53a2b0a83d20.png)

ACKs for top commit:
  Fuzzbawls:
    ACK 1ef737b
  furszy:
    utACK 1ef737b .

Tree-SHA512: 4da7c478ef8b2463bc80e002e25f6da4b2e18e47afbb024fa344945dbbe5dfc3b0fb75c6e821d67d19b373cf123aad1c827dfcf37b412d0fda5d8cd279aa5fff

src/qt/coincontroldialog.cpp

@@ -265,7 +265,11 @@ void CoinControlDialog::buttonToggleLockClicked()
             if (model->isLockedCoin(uint256(item->text(COLUMN_TXHASH).toStdString()), item->text(COLUMN_VOUT_INDEX).toUInt())) {
                 model->unlockCoin(outpt);
                 item->setDisabled(false);
-                item->setIcon(COLUMN_CHECKBOX, QIcon());
+                // restore cold-stake snowflake icon for P2CS which were previously locked
+                if (item->data(COLUMN_CHECKBOX, Qt::UserRole) == QString("Delegated"))
+                    item->setIcon(COLUMN_CHECKBOX, QIcon("://ic-check-cold-staking-off"));
+                else
+                    item->setIcon(COLUMN_CHECKBOX, QIcon());
             } else {
                 model->lockCoin(outpt);
                 item->setDisabled(true);
@@ -364,7 +368,11 @@ void CoinControlDialog::unlockCoin()
     COutPoint outpt(uint256(contextMenuItem->text(COLUMN_TXHASH).toStdString()), contextMenuItem->text(COLUMN_VOUT_INDEX).toUInt());
     model->unlockCoin(outpt);
     contextMenuItem->setDisabled(false);
-    contextMenuItem->setIcon(COLUMN_CHECKBOX, QIcon());
+    // restore cold-stake snowflake icon for P2CS which were previously locked
+    if (contextMenuItem->data(COLUMN_CHECKBOX, Qt::UserRole) == QString("Delegated"))
+        contextMenuItem->setIcon(COLUMN_CHECKBOX, QIcon("://ic-check-cold-staking-off"));
+    else
+        contextMenuItem->setIcon(COLUMN_CHECKBOX, QIcon());
     updateLabelLocked();
 }
 
@@ -836,9 +844,23 @@ void CoinControlDialog::updateView()
             }
 
             // address
+            const bool fDelegated = (bool)(mine & ISMINE_SPENDABLE_DELEGATED);
             CTxDestination outputAddress;
+            CTxDestination outputAddressStaker;
             QString sAddress = "";
-            if (ExtractDestination(out.tx->vout[out.i].scriptPubKey, outputAddress)) {
+            bool haveDest = false;
+            if (fDelegated) {
+                txnouttype type; std::vector<CTxDestination> addresses; int nRequired;
+                haveDest = (ExtractDestinations(out.tx->vout[out.i].scriptPubKey, type, addresses, nRequired)
+                            && addresses.size() == 2);
+                if (haveDest) {
+                    outputAddressStaker = addresses[0];
+                    outputAddress = addresses[1];
+                }
+            } else {
+                haveDest = ExtractDestination(out.tx->vout[out.i].scriptPubKey, outputAddress);
+            }
+            if (haveDest) {
                 sAddress = QString::fromStdString(CBitcoinAddress(outputAddress).ToString());
 
                 // if listMode or change => show PIVX address. In tree mode, address is not shown again for direct wallet address outputs
@@ -891,6 +913,16 @@ void CoinControlDialog::updateView()
             // vout index
             itemOutput->setText(COLUMN_VOUT_INDEX, QString::number(out.i));
 
+            // outputs delegated (for cold staking)
+            if (fDelegated) {
+                itemOutput->setData(COLUMN_CHECKBOX, Qt::UserRole, QString("Delegated"));
+                itemOutput->setIcon(COLUMN_CHECKBOX, QIcon("://ic-check-cold-staking-off"));
+                if (haveDest) {
+                    sAddress = QString::fromStdString(CBitcoinAddress(outputAddressStaker, CChainParams::STAKING_ADDRESS).ToString());
+                    itemOutput->setToolTip(COLUMN_CHECKBOX, tr("delegated to %1 for cold staking").arg(sAddress));
+                }
+            }
+
             // disable locked coins
             if (model->isLockedCoin(txhash, out.i)) {
                 COutPoint outpt(txhash, out.i);