app: Add relay fee setting

Add a relay fee to settings and allow changing. The fee is not yet used.

Author: JoeGruffins

tinywallet/tinywallet/app.py

@@ -13,6 +13,7 @@
 
 from decred.dcr import constants as DCR
 from decred.dcr.dcrdata import DcrdataBlockchain
+from decred.dcr.txscript import DefaultRelayFeePerKb
 from decred.util import chains, database, helpers
 from decred.wallet.wallet import Wallet
 from tinywallet import config, qutilities as Q, screens, ui
@@ -273,6 +274,8 @@ def loadSettings(self):
             self.settings[DB.dcrdata] = config.NetworkDefaults[self.cfg.netParams.Name][
                 "dcrdata"
             ].encode()
+        if DB.relayFee not in self.settings:
+            self.settings[DB.relayFee] = int(DefaultRelayFeePerKb)
 
     def registerSignal(self, sig, cb, *a, **k):
         """

tinywallet/tinywallet/config.py

@@ -102,6 +102,7 @@ class DB:
     wallet = "wallet".encode()
     theme = "theme".encode()
     dcrdata = "dcrdata".encode()
+    relayFee = "relayfee".encode()
 
 
 tinyConfig = None

tinywallet/tinywallet/screens.py

@@ -1103,6 +1103,16 @@ def __init__(self):
         self.layout.addWidget(wgt)
         grid.setColumnStretch(0, 1)
         row = 0
+        grid.addWidget(Q.makeLabel("Relay Fee", 14, Q.ALIGN_LEFT), row, 0)
+        row += 1
+        self.relayFeeField = QtWidgets.QLineEdit(str(app.settings[DB.relayFee]))
+        lbl = Q.makeLabel(" atoms / kb ", 14)
+        wgt, _ = Q.makeRow(self.relayFeeField, lbl)
+        grid.addWidget(wgt, row, 0)
+        bttn = app.getButton(SMALL, "change")
+        bttn.clicked.connect(self.relayFeeChangeClicked)
+        grid.addWidget(bttn, row, 1)
+        row += 1
         grid.addWidget(Q.makeLabel("Dcrdata URL", 14, Q.ALIGN_LEFT), row, 0)
         row += 1
         self.dcrdataField = QtWidgets.QLineEdit(app.settings[DB.dcrdata].decode())
@@ -1113,6 +1123,29 @@ def __init__(self):
 
         self.layout.addStretch(1)
 
+    def relayFeeChangeClicked(self, e=None):
+        """
+        Qt slot connected to relay fee change button clicked signal.
+        Changes the relay fee.
+        """
+
+        fee = int(self.relayFeeField.text())
+        if fee <= 0:
+            app.appWindow.showError("fee cannot be less than or equal to zero")
+            self.relayFeeField.setText(str(app.settings[DB.relayFee]))
+            return
+
+        # In documentation, a high fee is considered to be 1e4 * 1000 / kb.
+        highFee = int(1e4 * 1000)
+        if fee > highFee:
+            app.appWindow.showError(f"fee cannot be higher than {highFee}")
+            self.relayFeeField.setText(str(app.settings[DB.relayFee]))
+            return
+
+        app.settings[DB.relayFee] = fee
+        log.info(f"relay fee changed to {fee}")
+        app.appWindow.showSuccess("fee changed")
+
     def dcrdataChangeClicked(self, e=None):
         """
         Qt slot connected to dcrdata URL submission button clicked signal.