qml: split updating userinfo from determine_can_pay, check determine_can_pay also in event handlers

electrum/gui/qml/qeinvoice.py

@@ -170,12 +170,14 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
     def on_event_payment_succeeded(self, wallet, key):
         if wallet == self._wallet.wallet and key == self.key:
             self.statusChanged.emit()
+            self.determine_can_pay()
             self.userinfo = _('Paid!')
 
     @event_listener
     def on_event_payment_failed(self, wallet, key, reason):
         if wallet == self._wallet.wallet and key == self.key:
             self.statusChanged.emit()
+            self.determine_can_pay()
             self.userinfo = _('Payment failed: ') + reason
 
     @event_listener
@@ -183,6 +185,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
         if wallet == self._wallet.wallet and key == self.key:
             self.statusChanged.emit()
             if status in [PR_INFLIGHT, PR_ROUTING]:
+                self.determine_can_pay()
                 self.userinfo = _('In progress...')
 
     @pyqtProperty(int, notify=invoiceChanged)
@@ -231,6 +234,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
         if self._effectiveInvoice:
             self._effectiveInvoice.amount_msat = '!' if new_amount.isMax else int(new_amount.satsInt * 1000)
 
+        self.update_userinfo()
         self.determine_can_pay()
         self.invoiceChanged.emit()
 
@@ -242,12 +246,11 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
     def amountOverride(self, new_amount):
         self._logger.debug(f'set new override amount {repr(new_amount)}')
         self._amountOverride.copyFrom(new_amount)
-
-        self.determine_can_pay()
         self.amountOverrideChanged.emit()
 
     @pyqtSlot()
     def _on_amountoverride_value_changed(self):
+        self.update_userinfo()
         self.determine_can_pay()
 
     @pyqtProperty('quint64', notify=invoiceChanged)
@@ -338,6 +341,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
 
         self.set_lnprops()
 
+        self.update_userinfo()
         self.determine_can_pay()
 
         self.invoiceChanged.emit()
@@ -353,6 +357,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
                     self._timer.setInterval(interval)  # msec
                     self._timer.start()
         else:
+            self.update_userinfo()
             self.determine_can_pay() # status went to PR_EXPIRED
 
     @pyqtSlot()
@@ -360,9 +365,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
         self.statusChanged.emit()
         self.set_status_timer()
 
-    def determine_can_pay(self):
+    def update_userinfo(self):
-        self.canPay = False
-        self.canSave = False
         self.userinfo = ''
 
         if not self.amountOverride.isEmpty:
@@ -370,8 +373,6 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
         else:
             amount = self.amount
 
-        self.canSave = True
-
         if self.amount.isEmpty:
             self.userinfo = _('Enter the amount you want to send')
 
@@ -384,13 +385,9 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
                     lnaddr = self._effectiveInvoice._lnaddr
                     if lnaddr.amount and amount.satsInt < lnaddr.amount * COIN:
                         self.userinfo = _('Cannot pay less than the amount specified in the invoice')
-                    else:
+                elif self.address and self.get_max_spendable_onchain() < amount.satsInt:
-                        self.canPay = True
-                elif self.address and self.get_max_spendable_onchain() > amount.satsInt:
                     # TODO: validate address?
                     # TODO: subtract fee?
-                    self.canPay = True
-                else:
                     self.userinfo = _('Insufficient balance')
             else:
                 self.userinfo = {
@@ -402,13 +399,7 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
                     }[self.status]
         elif self.invoiceType == QEInvoice.Type.OnchainInvoice:
             if self.status in [PR_UNPAID, PR_FAILED]:
-                if amount.isMax and self.get_max_spendable_onchain() > 0:
+                if not ((amount.isMax and self.get_max_spendable_onchain() > 0) or (self.get_max_spendable_onchain() >= amount.satsInt)):
-                    # TODO: dust limit?
-                    self.canPay = True
-                elif self.get_max_spendable_onchain() >= amount.satsInt:
-                    # TODO: subtract fee?
-                    self.canPay = True
-                else:
                     self.userinfo = _('Insufficient balance')
             else:
                 self.userinfo = {
@@ -418,6 +409,39 @@ class QEInvoiceParser(QEInvoice, QtEventListener):
                         PR_UNKNOWN: _('Invoice has unknown status'),
                     }[self.status]
 
+    def determine_can_pay(self):
+        self.canPay = False
+        self.canSave = False
+
+        if not self.amountOverride.isEmpty:
+            amount = self.amountOverride
+        else:
+            amount = self.amount
+
+        self.canSave = True
+
+        if amount.isEmpty and self.status == PR_UNPAID: # unspecified amount
+            return
+
+        if self.invoiceType == QEInvoice.Type.LightningInvoice:
+            if self.status in [PR_UNPAID, PR_FAILED]:
+                if self.get_max_spendable_lightning() >= amount.satsInt:
+                    lnaddr = self._effectiveInvoice._lnaddr
+                    if not (lnaddr.amount and amount.satsInt < lnaddr.amount * COIN):
+                        self.canPay = True
+                elif self.address and self.get_max_spendable_onchain() > amount.satsInt:
+                    # TODO: validate address?
+                    # TODO: subtract fee?
+                    self.canPay = True
+        elif self.invoiceType == QEInvoice.Type.OnchainInvoice:
+            if self.status in [PR_UNPAID, PR_FAILED]:
+                if amount.isMax and self.get_max_spendable_onchain() > 0:
+                    # TODO: dust limit?
+                    self.canPay = True
+                elif self.get_max_spendable_onchain() >= amount.satsInt:
+                    # TODO: subtract fee?
+                    self.canPay = True
+
     def setValidOnchainInvoice(self, invoice: Invoice):
         self._logger.debug('setValidOnchainInvoice')
         if invoice.is_lightning():