add zeroconf handling to qt gui

electrum/gui/qt/receive_tab.py

@@ -98,6 +98,8 @@ class ReceiveTab(QWidget, MessageBoxMixin, Logger):
         self.receive_help_text.setLayout(QHBoxLayout())
         self.receive_rebalance_button = QPushButton('Rebalance')
         self.receive_rebalance_button.suggestion = None
+        self.receive_zeroconf_button = QPushButton(_('Accept'))
+        self.receive_zeroconf_button.clicked.connect(self.on_accept_zeroconf)
 
         def on_receive_rebalance():
             if self.receive_rebalance_button.suggestion:
@@ -115,6 +117,7 @@ class ReceiveTab(QWidget, MessageBoxMixin, Logger):
         buttons = QHBoxLayout()
         buttons.addWidget(self.receive_rebalance_button)
         buttons.addWidget(self.receive_swap_button)
+        buttons.addWidget(self.receive_zeroconf_button)
         vbox = QVBoxLayout()
         vbox.addWidget(self.receive_help_text)
         vbox.addLayout(buttons)
@@ -236,26 +239,37 @@ class ReceiveTab(QWidget, MessageBoxMixin, Logger):
         self.ln_help = help_texts.ln_help
         can_rebalance = help_texts.can_rebalance()
         can_swap = help_texts.can_swap()
+        can_zeroconf = help_texts.can_zeroconf()
         self.receive_rebalance_button.suggestion = help_texts.ln_rebalance_suggestion
         self.receive_swap_button.suggestion = help_texts.ln_swap_suggestion
         self.receive_rebalance_button.setVisible(can_rebalance)
         self.receive_swap_button.setVisible(can_swap)
         self.receive_rebalance_button.setEnabled(can_rebalance and self.window.num_tasks() == 0)
         self.receive_swap_button.setEnabled(can_swap and self.window.num_tasks() == 0)
+        self.receive_zeroconf_button.setVisible(can_zeroconf)
+        self.receive_zeroconf_button.setEnabled(can_zeroconf)
         text, data, help_text, title = self.get_tab_data()
         self.receive_e.setText(text)
         self.receive_qr.setData(data)
         self.receive_help_text.setText(help_text)
         for w in [self.receive_e, self.receive_qr]:
-            w.setEnabled(bool(text) and not help_text)
+            w.setEnabled(bool(text) and (not help_text or can_zeroconf))
             w.setToolTip(help_text)
         # macOS hack (similar to #4777)
         self.receive_e.repaint()
         # always show
+        if can_zeroconf:
+            # show the help message if zeroconf so user can first accept it and still sees the invoice
+            # after accepting
+            self.receive_widget.show_help()
         self.receive_widget.setVisible(True)
         self.toggle_qr_button.setEnabled(True)
         self.update_receive_qr_window()
 
+    def on_accept_zeroconf(self):
+        self.receive_zeroconf_button.setVisible(False)
+        self.update_receive_widgets()
+
     def get_tab_data(self):
         if self.URI:
             out = self.URI, self.URI, self.URI_help, _('Bitcoin URI')
@@ -374,9 +388,12 @@ class ReceiveWidget(QWidget):
             self.textedit.setVisible(not is_qr)
             self.qr.setVisible(is_qr)
         else:
-            self.help_widget.setVisible(True)
+            self.show_help()
-            self.textedit.setVisible(False)
+
-            self.qr.setVisible(False)
+    def show_help(self):
+        self.help_widget.setVisible(True)
+        self.textedit.setVisible(False)
+        self.qr.setVisible(False)
 
     def resizeEvent(self, e):
         # keep square aspect ratio when resized

electrum/wallet.py

@@ -53,6 +53,7 @@ from .i18n import _
 from .bip32 import BIP32Node, convert_bip32_intpath_to_strpath, convert_bip32_strpath_to_intpath
 from .crypto import sha256
 from . import util
+from .lntransport import extract_nodeid
 from .util import (NotEnoughFunds, UserCancelled, profiler, OldTaskGroup, ignore_exceptions,
                    format_satoshis, format_fee_satoshis, NoDynamicFeeEstimates,
                    WalletFileException, BitcoinException,
@@ -60,6 +61,7 @@ from .util import (NotEnoughFunds, UserCancelled, profiler, OldTaskGroup, ignore
                    Fiat, bfh, TxMinedInfo, quantize_feerate, OrderedDictWithIndex)
 from .simple_config import SimpleConfig
 from .fee_policy import FeePolicy, FixedFeePolicy, FeeMethod, FEE_RATIO_HIGH_WARNING, FEERATE_WARNING_HIGH_FEE
+from .lnutil import MIN_FUNDING_SAT
 from .bitcoin import COIN, TYPE_ADDRESS
 from .bitcoin import is_address, address_to_script, is_minikey, relayfee, dust_threshold
 from .bitcoin import DummyAddress, DummyAddressUsedInTxException
@@ -346,6 +348,7 @@ class ReceiveRequestHelp(NamedTuple):
 
     ln_swap_suggestion: Optional[Any] = None
     ln_rebalance_suggestion: Optional[Any] = None
+    ln_zeroconf_suggestion: bool = False
 
     def can_swap(self) -> bool:
         return bool(self.ln_swap_suggestion)
@@ -353,6 +356,9 @@ class ReceiveRequestHelp(NamedTuple):
     def can_rebalance(self) -> bool:
         return bool(self.ln_rebalance_suggestion)
 
+    def can_zeroconf(self) -> bool:
+        return self.ln_zeroconf_suggestion
+
 
 class TxWalletDelta(NamedTuple):
     is_relevant: bool  # "related to wallet?"
@@ -3250,12 +3256,19 @@ class Abstract_Wallet(ABC, Logger, EventListener):
         ln_is_error = False
         ln_swap_suggestion = None
         ln_rebalance_suggestion = None
+        ln_zeroconf_suggestion = False
         URI = self.get_request_URI(req) or ''
         lightning_has_channels = (
             self.lnworker and len([chan for chan in self.lnworker.channels.values() if chan.is_open()]) > 0
         )
         lightning_online = self.lnworker and self.lnworker.num_peers() > 0
         can_receive_lightning = self.lnworker and amount_sat <= self.lnworker.num_sats_can_receive()
+        try:
+            zeroconf_nodeid = extract_nodeid(self.config.ZEROCONF_TRUSTED_NODE)[0]
+        except Exception:
+            zeroconf_nodeid = None
+        can_get_zeroconf_channel = (self.lnworker and self.config.ACCEPT_ZEROCONF_CHANNELS
+                                        and zeroconf_nodeid in self.lnworker.peers)
         status = self.get_invoice_status(req)
 
         if status == PR_EXPIRED:
@@ -3281,21 +3294,33 @@ class Abstract_Wallet(ABC, Logger, EventListener):
                 address_help = URI_help = (_("This address has already been used. "
                                              "For better privacy, do not reuse it for new payments."))
             if req.is_lightning():
-                if not lightning_has_channels:
+                if not lightning_has_channels and not can_get_zeroconf_channel:
                     ln_is_error = True
                     ln_help = _("You must have an open Lightning channel to receive payments.")
                 elif not lightning_online:
                     ln_is_error = True
                     ln_help = _('You must be online to receive Lightning payments.')
-                elif not can_receive_lightning:
+                elif not can_receive_lightning or (amount_sat <= 0 and not lightning_has_channels):
-                    ln_is_error = True
                     ln_rebalance_suggestion = self.lnworker.suggest_rebalance_to_receive(amount_sat)
                     ln_swap_suggestion = self.lnworker.suggest_swap_to_receive(amount_sat)
-                    ln_help = _('You do not have the capacity to receive this amount with Lightning.')
+                    # prefer to use swaps over JIT channels if possible
-                    if bool(ln_rebalance_suggestion):
+                    if can_get_zeroconf_channel and not bool(ln_rebalance_suggestion) and not bool(ln_swap_suggestion):
-                        ln_help += '\n\n' + _('You may have that capacity if you rebalance your channels.')
+                        if amount_sat < MIN_FUNDING_SAT:
-                    elif bool(ln_swap_suggestion):
+                            ln_is_error = True
-                        ln_help += '\n\n' + _('You may have that capacity if you swap some of your funds.')
+                            ln_help = (_('Cannot receive this payment. Request at least {} '
+                                        'to purchase a Lightning channel from your service provider.')
+                                       .format(self.config.format_amount_and_units(amount_sat=MIN_FUNDING_SAT)))
+                        else:
+                            ln_zeroconf_suggestion = True
+                            ln_help = _(f'Receiving this payment will purchase a payment channel from your '
+                                        f'service provider. Service fees are deducted from the incoming payment.')
+                    else:
+                        ln_is_error = True
+                        ln_help = _('You do not have the capacity to receive this amount with Lightning.')
+                        if bool(ln_rebalance_suggestion):
+                            ln_help += '\n\n' + _('You may have that capacity if you rebalance your channels.')
+                        elif bool(ln_swap_suggestion):
+                            ln_help += '\n\n' + _('You may have that capacity if you swap some of your funds.')
                 # for URI that has LN part but no onchain part, copy error:
                 if not addr and ln_is_error:
                     URI_is_error = ln_is_error
@@ -3309,6 +3334,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
             ln_is_error=ln_is_error,
             ln_rebalance_suggestion=ln_rebalance_suggestion,
             ln_swap_suggestion=ln_swap_suggestion,
+            ln_zeroconf_suggestion=ln_zeroconf_suggestion
         )