swaps: homogenise gui messages

see https://github.com/spesmilo/electrum/issues/8940

electrum/gui/messages.py

@@ -1,4 +1,5 @@
 from electrum.i18n import _
+from electrum.submarine_swaps import MIN_FINAL_CLTV_DELTA_FOR_CLIENT
 
 
 def to_rtf(msg):
@@ -47,3 +48,22 @@ If you want to keep using this channel, you need to disable trampoline routing i
 
 MSG_FREEZE_ADDRESS = _("When you freeze an address, the funds in that address will not be used for sending bitcoins.")
 MSG_FREEZE_COIN = _("When you freeze a coin, it will not be used for sending bitcoins.")
+
+MSG_FORWARD_SWAP_FUNDING_MEMPOOL = (
+    _('Your funding transaction has been broadcast.') + " " +
+    _('The swap will be finalized once your transaction is confirmed.') + " " +
+    _("After the funding transaction is mined, the server will reveal the preimage needed to "
+      "fulfill the pending received lightning HTLCs. The HTLCs expire in {} blocks. "
+      "You will need to be online after the funding transaction is confirmed but before the HTLCs expire, "
+      "to claim your money. If you go offline for several days while the swap is pending, "
+      "you risk losing the swap amount!").format(MIN_FINAL_CLTV_DELTA_FOR_CLIENT) + " " +
+    _("Please remain online until the funding transaction is confirmed.")
+)
+
+MSG_REVERSE_SWAP_FUNDING_MEMPOOL = (
+    _('The funding transaction has been detected.') + " " +
+    _('Your claiming transaction will be broadcast when the funding transaction is confirmed.') + " " +
+    _('You may choose to broadcast it earlier, although that would not be trustless.') + " " +
+    _("If you go offline before broadcasting the claiming transaction and let the swap time out, "
+      "you will not get back the already pre-paid mining fees.")
+)

electrum/gui/qml/qeswaphelper.py

@@ -12,6 +12,8 @@ from electrum.logging import get_logger
 from electrum.transaction import PartialTxOutput, PartialTransaction
 from electrum.util import NotEnoughFunds, NoDynamicFeeEstimates, profiler, get_asyncio_loop
 
+from electrum.gui import messages
+
 from .auth import AuthMixin, auth_protect
 from .qetypes import QEAmount
 from .qewallet import QEWallet
@@ -386,9 +388,7 @@ class QESwapHelper(AuthMixin, QObject, QtEventListener):
                 try:  # swaphelper might be destroyed at this point
                     self.userinfo = ' '.join([
                         _('Success!'),
-                        _('Your funding transaction has been broadcast.'),
-                        _('The swap will be finalized once your transaction is confirmed.'),
-                        _('You will need to be online to finalize the swap, or the transaction will be refunded to you after some delay.'),
+                        messages.MSG_FORWARD_SWAP_FUNDING_MEMPOOL,
                     ])
                     self.state = QESwapHelper.State.Success
                 except RuntimeError:
@@ -459,9 +459,7 @@ class QESwapHelper(AuthMixin, QObject, QtEventListener):
                     if txid:
                         self.userinfo = ' '.join([
                             _('Success!'),
-                            _('The funding transaction has been detected.'),
-                            _('Your claiming transaction will be broadcast when the funding transaction is confirmed.'),
-                            _('You may choose to broadcast it earlier, although that would not be trustless.'),
+                            messages.MSG_REVERSE_SWAP_FUNDING_MEMPOOL,
                         ])
                         self.state = QESwapHelper.State.Success
                     else:

electrum/gui/qt/main_window.py

@@ -2686,14 +2686,17 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger, QtEventListener):
         d = RebalanceDialog(self, chan1, chan2, amount_sat)
         d.run()
 
-    def on_swap_result(self, txid):
+    def on_swap_result(self, txid: Optional[str], *, is_reverse: bool):
         msg = _("Submarine swap") + ': ' + (_("Success") if txid else _("Expired")) + '\n\n'
         if txid:
-            msg += _("Funding transaction") + ': ' + txid + '\n'
-            msg += _("Please remain online until the funding transaction is confirmed.")
+            msg += _("Funding transaction") + ': ' + txid + '\n\n'
+            if is_reverse:
+                msg += messages.MSG_REVERSE_SWAP_FUNDING_MEMPOOL
+            else:
+                msg += messages.MSG_FORWARD_SWAP_FUNDING_MEMPOOL
             self.show_message_signal.emit(msg)
         else:
-            msg += _("Lightning funds were not received.")
+            msg += _("Lightning funds were not received.")  # FIXME should this not depend on is_reverse?
             self.show_error_signal.emit(msg)
 
     def set_payment_identifier(self, pi: str):

electrum/gui/qt/send_tab.py

@@ -741,7 +741,7 @@ class SendTab(QWidget, MessageBoxMixin, Logger):
             coro = sm.wait_for_htlcs_and_broadcast(swap=swap, invoice=tx.swap_invoice, tx=tx)
             self.window.run_coroutine_dialog(
                 coro, _('Awaiting swap payment...'),
-                on_result=self.window.on_swap_result,
+                on_result=lambda funding_txid: self.window.on_swap_result(funding_txid, is_reverse=False),
                 on_cancelled=lambda: sm.cancel_normal_swap(swap))
             return
 

electrum/gui/qt/swap_dialog.py

@@ -255,7 +255,10 @@ class SwapDialog(WindowModalDialog, QtEventListener):
                 lightning_amount_sat=lightning_amount,
                 expected_onchain_amount_sat=onchain_amount + self.swap_manager.get_claim_fee(),
             )
-            self.window.run_coroutine_from_thread(coro, _('Swapping funds'), on_result=self.window.on_swap_result)
+            self.window.run_coroutine_from_thread(
+                coro, _('Swapping funds'),
+                on_result=lambda funding_txid: self.window.on_swap_result(funding_txid, is_reverse=True),
+            )
             return True
         else:
             lightning_amount = self.recv_amount_e.get_amount()
@@ -334,7 +337,7 @@ class SwapDialog(WindowModalDialog, QtEventListener):
         coro2 = sm.wait_for_htlcs_and_broadcast(swap=swap, invoice=invoice, tx=tx)
         self.window.run_coroutine_dialog(
             coro2, _('Awaiting swap payment...'),
-            on_result=self.window.on_swap_result,
+            on_result=lambda funding_txid: self.window.on_swap_result(funding_txid, is_reverse=False),
             on_cancelled=lambda: sm.cancel_normal_swap(swap))
 
     def get_description(self):