qt swap_dialog: "max" now takes into account the server-provided value

electrum/gui/qt/swap_dialog.py

@@ -5,7 +5,6 @@ from PyQt5.QtWidgets import QLabel, QVBoxLayout, QGridLayout, QPushButton
 from electrum.i18n import _
 from electrum.lnutil import ln_dummy_address
 from electrum.transaction import PartialTxOutput, PartialTransaction
-from electrum.submarine_swaps import SWAP_MAX_VALUE_SAT
 
 from .util import (WindowModalDialog, Buttons, OkButton, CancelButton,
                    EnterButton, ColorScheme, WWLabel, read_QIcon)
@@ -114,16 +113,17 @@ class SwapDialog(WindowModalDialog):
         self.update_tx('!')
         if self.tx:
             amount = self.tx.output_value_for_address(ln_dummy_address())
-            if amount > SWAP_MAX_VALUE_SAT:
-                amount = SWAP_MAX_VALUE_SAT
+            max_amt = self.swap_manager.get_max_amount()
+            if amount > max_amt:
+                amount = max_amt
                 self.update_tx(amount)
             if self.tx:
                 amount = self.tx.output_value_for_address(ln_dummy_address())
-                assert amount <= SWAP_MAX_VALUE_SAT
+                assert amount <= max_amt
                 self.send_amount_e.setAmount(amount)
 
     def _spend_max_reverse_swap(self):
-        amount = min(self.lnworker.num_sats_can_send(), SWAP_MAX_VALUE_SAT)
+        amount = min(self.lnworker.num_sats_can_send(), self.swap_manager.get_max_amount())
         self.send_amount_e.setAmount(amount)
 
     def on_send_edited(self):

electrum/submarine_swaps.py

@@ -25,9 +25,6 @@ if TYPE_CHECKING:
 API_URL = 'https://lightning.electrum.org/api'
 
 
-SWAP_MAX_VALUE_SAT = LN_MAX_HTLC_VALUE_MSAT // 1000
-
-
 WITNESS_TEMPLATE_SWAP = [
     opcodes.OP_HASH160,
     OPPushDataGeneric(lambda x: x == 20),
@@ -118,7 +115,7 @@ class SwapManager(Logger):
         self.lockup_fee = 0
         self.percentage = 0
         self.min_amount = 0
-        self.max_amount = 0
+        self._max_amount = 0
         self.network = network
         self.wallet = wallet
         self.lnworker = wallet.lnworker
@@ -365,12 +362,15 @@ class SwapManager(Logger):
         self.lockup_fee = fees['minerFees']['baseAsset']['reverse']['lockup']
         limits = pairs['pairs']['BTC/BTC']['limits']
         self.min_amount = limits['minimal']
-        self.max_amount = limits['maximal']
+        self._max_amount = limits['maximal']
+
+    def get_max_amount(self):
+        return min(self._max_amount, LN_MAX_HTLC_VALUE_MSAT // 1000)
 
     def get_recv_amount(self, send_amount: Optional[int], is_reverse: bool) -> Optional[int]:
         if send_amount is None:
             return
-        if send_amount < self.min_amount or send_amount > self.max_amount:
+        if send_amount < self.min_amount or send_amount > self._max_amount:
             return
         x = send_amount
         if is_reverse: