kivy: format_amount: minor clean-up

electrum/gui/kivy/main_window.py

@@ -24,6 +24,7 @@ from electrum import blockchain
 from electrum.network import Network, TxBroadcastError, BestEffortRequestFailed
 from electrum.interface import PREFERRED_NETWORK_PROTOCOL, ServerAddr
 from electrum.logging import Logger
+from electrum.bitcoin import COIN
 
 from electrum.gui import messages
 from .i18n import _
@@ -318,7 +319,7 @@ class ElectrumWindow(App, Logger):
         rate = self.fx.exchange_rate()
         if rate.is_nan():
             return ''
-        fiat_amount = self.get_amount(amount_str + ' ' + self.base_unit) * rate / pow(10, 8)
+        fiat_amount = self.get_amount(amount_str + ' ' + self.base_unit) * rate / COIN
         return "{:.2f}".format(fiat_amount).rstrip('0').rstrip('.')
 
     def fiat_to_btc(self, fiat_amount):
@@ -327,10 +328,12 @@ class ElectrumWindow(App, Logger):
         rate = self.fx.exchange_rate()
         if rate.is_nan():
             return ''
-        satoshis = int(pow(10,8) * Decimal(fiat_amount) / Decimal(rate))
+        satoshis = COIN * Decimal(fiat_amount) / Decimal(rate)
         return format_satoshis_plain(satoshis, decimal_point=self.decimal_point())
 
-    def get_amount(self, amount_str):
+    def get_amount(self, amount_str: str) -> Optional[int]:
+        if not amount_str:
+            return None
         a, u = amount_str.split()
         assert u == self.base_unit
         try:
@@ -958,19 +961,16 @@ class ElectrumWindow(App, Logger):
         return format_satoshis_plain(amount_after_all_fees, decimal_point=self.decimal_point())
 
     def format_amount(self, x, is_diff=False, whitespaces=False):
-        return format_satoshis(
-            x,
-            num_zeros=0,
-            decimal_point=self.decimal_point(),
-            is_diff=is_diff,
-            whitespaces=whitespaces,
-        )
+        return self.electrum_config.format_amount(x, is_diff=is_diff, whitespaces=whitespaces)
 
     def format_amount_and_units(self, x) -> str:
         if x is None:
             return 'none'
         if x == '!':
             return 'max'
+        # FIXME this is using format_satoshis_plain instead of config.format_amount
+        #       as we sometimes convert the returned string back to numbers,
+        #       via self.get_amount()... the need for converting back should be removed
         return format_satoshis_plain(x, decimal_point=self.decimal_point()) + ' ' + self.base_unit
 
     def format_fee_rate(self, fee_rate):

electrum/gui/kivy/uix/screens.py

@@ -418,11 +418,7 @@ class ReceiveScreen(CScreen):
 
     def get_URI(self):
         from electrum.util import create_bip21_uri
-        amount = self.amount
-        if amount:
-            a, u = self.amount.split()
-            assert u == self.app.base_unit
-            amount = Decimal(a) * pow(10, self.app.decimal_point())
+        amount = self.app.get_amount(self.amount)
         return create_bip21_uri(self.address, amount, self.message)
 
     def do_copy(self):

electrum/util.py

@@ -627,11 +627,16 @@ def chunks(items, size: int):
         yield items[i: i + size]
 
 
-def format_satoshis_plain(x, *, decimal_point=8) -> str:
+def format_satoshis_plain(
+        x: Union[int, float, Decimal, str],  # amount in satoshis,
+        *,
+        decimal_point: int = 8,  # how much to shift decimal point to left (default: sat->BTC)
+) -> str:
     """Display a satoshi amount scaled.  Always uses a '.' as a decimal
     point and has no thousands separator"""
     if x == '!':
         return 'max'
+    assert isinstance(x, (int, float, Decimal)), f"{x!r} should be a number"
     scale_factor = pow(10, decimal_point)
     return "{:.8f}".format(Decimal(x) / scale_factor).rstrip('0').rstrip('.')