feat: Add min margin to channel trade constraints

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Chore: Set minimum quantity to 1 if dlc channel is open
+- Chore: Enforce minimum margin of 250k instead of min quantity
+
 ## [1.8.2] - 2024-01-26
 
 - Feat: Add endpoint to force close ln-dlc channels

mobile/lib/common/amount_text_field.dart

@@ -2,11 +2,13 @@ import 'package:flutter/material.dart';
 import 'package:get_10101/common/domain/model.dart';
 
 class AmountTextField extends StatefulWidget {
-  const AmountTextField({super.key, required this.label, required this.value, this.suffixIcon});
+  const AmountTextField(
+      {super.key, required this.label, required this.value, this.suffixIcon, this.error});
 
   final Amount value;
   final String label;
   final Widget? suffixIcon;
+  final String? error;
 
   @override
   State<AmountTextField> createState() => _AmountTextState();
@@ -22,6 +24,10 @@ class _AmountTextState extends State<AmountTextField> {
         border: const OutlineInputBorder(),
         labelText: widget.label,
         labelStyle: const TextStyle(color: Colors.black87),
+        errorStyle: TextStyle(
+          color: Colors.red[900],
+        ),
+        errorText: widget.error,
         filled: true,
         suffixIcon: widget.suffixIcon,
         fillColor: Colors.grey[50],

mobile/lib/common/application/channel_info_service.dart

@@ -5,6 +5,10 @@ import 'package:get_10101/ffi.dart' as rust;
 class ChannelInfoService {
   const ChannelInfoService();
 
+  rust.TradeConstraints getTradeConstraints() {
+    return rust.api.channelTradeConstraints();
+  }
+
   Future<ChannelInfo?> getChannelInfo() async {
     rust.ChannelInfo? channelInfo = await rust.api.channelInfo();
     return channelInfo != null ? ChannelInfo.fromApi(channelInfo) : null;

mobile/lib/features/trade/application/trade_values_service.dart

@@ -41,6 +41,12 @@ class TradeValuesService {
     }
   }
 
+  Amount? orderMatchingFee({required Amount? quantity, required double? price}) {
+    return quantity != null && price != null
+        ? Amount(rust.api.orderMatchingFee(quantity: quantity.asDouble(), price: price))
+        : null;
+  }
+
   DateTime getExpiryTimestamp() {
     String network = const String.fromEnvironment('NETWORK', defaultValue: "regtest");
     return DateTime.fromMillisecondsSinceEpoch(

mobile/lib/features/trade/domain/trade_values.dart

@@ -2,7 +2,6 @@ import 'package:get_10101/common/domain/model.dart';
 import 'package:get_10101/features/trade/application/trade_values_service.dart';
 import 'package:get_10101/features/trade/domain/direction.dart';
 import 'package:get_10101/features/trade/domain/leverage.dart';
-import 'package:get_10101/ffi.dart' as rust;
 
 class TradeValues {
   Amount? margin;
@@ -47,7 +46,7 @@ class TradeValues {
             price: price, leverage: leverage, direction: direction)
         : null;
 
-    Amount? fee = orderMatchingFee(quantity, price);
+    Amount? fee = tradeValuesService.orderMatchingFee(quantity: quantity, price: price);
 
     DateTime expiry = tradeValuesService.getExpiryTimestamp();
 
@@ -78,7 +77,7 @@ class TradeValues {
             price: price, leverage: leverage, direction: direction)
         : null;
 
-    Amount? fee = orderMatchingFee(quantity, price);
+    Amount? fee = tradeValuesService.orderMatchingFee(quantity: quantity, price: price);
 
     DateTime expiry = tradeValuesService.getExpiryTimestamp();
 
@@ -146,12 +145,6 @@ class TradeValues {
   }
 
   _recalculateFee() {
-    fee = orderMatchingFee(quantity, price);
+    fee = tradeValuesService.orderMatchingFee(quantity: quantity, price: price);
   }
 }
-
-Amount? orderMatchingFee(Amount? quantity, double? price) {
-  return quantity != null && price != null
-      ? Amount(rust.api.orderMatchingFee(quantity: quantity.asDouble(), price: price))
-      : null;
-}

mobile/lib/features/trade/trade_bottom_sheet_tab.dart

@@ -1,5 +1,3 @@
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:get_10101/common/amount_text.dart';
 import 'package:get_10101/common/amount_text_field.dart';
@@ -22,6 +20,7 @@ import 'package:get_10101/features/trade/trade_dialog.dart';
 import 'package:get_10101/features/trade/trade_theme.dart';
 import 'package:get_10101/features/trade/trade_value_change_notifier.dart';
 import 'package:go_router/go_router.dart';
+import 'package:intl/intl.dart';
 import 'package:provider/provider.dart';
 
 const contractSymbol = ContractSymbol.btcusd;
@@ -57,13 +56,6 @@ class _TradeBottomSheetTabState extends State<TradeBottomSheetTab> {
     super.initState();
   }
 
-  Future<rust.TradeConstraints> _getTradeConstraints() async {
-    var completer = Completer<rust.TradeConstraints>();
-    var channelTradeConstraints = rust.api.channelTradeConstraints();
-    completer.complete(channelTradeConstraints);
-    return completer.future;
-  }
-
   @override
   void dispose() {
     marginController.dispose();
@@ -81,69 +73,35 @@ class _TradeBottomSheetTabState extends State<TradeBottomSheetTab> {
     String label = direction == Direction.long ? "Buy" : "Sell";
     Color color = direction == Direction.long ? tradeTheme.buy : tradeTheme.sell;
 
+    final channelInfoService = lspChangeNotifier.channelInfoService;
+    final channelTradeConstraints = channelInfoService.getTradeConstraints();
+
     return Form(
       key: _formKey,
       child: Column(
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
         crossAxisAlignment: CrossAxisAlignment.center,
         mainAxisSize: MainAxisSize.min,
         children: [
-          FutureBuilder<rust.TradeConstraints>(
-            future: _getTradeConstraints(), // a previously-obtained Future<String> or null
-            builder: (BuildContext context, AsyncSnapshot<rust.TradeConstraints> snapshot) {
-              List<Widget> children;
-
-              final channelInfoService = lspChangeNotifier.channelInfoService;
-
-              if (snapshot.hasData) {
-                var tradeConstraints = snapshot.data!;
-
-                children = <Widget>[
-                  buildChildren(direction, tradeConstraints, context, channelInfoService, _formKey),
-                ];
-              } else if (snapshot.hasError) {
-                children = <Widget>[
-                  const Icon(
-                    Icons.error_outline,
-                    color: Colors.red,
-                    size: 60,
-                  ),
-                  Padding(
-                    padding: const EdgeInsets.only(top: 16),
-                    child:
-                        Text('Error: Could not load confirmation screen due to ${snapshot.error}'),
-                  ),
-                ];
-              } else {
-                children = const <Widget>[
-                  SizedBox(
-                    width: 60,
-                    height: 60,
-                    child: CircularProgressIndicator(),
-                  ),
-                  Padding(
-                    padding: EdgeInsets.only(top: 16),
-                    child: Text('Loading confirmation screen...'),
-                  ),
-                ];
-              }
-              return Center(
-                child: Column(
-                  mainAxisAlignment: MainAxisAlignment.center,
-                  children: children,
-                ),
-              );
-            },
+          Center(
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: <Widget>[
+                buildChildren(
+                    direction, channelTradeConstraints, context, channelInfoService, _formKey)
+              ],
+            ),
           ),
           Column(
             crossAxisAlignment: CrossAxisAlignment.stretch,
             children: [
               ElevatedButton(
                   key: widget.buttonKey,
                   onPressed: () {
-                    if (_formKey.currentState!.validate()) {
-                      TradeValues tradeValues =
-                          context.read<TradeValuesChangeNotifier>().fromDirection(direction);
+                    TradeValues tradeValues =
+                        context.read<TradeValuesChangeNotifier>().fromDirection(direction);
+                    if (_formKey.currentState!.validate() &&
+                        channelTradeConstraints.minMargin <= (tradeValues.margin?.sats ?? 0)) {
                       final submitOrderChangeNotifier = context.read<SubmitOrderChangeNotifier>();
                       tradeBottomSheetConfirmation(
                           context: context,
@@ -209,14 +167,16 @@ class _TradeBottomSheetTabState extends State<TradeBottomSheetTab> {
           "\nWith your current balance, the maximum you can trade is ${formatUsd(Usd(maxQuantity.toInt()))}";
     }
 
+    var amountFormatter = NumberFormat.compact(locale: "en_UK");
+
     return Wrap(
       runSpacing: 12,
       children: [
         Padding(
           padding: const EdgeInsets.only(bottom: 10),
           child: Row(
             children: [
-              const Flexible(child: Text("Usable Balance:")),
+              const Flexible(child: Text("Balance:")),
               const SizedBox(width: 5),
               Flexible(child: AmountText(amount: Amount(usableBalance))),
               const SizedBox(
@@ -319,6 +279,9 @@ class _TradeBottomSheetTabState extends State<TradeBottomSheetTab> {
                       return AmountTextField(
                         value: margin,
                         label: "Margin (sats)",
+                        error: channelTradeConstraints.minMargin > margin.sats
+                            ? "Min margin is ${amountFormatter.format(channelTradeConstraints.minMargin)} sats"
+                            : null,
                         suffixIcon: showCapacityInfo
                             ? ModalBottomSheetInfo(
                                 closeButtonText: "Back to order",

mobile/native/src/api.rs

@@ -457,11 +457,13 @@ pub struct TradeConstraints {
     /// has in the channel. In the future we can consider splice in and allow the user to use more
     /// than just his channel balance.
     pub is_channel_balance: bool,
+    /// Smallest allowed margin
+    pub min_margin: u64,
 }
 
-pub fn channel_trade_constraints() -> Result<TradeConstraints> {
+pub fn channel_trade_constraints() -> Result<SyncReturn<TradeConstraints>> {
     let trade_constraints = channel_trade_constraints::channel_trade_constraints()?;
-    Ok(trade_constraints)
+    Ok(SyncReturn(trade_constraints))
 }
 
 pub fn max_channel_value() -> Result<u64> {

mobile/native/src/channel_trade_constraints.rs

@@ -11,7 +11,8 @@ pub fn channel_trade_constraints() -> Result<TradeConstraints> {
 
     // TODO(bonomat): retrieve these values from the coordinator. This can come from the liquidity
     // options.
-    let min_quantity = signed_channel.map(|_| 100).unwrap_or(500);
+    let min_quantity = 1;
+    let min_margin = signed_channel.map(|_| 1).unwrap_or(250_000);
 
     // TODO(bonomat): this logic should be removed once we have our liquidity options again and the
     // on-boarding logic. For now we take the highest liquidity option
@@ -40,6 +41,7 @@ pub fn channel_trade_constraints() -> Result<TradeConstraints> {
                 coordinator_leverage,
                 min_quantity,
                 is_channel_balance: false,
+                min_margin,
             }
         }
         Some(channel) => TradeConstraints {
@@ -48,6 +50,7 @@ pub fn channel_trade_constraints() -> Result<TradeConstraints> {
             coordinator_leverage,
             min_quantity,
             is_channel_balance: true,
+            min_margin,
         },
     };
     Ok(trade_constraints)

mobile/test/trade_test.dart

@@ -1,6 +1,7 @@
 import 'package:candlesticks/candlesticks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:get_10101/bridge_generated/bridge_definitions.dart' as bridge;
 import 'package:get_10101/common/amount_denomination_change_notifier.dart';
 @GenerateNiceMocks([MockSpec<ChannelInfoService>()])
 import 'package:get_10101/common/application/channel_info_service.dart';
@@ -96,6 +97,9 @@ void main() {
             price: anyNamed('price'), leverage: anyNamed('leverage'), margin: anyNamed('margin')))
         .thenReturn(Amount(1));
     when(tradeValueService.getExpiryTimestamp()).thenReturn(DateTime.now());
+    when(tradeValueService.orderMatchingFee(
+            quantity: anyNamed('quantity'), price: anyNamed('price')))
+        .thenReturn(Amount(42));
 
     // assuming this is an initial funding, no channel exists yet
     when(channelConstraintsService.getChannelInfo()).thenAnswer((_) async {
@@ -114,6 +118,15 @@ void main() {
       return 1;
     });
 
+    when(channelConstraintsService.getTradeConstraints()).thenAnswer((_) =>
+        const bridge.TradeConstraints(
+            maxLocalMarginSats: 20000000000,
+            maxCounterpartyMarginSats: 200000000000,
+            coordinatorLeverage: 2,
+            minQuantity: 1,
+            isChannelBalance: true,
+            minMargin: 1));
+
     when(candlestickService.fetchCandles(1000)).thenAnswer((_) async {
       return getDummyCandles(1000);
     });
@@ -133,11 +146,15 @@ void main() {
 
     LspChangeNotifier lspChangeNotifier = LspChangeNotifier(channelConstraintsService);
 
+    final tradeValuesChangeNotifier = TradeValuesChangeNotifier(tradeValueService);
+
+    final price = Price(bid: 30000.0, ask: 30000.0);
     // We have to have current price, otherwise we can't take order
-    positionChangeNotifier.price = Price(bid: 30000.0, ask: 30000.0);
+    positionChangeNotifier.price = price;
+    tradeValuesChangeNotifier.updatePrice(price);
 
     await tester.pumpWidget(MultiProvider(providers: [
-      ChangeNotifierProvider(create: (context) => TradeValuesChangeNotifier(tradeValueService)),
+      ChangeNotifierProvider(create: (context) => tradeValuesChangeNotifier),
       ChangeNotifierProvider(create: (context) => submitOrderChangeNotifier),
       ChangeNotifierProvider(create: (context) => OrderChangeNotifier(orderService)),
       ChangeNotifierProvider(create: (context) => positionChangeNotifier),