Add onchain logics pt2

.env-sample

@@ -113,9 +113,9 @@ MAX_SWAP_FEE = 0.1
 # Liquidity split point (LN/onchain) at which we use MAX_SWAP_FEE
 MAX_SWAP_POINT = 0
 # Shape of fee to available liquidity curve. Only 'linear' implemented. 
-SWAP_FEE_ = 'linear'
+SWAP_FEE_SHAPE = 'linear'
 # Min amount allowed for Swap 
-MIN_SWAP_AMOUNT = 800000
+MIN_SWAP_AMOUNT = 50000
 
 # Reward tip. Reward for every finished trade in the referral program (Satoshis)
 REWARD_TIP = 100

api/lightning/node.py

@@ -305,7 +305,7 @@ class LNNode:
                 lnpayment.num_satoshis * float(config("PROPORTIONAL_ROUTING_FEE_LIMIT")),
                 float(config("MIN_FLAT_ROUTING_FEE_LIMIT_REWARD")),
             ))  # 200 ppm or 10 sats
-        timeout_seconds = int(config("PAYOUT_TIMEOUT_SECONDS"))
+        timeout_seconds = int(config("REWARDS_TIMEOUT_SECONDS"))
         request = routerrpc.SendPaymentRequest(payment_request=lnpayment.invoice,
                                                fee_limit_sat=fee_limit_sat,
                                                timeout_seconds=timeout_seconds)

api/logics.py

@@ -4,7 +4,7 @@ from django.utils import timezone
 from api.lightning.node import LNNode
 from django.db.models import Q
 
-from api.models import Order, LNPayment, MarketTick, User, Currency
+from api.models import OnchainPayment, Order, LNPayment, MarketTick, User, Currency
 from api.tasks import send_message
 from decouple import config
 
@@ -494,10 +494,46 @@ class Logics:
         order.save()
         return True, None
 
+    def compute_swap_fee_rate(balance):
+        shape = str(config('SWAP_FEE_SHAPE'))
+
+        if shape == "linear":
+            MIN_SWAP_FEE = float(config('MIN_SWAP_FEE'))
+            MIN_POINT = float(config('MIN_POINT'))
+            MAX_SWAP_FEE = float(config('MAX_SWAP_FEE'))
+            MAX_POINT = float(config('MAX_POINT'))
+            if balance.onchain_fraction > MIN_POINT:
+                swap_fee_rate = MIN_SWAP_FEE
+            else:
+                slope = (MAX_SWAP_FEE - MIN_SWAP_FEE) / (MAX_POINT - MIN_POINT)
+                swap_fee_rate = slope * (balance.onchain_fraction - MAX_POINT) + MAX_SWAP_FEE
+
+        return swap_fee_rate
+
+    @classmethod
+    def create_onchain_payment(cls, order, estimate_sats):
+        '''
+        Creates an empty OnchainPayment for order.payout_tx.
+        It sets the fees to be applied to this order if onchain Swap is used.
+        If the user submits a LN invoice instead. The returned OnchainPayment goes unused.
+        '''
+        onchain_payment = OnchainPayment.objects.create()
+        onchain_payment.suggested_mining_fee_rate = LNNode.estimate_fee(amount_sats=estimate_sats)
+        onchain_payment.swap_fee_rate = cls.compute_swap_fee_rate(onchain_payment.balance)
+        onchain_payment.save()
+
+        order.payout_tx = onchain_payment
+        order.save()
+        return True, None
+
     @classmethod
     def payout_amount(cls, order, user):
         """Computes buyer invoice amount. Uses order.last_satoshis,
-        that is the final trade amount set at Taker Bond time"""
+        that is the final trade amount set at Taker Bond time
+        Adds context for onchain swap.
+        """
+        if not cls.is_buyer(order, user):
+            return False, None
 
         if user == order.maker:
             fee_fraction = FEE * MAKER_FEE_SPLIT
@@ -508,10 +544,25 @@ class Logics:
 
         reward_tip = int(config('REWARD_TIP')) if user.profile.is_referred else 0
 
-        if cls.is_buyer(order, user):
-            invoice_amount = round(order.last_satoshis - fee_sats - reward_tip)  # Trading fee to buyer is charged here.
+        context = {}
+        # context necessary for the user to submit a LN invoice
+        context["invoice_amount"] = round(order.last_satoshis - fee_sats - reward_tip)  # Trading fee to buyer is charged here.
 
-        return True, {"invoice_amount": invoice_amount}
+        # context necessary for the user to submit an onchain address
+        MIN_SWAP_AMOUNT = int(config("MIN_SWAP_AMOUNT"))
+
+        if context["invoice_amount"] < MIN_SWAP_AMOUNT:
+            context["swap_allowed"] = False
+            return True, context
+
+        if order.payout_tx == None:
+            cls.create_onchain_payment(order, estimate_sats=context["invoice_amount"])
+
+        context["swap_allowed"] = True
+        context["suggested_mining_fee_rate"] = order.payout_tx.suggested_mining_fee_rate
+        context["swap_fee_rate"] = order.payout_tx.swap_fee_rate
+
+        return True, context
 
     @classmethod
     def escrow_amount(cls, order, user):

api/models.py

@@ -219,10 +219,11 @@ class OnchainPayment(models.Model):
                                                     blank=False)
 
     # platform onchain/channels balance at creattion, swap fee rate as percent of total volume
-    node_balance = models.ForeignKey(BalanceLog, 
-                                    related_name="balance", 
-                                    on_delete=models.SET_NULL,
-                                    null=True)
+    balance = models.ForeignKey(BalanceLog, 
+                                related_name="balance", 
+                                on_delete=models.SET_NULL,
+                                default=BalanceLog.objects.create)
+
     swap_fee_rate = models.DecimalField(max_digits=4, 
                                         decimal_places=2, 
                                         default=2, 
@@ -452,7 +453,16 @@ class Order(models.Model):
     # buyer payment LN invoice
     payout = models.OneToOneField(
         LNPayment,
-        related_name="order_paid",
+        related_name="order_paid_LN",
+        on_delete=models.SET_NULL,
+        null=True,
+        default=None,
+        blank=True,
+    )
+
+    payout_tx = models.OneToOneField(
+        OnchainPayment,
+        related_name="order_paid_TX",
         on_delete=models.SET_NULL,
         null=True,
         default=None,

api/serializers.py

@@ -54,6 +54,10 @@ class UpdateOrderSerializer(serializers.Serializer):
                                     allow_null=True,
                                     allow_blank=True,
                                     default=None)
+    address = serializers.CharField(max_length=100,
+                                    allow_null=True,
+                                    allow_blank=True,
+                                    default=None)
     statement = serializers.CharField(max_length=10000,
                                       allow_null=True,
                                       allow_blank=True,
@@ -63,6 +67,7 @@ class UpdateOrderSerializer(serializers.Serializer):
             "pause",
             "take",
             "update_invoice",
+            "update_address",
             "submit_statement",
             "dispute",
             "cancel",
@@ -79,6 +84,7 @@ class UpdateOrderSerializer(serializers.Serializer):
         default=None,
     )
     amount = serializers.DecimalField(max_digits=18, decimal_places=8, allow_null=True, required=False, default=None)
+    mining_fee_rate = serializers.DecimalField(max_digits=6, decimal_places=3, allow_null=True, required=False, default=None)
 
 class UserGenSerializer(serializers.Serializer):
     # Mandatory fields

api/tasks.py

@@ -79,7 +79,7 @@ def follow_send_payment(hash):
             float(config("PROPORTIONAL_ROUTING_FEE_LIMIT")),
             float(config("MIN_FLAT_ROUTING_FEE_LIMIT")),
         ))  # 1000 ppm or 10 sats
-    timeout_seconds = int(config("REWARDS_TIMEOUT_SECONDS"))
+    timeout_seconds = int(config("PAYOUT_TIMEOUT_SECONDS"))
 
     request = LNNode.routerrpc.SendPaymentRequest(
         payment_request=lnpayment.invoice,

api/views.py

@@ -420,6 +420,7 @@ class OrderView(viewsets.ViewSet):
         action = serializer.data.get("action")
         invoice = serializer.data.get("invoice")
         address = serializer.data.get("address")
+        mining_fee_rate = serializer.data.get("mining_fee_rate")
         statement = serializer.data.get("statement")
         rating = serializer.data.get("rating")
 
@@ -469,7 +470,7 @@ class OrderView(viewsets.ViewSet):
         # 2.b) If action is 'update invoice'
         if action == "update_address":
             valid, context = Logics.update_address(order, request.user,
-                                                   address)
+                                                   address, mining_fee_rate)
             if not valid:
                 return Response(context, status.HTTP_400_BAD_REQUEST)