Add automatic dispute resolution (#437)

* Add automatic dispute resolution logic

* Small fixes

api/logics.py

@@ -11,6 +11,7 @@ from api.lightning.node import LNNode
 from api.models import Currency, LNPayment, MarketTick, OnchainPayment, Order, User
 from api.tasks import send_notification
 from api.utils import validate_onchain_address
+from chat.models import Message
 
 FEE = float(config("FEE"))
 MAKER_FEE_SPLIT = float(config("MAKER_FEE_SPLIT"))
@@ -428,6 +429,65 @@ class Logics:
         cls.publish_order(order)
         return True
 
+    @classmethod
+    def automatic_dispute_resolution(cls, order):
+        """Simple case where a dispute can be solved with a
+        priori knowledge. For example, a dispute that opens
+        at expiration on an order where one of the participants
+        never sent a message on the chat and never marked 'fiat
+        sent'. By solving the dispute automatically before
+        flagging it as dispute, we avoid having to settle the
+        bonds"""
+
+        # If fiat has been marked as sent, automatic dispute
+        # resolution is not possible.
+        if order.is_fiat_sent:
+            return False
+
+        # If the order has not entered dispute due to time expire
+        # (a user triggered it), automatic dispute resolution is
+        # not possible.
+        if order.expires_at >= timezone.now():
+            return False
+
+        num_messages_taker = len(
+            Message.objects.filter(order=order, sender=order.taker)
+        )
+        num_messages_maker = len(
+            Message.objects.filter(order=order, sender=order.maker)
+        )
+
+        if num_messages_maker == num_messages_taker == 0:
+            cls.return_escrow(order)
+            cls.settle_bond(order.maker_bond)
+            cls.settle_bond(order.taker_bond)
+            order.status = Order.Status.DIS
+
+        elif num_messages_maker == 0:
+            cls.return_escrow(order)
+            cls.settle_bond(order.maker_bond)
+            cls.return_bond(order.taker_bond)
+            cls.add_slashed_rewards(order.maker_bond, order.taker.profile)
+            order.status = Order.Status.MLD
+
+        elif num_messages_maker == 0:
+            cls.return_escrow(order)
+            cls.settle_bond(order.maker_bond)
+            cls.return_bond(order.taker_bond)
+            cls.add_slashed_rewards(order.taker_bond, order.maker.profile)
+            order.status = Order.Status.TLD
+        else:
+            return False
+
+        order.is_disputed = True
+        order.expires_at = timezone.now() + timedelta(
+            seconds=order.t_to_expire(Order.Status.DIS)
+        )
+        order.save()
+        send_notification.delay(order_id=order.id, message="dispute_opened")
+
+        return True
+
     @classmethod
     def open_dispute(cls, order, user=None):
 
@@ -446,6 +506,11 @@ class Logics:
                 "bad_request": "You cannot open a dispute of this order at this stage"
             }
 
+        automatically_solved = cls.automatic_dispute_resolution(order)
+
+        if automatically_solved:
+            return True, None
+
         if not order.trade_escrow.status == LNPayment.Status.SETLED:
             cls.settle_escrow(order)
             cls.settle_bond(order.maker_bond)
@@ -481,9 +546,9 @@ class Logics:
                 "bad_request": "Only orders in dispute accept dispute statements"
             }
 
-        if len(statement) > 10000:
+        if len(statement) > 50000:
             return False, {
-                "bad_statement": "The statement is longer than 10000 characters"
+                "bad_statement": "The statement and chatlogs are longer than 50000 characters"
             }
 
         if len(statement) < 100:
@@ -1601,7 +1666,6 @@ class Logics:
     def add_slashed_rewards(cls, bond, profile):
         """
         When a bond is slashed due to overtime, rewards the user that was waiting.
-        If participants of the order were referred, the reward is given to the referees.
         """
         reward_fraction = float(config("SLASHED_BOND_REWARD_SPLIT"))
         reward = int(bond.num_satoshis * reward_fraction)

api/models.py

@@ -444,10 +444,10 @@ class Order(models.Model):
     # in dispute
     is_disputed = models.BooleanField(default=False, null=False)
     maker_statement = models.TextField(
-        max_length=10000, null=True, default=None, blank=True
+        max_length=50000, null=True, default=None, blank=True
     )
     taker_statement = models.TextField(
-        max_length=10000, null=True, default=None, blank=True
+        max_length=50000, null=True, default=None, blank=True
     )
 
     # LNpayments

api/serializers.py

@@ -492,7 +492,7 @@ class UpdateOrderSerializer(serializers.Serializer):
     routing_budget_ppm = serializers.IntegerField(
         default=0,
         min_value=0,
-        max_value=100000,
+        max_value=100001,
         allow_null=True,
         required=False,
         help_text="Max budget to allocate for routing in PPM",
@@ -501,7 +501,7 @@ class UpdateOrderSerializer(serializers.Serializer):
         max_length=100, allow_null=True, allow_blank=True, default=None
     )
     statement = serializers.CharField(
-        max_length=11000, allow_null=True, allow_blank=True, default=None
+        max_length=500000, allow_null=True, allow_blank=True, default=None
     )
     action = serializers.ChoiceField(
         choices=(