Fix Quipuswap empty pool edge case (#42)

Author: droserasprout

src/demo_quipuswap/handlers/on_fa12_divest_liquidity.py

@@ -29,7 +29,14 @@ async def on_fa12_divest_liquidity(
     token_qty = Decimal(transfer.parameter.value) / (10 ** decimals)
     shares_qty = int(divest_liquidity.parameter.shares)
 
-    price = (Decimal(storage.storage.tez_pool) / (10 ** 6)) / (Decimal(storage.storage.token_pool) / (10 ** decimals))
+    tez_pool = Decimal(storage.storage.tez_pool) / (10 ** 6)
+    token_pool = Decimal(storage.storage.token_pool) / (10 ** decimals)
+    if tez_pool and token_pool:
+        price = tez_pool / token_pool
+    else:
+        last_trade = await models.Trade.filter(symbol=symbol).order_by('-id').first()
+        assert last_trade
+        price = last_trade.price
     share_px = (tez_qty + price * token_qty) / shares_qty
 
     position.realized_pl += shares_qty * (share_px - position.avg_share_px)

src/demo_quipuswap/handlers/on_fa20_divest_liquidity.py

@@ -27,11 +27,20 @@ async def on_fa20_divest_liquidity(
     transaction = next(op for op in ctx.operations if op.amount)
 
     tez_qty = Decimal(transaction.amount) / (10 ** 6)
-    token_qty = Decimal(transfer.parameter.__root__[0].txs[0].amount) / (10 ** decimals)
+    token_qty = sum(Decimal(tx.amount) for tx in transfer.parameter.__root__[0].txs) / (10 ** decimals)
     shares_qty = int(divest_liquidity.parameter.shares)
 
-    price = (Decimal(storage.storage.tez_pool) / (10 ** 6)) / (Decimal(storage.storage.token_pool) / (10 ** decimals))
-    share_px = (tez_qty + price * token_qty) / shares_qty
+    tez_pool = Decimal(storage.storage.tez_pool) / (10 ** 6)
+    token_pool = Decimal(storage.storage.token_pool) / (10 ** decimals)
+    if tez_pool and token_pool:
+        price = tez_pool / token_pool
+        share_px = (tez_qty + price * token_qty) / shares_qty
+    else:
+        last_trade = await models.Trade.filter(symbol=symbol).order_by('-id').first()
+        assert last_trade
+        price = last_trade.price
+        shares_qty = 0
+        share_px = 0
 
     position.realized_pl += shares_qty * (share_px - position.avg_share_px)
     position.shares_qty -= shares_qty  # type: ignore

src/demo_quipuswap/handlers/on_fa20_invest_liquidity.py

@@ -26,7 +26,7 @@ async def on_fa20_invest_liquidity(
     position, _ = await models.Position.get_or_create(trader=trader, symbol=symbol)
 
     tez_qty = Decimal(invest_liquidity.data.amount) / (10 ** 6)
-    token_qty = Decimal(transfer.parameter.__root__[0].txs[0].amount) / (10 ** decimals)
+    token_qty = sum(Decimal(tx.amount) for tx in transfer.parameter.__root__[0].txs) / (10 ** decimals)
     new_shares_qty = int(storage.storage.ledger[trader].balance) + int(storage.storage.ledger[trader].frozen_balance)  # type: ignore
 
     price = (Decimal(storage.storage.tez_pool) / (10 ** 6)) / (Decimal(storage.storage.token_pool) / (10 ** decimals))

src/demo_quipuswap/handlers/on_fa2_tez_to_token.py

@@ -21,7 +21,7 @@ async def on_fa2_tez_to_token(
     trader = tez_to_token_payment.data.sender_address
 
     min_token_quantity = Decimal(tez_to_token_payment.parameter.min_out) / (10 ** decimals)
-    token_quantity = Decimal(transfer.parameter.__root__[0].txs[0].amount) / (10 ** decimals)
+    token_quantity = sum(Decimal(tx.amount) for tx in transfer.parameter.__root__[0].txs) / (10 ** decimals)
     tez_quantity = Decimal(tez_to_token_payment.data.amount) / (10 ** 6)
     assert min_token_quantity <= token_quantity, tez_to_token_payment.data.hash