From ad906df788939ebe7ba1d12428c478cc366a1594 Mon Sep 17 00:00:00 2001
From: callebtc <93376500+callebtc@users.noreply.github.com>
Date: Sun, 18 Feb 2024 12:24:41 +0100
Subject: [PATCH] Mint: blink fix fee estimation (#439)

* blink: fix fee esimation

* fix line length

* fix line length

* fix line length

* remove noqa
---
 cashu/lightning/blink.py           |  2 +-
 cashu/mint/ledger.py               |  2 ++
 tests/test_mint_lightning_blink.py | 12 ++++++++++--
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/cashu/lightning/blink.py b/cashu/lightning/blink.py
index d4f11e8..24b223d 100644
--- a/cashu/lightning/blink.py
+++ b/cashu/lightning/blink.py
@@ -327,7 +327,7 @@ class BlinkWallet(LightningBackend):
         fees_response_msat = int(resp["data"]["lnInvoiceFeeProbe"]["amount"]) * 1000
         # we either take fee_msat_response or the BLINK_MAX_FEE_PERCENT, whichever is higher
         fees_msat = max(
-            fees_response_msat, math.ceil(amount_msat * BLINK_MAX_FEE_PERCENT)
+            fees_response_msat, math.ceil(amount_msat / 100 * BLINK_MAX_FEE_PERCENT)
         )
 
         fees = Amount(unit=Unit.msat, amount=fees_msat)
diff --git a/cashu/mint/ledger.py b/cashu/mint/ledger.py
index 1a97364..3782b0c 100644
--- a/cashu/mint/ledger.py
+++ b/cashu/mint/ledger.py
@@ -380,6 +380,7 @@ class Ledger(LedgerVerification, LedgerSpendingConditions):
         method = Method[quote.method]
 
         if not quote.paid:
+            assert quote.checking_id, "quote has no checking id"
             logger.trace(f"Lightning: checking invoice {quote.checking_id}")
             status: PaymentStatus = await self.backends[method][
                 unit
@@ -482,6 +483,7 @@ class Ledger(LedgerVerification, LedgerSpendingConditions):
             assert mint_quote.method == method.name, "methods do not match"
             assert not mint_quote.paid, "mint quote already paid"
             assert not mint_quote.issued, "mint quote already issued"
+            assert mint_quote.checking_id, "mint quote has no checking id"
             payment_quote = PaymentQuoteResponse(
                 checking_id=mint_quote.checking_id,
                 amount=Amount(unit, mint_quote.amount),
diff --git a/tests/test_mint_lightning_blink.py b/tests/test_mint_lightning_blink.py
index 7339fc2..3071c69 100644
--- a/tests/test_mint_lightning_blink.py
+++ b/tests/test_mint_lightning_blink.py
@@ -49,7 +49,6 @@ async def test_blink_create_invoice():
             }
         }
     }
-
     respx.post(blink.endpoint).mock(return_value=Response(200, json=mock_response))
     invoice = await blink.create_invoice(Amount(Unit.sat, 1000))
     assert invoice.checking_id == invoice.payment_request
@@ -129,9 +128,18 @@ async def test_blink_get_payment_status():
 @respx.mock
 @pytest.mark.asyncio
 async def test_blink_get_payment_quote():
+    # response says 1 sat fees but invoice * 0.5% is 5 sat so we expect 5 sat
+    mock_response = {"data": {"lnInvoiceFeeProbe": {"amount": 1}}}
+    respx.post(blink.endpoint).mock(return_value=Response(200, json=mock_response))
+    quote = await blink.get_payment_quote(payment_request)
+    assert quote.checking_id == payment_request
+    assert quote.amount == Amount(Unit.msat, 1000000)  # msat
+    assert quote.fee == Amount(Unit.msat, 5000)  # msat
+
+    # response says 10 sat fees but invoice * 0.5% is 5 sat so we expect 10 sat
     mock_response = {"data": {"lnInvoiceFeeProbe": {"amount": 10}}}
     respx.post(blink.endpoint).mock(return_value=Response(200, json=mock_response))
     quote = await blink.get_payment_quote(payment_request)
     assert quote.checking_id == payment_request
     assert quote.amount == Amount(Unit.msat, 1000000)  # msat
-    assert quote.fee == Amount(Unit.msat, 500000)  # msat
+    assert quote.fee == Amount(Unit.msat, 10000)  # msat