FakeWallet: provide payment preimage

lnbits/wallets/fake.py

@@ -1,9 +1,8 @@
 import asyncio
 import hashlib
-import random
 from datetime import datetime
 from os import urandom
-from typing import AsyncGenerator, Optional
+from typing import AsyncGenerator, Dict, Optional, Set
 
 from bolt11 import (
     Bolt11,
@@ -29,6 +28,8 @@ from .base import (
 
 class FakeWallet(Wallet):
     queue: asyncio.Queue = asyncio.Queue(0)
+    payment_secrets: Dict[str, str] = dict()
+    paid_invoices: Set[str] = set()
     secret: str = settings.fake_wallet_secret
     privkey: str = hashlib.pbkdf2_hmac(
         "sha256",
@@ -70,20 +71,18 @@ class FakeWallet(Wallet):
         if expiry:
             tags.add(TagChar.expire_time, expiry)
 
-        # random hash
-        checking_id = (
-            self.privkey[:6]
-            + hashlib.sha256(str(random.getrandbits(256)).encode()).hexdigest()[6:]
-        )
-
-        tags.add(TagChar.payment_hash, checking_id)
-
         if payment_secret:
             secret = payment_secret.hex()
         else:
             secret = urandom(32).hex()
         tags.add(TagChar.payment_secret, secret)
 
+        payment_hash = hashlib.sha256(secret.encode()).hexdigest()
+
+        tags.add(TagChar.payment_hash, payment_hash)
+
+        self.payment_secrets[payment_hash] = secret
+
         bolt11 = Bolt11(
             currency="bc",
             amount_msat=MilliSatoshi(amount * 1000),
@@ -93,7 +92,9 @@ class FakeWallet(Wallet):
 
         payment_request = encode(bolt11, self.privkey)
 
-        return InvoiceResponse(True, checking_id, payment_request)
+        return InvoiceResponse(
+            ok=True, checking_id=payment_hash, payment_request=payment_request
+        )
 
     async def pay_invoice(self, bolt11: str, _: int) -> PaymentResponse:
         try:
@@ -101,16 +102,23 @@ class FakeWallet(Wallet):
         except Bolt11Exception as exc:
             return PaymentResponse(ok=False, error_message=str(exc))
 
-        if invoice.payment_hash[:6] == self.privkey[:6]:
+        if invoice.payment_hash in self.payment_secrets:
             await self.queue.put(invoice)
-            return PaymentResponse(True, invoice.payment_hash, 0)
+            self.paid_invoices.add(invoice.payment_hash)
+            return PaymentResponse(
+                ok=True,
+                checking_id=invoice.payment_hash,
+                fee_msat=0,
+                preimage=self.payment_secrets.get(invoice.payment_hash) or "0" * 64,
+            )
         else:
             return PaymentResponse(
                 ok=False, error_message="Only internal invoices can be used!"
             )
 
-    async def get_invoice_status(self, _: str) -> PaymentStatus:
-        return PaymentStatus(None)
+    async def get_invoice_status(self, checking_id: str) -> PaymentStatus:
+        paid = checking_id in self.paid_invoices
+        return PaymentStatus(paid)
 
     async def get_payment_status(self, _: str) -> PaymentStatus:
         return PaymentStatus(None)