Store proofs used for paying a lightning invoice

cashu/mint/crud.py

@@ -1,6 +1,7 @@
 from typing import Any, List, Optional
 
 from ..core.base import BlindedSignature, Invoice, MintKeyset, Proof
+from ..core.bolt11 import Invoice as bolt11_invoice
 from ..core.db import Connection, Database, table_with_schema
 
 
@@ -47,6 +48,9 @@ async def get_promise(*args, **kwags):
     async def update_lightning_invoice(*args, **kwags):
         return await update_lightning_invoice(*args, **kwags)  # type: ignore
 
+    async def store_invoice_and_proofs(*args, **kwargs):
+        return await store_invoice_and_proofs(*args, **kwargs)
+
 
 async def store_promise(
     db: Database,
@@ -264,3 +268,26 @@ async def get_keyset(
         tuple(values),
     )
     return [MintKeyset(**row) for row in rows]
+
+
+async def store_invoice_and_proofs(
+    db: Database,
+    invoice: bolt11_invoice,
+    proof: Proof,
+    conn: Optional[Connection] = None,
+):
+    await (conn or db).execute(
+        f"""
+            INSERT INTO {table_with_schema(db, 'payments')}
+              (invoice_amount, date, payment_hash, proof_amount, proof_C, proof_secret)
+            VALUES (?, ?, ?, ?, ?, ?)
+            """,
+        (
+            invoice.amount_msat / 1000,
+            invoice.date,
+            invoice.payment_hash,
+            proof.amount,
+            proof.C,
+            proof.secret,
+        ),
+    )

cashu/mint/ledger.py

@@ -955,6 +955,8 @@ async def melt(
             )
 
             if status:
+                for p in proofs:
+                    await self.crud.store_invoice_and_proofs(self.db, invoice_obj, p)
                 logger.trace("invalidating proofs")
                 await self._invalidate_proofs(proofs)
                 logger.trace("invalidated proofs")

cashu/mint/migrations.py

@@ -156,3 +156,22 @@ async def m007_proofs_and_promises_store_id(db: Database):
     await db.execute(
         f"ALTER TABLE {table_with_schema(db, 'promises')} ADD COLUMN id TEXT"
     )
+
+
+async def m008_paid_invoices_and_proofs(db: Database):
+    """
+    Table to store invoices paid by the mint and corresponding proofs.
+    """
+    await db.execute(f"""
+                CREATE TABLE IF NOT EXISTS {table_with_schema(db, 'payments')} (
+                    invoice_amount {db.big_int} NOT NULL,
+                    date TEXT NOT NULL,
+                    payment_hash TEXT NOT NULL,
+                    proof_amount TEXT NOT NULL,
+                    proof_C TEXT NOT NULL,
+                    proof_secret TEXT NOT NULL,
+
+                    UNIQUE (proof_secret)
+
+                );
+            """)