From b6c4d676f6fba0ff1d8371c59e1501bab1fbb414 Mon Sep 17 00:00:00 2001
From: callebtc <93376500+callebtc@users.noreply.github.com>
Date: Sat, 1 Oct 2022 02:52:48 +0200
Subject: [PATCH] refactor deterministic key generation

---
 cashu/mint/ledger.py   |  2 +-
 cashu/wallet/cli.py    | 11 ++++++-----
 cashu/wallet/wallet.py | 13 +++++++++----
 tests/test_wallet.py   |  2 +-
 4 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/cashu/mint/ledger.py b/cashu/mint/ledger.py
index 1c4874f..5896aa3 100644
--- a/cashu/mint/ledger.py
+++ b/cashu/mint/ledger.py
@@ -239,7 +239,7 @@ class Ledger:
             raise Exception("split amount is higher than the total sum.")
         # verify that only unique proofs and outputs were used
         if not self._verify_no_duplicates(proofs, outputs):
-            raise Exception("duplicate proofs or promises.")
+            raise Exception("empty or duplicate proofs or promises.")
         # verify that outputs have the correct amount
         if not self._verify_outputs(total, amount, outputs):
             raise Exception("split of promises is not as expected.")
diff --git a/cashu/wallet/cli.py b/cashu/wallet/cli.py
index c9d5b77..a094aba 100755
--- a/cashu/wallet/cli.py
+++ b/cashu/wallet/cli.py
@@ -172,9 +172,11 @@ async def pending(ctx):
     wallet.load_mint()
     reserved_proofs = await get_reserved_proofs(wallet.db)
     if len(reserved_proofs):
+        print(f"--------------------------\n")
         sorted_proofs = sorted(reserved_proofs, key=itemgetter("send_id"))
-        grouped_proofs = groupby(sorted_proofs, key=itemgetter("send_id"))
-        for i, (key, value) in enumerate(grouped_proofs):
+        for i, (key, value) in enumerate(
+            groupby(sorted_proofs, key=itemgetter("send_id"))
+        ):
             grouped_proofs = list(value)
             token = await wallet.serialize_proofs(grouped_proofs)
             token_hidden_secret = await wallet.serialize_proofs(
@@ -184,11 +186,10 @@ async def pending(ctx):
                 int(grouped_proofs[0].time_reserved)
             ).strftime("%Y-%m-%d %H:%M:%S")
             print(
-                f"Amount: {sum([p['amount'] for p in grouped_proofs])} sat Sent: {reserved_date} ID: {key} #{i+1}/{len(grouped_proofs)}\n"
+                f"#{i} Amount: {sum([p['amount'] for p in grouped_proofs])} sat Time: {reserved_date} ID: {key}\n"
             )
             print(f"With secret: {token}\n\nSecretless: {token_hidden_secret}\n")
-            if i < len(grouped_proofs) - 1:
-                print(f"--------------------------\n")
+            print(f"--------------------------\n")
     wallet.status()
 
 
diff --git a/cashu/wallet/wallet.py b/cashu/wallet/wallet.py
index e946855..21eb275 100644
--- a/cashu/wallet/wallet.py
+++ b/cashu/wallet/wallet.py
@@ -103,6 +103,11 @@ class LedgerAPI:
             if await secret_used(s, db=self.db):
                 raise Exception(f"secret already used: {s}")
 
+    @staticmethod
+    def generate_deterministic_secrets(secret, n):
+        """`secret` is the base string that will be tweaked n times"""
+        return [f"{secret}_{i}" for i in range(n)]
+
     async def mint(self, amounts, payment_hash=None):
         """Mints new coins and returns a proof of promise."""
         secrets = [self._generate_secret() for s in range(len(amounts))]
@@ -146,8 +151,9 @@ class LedgerAPI:
             secrets = [self._generate_secret() for _ in range(len(amounts))]
         else:
             logger.debug(f"Creating proofs with custom secret: {snd_secret}")
-            # TODO: serialize them here
-            snd_secrets = [f"{snd_secret}_{i}" for i in range(len(snd_outputs))]
+            snd_secrets = self.generate_deterministic_secrets(
+                snd_secret, len(snd_outputs)
+            )
             assert len(snd_secrets) == len(
                 snd_outputs
             ), "number of snd_secrets does not match number of ouptus."
@@ -241,8 +247,7 @@ class Wallet(LedgerAPI):
     async def redeem(self, proofs: List[Proof], snd_secret: str = None):
         if snd_secret:
             logger.debug(f"Redeption secret: {snd_secret}")
-            # TODO: serialize them here
-            snd_secrets = [f"{snd_secret}_{i}" for i in range(len(proofs))]
+            snd_secrets = self.generate_deterministic_secrets(snd_secret, len(proofs))
             assert len(proofs) == len(snd_secrets)
             # overload proofs with custom secrets for redemption
             for p, s in zip(proofs, snd_secrets):
diff --git a/tests/test_wallet.py b/tests/test_wallet.py
index 4f147ef..e90fdfa 100644
--- a/tests/test_wallet.py
+++ b/tests/test_wallet.py
@@ -135,7 +135,7 @@ async def run_test():
         p.secret = ""
     await assert_err(
         wallet2.redeem(w1_snd_proofs_manipulated),
-        "Error: duplicate proofs or promises.",
+        "Error: empty or duplicate proofs or promises.",
     )
 
     # redeem with wrong secret