From ff23639ab29891a0bcd404731779f9e04c069f60 Mon Sep 17 00:00:00 2001
From: benesjan <janbenes1234@gmail.com>
Date: Fri, 8 Nov 2024 01:59:00 +0000
Subject: [PATCH] WIP

---
 .../noir-contracts/contracts/fpc_contract/src/main.nr    | 4 ++--
 .../noir-contracts/contracts/token_contract/src/main.nr  | 1 +
 .../aztec.js/src/fee/private_fee_payment_method.ts       | 9 +++++----
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/noir-projects/noir-contracts/contracts/fpc_contract/src/main.nr b/noir-projects/noir-contracts/contracts/fpc_contract/src/main.nr
index 2f922be71e7d..9a9376abfc9f 100644
--- a/noir-projects/noir-contracts/contracts/fpc_contract/src/main.nr
+++ b/noir-projects/noir-contracts/contracts/fpc_contract/src/main.nr
@@ -27,13 +27,13 @@ contract FPC {
     }
 
     #[private]
-    fn fee_entrypoint_private(amount: Field, asset: AztecAddress) {
+    fn fee_entrypoint_private(amount: Field, asset: AztecAddress, nonce: Field) {
         // TODO(PR #8022): Once SharedImmutable performs only 1 merkle proof here, we'll save ~4k gates
         let settings = storage.settings.read_private();
 
         assert(asset == settings.other_asset);
 
-        Token::at(asset).setup_refund(settings.admin, context.msg_sender(), amount).call(
+        Token::at(asset).setup_refund(settings.admin, context.msg_sender(), amount, nonce).call(
             &mut context,
         );
         context.set_as_fee_payer();
diff --git a/noir-projects/noir-contracts/contracts/token_contract/src/main.nr b/noir-projects/noir-contracts/contracts/token_contract/src/main.nr
index 65968ff06228..2c9ee70ec48c 100644
--- a/noir-projects/noir-contracts/contracts/token_contract/src/main.nr
+++ b/noir-projects/noir-contracts/contracts/token_contract/src/main.nr
@@ -675,6 +675,7 @@ contract Token {
         fee_payer: AztecAddress, // Address of the entity which will receive the fee note.
         user: AztecAddress, // A user for which we are setting up the fee refund.
         funded_amount: Field, // The amount the user funded the fee payer with (represents fee limit).
+        nonce: Field // A nonce to make authwitness unique.
     ) {
         // 1. This function is called by fee paying contract (fee_payer) when setting up a refund so we need to support
         // the authwit flow here and check that the user really permitted fee_payer to set up a refund on their behalf.
diff --git a/yarn-project/aztec.js/src/fee/private_fee_payment_method.ts b/yarn-project/aztec.js/src/fee/private_fee_payment_method.ts
index 6da919efc5a3..0578179ef1c6 100644
--- a/yarn-project/aztec.js/src/fee/private_fee_payment_method.ts
+++ b/yarn-project/aztec.js/src/fee/private_fee_payment_method.ts
@@ -59,13 +59,14 @@ export class PrivateFeePaymentMethod implements FeePaymentMethod {
     // We assume 1:1 exchange rate between fee juice and token. But in reality you would need to convert feeLimit
     // (maxFee) to be in token denomination.
     const maxFee = this.setMaxFeeToOne ? Fr.ONE : gasSettings.getFeeLimit();
+    const nonce = Fr.random();
 
     await this.wallet.createAuthWit({
       caller: this.paymentContract,
       action: {
         name: 'setup_refund',
-        args: [this.feeRecipient, this.wallet.getAddress(), maxFee],
-        selector: FunctionSelector.fromSignature('setup_refund((Field),(Field),Field)'),
+        args: [this.feeRecipient, this.wallet.getAddress(), maxFee, nonce],
+        selector: FunctionSelector.fromSignature('setup_refund((Field),(Field),Field,Field)'),
         type: FunctionType.PRIVATE,
         isStatic: false,
         to: this.asset,
@@ -77,10 +78,10 @@ export class PrivateFeePaymentMethod implements FeePaymentMethod {
       {
         name: 'fee_entrypoint_private',
         to: this.paymentContract,
-        selector: FunctionSelector.fromSignature('fee_entrypoint_private(Field,(Field))'),
+        selector: FunctionSelector.fromSignature('fee_entrypoint_private(Field,(Field),Field)'),
         type: FunctionType.PRIVATE,
         isStatic: false,
-        args: [maxFee, this.asset],
+        args: [maxFee, this.asset, nonce],
         returnTypes: [],
       },
     ];