From 6e271d8ce4edfa8afcd8cbbc471cf371acfeb98b Mon Sep 17 00:00:00 2001
From: Padreug <padreug@aiolabs.dev>
Date: Mon, 1 Jun 2026 10:53:26 +0200
Subject: [PATCH] refactor(state-machine): zero fee fraction defaults
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`initialContext.cashInFeeFraction` / `cashOutFeeFraction` drop from
0.0333 / 0.0777 → 0. The state-machine no longer carries a fee
opinion; callers (the renderer's atm-store) are responsible for
supplying explicit fractions via `createATMMachine(..., options)`.

Why now: aiolabs/lamassu-next#57 makes the operator's Nostr-pushed
fee config the source of truth on the ATM. Keeping non-zero defaults
in the state machine would mean a misconfigured caller could silently
fall back to a 7.77% cash-out fee instead of failing closed into the
"awaiting fee configuration" maintenance screen.

Extracts `ATMMachineOptions` as a named interface (was inline). No
functional change to the option spread.

Updates the `should calculate sats amount from fiat with fee` test
to pass `cashOutFeeFraction: 0.0777` explicitly so it still exercises
the cash-out fee math; the post-refactor zero default would otherwise
land 50,000 sats instead of 53,885.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 packages/state-machine/src/__tests__/machine.test.ts |  4 +++-
 packages/state-machine/src/machine.ts                |  8 +++++++-
 packages/state-machine/src/types.ts                  | 10 +++++++---
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/packages/state-machine/src/__tests__/machine.test.ts b/packages/state-machine/src/__tests__/machine.test.ts
index 0d59d12..4d50ad2 100644
--- a/packages/state-machine/src/__tests__/machine.test.ts
+++ b/packages/state-machine/src/__tests__/machine.test.ts
@@ -153,7 +153,9 @@ describe('ATM State Machine', () => {
     })
 
     it('should calculate sats amount from fiat with fee', async () => {
-      const machine = createATMMachine(mockServices)
+      // Fee fractions default to 0 post-aiolabs/lamassu-next#57; pass
+      // explicit values to exercise the cash-out fee math.
+      const machine = createATMMachine(mockServices, { cashOutFeeFraction: 0.0777 })
       const actor = createActor(machine)
       actor.start()
 
diff --git a/packages/state-machine/src/machine.ts b/packages/state-machine/src/machine.ts
index b7dbce1..fc87fca 100644
--- a/packages/state-machine/src/machine.ts
+++ b/packages/state-machine/src/machine.ts
@@ -18,9 +18,15 @@ import {
 /**
  * Create the ATM state machine with injected services
  */
+export interface ATMMachineOptions {
+  currency?: string
+  cashInFeeFraction?: number
+  cashOutFeeFraction?: number
+}
+
 export function createATMMachine(
   services: Partial<ATMServices> = {},
-  options?: { currency?: string; cashInFeeFraction?: number; cashOutFeeFraction?: number }
+  options?: ATMMachineOptions
 ) {
   return setup({
     types: {
diff --git a/packages/state-machine/src/types.ts b/packages/state-machine/src/types.ts
index 2fc6fde..b99c78b 100644
--- a/packages/state-machine/src/types.ts
+++ b/packages/state-machine/src/types.ts
@@ -163,9 +163,13 @@ export const initialContext: ATMContext = {
   satsAmount: 0,
   currency: 'USD',
   exchangeRate: 0,
-  feeFraction: 0.0333,
-  cashInFeeFraction: 0.0333,
-  cashOutFeeFraction: 0.0777,
+  // Zero defaults — operator's Nostr-pushed fee config is the source of
+  // truth (aiolabs/lamassu-next#57). The atm-store gates production boot
+  // on a persisted config existing; no transaction reaches this context
+  // until the operator's publish has been received.
+  feeFraction: 0,
+  cashInFeeFraction: 0,
+  cashOutFeeFraction: 0,
   availableBalance: 0,
   invoice: null,
   clinkOffer: null,