fix: negative bigint formatting and session remaining_secs clock

.changelog/negative-format-and-session-now.md

@@ -0,0 +1,5 @@
+---
+wallet-cli: patch
+---
+
+Format negative bigint token and credit balances without embedding the minus sign inside padded fractional digits. Cache `nowSeconds()` in session list remaining-seconds so a clock tick cannot produce a negative grace countdown.

src/commands/sessions.ts

@@ -654,6 +654,8 @@ function closeTarget(record: ChannelRecord) {
 }
 
 function sessionItem(record: ChannelRecord) {
+  // Single clock read: comparing and subtracting separate nowSeconds() calls can go negative.
+  const now = nowSeconds();
   const spent =
     record.accepted_cumulative > 0n ? record.accepted_cumulative : record.cumulative_amount;
   const remaining = record.deposit > spent ? record.deposit - spent : 0n;
@@ -669,8 +671,7 @@ function sessionItem(record: ChannelRecord) {
     status,
     ...(status === "closing" || status === "finalizable"
       ? {
-          remaining_secs:
-            record.grace_ready_at > nowSeconds() ? record.grace_ready_at - nowSeconds() : 0,
+          remaining_secs: record.grace_ready_at > now ? record.grace_ready_at - now : 0,
         }
       : {}),
     created_at: formatUnixTimestamp(record.created_at),

src/shared/utils.ts

@@ -38,20 +38,29 @@ export function formatMicroUnits(value: string) {
 }
 
 export function formatTokenUnits(value: bigint, decimals: number) {
+  const negative = value < 0n;
+  const abs = negative ? -value : value;
   const divisor = 10n ** BigInt(decimals);
-  const whole = value / divisor;
-  const fractional = value % divisor;
-  if (decimals === 0) return whole.toString();
-  if (fractional === 0n) return `${whole}.${"0".repeat(decimals)}`;
-  return `${whole}.${fractional.toString().padStart(decimals, "0")}`;
+  const whole = abs / divisor;
+  const fractional = abs % divisor;
+  const formatted =
+    decimals === 0
+      ? whole.toString()
+      : fractional === 0n
+        ? `${whole}.${"0".repeat(decimals)}`
+        : `${whole}.${fractional.toString().padStart(decimals, "0")}`;
+  return negative ? `-${formatted}` : formatted;
 }
 
 export function formatCreditBalance(rawBalance: bigint) {
+  const negative = rawBalance < 0n;
+  const abs = negative ? -rawBalance : rawBalance;
   const divisor = 10_000n;
-  const whole = rawBalance / divisor;
-  const fractional = rawBalance % divisor;
-  if (fractional === 0n) return whole.toString();
-  return `${whole}.${fractional.toString().padStart(4, "0")}`;
+  const whole = abs / divisor;
+  const fractional = abs % divisor;
+  const formatted =
+    fractional === 0n ? whole.toString() : `${whole}.${fractional.toString().padStart(4, "0")}`;
+  return negative ? `-${formatted}` : formatted;
 }
 
 export function isChannelId(value: string) {

test/format-units.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, it } from "vitest";
+
+import { formatCreditBalance, formatTokenUnits } from "../src/shared/utils.js";
+
+describe("formatTokenUnits", () => {
+  it("formats non-negative values", () => {
+    expect(formatTokenUnits(0n, 6)).toBe("0.000000");
+    expect(formatTokenUnits(1_000_000n, 6)).toBe("1.000000");
+    expect(formatTokenUnits(1_234_567n, 6)).toBe("1.234567");
+    expect(formatTokenUnits(42n, 0)).toBe("42");
+  });
+
+  it("keeps the sign outside padded fractional digits for negative values", () => {
+    expect(formatTokenUnits(-5n, 6)).toBe("-0.000005");
+    expect(formatTokenUnits(-1_234_567n, 6)).toBe("-1.234567");
+    expect(formatTokenUnits(-42n, 0)).toBe("-42");
+  });
+});
+
+describe("formatCreditBalance", () => {
+  it("formats non-negative credit balances", () => {
+    expect(formatCreditBalance(0n)).toBe("0");
+    expect(formatCreditBalance(10_000n)).toBe("1");
+    expect(formatCreditBalance(12_345n)).toBe("1.2345");
+  });
+
+  it("keeps the sign outside padded fractional digits for negative balances", () => {
+    expect(formatCreditBalance(-5n)).toBe("-0.0005");
+    expect(formatCreditBalance(-12_345n)).toBe("-1.2345");
+  });
+});