Msats to sats floor (#1307)

* make wallet invoice creation tests make full sat invoice

* handle rounded/floored msats for receiving wallets

* msats flooring to sats function

api/paidAction/index.js

@@ -231,7 +231,7 @@ export async function createLightningInvoice (actionType, args, context) {
       }, { models })
 
       const { invoice: wrappedInvoice, maxFee } = await wrapInvoice(
-        bolt11, { description }, { lnd })
+        bolt11, { msats: cost, description }, { lnd })
 
       return {
         bolt11,

lib/format.js

@@ -52,6 +52,7 @@ export const msatsToSats = msats => {
   if (msats === null || msats === undefined) {
     return null
   }
+  // implicitly floors the result
   return Number(BigInt(msats) / 1000n)
 }
 
@@ -62,6 +63,8 @@ export const satsToMsats = sats => {
   return BigInt(sats) * 1000n
 }
 
+export const msatsSatsFloor = msats => satsToMsats(msatsToSats(msats))
+
 export const msatsToSatsDecimal = msats => {
   if (msats === null || msats === undefined) {
     return null

wallets/cln/server.js

@@ -3,7 +3,7 @@ import { createInvoice as clnCreateInvoice } from '@/lib/cln'
 export * from 'wallets/cln'
 
 export const testConnectServer = async ({ socket, rune, cert }) => {
-  return await createInvoice({ msats: 1, expiry: 1, description: '' }, { socket, rune, cert })
+  return await createInvoice({ msats: 1000, expiry: 1, description: '' }, { socket, rune, cert })
 }
 
 export const createInvoice = async (

wallets/lightning-address/server.js

@@ -1,3 +1,4 @@
+import { msatsSatsFloor } from '@/lib/format'
 import { lnAddrOptions } from '@/lib/lnurl'
 
 export * from 'wallets/lightning-address'
@@ -12,6 +13,10 @@ export const createInvoice = async (
 ) => {
   const { callback, commentAllowed } = await lnAddrOptions(address)
   const callbackUrl = new URL(callback)
+
+  // most lnurl providers suck nards so we have to floor to nearest sat
+  msats = msatsSatsFloor(msats)
+
   callbackUrl.searchParams.append('amount', msats)
 
   if (commentAllowed >= description?.length) {

wallets/lnbits/server.js

@@ -1,7 +1,7 @@
 export * from 'wallets/lnbits'
 
 export async function testConnectServer ({ url, invoiceKey }) {
-  return await createInvoice({ msats: 1, expiry: 1 }, { url, invoiceKey })
+  return await createInvoice({ msats: 1000, expiry: 1 }, { url, invoiceKey })
 }
 
 export async function createInvoice (

wallets/lnd/server.js

@@ -4,7 +4,7 @@ import { authenticatedLndGrpc, createInvoice as lndCreateInvoice } from 'ln-serv
 export * from 'wallets/lnd'
 
 export const testConnectServer = async ({ cert, macaroon, socket }) => {
-  return await createInvoice({ msats: 1, expiry: 1 }, { cert, macaroon, socket })
+  return await createInvoice({ msats: 1000, expiry: 1 }, { cert, macaroon, socket })
 }
 
 export const createInvoice = async (

wallets/server.js

@@ -53,7 +53,21 @@ export async function createInvoice (userId, { msats, description, descriptionHa
 
       const bolt11 = await parsePaymentRequest({ request: invoice })
       if (BigInt(bolt11.mtokens) !== BigInt(msats)) {
-        throw new Error('invoice has incorrect amount')
+        if (BigInt(bolt11.mtokens) > BigInt(msats)) {
+          throw new Error(`invoice is for an amount greater than requested ${bolt11.mtokens} > ${msats}`)
+        }
+        if (BigInt(bolt11.mtokens) === 0n) {
+          throw new Error('invoice is for 0 msats')
+        }
+        if (BigInt(msats) - BigInt(bolt11.mtokens) >= 1000n) {
+          throw new Error(`invoice has a different satoshi amount ${bolt11.mtokens} !== ${msats}`)
+        }
+
+        await addWalletLog({
+          wallet,
+          level: 'INFO',
+          message: `wallet does not support msats so we floored ${msats} msats to nearest sat ${BigInt(bolt11.mtokens)} msats`
+        }, { models })
       }
 
       return { invoice, wallet }

wallets/wrap.js

@@ -19,10 +19,10 @@ const ZAP_SYBIL_FEE_MULT = 10 / 9 // the fee for the zap sybil service
   @param options {object}
   @returns {
     invoice: the wrapped incoming invoice,
-    outgoingMaxFeeMsat: number
+    maxFee: number
   }
 */
-export default async function wrapInvoice (bolt11, { description, descriptionHash }, { lnd }) {
+export default async function wrapInvoice (bolt11, { msats, description, descriptionHash }, { lnd }) {
   try {
     console.group('wrapInvoice', description)
 
@@ -38,7 +38,7 @@ export default async function wrapInvoice (bolt11, { description, descriptionHas
 
     console.log('invoice', inv.mtokens, inv.expires_at, inv.cltv_delta)
 
-    // validate amount
+    // validate outgoing amount
     if (inv.mtokens) {
       outgoingMsat = toPositiveNumber(inv.mtokens)
       if (outgoingMsat < MIN_OUTGOING_MSATS) {
@@ -48,7 +48,17 @@ export default async function wrapInvoice (bolt11, { description, descriptionHas
         throw new Error(`Invoice amount is too high: ${outgoingMsat}`)
       }
     } else {
-      throw new Error('Invoice amount is missing')
+      throw new Error('Outgoing invoice is missing amount')
+    }
+
+    // validate incoming amount
+    if (msats) {
+      msats = toPositiveNumber(msats)
+      if (outgoingMsat * ZAP_SYBIL_FEE_MULT > msats) {
+        throw new Error('Sybil fee is too low')
+      }
+    } else {
+      throw new Error('Incoming invoice amount is missing')
     }
 
     // validate features
@@ -145,13 +155,13 @@ export default async function wrapInvoice (bolt11, { description, descriptionHas
 
     // validate the fee budget
     const minEstFees = toPositiveNumber(routingFeeMsat)
-    const outgoingMaxFeeMsat = Math.ceil(outgoingMsat * MAX_FEE_ESTIMATE_PERCENT)
+    const outgoingMaxFeeMsat = Math.ceil(msats * MAX_FEE_ESTIMATE_PERCENT)
     if (minEstFees > outgoingMaxFeeMsat) {
       throw new Error('Estimated fees are too high')
     }
 
     // calculate the incoming invoice amount, without fees
-    wrapped.mtokens = String(Math.ceil(outgoingMsat * ZAP_SYBIL_FEE_MULT))
+    wrapped.mtokens = String(msats)
     console.log('outgoingMaxFeeMsat', outgoingMaxFeeMsat, 'wrapped', wrapped)
 
     return {

worker/autowithdraw.js

@@ -1,4 +1,4 @@
-import { msatsToSats, satsToMsats } from '@/lib/format'
+import { msatsSatsFloor, msatsToSats, satsToMsats } from '@/lib/format'
 import { createWithdrawal } from '@/api/resolvers/wallet'
 import { createInvoice } from 'wallets/server'
 
@@ -12,14 +12,13 @@ export async function autoWithdraw ({ data: { id }, models, lnd }) {
   // excess must be greater than 10% of threshold
   if (excess < Number(threshold) * 0.1) return
 
-  const maxFeeMsats = Math.ceil(excess * (user.autoWithdrawMaxFeePercent / 100.0))
-  const msats = excess - maxFeeMsats
+  // floor fee to nearest sat but still denominated in msats
+  const maxFeeMsats = msatsSatsFloor(Math.ceil(excess * (user.autoWithdrawMaxFeePercent / 100.0)))
+  // msats will be floored by createInvoice if it needs to be
+  const msats = BigInt(excess) - maxFeeMsats
 
   // must be >= 1 sat
-  if (msats < 1000) return
-
-  // maxFee is expected to be in sats, ie "msatsFeePaying" is always divisible by 1000
-  const maxFee = msatsToSats(maxFeeMsats)
+  if (msats < 1000n) return
 
   // check that
   // 1. the user doesn't have an autowithdraw pending
@@ -33,7 +32,7 @@ export async function autoWithdraw ({ data: { id }, models, lnd }) {
       OR (
         status <> 'CONFIRMED' AND
         now() < created_at + interval '1 hour' AND
-        "msatsFeePaying" >= ${satsToMsats(maxFee)}
+        "msatsFeePaying" >= ${maxFeeMsats}
       ))
     )`
 
@@ -41,6 +40,6 @@ export async function autoWithdraw ({ data: { id }, models, lnd }) {
 
   const { invoice, wallet } = await createInvoice(id, { msats, description: 'SN: autowithdrawal', expiry: 360 }, { models })
   return await createWithdrawal(null,
-    { invoice, maxFee },
+    { invoice, maxFee: msatsToSats(maxFeeMsats) },
     { me: { id }, models, lnd, walletId: wallet.id })
 }