fix: service fee

example.env

@@ -5,8 +5,11 @@ LETSENCRYPT_HOST=
 # server settings
 PORT=8000
 
-#commision for service
-SERVICE_FEE=0.05
+# commission for service
+# transfer fee is a fixed value in ether, 0.01 means 0.01 ether
+TRANSFER_SERVICE_FEE=0.01
+# withdrawal fee is a percentage of the amount, 0.05 means 0.05%
+WITHDRAWAL_SERVICE_FEE=0.05
 REWARD_ADDRESS=
 
 # tx-manager settings

src/config/configuration.ts

@@ -1,4 +1,5 @@
 import { Wallet } from 'ethers';
+import { toWei } from '@/utilities';
 import { NETWORKS_INFO } from '@/constants';
 
 import { version } from '../../package.json';
@@ -8,7 +9,10 @@ export const baseConfig = () => ({
     version,
     port: process.env.PORT,
     chainId: process.env.CHAIN_ID,
-    serviceFee: process.env.SERVICE_FEE,
+    serviceFee: {
+      transfer: toWei(process.env.TRANSFER_SERVICE_FEE).toString(),
+      withdrawal: Number(process.env.WITHDRAWAL_SERVICE_FEE),
+    },
     rewardAddress: process.env.REWARD_ADDRESS,
     address: new Wallet(process.env.PRIVATE_KEY).address,
     gasLimit: NETWORKS_INFO[process.env.CHAIN_ID].gasLimit,

src/constants/variables.ts

@@ -3,11 +3,11 @@ import { ChainId } from '@/types';
 
 const NETWORKS_INFO: { [chainId in ChainId] } = {
   [ChainId.MAINNET]: {
-    gasLimit: BigNumber.from(600000),
+    gasLimit: BigNumber.from(400000),
     minimumBalance: '0.5',
   },
   [ChainId.GOERLI]: {
-    gasLimit: BigNumber.from(600000),
+    gasLimit: BigNumber.from(400000),
     minimumBalance: '0.5',
   },
   [ChainId.OPTIMISM]: {
@@ -20,6 +20,8 @@ const numbers = {
   ZERO: 0,
   ONE: 1,
   TWO: 2,
+  TEN: 10,
+  ONE_HUNDRED: 100,
   SECOND: 1000,
   ETH_DECIMALS: 18,
   MERKLE_TREE_HEIGHT: 23,

src/modules/api/api.service.ts

@@ -21,9 +21,9 @@ class ApiService {
     return {
       health,
       version,
+      serviceFee,
       rewardAddress,
       chainId: Number(chainId),
-      serviceFee: Number(serviceFee),
     };
   }
 

src/modules/api/api.validator.ts

@@ -26,9 +26,6 @@ const arrayType = { type: 'array', items: bytes32Type };
 const transactionSchema = {
   type: 'object',
   properties: {
-    amount: {
-      type: 'string',
-    },
     extData: {
       type: 'object',
       properties: {
@@ -55,7 +52,7 @@ const transactionSchema = {
     },
   },
   additionalProperties: false,
-  required: ['extData', 'args', 'amount'],
+  required: ['extData', 'args'],
 };
 
 const validateTornadoTransaction = ajv.compile(transactionSchema);

src/modules/api/types/index.ts

@@ -3,10 +3,15 @@ type Health = {
   error: string;
 };
 
+type ServiceFee = {
+  transfer: string;
+  withdrawal: number;
+};
+
 type Status = {
   health: Health;
-  rewardAddress: string;
-  version: string;
-  serviceFee: number;
   chainId: number;
+  version: string;
+  rewardAddress: string;
+  serviceFee: ServiceFee;
 };

src/modules/queue/transaction.processor.ts

@@ -7,7 +7,8 @@ import { Injectable } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import { InjectQueue, Process, Processor } from '@nestjs/bull';
 
-import { toWei } from '@/utilities';
+import { numbers } from '@/constants';
+import { toWei, getToIntegerMultiplier } from '@/utilities';
 import { GasPriceService, ProviderService } from '@/services';
 import txMangerConfig from '@/config/txManager.config';
 
@@ -37,7 +38,6 @@ export type ArgsProof = {
 export interface Transaction {
   extData: ExtData;
   args: ArgsProof;
-  amount: string;
   txHash: string;
   status: string;
   confirmations: number;
@@ -62,9 +62,9 @@ export class TransactionProcessor extends BaseProcessor<Transaction> {
     try {
       await job.isActive();
 
-      const { extData, amount } = job.data;
+      const { extData } = job.data;
 
-      await this.checkFee({ fee: extData.fee, amount });
+      await this.checkFee({ fee: extData.fee, externalAmount: extData.extAmount });
       await this.submitTx(job);
     } catch (err) {
       await job.moveToFailed(err, true);
@@ -140,16 +140,29 @@ export class TransactionProcessor extends BaseProcessor<Transaction> {
     };
   }
 
-  async checkFee({ fee, amount }) {
-    const { gasLimit, serviceFee } = this.configService.get('base');
+  getServiceFee(externalAmount) {
+    const amount = BigNumber.from(externalAmount);
+    const { serviceFee } = this.configService.get('base');
+
+    // for withdrawals the amount is negative
+    if (amount.isNegative()) {
+      const integerMultiplier = getToIntegerMultiplier(serviceFee.withdrawal);
+      return BigNumber.from(amount)
+        .mul(serviceFee.withdrawal * integerMultiplier)
+        .div(numbers.ONE_HUNDRED * integerMultiplier);
+    }
+
+    return serviceFee.transfer;
+  }
+
+  async checkFee({ fee, externalAmount }) {
+    const { gasLimit } = this.configService.get('base');
 
     const { fast } = await this.gasPriceService.getGasPrice();
 
     const expense = BigNumber.from(toWei(fast.toString(), 'gwei')).mul(gasLimit);
 
-    const feePercent = BigNumber.from(amount)
-      .mul(serviceFee * 1e10)
-      .div(100 * 1e10);
+    const feePercent = this.getServiceFee(externalAmount);
 
     const desiredFee = expense.add(feePercent);
 

src/utilities/crypto.ts

@@ -10,7 +10,7 @@ export function toChecksumAddress(value: string): string {
   return utils.getAddress(value);
 }
 
-export function toWei(value: string, uintName = 'wei') {
+export function toWei(value: string, uintName = 'ether') {
   return utils.parseUnits(value, uintName);
 }
 
@@ -25,3 +25,13 @@ export function numberToHex(value: number) {
 export function fromWei(balance: BigNumberish) {
   return utils.formatUnits(balance, numbers.ETH_DECIMALS);
 }
+
+export function getToIntegerMultiplier(value: number | string): number {
+  const [, decimals] = String(value).split('.');
+
+  if (!decimals) {
+    return numbers.ZERO;
+  }
+
+  return Math.pow(numbers.TEN, decimals.length);
+}