cardano: withdraw rewards

Author: nooxx

examples/ada.ts

@@ -19,8 +19,7 @@ const f = async () => {
       ],
     });
 
-    const tx = await k.ada.craftStakeTx(
-      '376acfff-e35d-4b7c-90da-c6acb8ea7197',
+    const tx = await k.ada.craftWithdrawRewardsTx(
       'addr_test1qpy358g8glafrucevf0rjpmzx2k5esn5uvjh7dzuakpdhv4g2egyt3y3qw6jrguz0lmyhxygjdg2ytaf5z6ueaety7dsmpcee5',
     );
     const txSigned = await k.ada.sign('vault1', tx);

src/globals.ts

@@ -23,5 +23,13 @@ export const ADDRESSES = {
     mainnet: {
       validatorAddress: 'cosmosvaloper1uxlf7mvr8nep3gm7udf2u9remms2jyjqvwdul2'
     }
+  },
+  ada: {
+    testnet: {
+      poolId: 'pool1xjt9ylq7rvsd2mxf6njkzhrkhgjzrtflz039vxs66ntvv82rdky'
+    },
+    mainnet: {
+      poolId: 'pool10rdglgh4pzvkf936p2m669qzarr9dusrhmmz9nultm3uvq4eh5k'
+    }
   }
 };

src/services/ada.ts

@@ -26,7 +26,7 @@ import {
   Value,
   Vkey,
   Vkeywitness,
-  Vkeywitnesses,
+  Vkeywitnesses, Withdrawals,
 } from '@emurgo/cardano-serialization-lib-nodejs';
 import { Service } from "./service";
 import { AdaStakeOptions, InternalAdaConfig, UTXO } from "../types/ada";
@@ -35,6 +35,7 @@ import {
   BlockfrostServerError,
 } from "@blockfrost/blockfrost-js";
 import { InvalidIntegration, InvalidSignature } from "../errors/integrations";
+import { ADDRESSES } from "../globals";
 
 const CARDANO_PARAMS = {
   COINS_PER_UTXO_WORD: '34482',
@@ -44,6 +45,7 @@ const CARDANO_PARAMS = {
   MIN_FEE_B: '155381',
   POOL_DEPOSIT: '500000000',
   KEY_DEPOSIT: '2000000',
+  MIN_UTXO_VALUE_ADA_ONLY: 1000000,
 };
 
 export class AdaService extends Service {
@@ -66,8 +68,8 @@ export class AdaService extends Service {
     options?: AdaStakeOptions,
   ): Promise<Transaction> {
     const poolId = options?.poolId ? options.poolId :
-      this.testnet ? 'pool1xjt9ylq7rvsd2mxf6njkzhrkhgjzrtflz039vxs66ntvv82rdky' :
-        'pool10rdglgh4pzvkf936p2m669qzarr9dusrhmmz9nultm3uvq4eh5k';
+      this.testnet ? ADDRESSES.ada.testnet.poolId :
+        ADDRESSES.ada.mainnet.poolId;
 
     try {
       const utxos = await this.getUtxos(walletAddress);
@@ -115,6 +117,62 @@ export class AdaService extends Service {
     }
   }
 
+  /**
+   * Craft ada withdraw rewards transaction
+   * @param walletAddress wallet delegating that will receive the rewards
+   * @param amountToWithdraw amount of rewards to withdraw, if not provided all rewards are withdrawn
+   */
+  async craftWithdrawRewardsTx(
+    walletAddress: string,
+    amountToWithdraw?: number,
+  ): Promise<Transaction> {
+
+
+    try {
+      const utxos = await this.getUtxos(walletAddress);
+      const address = await this.client.addresses(walletAddress);
+      if (!address.stake_address) {
+        throw Error('No stake address');
+      }
+
+      const stakeKeyHash = await this.getStakeKeyHash(address.stake_address);
+      if (!stakeKeyHash) {
+        throw Error('Could not hash stake key');
+      }
+
+      const withdrawals = Withdrawals.new();
+      const rewardAddress = RewardAddress.from_address(Address.from_bech32(address.stake_address));
+
+      if (!rewardAddress) {
+        throw Error('Could not retrieve rewards address');
+      }
+
+      const rewardsHistory = await this.client.accountsRewardsAll(address.stake_address);
+      let totalRewards: number = 0;
+      for(const rewards of rewardsHistory){
+        totalRewards += Number(rewards.amount);
+      }
+
+      const amountToWithdrawLovelace = amountToWithdraw ? this.adaToLovelace(amountToWithdraw.toString()) : totalRewards.toString();
+      withdrawals.insert(rewardAddress, BigNum.from_str(amountToWithdrawLovelace));
+
+      let walletBalance = 0;
+      for(const utxo of utxos){
+        if(utxo.amount.length > 0 && utxo.amount[0].unit === 'lovelace'){
+          walletBalance += Number(utxo.amount[0].quantity);
+        }
+      }
+      // Not sure about this value (might need to be BALANCE + REWARDS + FEES)
+      const outAmount = (CARDANO_PARAMS.MIN_UTXO_VALUE_ADA_ONLY + totalRewards).toString();
+      const outputs = this.prepareTx(outAmount, walletAddress);
+
+      const tx = await this.buildTx(walletAddress, utxos, outputs, null, withdrawals);
+      return tx;
+    } catch (error) {
+      throw error;
+    }
+  }
+
   /**
    * Prepare outputs (destination addresses and amounts) for a transaction
    * @param lovelaceValue
@@ -140,9 +198,16 @@ export class AdaService extends Service {
    * @param utxos
    * @param outputs
    * @param certificates
+   * @param withdrawals
    * @private
    */
-  private async buildTx(changeAddress: string, utxos: UTXO, outputs: TransactionOutputs, certificates: Certificates | null = null) {
+  private async buildTx(
+    changeAddress: string,
+    utxos: UTXO,
+    outputs: TransactionOutputs,
+    certificates: Certificates | null = null,
+    withdrawals: Withdrawals | null = null,
+  ): Promise<Transaction> {
     const txBuilder = TransactionBuilder.new(
       TransactionBuilderConfigBuilder.new()
         .fee_algo(
@@ -165,6 +230,10 @@ export class AdaService extends Service {
       txBuilder.set_certs(certificates);
     }
 
+    if(withdrawals){
+      txBuilder.set_withdrawals(withdrawals);
+    }
+
     // Inputs
     const lovelaceUtxos = utxos.filter(
       (u: any) => !u.amount.find((a: any) => a.unit !== 'lovelace'),