From ab0299b0514cef9f2e16e2952b388766872f1236 Mon Sep 17 00:00:00 2001
From: Venkatesh V <venkateshv@bitgo.com>
Date: Thu, 12 Sep 2024 17:03:13 +0530
Subject: [PATCH] feat(abstract-eth): fetch gasPrice and gasLimit from explorer

TICKET: COIN-1201
---
 .../src/abstractEthLikeNewCoins.ts            | 107 +++++++++++++++---
 .../src/lib/transactionBuilder.ts             |   2 +-
 2 files changed, 90 insertions(+), 19 deletions(-)

diff --git a/modules/abstract-eth/src/abstractEthLikeNewCoins.ts b/modules/abstract-eth/src/abstractEthLikeNewCoins.ts
index 1bdb28869b..65aeec45ba 100644
--- a/modules/abstract-eth/src/abstractEthLikeNewCoins.ts
+++ b/modules/abstract-eth/src/abstractEthLikeNewCoins.ts
@@ -1520,10 +1520,14 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
       }
     }
 
-    const gasLimit = new optionalDeps.ethUtil.BN(this.setGasLimit(params.gasLimit));
+    // If gasLimit is not passed as a param, then default gasLimit 50000 will be set here
+    let gasLimit = new optionalDeps.ethUtil.BN(this.setGasLimit(params.gasLimit));
+
     const gasPrice = params.eip1559
       ? new optionalDeps.ethUtil.BN(params.eip1559.maxFeePerGas)
-      : new optionalDeps.ethUtil.BN(this.setGasPrice(params.gasPrice));
+      : params.gasPrice
+      ? new optionalDeps.ethUtil.BN(this.setGasPrice(params.gasPrice))
+      : await this.getGasPriceFromExternalAPI();
 
     const bitgoFeeAddressNonce = await this.getAddressNonce(bitgoFeeAddress);
 
@@ -1588,14 +1592,6 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
     await new Promise((resolve) => setTimeout(resolve, 1000));
     const sequenceId = await this.querySequenceId(walletContractAddress);
 
-    const txInfo = {
-      recipients: recipients,
-      expireTime: this.getDefaultExpireTime(),
-      contractSequenceId: sequenceId,
-      gasLimit: gasLimit.toString(10),
-      isEvmBasedCrossChainRecovery: true,
-    };
-
     const network = this.getNetwork();
     const batcherContractAddress = network?.batcherContractAddress as string;
 
@@ -1646,8 +1642,30 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
       txBuilder.walletVersion(4);
     }
 
+    // If gasLimit was not passed as a param, then fetch the gasLimit from Explorer
+    if (!params.gasLimit) {
+      const sendData = txBuilder.getSendData();
+      gasLimit = await this.getGasLimitFromExternalAPI(
+        params.bitgoFeeAddress as string,
+        params.walletContractAddress,
+        sendData
+      );
+      txBuilder.fee({
+        ...txFee,
+        gasLimit: gasLimit.toString(),
+      });
+    }
+
     const tx = await txBuilder.build();
 
+    const txInfo = {
+      recipients: recipients,
+      expireTime: this.getDefaultExpireTime(),
+      contractSequenceId: sequenceId,
+      gasLimit: gasLimit.toString(10),
+      isEvmBasedCrossChainRecovery: true,
+    };
+
     const response: OfflineVaultTxInfo = {
       txHex: tx.toBroadcastFormat(),
       userKey,
@@ -1740,14 +1758,6 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
     await new Promise((resolve) => setTimeout(resolve, 1000));
     const sequenceId = await this.querySequenceId(params.walletContractAddress);
 
-    const txInfo = {
-      recipients: recipients,
-      expireTime: this.getDefaultExpireTime(),
-      contractSequenceId: sequenceId,
-      gasLimit: gasLimit.toString(10),
-      isEvmBasedCrossChainRecovery: true,
-    };
-
     const txBuilder = this.getTransactionBuilder(params.common) as TransactionBuilder;
     txBuilder.counter(bitgoFeeAddressNonce);
     txBuilder.contract(params.walletContractAddress as string);
@@ -1799,8 +1809,29 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
       txBuilder.walletVersion(4);
     }
 
+    if (!params.gasLimit) {
+      const sendData = txBuilder.getSendData();
+      gasLimit = await this.getGasLimitFromExternalAPI(
+        params.bitgoFeeAddress as string,
+        params.walletContractAddress,
+        sendData
+      );
+      txBuilder.fee({
+        ...txFee,
+        gasLimit: gasLimit.toString(),
+      });
+    }
+
     const tx = await txBuilder.build();
 
+    const txInfo = {
+      recipients: recipients,
+      expireTime: this.getDefaultExpireTime(),
+      contractSequenceId: sequenceId,
+      gasLimit: gasLimit.toString(10),
+      isEvmBasedCrossChainRecovery: true,
+    };
+
     const response: OfflineVaultTxInfo = {
       txHex: tx.toBroadcastFormat(),
       userKey,
@@ -2599,4 +2630,44 @@ export abstract class AbstractEthLikeNewCoins extends AbstractEthLikeCoin {
       }
     }
   }
+
+  /**
+   * Fetch the gas price from the explorer
+   */
+  async getGasPriceFromExternalAPI(): Promise<BN> {
+    try {
+      const res = await this.recoveryBlockchainExplorerQuery({
+        module: 'proxy',
+        action: 'eth_gasPrice',
+      });
+      const gasPrice = new BN(res.result.slice(2), 16);
+      console.log(` Got gas price: ${gasPrice}`);
+      return gasPrice;
+    } catch (e) {
+      throw new Error('Failed to get gas price');
+    }
+  }
+
+  /**
+   * Fetch the gas limit from the explorer
+   * @param from
+   * @param to
+   * @param data
+   */
+  async getGasLimitFromExternalAPI(from: string, to: string, data: string): Promise<BN> {
+    try {
+      const res = await this.recoveryBlockchainExplorerQuery({
+        module: 'proxy',
+        action: 'eth_estimateGas',
+        from,
+        to,
+        data,
+      });
+      const gasLimit = new BN(res.result.slice(2), 16);
+      console.log(`Got gas limit: ${gasLimit}`);
+      return gasLimit;
+    } catch (e) {
+      throw new Error('Failed to get gas limit: ');
+    }
+  }
 }
diff --git a/modules/abstract-eth/src/lib/transactionBuilder.ts b/modules/abstract-eth/src/lib/transactionBuilder.ts
index 24a8110b2a..7f18451c5e 100644
--- a/modules/abstract-eth/src/lib/transactionBuilder.ts
+++ b/modules/abstract-eth/src/lib/transactionBuilder.ts
@@ -621,7 +621,7 @@ export abstract class TransactionBuilder extends BaseTransactionBuilder {
    *
    * @returns {string} serialized sendMultiSig data
    */
-  private getSendData(): string {
+  public getSendData(): string {
     if (!this._transfer) {
       throw new BuildTransactionError('Missing transfer information');
     }