Add stateless transaction estimate method (#73)

* Add stateless transaction estimate

* version

* minor fixes

* minor fix

package.json

@@ -1,6 +1,6 @@
 {
   "name": "etherspot",
-  "version": "1.13.2",
+  "version": "1.14.0",
   "description": "Etherspot SDK",
   "keywords": [
     "ether",

src/sdk/gateway/gateway.service.ts

@@ -363,12 +363,12 @@ export class GatewayService extends Service {
     return result;
   }
 
-  async estimateGatewayBatch(feeToken: string): Promise<GatewayBatch> {
-    if (!this.gatewayBatch) {
+  async estimateGatewayBatch(feeToken: string, statelessBatch?: GatewayBatch): Promise<GatewayBatch> {
+    if (!this.gatewayBatch && !statelessBatch) {
       throw new Exception('Can not estimate empty batch');
     }
 
-    const { to, data } = this.extractToAndData();
+    const { to, data } = this.extractToAndData(statelessBatch);
     const nonce = uniqueNonce();
 
     const { accountService, apiService } = this.services;
@@ -419,6 +419,13 @@ export class GatewayService extends Service {
       },
     );
 
+    if (statelessBatch) {
+      return {
+        ...statelessBatch,
+        estimation,
+      };
+    }
+
     this.estimationOptions = {
       nonce,
       feeToken,
@@ -464,18 +471,18 @@ export class GatewayService extends Service {
     return result;
   }
 
-  async submitGatewayBatch(): Promise<GatewaySubmittedBatch> {
-    if (!this.gatewayBatch) {
+  async submitGatewayBatch(statelessBatch?: GatewayBatch): Promise<GatewaySubmittedBatch> {
+    if (!this.gatewayBatch && !statelessBatch) {
       throw new Exception('Can not submit empty batch');
     }
 
-    const { estimation } = this.gatewayBatch;
+    const { estimation } = statelessBatch || this.gatewayBatch;
 
     if (!estimation || estimation.expiredAt.getTime() < estimation.createdAt.getTime()) {
       throw new Exception('Can not submit not estimated batch');
     }
 
-    const { to, data } = this.extractToAndData();
+    const { to, data } = this.extractToAndData(statelessBatch);
     const {
       feeTokenReceiver,
       feeAmount,
@@ -594,7 +601,9 @@ export class GatewayService extends Service {
       },
     );
 
-    this.clearGatewayBatch();
+    if (!statelessBatch) {
+      this.clearGatewayBatch();
+    }
 
     return result;
   }
@@ -629,8 +638,8 @@ export class GatewayService extends Service {
     return result;
   }
 
-  private extractToAndData(): { to: string[]; data: string[] } {
-    return this.gatewayBatch.requests.reduce(
+  private extractToAndData(statelessBatch?: GatewayBatch): { to: string[]; data: string[] } {
+    return (statelessBatch || this.gatewayBatch).requests.reduce(
       (result, { to, data }) => {
         result.to.push(to);
         result.data.push(data);

src/sdk/sdk.ts

@@ -1,4 +1,4 @@
-import { BigNumber } from 'ethers';
+import { BigNumber, utils } from 'ethers';
 import { BehaviorSubject, Subject } from 'rxjs';
 import {
   Account,
@@ -425,6 +425,38 @@ export class Sdk {
     return this.services.gatewayService.estimateGatewayBatch(feeToken);
   }
 
+  /**
+   * estimates stateless account transactions
+   * @param dto
+   * @return Promise<GatewayBatch>
+   */
+  async estimateStatelessAccountTransactions(
+    transactionsDto: ExecuteAccountTransactionDto[],
+    estimationDto: EstimateGatewayBatchDto = {},
+  ): Promise<GatewayBatch> {
+    const { gatewayService } = this.services;
+
+    const gatewayBatch: GatewayBatch = {
+      requests: [],
+      estimation: null,
+    };
+
+    const { feeToken } = await validateDto(estimationDto, EstimateGatewayBatchDto, {
+      addressKeys: ['feeToken'],
+    });
+
+    for (const transactionDto of transactionsDto) {
+      const encodedAccountTransaction = await this.encodeExecuteAccountTransaction(transactionDto);
+      const { to, data } = encodedAccountTransaction;
+      gatewayBatch.requests.push({
+        to,
+        data: utils.hexlify(data),
+      });
+    }
+
+    return gatewayService.estimateGatewayBatch(feeToken, gatewayBatch);
+  }
+
   /**
    * submits gateway batch
    * @param dto