prepares tx in token simulation flow (#29)

* prepares tx in token simulation flow

* removes unused import

* removes unused import

* parse amount as string for soroban token transfer

* fixes query param validator to accept multiple contract IDs, tweaks history transformer to skip over host fn invocations that are not invokeHostFn

* updates test for fixed contract ids query param pattern, tweaks transformer to allow operation type to match post filter

src/helper/soroban-rpc.ts

@@ -159,7 +159,7 @@ const getOpArgs = (fnName: string, args: xdr.ScVal[]) => {
       to = StrKey.encodeEd25519PublicKey(
         args[1].address().accountId().ed25519()
       );
-      amount = scValToNative(args[2]);
+      amount = scValToNative(args[2]).toString();
       break;
     case SorobanTokenInterface.mint:
       to = StrKey.encodeEd25519PublicKey(

src/route/index.test.ts

@@ -55,21 +55,21 @@ describe("API routes", () => {
     });
 
     it("can fetch account balances for a pub key & multiple contract IDs", async () => {
-      const params = {
-        contract_ids: [
-          "CCWAMYJME4H5CKG7OLXGC2T4M6FL52XCZ3OQOAV6LL3GLA4RO4WH3ASP",
-          "CBGTG7XFRY3L6OKAUTR6KGDKUXUQBX3YDJ3QFDYTGVMOM7VV4O7NCODG",
-        ],
-        network: "TESTNET",
-      };
+      const contractIds = [
+        "CCWAMYJME4H5CKG7OLXGC2T4M6FL52XCZ3OQOAV6LL3GLA4RO4WH3ASP",
+        "CBGTG7XFRY3L6OKAUTR6KGDKUXUQBX3YDJ3QFDYTGVMOM7VV4O7NCODG",
+      ];
       const server = await getDevServer();
-      const response = await fetch(
+      const url = new URL(
         `http://localhost:${
           (server?.server?.address() as any).port
-        }/api/v1/account-balances/${pubKey}?${new URLSearchParams(
-          params as any
-        )}`
+        }/api/v1/account-balances/${pubKey}`
       );
+      url.searchParams.append("network", "TESTNET");
+      for (const id of contractIds) {
+        url.searchParams.append("contract_ids", id);
+      }
+      const response = await fetch(url.href);
       expect(response.status).toEqual(200);
       register.clear();
       await server.close();

src/route/index.ts

@@ -16,14 +16,15 @@ import {
 } from "../helper/validate";
 import { submitTransaction } from "../helper/horizon-rpc";
 import {
+  Address,
   BASE_FEE,
   Memo,
   MemoType,
   Operation,
   SorobanRpc,
   Transaction,
   TransactionBuilder,
-  xdr,
+  XdrLargeInt,
 } from "stellar-sdk";
 import { buildTransfer, simulateTx } from "../helper/soroban-rpc";
 
@@ -161,8 +162,9 @@ export async function initApiServer(
           },
           querystring: {
             ["contract_ids"]: {
-              type: "string",
-              validator: (qStr: string) => qStr.split(",").every(isContractId),
+              type: "array",
+              validator: (qStr: Array<unknown>) =>
+                qStr.map((q) => String(q)).every(isContractId),
             },
             ["network"]: {
               type: "string",
@@ -180,7 +182,7 @@ export async function initApiServer(
           request: FastifyRequest<{
             Params: { ["pubKey"]: string };
             Querystring: {
-              ["contract_ids"]: string;
+              ["contract_ids"]: string[];
               ["network"]: NetworkNames;
               ["horizon_url"]?: string;
               ["soroban_url"]?: string;
@@ -190,9 +192,7 @@ export async function initApiServer(
         ) => {
           const pubKey = request.params["pubKey"];
           const { network, horizon_url, soroban_url } = request.query;
-          const contractIds = request.query["contract_ids"]
-            ? request.query["contract_ids"].split(",")
-            : [];
+          const contractIds = request.query["contract_ids"] || ([] as string[]);
           const { data, error } = await mercuryClient.getAccountBalances(
             pubKey,
             contractIds,
@@ -513,7 +513,7 @@ export async function initApiServer(
               pub_key: string;
               memo: string;
               fee?: string;
-              params: xdr.ScVal[];
+              params: Record<string, string>;
               network_url: string;
               network_passphrase: string;
             };
@@ -540,14 +540,22 @@ export async function initApiServer(
               fee: _fee,
               networkPassphrase: network_passphrase,
             });
-            const tx = buildTransfer(address, params, memo, builder);
-            const simulationResponse = await simulateTx<unknown>(
-              tx as Transaction<Memo<MemoType>, Operation[]>,
-              server
+            const _params = [
+              new Address(params.publicKey).toScVal(), // from
+              new Address(params.destination).toScVal(), // to
+              new XdrLargeInt("i128", params.amount).toI128(), // amount
+            ];
+            const tx = buildTransfer(address, _params, memo, builder);
+            const simulationResponse = (await server.simulateTransaction(
+              tx
+            )) as SorobanRpc.Api.SimulateTransactionSuccessResponse;
+            const preparedTransaction = SorobanRpc.assembleTransaction(
+              tx,
+              simulationResponse
             );
             const data = {
               simulationResponse,
-              raw: tx.toXDR(),
+              preparedTransaction: preparedTransaction.build().toXDR(),
             };
             reply.code(200).send(data);
           } catch (error) {

src/route/validators.ts

@@ -7,7 +7,7 @@ import Ajv, {
 const ajv = new Ajv({
   removeAdditional: true,
   useDefaults: true,
-  coerceTypes: true,
+  coerceTypes: "array",
 });
 
 ajv.addKeyword("validator", {

src/service/mercury/helpers/transformers.ts

@@ -866,34 +866,49 @@ const transformAccountHistory = async (
 ): Promise<Partial<Horizon.ServerApi.OperationRecord>[]> => {
   const invokeHostFnEdges =
     rawResponse.data?.invokeHostFnByPublicKey.edges || [];
-  const invokeHostFn = invokeHostFnEdges.map((edge) => {
-    const hostFn = xdr.HostFunction.fromXDR(
-      Buffer.from(edge.node.hostFunction, "base64")
-    );
-    const invocation = hostFn.invokeContract();
-    const fnName = invocation.functionName().toString();
-    return {
-      auth: edge.node.auth,
-      created_at: new Date(
-        edge.node.txInfoByTx.ledgerByLedger.closeTime * 1000
-      ).toISOString(),
-      sorobanMeta: edge.node.sorobanMeta,
-      source_account: edge.node.accountBySource.publickey,
-      tx: edge.node.tx,
-      type: "invoke_host_function",
-      type_i: 24,
-      id: edge.node.opId,
-      transaction_attr: {
-        contractId: StrKey.encodeContract(
-          invocation.contractAddress().contractId()
-        ),
-        fnName,
-        args: getOpArgs(fnName, invocation.args()),
-        operation_count: edge.node.txInfoByTx.opCount,
-        fee_charged: edge.node.txInfoByTx.fee,
-      },
-    } as Partial<Horizon.ServerApi.InvokeHostFunctionOperationRecord>;
-  });
+  const invokeHostFn = invokeHostFnEdges
+    .filter((edge) => {
+      // we only want to keep these history entries if the Host Fn is
+      // for invoking a contract, we dont show contract create or wasm upload in wallet history right now.
+      try {
+        const hostFn = xdr.HostFunction.fromXDR(
+          Buffer.from(edge.node.hostFunction, "base64")
+        );
+        hostFn.invokeContract();
+        return true;
+      } catch (error) {
+        return false;
+      }
+    })
+    .map((edge) => {
+      const hostFn = xdr.HostFunction.fromXDR(
+        Buffer.from(edge.node.hostFunction, "base64")
+      );
+
+      const invocation = hostFn.invokeContract();
+      const fnName = invocation.functionName().toString();
+      return {
+        auth: edge.node.auth,
+        created_at: new Date(
+          edge.node.txInfoByTx.ledgerByLedger.closeTime * 1000
+        ).toISOString(),
+        sorobanMeta: edge.node.sorobanMeta,
+        source_account: edge.node.accountBySource.publickey,
+        tx: edge.node.tx,
+        type: "invoke_host_function",
+        type_i: 24,
+        id: edge.node.opId,
+        transaction_attr: {
+          contractId: StrKey.encodeContract(
+            invocation.contractAddress().contractId()
+          ),
+          fnName,
+          args: getOpArgs(fnName, invocation.args()),
+          operation_count: edge.node.txInfoByTx.opCount,
+          fee_charged: edge.node.txInfoByTx.fee,
+        },
+      } as Partial<Horizon.ServerApi.InvokeHostFunctionOperationRecord>;
+    });
 
   const createAccountEdges =
     rawResponse.data?.createAccountByPublicKey.edges || [];