Simulating Transactions

// transfer_coin is an example of how to make a coin transfer transaction in the simplest possible way
package main
 
import (
	"fmt"
 
	"github.com/aptos-labs/aptos-go-sdk"
	"github.com/aptos-labs/aptos-go-sdk/bcs"
)
 
const FundAmount = 100_000_000
const TransferAmount = 1_000
 
// example This example shows you how to make an APT transfer transaction in the simplest possible way
func example(networkConfig aptos.NetworkConfig) {
	// Create a client for Aptos
	client, err := aptos.NewClient(networkConfig)
	if err != nil {
		panic("Failed to create client:" + err.Error())
	}
 
	// Create accounts locally for alice and bob
	alice, err := aptos.NewEd25519Account()
	if err != nil {
		panic("Failed to create alice:" + err.Error())
	}
	bob, err := aptos.NewEd25519Account()
	if err != nil {
		panic("Failed to create bob:" + err.Error())
	}
 
	fmt.Printf("\n=== Addresses ===\n")
	fmt.Printf("Alice: %s\n", alice.Address.String())
	fmt.Printf("Bob:%s\n", bob.Address.String())
 
	// Fund the sender with the faucet to create it on-chain
	err = client.Fund(alice.Address, FundAmount)
	if err != nil {
		panic("Failed to fund alice:" + err.Error())
	}
 
	aliceBalance, err := client.AccountAPTBalance(alice.Address)
	if err != nil {
		panic("Failed to retrieve alice balance:" + err.Error())
	}
	bobBalance, err := client.AccountAPTBalance(bob.Address)
	if err != nil {
		panic("Failed to retrieve bob balance:" + err.Error())
	}
	fmt.Printf("\n=== Initial Balances ===\n")
	fmt.Printf("Alice: %d\n", aliceBalance)
	fmt.Printf("Bob:%d\n", bobBalance)
 
	// 1. Build transaction
	accountBytes, err := bcs.Serialize(&bob.Address)
	if err != nil {
		panic("Failed to serialize bob's address:" + err.Error())
	}
 
	amountBytes, err := bcs.SerializeU64(TransferAmount)
	if err != nil {
		panic("Failed to serialize transfer amount:" + err.Error())
	}
	rawTxn, err := client.BuildTransaction(alice.AccountAddress(), aptos.TransactionPayload{
		Payload: &aptos.EntryFunction{
			Module: aptos.ModuleId{
				Address: aptos.AccountOne,
				Name:    "aptos_account",
			},
			Function: "transfer",
			ArgTypes: []aptos.TypeTag{},
			Args: [][]byte{
				accountBytes,
				amountBytes,
			},
		}},
	)
 
	if err != nil {
		panic("Failed to build transaction:" + err.Error())
	}
 
	// 2. Simulate transaction
	// This is useful for understanding how much the transaction will cost
	// and to ensure that the transaction is valid before sending it to the network
	// This is optional, but recommended
	simulationResult, err := client.SimulateTransaction(rawTxn, alice)
	if err != nil {
		panic("Failed to simulate transaction:" + err.Error())
	}
	fmt.Printf("\n=== Simulation ===\n")
	fmt.Printf("Gas unit price: %d\n", simulationResult[0].GasUnitPrice)
	fmt.Printf("Gas used: %d\n", simulationResult[0].GasUsed)
	fmt.Printf("Total gas fee: %d\n", simulationResult[0].GasUsed*simulationResult[0].GasUnitPrice)
	fmt.Printf("Status: %s\n", simulationResult[0].VmStatus)
}
 
func main() {
	example(aptos.DevnetConfig)
}