BTC Staking Simulation

Simulating a BTC staking transaction is a crucial step before broadcasting it to the network. Simulation helps:

• Prepare expected outputs
• Verify the success of the transaction
• Avoid errors like No valid UTXO found for treasury fee

Example:

const resDeposit = await simulateStakeBTC({
    motoChefContract,
    stakeAmount,
    feeAmount,
    netStakeAmount,
    treasuryAddressP2TR,
    accountAddressTyped,
});

The returned object contains:

• Outputs: The fee and staking outputs to include
• Result: The simulated transaction to send later

Always run this simulation step before sendTransaction().

---

Full example:

This full implementation is an example taken from a MotoChef staking use case. It demonstrates how to manually construct simulation outputs for a specific pool and pass them to the contract before calling stakeBTC().

export async function simulateStakeBTC({
  motoChefContract,
  stakeAmount,
  feeAmount,
  netStakeAmount,
  treasuryAddressP2TR,
  accountAddressTyped,
}: {
  motoChefContract: IMotoChef;
  stakeAmount: bigint;
  feeAmount: bigint;
  netStakeAmount: bigint;
  treasuryAddressP2TR: string;
  accountAddressTyped: string;
}): Promise<{ result: StakeBTC; outputs: PsbtOutputExtended[] }> {
  const outSimulation: StrippedTransactionOutput[] = [];
  const outputs: PsbtOutputExtended[] = [];
  let index = 2;

  // Treasury output
  outputs.push({
    address: treasuryAddressP2TR,
    value: Number(feeAmount),
  });
  outSimulation.push({
    index,
    to: treasuryAddressP2TR,
    value: feeAmount,
    flags: TransactionOutputFlags.hasTo,
    scriptPubKey: undefined,
  });
  index++;

  // Stake output
  outputs.push({
    address: accountAddressTyped,
    value: Number(netStakeAmount),
  });
  outSimulation.push({
    index,
    to: accountAddressTyped,
    value: netStakeAmount,
    flags: TransactionOutputFlags.hasTo,
    scriptPubKey: undefined,
  });

  // Set simulation details
  const details: ParsedSimulatedTransaction = {
    inputs: [],
    outputs: outSimulation,
  };
  motoChefContract.setTransactionDetails(details);

  // Simulate stakeBTC
  const result = await motoChefContract.stakeBTC(stakeAmount);
  if (!result.properties.success) throw new Error("Failed to simulate stake");

  return { result, outputs };
}