Unstake bfBTC

Currently, we support RedStone Oracle for price feeds. BitFi plans to integrate more underlying asset oracles in the future.

Preview Withdrawal

function previewWithdraw(uint256 share, bool native) public view returns (uint256 underlyingAmount, uint256 fee)

Description: Preview the amount of underlying asset (BTC/BTCB/hemiBTC) you will receive when withdrawing bfBTC, including fee calculations.

Parameters:

• share: Amount of bfBTC to withdraw

• native: true = withdraw to Bitcoin network; false = withdraw to EVM network. This parameter (bool) is currently unused on Bitlayer.

Returns:

• underlyingAmount: Amount of underlying asset you will receive

• fee: Total fee to be paid (percentage + fixed)

Notes:

• Fees are calculated based on current fee configuration

• If total fee exceeds withdrawal amount, returns (0, fee)

• Actual received amount may vary due to ratio changes between preview and actual withdrawal

Request Withdrawal

function requestWithdraw(uint256 amount) external

Description: Initiate a withdrawal request by locking specified amount of bfBTC in the contract, awaiting administrator approval.

Parameters:

• amount: Amount of bfBTC to withdraw

Notes:

• Amount must exceed minWithdrawBfbtcAmount

• Transaction reverts if calculated fees exceed withdrawal amount

• Initial status: WITHDRAWAL_STATUS_PENDING

• bfBTC is transferred to contract but not burned yet

Approve Withdrawal

function approveWithdraw(uint256 epoch, uint256[] calldata withdrawIds) external

Description: Administrator function to approve multiple withdrawal requests, updating their status to claimable (or approved in modeP002).

Parameters:

• epoch: Historical epoch number for exchange rate calculation (must be less than current epoch)

• withdrawIds: Array of withdrawal request IDs to approve

Notes:

• Only callable by multisig manager address

• Requests must be in WITHDRAWAL_STATUS_PENDING state

• Must satisfy cooldown period requirement

• In modeP002: Emits UnboundRequired event instead of setting status to claimable on Bitlayer only.

Claim Withdrawal

function claim(uint256[] calldata withdrawIds) external

Description: Claim approved withdrawals, receiving underlying assets (BTC, BTCB, hemiBTC) to user's address.

Parameters:

• withdrawIds: Array of withdrawal request IDs to claim

Notes:

• Only original requestor can claim

• Requests must be in WITHDRAWAL_STATUS_CLAIMABLE state

• Status changes to WITHDRAWAL_STATUS_CLAIMED after successful claim

• Actual received amount calculated based on withdrawal epoch's ratio

Withdrawal Process Flow

Status Transitions

Standard Flow:

Pending -> Approved -> Claimed

Bitlayer Specific Flow (modeP002 enabled):

Pending -> Approved -> Unbound -> Claimed

Notes:

• On Bitlayer, after approval, funds must be transferred via bridge before status changes to Unbound

• Withdrawal approval timing varies based on Ceffu's processing speed

Withdrawal Amount Calculation

For WBTC withdrawals on Ethereum, actual amount is calculated using Oracle price:

$$Recv = \text{WithdrawAmount} * \max\left(1, \frac{\text{OraclePrice}}{1e6}\right) * \frac{\text{1e8}}{Ratio}$$

Where:

• Recv: Amount of WBTC received (8 decimals)

• WithdrawAmount: Amount of bfBTC withdrawn (8 decimals)

• OraclePrice: WBTC/BTC price from oracle

• Ratio: Exchange ratio between BTC and bfBTC

Additional Information

• Use claimable(withdrawId) to check available amount before claiming

• Preview withdrawal amount using previewWithdraw() before initiating request

• Consider fee implications when planning withdrawal amount

• Monitor ratio changes between request and claim for potential amount variations

Important Notes

• Stakes and Unstakes must be made while the contract is not paused.

• Unstake require a cooldown period. (1 epoch)

• The actual amount of BTC received depends on the current epoch's ratio and price.

• The displayed receive amount may differ.

• Unstake approval time may vary depending on Ceffu's processing speed. BitFi aims to process unstake request within 5 epochs.