HelloBitcoin

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State Variables

btcSellOrders

Mapping to store BTC to USDT (or other ERC20) swap orders based on their unique identifiers. Each order is associated with a unique ID, and the order details are stored in the BtcSellOrder struct.

mapping(uint256 => BtcSellOrder) public btcSellOrders;

ordinalSellOrders

Mapping to store ordinal sell orders for swapping BTC to USDT (or other ERC20) based on their unique identifiers. Each ordinal sell order is associated with a unique ID, and the order details are stored in the OrdinalSellOrder struct.

mapping(uint256 => OrdinalSellOrder) public ordinalSellOrders;

usdtContractAddress

The address of the ERC-20 contract. You can use this variable for any ERC-20 token, not just USDT (Tether). Make sure to set this to the appropriate ERC-20 contract address.

IERC20 public usdtContractAddress;

nextBtcOrderId

Counter for generating unique identifiers for BTC to USDT swap orders. The nextBtcOrderId is incremented each time a new BTC to USDT swap order is created, ensuring that each order has a unique identifier.

uint256 nextBtcOrderId;

nextOrdinalOrderId

Counter for generating unique identifiers for ordinal sell orders. The nextOrdinalOrderId is incremented each time a new ordinal sell order is created, ensuring that each ordinal order has a unique identifier.

uint256 nextOrdinalOrderId;

relay

BridgeState.Storage internal relay;

testLightRelay

TestLightRelay internal testLightRelay;

Functions

constructor

Constructor to initialize the contract with the relay and ERC20 token address.

constructor(IRelay _relay, address _usdtContractAddress);

Parameters

Name	Type	Description
_relay	IRelay	The relay contract implementing the IRelay interface.
_usdtContractAddress	address	The address of the USDT contract. Additional functionalities of the relay can be found in the documentation available at: https://docs.gobob.xyz/docs/contracts/src/src/relay/LightRelay.sol/contract.LightRelay

setRelay

Set the relay contract for the bridge.

function setRelay(IRelay _relay) internal;

Parameters

Name	Type	Description
_relay	IRelay	The relay contract implementing the IRelay interface.

placeBtcSellOrder

Places a BTC sell order in the contract.

Emits a btcSellOrderSuccessfullyPlaced event upon successful placement.

*Requirements:

• sellAmountBtc must be greater than 0.
• buyAmount must be greater than 0.*

function placeBtcSellOrder(uint256 sellAmountBtc, uint256 buyAmount) public;

Parameters

Name	Type	Description
sellAmountBtc	uint256	The amount of BTC to sell.
buyAmount	uint256	The corresponding amount to be received in exchange for the BTC.

acceptBtcSellOrder

Accepts a BTC sell order, providing the Bitcoin address for the buyer.

Transfers the corresponding currency from the buyer to the contract and updates the order details.

*Requirements:

• The specified order must not have been accepted previously.
• The buyer must transfer the required currency amount to the contract.*

Emits a btcSellOrderBtcSellOrderAccepted event upon successful acceptance.

function acceptBtcSellOrder(uint256 id, BitcoinAddress calldata bitcoinAddress) public;

Parameters

Name	Type	Description
id	uint256	The unique identifier of the BTC sell order.
bitcoinAddress	BitcoinAddress	The Bitcoin address of the buyer to receive the BTC.

completeBtcSellOrder

Completes a BTC sell order by validating and processing the provided Bitcoin transaction proof.

This function is intended to be called by the original seller.

*Requirements:

• The specified order must have been previously accepted.
• The caller must be the original seller of the BTC.
• The Bitcoin transaction proof must be valid.
• The BTC transaction output must match the expected amount and recipient.*

*Effects:

• Sets the relay difficulty based on the Bitcoin headers in the proof.
• Transfers the locked USDT amount to the original seller.
• Removes the order from the mapping after successful processing.*

Emits a btcSuccessfullySendtoDestination event upon successful completion.

function completeBtcSellOrder(uint256 id, BitcoinTx.Info calldata transaction, BitcoinTx.Proof calldata proof) public;

Parameters

Name	Type	Description
id	uint256	The unique identifier of the BTC sell order.
transaction	BitcoinTx.Info	Information about the Bitcoin transaction.
proof	BitcoinTx.Proof	Proof associated with the Bitcoin transaction.

placeOrdinalSellOrder

Places an ordinal sell order in the contract.

Emits an ordinalSellOrderSuccessfullyPlaced event upon successful placement.

*Requirements:

• buyAmount must be greater than 0.*

*Effects:

• Creates a new ordinal sell order with the provided details.*

function placeOrdinalSellOrder(OrdinalId calldata ordinalID, BitcoinTx.UTXO calldata utxo, uint256 buyAmount) public;

Parameters

Name	Type	Description
ordinalID	OrdinalId	The unique identifier for the ordinal.
utxo	BitcoinTx.UTXO	Information about the Bitcoin UTXO associated with the ordinal.
buyAmount	uint256	The amount to be received in exchange for the ordinal.

acceptOrdinalSellOrder

Accepts an ordinal sell order, providing the Bitcoin address for the buyer.

Transfers the corresponding currency from the buyer to the contract and updates the order details.

*Requirements:

• The specified order must not have been accepted previously.
• The buyer must transfer the required currency amount to this contract.*

*Effects:

• "Locks" the selling token by transferring it to the contract.
• Updates the ordinal sell order with the buyer's Bitcoin address and marks the order as accepted.*

Emits an ordinalSellOrderBtcSellOrderAccepted event upon successful acceptance.

function acceptOrdinalSellOrder(uint256 id, BitcoinAddress calldata bitcoinAddress) public;

Parameters

Name	Type	Description
id	uint256	The unique identifier of the ordinal sell order.
bitcoinAddress	BitcoinAddress	The Bitcoin address of the buyer to receive the ordinal.

completeOrdinalSellOrder

Completes an ordinal sell order by validating and processing the provided Bitcoin transaction proof.

This function is intended to be called by the original seller.

*Requirements:

• The specified order must have been previously accepted.
• The caller must be the original seller of the ordinal.
• The Bitcoin transaction proof must be valid.
• The BTC transaction input must spend the specified UTXO associated with the ordinal sell order.
• The BTC transaction output must be to the buyer's address.*

*Effects:

• Sets the relay difficulty based on the Bitcoin headers in the proof.
• Validates the BTC transaction proof using the relay.
• Ensures that the BTC transaction input spends the specified UTXO.
• Checks the BTC transaction output to the buyer's address.
• Transfers the locked USDT amount to the original seller.
• Removes the ordinal sell order from storage after successful processing.*

Emits an ordinalSuccessfullySendtoDestination event upon successful completion.

function completeOrdinalSellOrder(uint256 id, BitcoinTx.Info calldata transaction, BitcoinTx.Proof calldata proof)
    public;

Parameters

Name	Type	Description
id	uint256	The unique identifier of the ordinal sell order.
transaction	BitcoinTx.Info	Information about the Bitcoin transaction.
proof	BitcoinTx.Proof	Proof associated with the Bitcoin transaction.

_checkBitcoinTxOutput

Checks output script pubkey (recipient address) and amount. Reverts if transaction amount is lower or bitcoin address is not found.

function _checkBitcoinTxOutput(
    uint256 expectedBtcAmount,
    BitcoinAddress storage bitcoinAddress,
    BitcoinTx.Info calldata transaction
) private;

Parameters

Name	Type	Description
expectedBtcAmount	uint256	BTC amount requested in order.
bitcoinAddress	BitcoinAddress	Recipient's bitcoin address.
transaction	BitcoinTx.Info	Transaction fulfilling the order.

Events

btcSellOrderSuccessfullyPlaced

event btcSellOrderSuccessfullyPlaced(uint256 indexed orderId, uint256 sellAmountBtc, uint256 buyAmount);

btcSellOrderBtcSellOrderAccepted

event btcSellOrderBtcSellOrderAccepted(uint256 indexed id, BitcoinAddress bitcoinAddress);

btcSuccessfullySendtoDestination

event btcSuccessfullySendtoDestination(uint256 id);

ordinalSellOrderSuccessfullyPlaced

event ordinalSellOrderSuccessfullyPlaced(uint256 indexed id, OrdinalId ordinalID, uint256 buyAmount);

ordinalSellOrderBtcSellOrderAccepted

event ordinalSellOrderBtcSellOrderAccepted(uint256 indexed id, BitcoinAddress bitcoinAddress);

ordinalSuccessfullySendtoDestination

event ordinalSuccessfullySendtoDestination(uint256 id);

Structs

BtcSellOrder

Struct representing a BTC to USDT swap order.

struct BtcSellOrder {
    uint256 sellAmountBtc;
    uint256 buyAmount;
    address btcSeller;
    BitcoinAddress btcBuyer;
    bool isOrderAccepted;
}

OrdinalSellOrder

Struct representing an ordinal sell order for swapping Ordinal to USDT.

struct OrdinalSellOrder {
    OrdinalId ordinalID;
    uint256 buyAmount;
    BitcoinTx.UTXO utxo;
    address ordinalSeller;
    BitcoinAddress ordinalBuyer;
    bool isOrderAccepted;
}

OrdinalId

Struct representing a unique identifier for an ordinal sell order.

struct OrdinalId {
    bytes32 txId;
    uint32 index;
}

BitcoinAddress

Struct representing a Bitcoin address with a scriptPubKey.

struct BitcoinAddress {
    bytes scriptPubKey;
}