[v1] sPMM liquidity integration

Contracts

Two main contracts of WOOFi's swap function are as follows:

• WooPP.sol: the main swap contract that handles the logic operation, including setting the token info, calculating slippage, calculating the exchange amount and executing trades. it stores all tokens that are supported for trading. In this contract, it defines quote token and base token. Quote token is the reference token (i.e. stablecoins) in the contract and there is only one quote token. The contract can have multiple base tokens and they can be added by the strategist.

• WooRouter.sol: the router contract that frontend users interact with. It interacts with the lower layer WooPP.sol to execute the sell logic and send back users the desired amount of tokens. This contract also implements the logic to route user orders to 3rd party aggregator (e.g. 1inch) when WooPP.sol does not have sufficient liquidity.

More details about WOOFi smart contract architecture, implementation info, and addresses can be found in .

Supported assets

WooPP.sol currently supports the following tokens. Quote token is the stablecoin and the rest are base tokens.

BNB Chain

Token	Address
BNB	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
WBNB	0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c
BTCB	0x7130d2A12B9BCbFAe4f2634d864A1Ee1Ce3Ead9c
ETH	0x2170ed0880ac9a755fd29b2688956bd959f933f8
WOO	0x4691937a7508860f876c9c0a2a617e7d9e945d4b
USDT	0x55d398326f99059fF775485246999027B3197955

Avalanche

Fantom

Polygon

Integrate WOOFi as a liquidity source

When integrating WOOFi as a liquidity source, you can either interact directly with WooPP.sol or throughWooRouter.sol.

Integrating WooPP.sol (recommended)

For aggregators or trading bots, we recommend integrate directly with WooPP.sol to be more gas efficient.

Contract addresses:

BNB Chain: 0xbf365Ce9cFcb2d5855521985E351bA3bcf77FD3F

Avalanche: 0x1df3009c57a8B143c6246149F00B090Bce3b8f88

Fantom: 0x9503E7517D3C5bc4f9E4A1c6AE4f8B33AC2546f2

Polygon: 0x7400B665C8f4f3a951a99f1ee9872efb8778723d

Interface:

    /// @dev get the quote token address (immutable)
    /// @return address of quote token
    function quoteToken() external view returns (address);

    /// @dev Query the amount for selling the base token amount.
    /// @param baseToken the base token to sell
    /// @param baseAmount the amount to sell
    /// @return quoteAmount the swapped quote amount
    function querySellBase(address baseToken, uint256 baseAmount) external view returns (uint256 quoteAmount);

    /// @dev Query the amount for selling the quote token.
    /// @param baseToken the base token to receive (buy)
    /// @param quoteAmount the amount to sell
    /// @return baseAmount the swapped base token amount
    function querySellQuote(address baseToken, uint256 quoteAmount) external view returns (uint256 baseAmount);

    /// @dev Swap baseToken into quoteToken
    /// @param baseToken the base token
    /// @param baseAmount amount of baseToken that user want to swap
    /// @param minQuoteAmount minimum amount of quoteToken that user accept to receive
    /// @param to quoteToken receiver address
    /// @param rebateTo the wallet address for rebate
    /// @return quoteAmount the swapped amount of quote token
    function sellBase(
        address baseToken,
        uint256 baseAmount,
        uint256 minQuoteAmount,
        address to,
        address rebateTo
    ) external returns (uint256 quoteAmount);

    /// @dev Swap quoteToken into baseToken
    /// @param baseToken the base token
    /// @param quoteAmount amount of quoteToken that user want to swap
    /// @param minBaseAmount minimum amount of baseToken that user accept to receive
    /// @param to baseToken receiver address
    /// @param rebateTo the wallet address for rebate
    /// @return baseAmount the swapped amount of base token
    function sellQuote(
        address baseToken,
        uint256 quoteAmount,
        uint256 minBaseAmount,
        address to,
        address rebateTo
    ) external returns (uint256 baseAmount);

Query & swap functions

    address public immutable pool; // IWooPP smart contract
    
    function query(
        uint _amountIn, 
        address _tokenIn, 
        address _tokenOut
    ) internal override view returns (uint256 amountOut) {
        if (_amountIn == 0) { 
            return 0; 
        }
        if (_tokenIn == quoteToken) {
            amountOut = IWooPP(pool).querySellQuote(_tokenOut, _amountIn);
        } else if (_tokenOut == quoteToken) {
            amountOut = IWooPP(pool).querySellBase(_tokenIn, _amountIn);
        } else {
            uint quoteAmount = IWooPP(pool).querySellBase(_tokenIn, _amountIn);
            amountOut = IWooPP(pool).querySellQuote(_tokenOut, quoteAmount);
        }
    }

    function swap(
        uint _amountIn, 
        uint _amountOut, 
        address _tokenIn, 
        address _tokenOut, 
        address _to
    ) external returns (uint256 realToAmount) {
        // check parameters and approve the allowrance if needed
    
        if (_tokenIn == quoteToken) {
            // case 1: quoteToken --> baseToken
            realToAmount = IWooPP(pool).sellQuote(
                _tokenOut,
                _amountIn,
                _amountOut,
                _to,
                address(0)
            );
        } else if (_tokenOut == quoteToken) {
            // case 2: fromToken --> quoteToken
            realToAmount = IWooPP(pool).sellBase(
                _tokenIn, 
                _amountIn, 
                _amountOut, 
                _to, 
                address(0)
            );
        } else {
            // case 3: fromToken --> quoteToken --> toToken
            uint256 quoteAmount = IWooPP(pool).sellBase(
                _tokenIn, 
                _amountIn, 
                0, 
                address(this), 
                address(0)
            );
            _approveIfNeeded(quoteToken, quoteAmount);
            realToAmount = IWooPP(pool).sellQuote(
                _tokenOut, 
                quoteAmount, 
                _amountOut, 
                _to, 
                address(0)
            );
        }

        // emit events if needed
    }

Sample integration code (Yield Yak)

https://snowtrace.io/address/0xa64c5c58fc1510de3ff2ee644e030d666b660ea6#code

Integrating WooRouter.sol

A simpler way is calling WooRouter.sol contract which provides the similar query and swap as above. This way costs slightly more gas than directly integrating with WooPP.sol.

Contract addresses

BNB Chain: 0xcef5be73ae943b77f9bc08859367d923c030a269

Avalanche: 0x5AA6a4E96A9129562e2fc06660D07FEdDAAf7854

Fantom: 0x37b5a5a730dad670874f26cc5507bb1b9705e447

Polygon: 0x9D1A92e601db0901e69bd810029F2C14bCCA3128

Query function

    /// @dev query the amount to swap fromToken -> toToken
    /// @param fromToken the from token
    /// @param toToken the to token
    /// @param fromAmount the amount of fromToken to swap
    /// @return toAmount the swapped amount to receive
    function querySwap(
        address fromToken,
        address toToken,
        uint256 fromAmount
    ) external view returns (uint256 toAmount);

Sample code to retrieve quote on selling 1 BTC:

wooRouter.querySwap(
  0x7130d2A12B9BCbFAe4f2634d864A1Ee1Ce3Ead9c, // btcb token address
  0x55d398326f99059fF775485246999027B3197955, // usdt token address
  1000000000000000000);                       // btcb amount to swap in decimal 18

Swap function

    /// @dev swap fromToken -> toToken
    /// @param fromToken the from token
    /// @param toToken the to token
    /// @param fromAmount the amount of fromToken to swap
    /// @param minToAmount the minimum amount of toToken required or the tx reverts
    /// @param to the destination address
    /// @param rebateTo the address to receive rebate (rebate rate is set to 0 now)
    /// @return realToAmount the amount of toToken to receive
    function swap(
        address fromToken,
        address toToken,
        uint256 fromAmount,
        uint256 minToAmount,
        address payable to,
        address rebateTo
    ) external payable returns (uint256 realToAmount);

Sample code to swap 1 BTC to USDT:

wooRouter.swap(
  0x7130d2A12B9BCbFAe4f2634d864A1Ee1Ce3Ead9c, // btcb token address
  0x55d398326f99059fF775485246999027B3197955, // usdt token address
  1000000000000000000,                        // btcb amount to swap in decimal 18
   990000000000000000,                        // min amount for 1% slippage
  0xd51062A4aF7B76ee0b2893Ef8b52aCC155393E3D, // the address to receive the swap fund
  0);                                         // the rebate address

sPMM offchain simulation

For aggregators running offchain routing simulation, you can find the typescript implementation of WOOFi's sPMM algorithm in the github.