Open a Position

The openPosition function is used to open a new farming position. This function requires, as input, the FarmingPositionRequest struct:

function openPosition(FarmingPositionRequest memory request) public override payable activeSetupOnly(request.setupIndex) returns(uint256 positionId) {

At the moment of creation, a positionID that represents the position is generated:

positionId = uint256(keccak256(abi.encode(uniqueOwner);

Each generated id is encoded with the uniqueOwner (owner position) address. This means that each address can correspond to one and only one position within each setup; a single address cannot have multiple positions in a setup.

A user can also open a position for another address. In this case, the uniqueOwner is not the msg.sender, but rather the address passed in the FarmingPositionRequest:

address uniqueOwner = (request.positionOwner != address(0)) ? request.positionOwner : msg.sender;

Initial liquidity is transferred from the user to the contract and added to the setup via the _addLiquidity function, which calculates the amount of inserted liquidity (liquidityAmount).

uint128 liquidityAmount = _addLiquidity(request.setupIndex, request);

When the first user opens a position in the setup, the _addLiquidity function mints the NFT, using the parameters previously passed by the host at the moment of setup creation. See here for more details.

(_addLiquidity can then call the increaseLiquidity method of INonfungiblePositionManager).

data[0] = abi.encodeWithSelector(nonfungiblePositionManager.increaseLiquidity.selector, abi.encode(INonfungiblePositionManager.IncreaseLiquidityParams({ 
    tokenId: _setups[request.setupIndex].objectId, 
    amount0Desired: request.amount0, 
    amount1Desired: request.amount1,
    amount0Min: 1,
    amount1Min: 1,
    deadline: block.timestamp + 10000
 })));
 (liquidityAmount,,) = abi.decode(IMulticall(address(nonfungiblePositionManager)).multicall{ value : ethValue }(data)[0], (uint128, uint256, uint256));

At this point, the FarmingPosition struct for the created position is populated as follow:

_positions[positionId] = FarmingPosition({ uniqueOwner: uniqueOwner, setupIndex : request.setupIndex, liquidityPoolTokenAmount: liquidityPoolData.amount, mainTokenAmount: mainTokenAmount, reward: reward, lockedRewardPerBlock: lockedRewardPerBlock, creationBlock: block.number

Creating a position increases the number of positions within a specific setup by one, given by:

mapping(uint256 => uint256) private _setupPositionsCount;

_setupPositionsCount[request.setupIndex] += 1