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;

When opening a position, the Farming contract interact with the Uniswap v3 nonFungiblePositionManager to mint the position NFT.

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
})));
(tokenId, liquidityAmount, amount0, amount1) = abi.decode(IMulticall(address(nonfungiblePositionManager)).multicall{ value: ethValue }(data)[0], (uint256, 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, tokenId: tokenId, 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