Unstake

The unstake function takes streamId as input, and unstakes the stream by transferring the Sablier NFT back to the user.

function unstake(uint256 streamId) public updateReward(msg.sender) {
    // code goes here.
}

As the first step, we will check if the user is a staker.

if (stakedUsers[streamId] != msg.sender) {
    revert UnauthorizedCaller(msg.sender, streamId);
}

As the second step, we will reduce the total amount of underlying ERC20 token staked.

totalERC20StakedSupply -= _getAmountInStream(streamId);

As the final step, we will update some storage variables and transfer the NFT:

delete stakedUsers[streamId];

delete stakedStreams[account];

sablierLockup.safeTransferFrom({ from: address(this), to: account, tokenId: streamId });