Untitled

pragma solidity 0.8.19;


import {Pausable} from "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/security/Pausable.sol";
import {IERC20} from "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/utils/SafeERC20.sol";


interface IWETH is IERC20 {
  function deposit() external payable;
  function withdraw(uint256) external;
}


contract Vault is Pausable {
  using SafeERC20 for IWETH;


  address public immutable controller;
  IWETH public immutable WETH;


  // about 4700 ETH
  uint72 public constant TOTAL_CONTRIBUTION_CAP = type(uint72).max;
  // ALLOWANCE_CAP = 40% of TOTAL_CONTRIBUTION_CAP
  uint256 public immutable ALLOWANCE_CAP = 40 * uint256(TOTAL_CONTRIBUTION_CAP) / 100;
  uint72 public totalContributions;
  mapping (address => uint72) individualContributions;


  uint256 numContributors;
  event ContributorsUpdated(address newContributor, uint256 indexed oldNumContributors, uint256 indexed newNumContributors);


  constructor(address _controller, IWETH _weth) {
      controller = _controller;
      WETH = _weth;
  }


  function deposit(uint72 amount) external payable whenNotPaused {
      if (msg.value > 0) {
          WETH.deposit{value: amount}();
      } else {
          WETH.transferFrom(msg.sender, address(this), amount);
      }
      require((totalContributions += amount) <= TOTAL_CONTRIBUTION_CAP, "cap exceeded");
      if (individualContributions[msg.sender] == 0) emit ContributorsUpdated(msg.sender, numContributors, numContributors++);
      individualContributions[msg.sender] += amount;
  }


  function withdraw(uint72 amount) external whenNotPaused {
      individualContributions[msg.sender] -= amount;
      totalContributions -= amount;
      // unwrap and call
      WETH.withdraw(amount);
      (bool success, ) = payable(address(msg.sender)).call{value: amount}("");
      require(success, "failed to transfer ETH");
  }


  function requestAllowance(uint256 amount) external {
      // ALLOWANCE_CAP is 40% of TOTAL_CAP
      uint256 allowanceCap = ALLOWANCE_CAP;
      uint256 allowance = amount > totalContributions ? allowanceCap : amount;
      WETH.safeApprove(controller, allowance);
  }


  // for unwrapping WETH -> ETH
  receive() external payable {
      require(msg.sender == address(WETH), "only WETH contract");
  }
}