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contracts...26_EscrowContract.sol

pragma solidity >=0.7.0 <0.9.0;

contract Escrow {

  //Variables

  enum State { NOT_INITIATED,  AWAITING_PAYMENT, AWAITING_DELIVERY, COMPLETE }
 
  State public currentState;

  bool public isBuyerIn;
  bool public isSellerIn;

  uint public price;

  address public buyer;
  address payable public seller;

  // Modifers

  modifier onlyBuyer() {
      require(msg.sender == buyer, "Not authorized!");
      _;
  }

  modifier escrowNotStarted() {
      require(currentState == State.NOT_INITIATED);
      _;
  }

  // Functions

  constructor(address _buyer, address payable _seller, uint _price) {
    buyer = _buyer;
    seller = _seller;
    price = _price *(1 ether);
  }

  function initContract() public escrowNotStarted {
    if(msg.sender == buyer) {
      isBuyerIn = true;
    }
    if(msg.sender == seller) {
        isSellerIn = true;
    }
    if(isBuyerIn && isSellerIn) {
        currentState = State.AWAITING_PAYMENT;
    }
  }

  function depositFunds() public payable onlyBuyer {
    require(currentState == State.AWAITING_PAYMENT, "Already paid!");
    require(msg.value == price, "Incorrect depoist amount!");
    currentState = State.AWAITING_DELIVERY;
  }

  function confirmDelivery() public payable onlyBuyer {
    require(currentState == State.AWAITING_DELIVERY, "Cannot confirm delivery");
    seller.transfer(price);
    currentState == State.COMPLETE;

  }

  function withdraw() public payable onlyBuyer {
    require(currentState == State.AWAITING_DELIVERY, "Cannot withdraw at this stage!");
    payable(msg.sender).transfer(price);
    currentState == State.COMPLETE;
  }
}