1pragma solidity ^0.6.0;
 2
 3import './verifier.sol';
 4
 5contract Miksi {
 6  Verifier    verifier;
 7
 8  constructor( address _verifierContractAddr) public {
 9    verifier = Verifier(_verifierContractAddr);
10  }
11  uint256 amount = uint256(1000000000000000000);
12  uint256 root;
13  uint256[] commitments;
14  mapping(uint256 => bool) nullifiers;
15
16  function deposit(
17            uint256 _commitment,
18            uint256 _root
19  ) public payable {
20    // TODO check root state transition update with zkp
21
22    require(msg.value==amount, "value should be 1 ETH"); // this can be flexible with a wrapper with preset fixed amounts
23    commitments.push(_commitment);
24    root = _root;
25  }
26
27  function getCommitments() public view returns (uint256[] memory, uint256) {
28    return (commitments, root);
29  }
30
31  function withdraw(
32            address payable _address,
33            uint256 nullifier,
34            uint[2] memory a,
35            uint[2][2] memory b,
36            uint[2] memory c
37  ) public {
38
39    uint256[5] memory input = [
40      0,
41      amount,
42      nullifier,
43      root,
44      uint256(_address)
45    ];
46    require(verifier.verifyProof(a, b, c, input), "zkProof withdraw could not be verified");
47    // zk verification passed
48    require(useNullifier(nullifier), "nullifier already used");
49    // nullifier check passed
50    // proceed with the withdraw
51
52    _address.send(amount);
53    // _address.call.value(amount).gas(20317)();
54  }
55
56  function useNullifier(
57    uint256 nullifier
58  ) internal returns (bool) {
59    if (nullifiers[nullifier]) {
60      return false;
61    }
62    nullifiers[nullifier] = true;
63    return true;
64  }
65}