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// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Votes.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

interface Escrow {
    function getAddresses() external view returns(address[] memory);

function balanceOf(address holder) external view returns(uint256);
}

abstract contract ERC20VotesEscrowed is ERC20Votes, Ownable {

Escrow escrow;

bool initialized = false;

error AlreadyInitialized();

// to be called after tokens have been transferred to the escrow contract
    function setUpVotingPower(address _escrowAddress) external onlyOwner {
        if (initialized) revert AlreadyInitialized();
    
        escrow = Escrow(_escrowAddress);
        address[] memory addresses = escrow.getAddresses();

for (uint i = 0; i < addresses.length; i++) {
            address a = addresses[i];
            _jankyMoveVotingPower(_escrowAddress, a, escrow.balanceOf(a));
        }

initialized = true;
    }

function _afterTokenTransfer(address _from, address _to, uint256 _amount) internal override {
        // if it's the escrow contract, don't transfer any voting power when it leaves escrow, the 
        // power will remain with whoever it's been delegated to already
        if (address(escrow) != _from) {
            super._afterTokenTransfer(_from, _to, _amount);
        }
    }

function _delegate(address delegator, address delegatee) internal override {
        super._delegate(delegator, delegatee);

// adds the escrow balance to the new delegatee's voting power
        address currentDelegate = delegates(delegator);
        uint256 escrowBalance = escrow.balanceOf(delegator);
        _jankyMoveVotingPower(currentDelegate, delegatee, escrowBalance);
    }

// Moves voting power with the normally private `_moveVotingPower` function 
    // by calling the `_afterTokenTransfer` function.
    //
    // see https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfef6a68ee18dbd2e1f5a099061a3b8a0e404485/contracts/token/ERC20/extensions/ERC20Votes.sol#LL217C6-L217C6
    // see https://github.com/OpenZeppelin/openzeppelin-contracts/blob/dfef6a68ee18dbd2e1f5a099061a3b8a0e404485/contracts/token/ERC20/ERC20.sol#L364
    function _jankyMoveVotingPower(address _src, address _dst, uint256 _amount) internal {
        super._afterTokenTransfer(_src, _dst, _amount);
    }
}