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contracts...EscrowAgent.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;
import "hardhat/console.sol";

contract EscrowAgent {
    address public agent;

    enum Stages {
        NONE,
        IN_PROGRESS,
        COMPLETED
    }
    struct Service {
        uint amount;
        Stages stage;
    }

    mapping(address => Service) public deposits;

    constructor(address _owner){
        agent = _owner;
    }

    modifier isAgent() {
        console.log("AGENT & SENDER %s => %s", agent, msg.sender);
        require(agent == msg.sender, "Only agent allowed call this method");
        _;
    }

    modifier hasDeposit(address _receiver) {
        require(deposits[_receiver].stage != Stages.NONE, "No deposits have been made");
        _;
    }

    modifier canComplete(address _receiver) {
        require(deposits[_receiver].stage == Stages.IN_PROGRESS, "Can not complete a service that was never started");
        _;
    }

    modifier canWithdaw(address _receiver) {
        require(deposits[_receiver].stage == Stages.COMPLETED, "Can not withdraw until the service is completed");
        _;
    }

    function deposit(address _receiver) payable public isAgent {
        Service storage service = deposits[_receiver];
        service.amount += msg.value;
        service.stage = Stages.IN_PROGRESS;
    }

    function completed(address _receiver) public isAgent canComplete(_receiver) {
        deposits[_receiver].stage = Stages.COMPLETED;
    }

    function withdraw(address payable _receiver) public isAgent canWithdaw(_receiver) {
        Service storage service = deposits[_receiver];
        _receiver.transfer(service.amount);
        service.amount = 0;
        service.stage = Stages.NONE;

    }
}