gist

PaymentToken.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

import "https://github.com/lexDAO/Kali/blob/main/contracts/tokens/erc20/ERC20.sol";

interface IERC20 {
    function balance(address account) external view returns (uint256);
    function transfer(address to, uint256 amount) external;
}

contract Payment is ERC20 {
    address public owner = msg.sender;

    string public agreement;

    uint256 public price = 0.1 ether;

    uint256 public payment = 0.1 ether;

    uint256 public userPayment = 0.01 ether;

    IERC20 public paymentToken = IERC20(0x8ad3aA5d5ff084307d28C8f514D7a193B2Bfe725);

    mapping(address => bool) whitelisted;

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    modifier onlyWhitelisted {
        require(whitelisted[msg.sender]);
        _;
    }

    constructor() ERC20("rossCO", "RC", 18) {}

    function whitelist(address[] calldata users) public onlyOwner {
        unchecked {
            for (uint256 i; i < users.length; i++) {
                whitelisted[users[i]] = true;
            }
        }
    }

    function setAgreement(string calldata agreement_) public onlyOwner {
        agreement = agreement_;
    }

    function takePayUser() public onlyWhitelisted {
        paymentToken.transfer(msg.sender, 10 ether);
    }

    function payGroup(address[] calldata users) public payable {
        unchecked {
            for (uint256 i; i < users.length; i++) {
                (bool success, ) = users[i].call{value: msg.value / users.length}("");
                require(success);
            }
        }
    }

    function takePay() public onlyOwner {
        (bool success, ) = msg.sender.call{value: payment}("");
        require(success);
    }

    /// @notice User by calling this function agrees to the terms set in `agreement`
    receive() external payable {
        require(msg.value == price);

        _mint(msg.sender, 100 ether);
    }
}