// File: Swap/TestExchange.sol



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

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract TestExchange {
    address public owner;
    address public treasury;
    address public customTokenAddress; // Address of the custom ERC-20 token
    address public baseTokenAddress; // Address of payment token e.x USDT
    // address public wethAddress = 0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14; // mainnet -> 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2

    modifier onlyOwner() {
        require(
            msg.sender == owner,
            "Only the contract owner can call this function"
        );
        _;
    }

    // Constructor to initialize the contract
    constructor(
        address _treasury,
        address _customTokenAddress,
        address _baseTokenAddress
    ) {
        owner = msg.sender;
        treasury = _treasury;
        customTokenAddress = _customTokenAddress;
        baseTokenAddress = _baseTokenAddress;
    }

    function setTreasury(address _treasury) external onlyOwner {
        require(_treasury != address(0), "Address should be valid");
        treasury = _treasury;
    }

    function setCustomTokenAddress(address _token) external onlyOwner {
        require(_token != address(0), "Address should be valid");
        customTokenAddress = _token;
    }

    function setBaseTokenAddress(address _token) external onlyOwner {
        require(_token != address(0), "Address should be valid");
        baseTokenAddress = _token;
    }

    // Function to receive and swap tokens
    function pay(uint256 amount) external {
        require(amount > 0, "Amount must be greater than 0");

        // Transfer the user's ERC-20 token (e.g., USDT) to this contract
        // Ensure the sender has approved the contract to spend their tokens
        require(
            IERC20(baseTokenAddress).transferFrom(
                msg.sender,
                address(this),
                amount
            ),
            "Transfer failed"
        );

        // Transfer the received tokens to the treasury
        require(
            IERC20(baseTokenAddress).transfer(treasury, amount),
            "Treasury transfer failed"
        );

        // Transfer custom tokens back to the sender
        require(
            IERC20(customTokenAddress).transfer(msg.sender, amount),
            "Custom token transfer failed"
        );
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}