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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @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 amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves `amount` 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 amount) 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 `amount` 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 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` 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 amount
    ) external returns (bool);
}

// File: contracts/vault.sol



pragma solidity ^0.8.4;

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

interface IWETH is IERC20 {
    function deposit() external payable;

    function withdraw(uint256 amount) external;
}

contract Vault {
    mapping(address => mapping(address => uint256)) public balances; // this is for users to deposit and withdraw funds
    address public wethAddress;
    IWETH weth;

    constructor(address _wethAddress) {
        wethAddress = _wethAddress;
        weth = IWETH(wethAddress);
    }

    function deposit(address _token, uint256 amount) external {
        require(amount > 0, "Amount must be greater than zero.");
        IERC20 token = IERC20(_token);
        balances[msg.sender][address(token)] += amount;
        require(
            token.transferFrom(msg.sender, address(this), amount),
            "Transfer failed."
        );
    }

    function withdraw(address _token, uint256 amount) external {
        require(amount > 0, "Amount must be greater than zero.");
        IERC20 token = IERC20(_token);
        require(
            balances[msg.sender][address(token)] >= amount,
            "Insufficient balance."
        );

        balances[msg.sender][address(token)] -= amount;
        require(token.transfer(msg.sender, amount), "Transfer failed.");
    }

    function depositETH() external payable {
        require(msg.value > 0, "Amount must be greater than zero.");
        balances[msg.sender][address(weth)] += msg.value;
        weth.deposit{value: msg.value}();
        weth.transfer(address(this), msg.value);
    }

    function withdrawETH(uint256 amount) external {
        require(amount > 0, "Amount must be greater than zero.");
        require(
            balances[msg.sender][address(weth)] >= amount,
            "Insufficient balance."
        );
        balances[msg.sender][address(weth)] -= amount;
        weth.transfer(msg.sender, amount);
    }
}