// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/access/AccessControl.sol";

error UnmatchedLengths();

contract RollaFaucet is AccessControl {
    using SafeERC20 for IERC20;

    mapping(address => uint256) public asset_maxValue;
    address public whitelist;
    bytes32 public constant ADMIN_ROLE = keccak256("ADMIN_ROLE");

    event FaucetTransfer(address token, uint256 amount, address to, uint256 timestamp);

    constructor() {
        _setupRole(ADMIN_ROLE, msg.sender);
    }

    function multiTransfer(address to, address[] calldata token, uint256[] calldata amount) public {
        uint256 length = token.length;

        if (length != amount.length) {
            revert UnmatchedLengths();
        }

        for (uint256 i = 0; i < length;) {
            transfer(to, token[i], amount[i]);
            unchecked {
                i++;
            }
        }
    }

    function transfer(address to, address token, uint256 amount) public {
        require(msg.sender == whitelist || whitelist == address(0), "Faucet: caller not whitelisted");
        require(IERC20(token).balanceOf(to) + amount <= asset_maxValue[token], "Faucet: excessive funds transfer"); // Check existing balance of the user
        IERC20(token).safeTransfer(to, amount);
        emit FaucetTransfer(token, amount, to, block.timestamp);
    }

    function getFaucetBalance(address token) public view returns (uint256 balance) {
        return IERC20(token).balanceOf(address(this));
    }

    function getTokenBalanceOf(address token, address user) public view returns (uint256 balance) {
        return IERC20(token).balanceOf(user);
    }

    function setMaxValue(address token, uint256 maxTransferValue) public {
        require(hasRole(ADMIN_ROLE, msg.sender), "Faucet: caller not an admin");
        asset_maxValue[token] = maxTransferValue;
    }

    function withdrawNativeToken() public {
        require(hasRole(ADMIN_ROLE, msg.sender), "Faucet: caller not an admin");
        (bool success,) = msg.sender.call{value: address(this).balance}("");
        require(success, "Faucet: withdrawal successful");
    }

    function setWhitelistAddress(address whitelistAddress) public {
        require(hasRole(ADMIN_ROLE, msg.sender), "Faucet: caller not an admin");
        whitelist = whitelistAddress;
    }

    receive() external payable {}
}