Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

//SPDX-License-Identifier: MIT

pragma solidity ^0.8.19;

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

contract ReferalPool is Ownable {
    enum ReferalLevels {
        Basic,
        Advanced,
        Pro
    }
    struct Referals {
        ReferalLevels level;
        uint256 totalRewards;
        uint256 claimedRewards;
        uint256 lastClaimedAt;
        uint256 lastRewardsAt;
        address lastRewardFrom;
        bool isAtMaxLevel;
        uint256 referalCount;
    }

    struct TierStructure {
        uint256 minReferals;
        uint256 rewardPercentage;
    }

    uint256 constant DEVIDE_FACTOR = 10000;

    address public superAdmin;
    IERC20 public Token;

    uint256 public totalRewardsSent;

    mapping(ReferalLevels => TierStructure) public levelDetails;

    mapping(address => Referals) public referalDetails;

    mapping(address => address) public userReferal;

    event NewReferalAdded(address referee, address referal);
    event NewReferalBonusAdded(address from, address to, uint256 amount);

    modifier onlySuper() {
        require(
            msg.sender == superAdmin,
            "Ownable: caller is not the Super admin"
        );
        _;
    }

    constructor(address _superAdmin, address _token) {
        TierStructure storage _level1 = levelDetails[ReferalLevels.Basic];
        TierStructure storage _level2 = levelDetails[ReferalLevels.Advanced];
        TierStructure storage _level3 = levelDetails[ReferalLevels.Pro];

        _level1.minReferals = 1;
        _level1.rewardPercentage = 100;

        _level2.minReferals = 4;
        _level2.rewardPercentage = 200;

        _level3.minReferals = 7;
        _level3.rewardPercentage = 300;

        superAdmin = _superAdmin;
        Token = IERC20(_token);
    }

    function setReferal(address _referal) external {
        require(
            userReferal[msg.sender] == address(0),
            "Referal address already set"
        );

        require(msg.sender != _referal, "Can not set own address");

        userReferal[msg.sender] = _referal;

        Referals storage referal = referalDetails[_referal];

        referal.referalCount++;

        if (!referal.isAtMaxLevel) {
            updateReferalLevel(_referal);
        }

        emit NewReferalAdded(msg.sender, _referal);
    }

    function setReferalBonus(
        address from,
        uint256 buyAmount
    ) external onlyOwner {
        if (userReferal[from] == address(0)) return;
        Referals storage referal = referalDetails[userReferal[from]];
        TierStructure memory tier = levelDetails[referal.level];

        uint256 _bonus = (buyAmount * tier.rewardPercentage) / DEVIDE_FACTOR;

        referal.lastRewardFrom = from;
        referal.lastRewardsAt = block.timestamp;
        referal.totalRewards += _bonus;

        Token.transfer(userReferal[from], _bonus);

        emit NewReferalBonusAdded(from, userReferal[from], _bonus);
    }

    function changeTiers(
        ReferalLevels level,
        uint256 newMinReferals,
        uint256 newRewardPercentage
    ) external onlySuper {
        TierStructure storage tier = levelDetails[level];

        // Check that the provided values are valid
        require(newMinReferals > 0, "Minimum referrals must be greater than 0");
        require(
            newRewardPercentage > 0,
            "Reward percentage must be greater than 0"
        );

        // Update the tier structure with the new values
        tier.minReferals = newMinReferals;
        tier.rewardPercentage = newRewardPercentage;
    }

    function updateReferalLevel(address _user) internal {
        Referals storage referal = referalDetails[_user];

        uint256 referalCount = referal.referalCount;
        ReferalLevels newLevel;

        if (referalCount >= levelDetails[ReferalLevels.Pro].minReferals) {
            newLevel = ReferalLevels.Pro;
        } else if (
            referalCount >= levelDetails[ReferalLevels.Advanced].minReferals
        ) {
            newLevel = ReferalLevels.Advanced;
        } else {
            newLevel = ReferalLevels.Basic;
        }

        // Update the referral's level if it has changed
        if (referal.level != newLevel) {
            referal.level = newLevel;
            if (newLevel == ReferalLevels.Pro) referal.isAtMaxLevel = true;
        }
    }

    function claimRewards() external {
        Referals storage referal = referalDetails[msg.sender];

        require(referal.totalRewards > 0, "you didn't start earning yet");

        uint256 claimabaleRewards = referal.totalRewards -
            referal.claimedRewards;

        require(claimabaleRewards > 0, "you don't have any claiamble rewards");

        referal.claimedRewards += claimabaleRewards;

        referal.lastClaimedAt = block.timestamp;
        Token.transfer(msg.sender, claimabaleRewards);

        totalRewardsSent += claimabaleRewards;
    }
}