WPSmartContracts · September 17, 2024 04:17
diff --git a/CaramelCrowdsale.sol b/CaramelCrowdsale.sol
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.2;

 /**
 * @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;
    }
 }

 /**
 * @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);
 }

 /**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
 interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
 }

 /**
 * @dev Collection of functions related to the address type
 */
 library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
 }
    
 /**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
 library SafeERC20 {
    using Address for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

 }

 /**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
 abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
 }

 /**
 * @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() {
        _setOwner(_msgSender());
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

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

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
 }

 /**
 * @dev Standard math utilities missing in the Solidity language.
 */
 library Math {
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
 }

 /**
 * @title Crowdsale
 * @dev Base contract for managing a token crowdsale.
 * Allows investors to purchase tokens with ether until the contract is paused.
 * This contract can be extended to provide additional functionality.
 * The external interface represents the basic interface for purchasing tokens.
 * The internal interface is for extensible and modifiable surface of crowdsales.
 * Do not modify the external interface. Override methods for additional functionality.
 */
 contract Crowdsale is Ownable, ReentrancyGuard {

    using SafeERC20 for IERC20Metadata;

    // The token being sold
    IERC20Metadata public token;

    // Address where funds are collected
    address payable public wallet;

    // The rate determines how many token units a buyer receives per wei.
    // It represents the conversion between wei and the smallest, indivisible token unit.
    // The 'rate' is expressed as a wei-like precision, where a rate of 10^18 is equal to one unit.
    // This approach allows for token decimal conversions and rates less than 1.
    uint256 public rate;

    // Amount of wei raised
    uint256 public weiRaised;

    /**
     * @dev Event emitted when tokens are purchased.
     * @param purchaser Address of the user who purchased tokens
     * @param beneficiary Address where purchased tokens were sent
     * @param value Amount of ether paid for purchase
     * @param amount Amount of tokens purchased
     */
    event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);

    /**
     * @dev Event emitted when the rate is changed.
     * @param rate the new rate
     */
    event RateChanged(uint256 rate);

    /**
     * @dev The rate is the conversion between wei and the smallest and indivisible
     * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
     * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
     * @param rate_ Number of token units a buyer gets per wei
     * @param wallet_ Address where collected funds will be forwarded to
     * @param token_ Address of the token being sold
     * @param owner_ Address of the contract owner
     */
    constructor (uint256 rate_, address payable wallet_, IERC20Metadata token_, address owner_) Ownable() {
        setRate(rate_);
        setWallet(wallet_);
        setToken(token_);
        transferOwnership(owner_);
    }

    /**
     * @dev Owner can change the rate.
     * @param rate_ Number of token units a buyer gets per wei
     */
    function setRate(uint256 rate_) public virtual onlyOwner() {
        require(rate_ > 0, "Crowdsale: rate is 0");
        require(weiRaised == 0, "Crowdsale has started");
        emit RateChanged(rate_);
        rate = rate_;
    }

    /**
     * @dev Owner can change the wallet.
     * @param wallet_ Address where collected funds will be forwarded to
     */
    function setWallet(address payable wallet_) public onlyOwner() {
        require(wallet_ != address(0), "Crowdsale: wallet is the zero address");
        wallet = wallet_;
    }

    /**
     * @dev Owner can change the token if the crowdsale hasn't started yet.
     * @param token_ Address of the token being sold
     */
    function setToken(IERC20Metadata token_) public onlyOwner() {
        require(weiRaised == 0, "Crowdsale has started");
        require(address(token_) != address(0), "Crowdsale: token is the zero address");
        token = token_;
    }

    /**
     * @dev Fallback function ***DO NOT OVERRIDE***
     * Note that other contracts will transfer funds with a base gas stipend
     * of 2300, which is not enough to call buyTokens. Consider calling
     * buyTokens directly when purchasing tokens from a contract.
     * This function is automatically called when ether is sent to the contract address.
     * Users should send Ethers from the beneficiary address in the transaction.
     */
    receive() external payable {
        buyTokens(_msgSender());
    }

    /**
     * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
     * tokens.
     * @param beneficiary Address receiving the tokens
     * @param tokenAmount Number of tokens to be purchased
     */
    function _processPurchase(address beneficiary, uint256 tokenAmount) virtual internal {
        _deliverTokens(beneficiary, tokenAmount);
    }

    /**
     * @dev Low-level token purchase ***DO NOT OVERRIDE***
     * Allows users to purchase tokens with ether.
     * This function has a non-reentrancy guard, so it shouldn't be called by
     * another `nonReentrant` function.
     * @param beneficiary Address where purchased tokens will be sent
     */
    function buyTokens(address beneficiary) public virtual nonReentrant payable {

        uint256 weiAmount = msg.value;
        _preValidatePurchase(beneficiary, weiAmount);

        require(beneficiary != address(0), "Crowdsale: beneficiary is the zero address");
        require(weiAmount != 0, "Crowdsale: weiAmount is 0");

        // Calculate token amount to be created
        uint256 tokens = getTokenAmount(weiAmount);
        require(tokens != 0, "Crowdsale: cannot buy 0 tokens");

        // Update state
        weiRaised += weiAmount;

        _processPurchase(beneficiary, tokens);
        emit TokensPurchased(_msgSender(), beneficiary, weiAmount, tokens);

        wallet.transfer(msg.value);

    }

    /**
     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
     * Use `super` in contracts that inherit from Crowdsale to extend their validations.
     * Example from CappedCrowdsale.sol's _preValidatePurchase method:
     *     super._preValidatePurchase(beneficiary, weiAmount);
     *     require(weiRaised().add(weiAmount) <= cap);
     * @param beneficiary Address performing the token purchase
     * @param weiAmount Value in wei involved in the purchase
     */
    function _preValidatePurchase(address beneficiary, uint256 weiAmount) virtual internal view {
        require(beneficiary != address(0), "Crowdsale: beneficiary is the zero address");
        require(weiAmount != 0, "Crowdsale: weiAmount is 0");
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    }

    /**
     * @dev Calculate the number of tokens that can be purchased with a specified amount of wei.
     *
     * This function provides a conversion mechanism for converting Ethereum wei (the smallest unit of Ether) into tokens
     * based on the current rate and the number of decimal places in the token's representation.
     *
     * @param weiAmount The amount of wei to be converted into tokens.
     * @return The number of tokens that can be purchased with the specified `weiAmount`.
     */
    function getTokenAmount(uint256 weiAmount) public view returns (uint256) {
        // Calculate the number of tokens using the specified wei amount, rate, and token decimals.
        // The formula is: (weiAmount * rate * 10^tokenDecimals) / (10^18 / 10^rateDecimals)
        // where 10^18 is used to account for Ether's 18 decimal places and 10^rateDecimals is used to adjust for rate precision.
        return (weiAmount * rate * 10**token.decimals()) / 10**36;
    }

    /**
     * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
     * its tokens.
     * @param beneficiary Address performing the token purchase
     * @param tokenAmount Number of tokens to be emitted
     */
    function _deliverTokens(address beneficiary, uint256 tokenAmount) virtual internal {}

 }

 /**
 * @title BubblegumCrowdsale
 * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
 */
 contract BubblegumCrowdsale is Crowdsale {

    using SafeERC20 for IERC20Metadata;

    address private _tokenWallet;

    /**
     * @dev The rate is the conversion between wei and the smallest and indivisible
     * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
     * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
     * @param wallet_ Address where collected funds will be forwarded to
     * @param token_ Address of the token being sold
     * @param rate_ Number of token units a buyer gets per wei
     * @param owner_ Address of the contract owner
     * @param distributionWallet_ Address holding the tokens, which has approved allowance to the crowdsale.
     */
    constructor (uint256 rate_, address payable wallet_, IERC20Metadata token_, address distributionWallet_, address owner_) 
        Crowdsale(rate_, wallet_, token_, owner_) {
        require(distributionWallet_ != address(0), "AllowanceCrowdsale: token wallet is the zero address");
        _tokenWallet = distributionWallet_;
    }

    /**
     * @dev Owner can change the token wallet.
     * @param distributionWallet_ Address that holds the token to be distributed
     */
    function setTokenWallet(address distributionWallet_) external onlyOwner() {
        require(distributionWallet_ != address(0), "Crowdsale: token wallet is the zero address");
        _tokenWallet = distributionWallet_;
    }

    /**
     * @return the address of the wallet that will hold the tokens.
     */
    function tokenWallet() external view returns (address) {
        return _tokenWallet;
    }

    /**
     * @dev Checks the amount of tokens left in the allowance.
     * @return Amount of tokens left in the allowance
     */
    function remainingTokens() external view returns (uint256) {
        return Math.min(token.balanceOf(_tokenWallet), token.allowance(_tokenWallet, address(this)));
    }

    /**
     * @dev Overrides parent behavior by transferring tokens from wallet.
     * @param beneficiary Token purchaser
     * @param tokenAmount Amount of tokens purchased
     */
    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal override {
        token.safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
    }

 }

 /**
 * @title TimedCrowdsale
 * @dev Crowdsale accepting contributions only within a time frame.
 */
 contract TimedCrowdsale is BubblegumCrowdsale {

    // Optional opening and closing times
    // If both are zero we assume that the ICO is not timed
    uint256 private _openingTime;
    uint256 private _closingTime;

    /**
     * Event for crowdsale extending
     * @param newClosingTime new closing time
     * @param prevClosingTime old closing time
     */
    event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);

    /**
     * @dev Reverts if not in crowdsale time range.
     */
    modifier onlyWhileOpen {
        require(isOpen(), "TimedCrowdsale: not open");
        _;
    }

    constructor (uint256 rate_, address payable wallet_, IERC20Metadata token_, address distributionWallet_, address owner_,
        uint256 openingTime_, uint256 closingTime_) 
        BubblegumCrowdsale(rate_, wallet_, token_, distributionWallet_, owner_) {
        require(closingTime_ > openingTime_ || (closingTime_ == 0 && openingTime_ == 0), "TimedCrowdsale: opening time is not before closing time");
        _openingTime = openingTime_;
        _closingTime = closingTime_;
    }

    /**
     * @dev setTimes, set crowdsale opening and closing times.
     * @param openingTime_ Crowdsale opening time
     * @param closingTime_ Crowdsale closing time
     */
    function setTimes(uint256 openingTime_, uint256 closingTime_) public virtual onlyOwner() {
        require(closingTime_ > openingTime_, "TimedCrowdsale: opening time is not before closing time");
        _openingTime = openingTime_;
        _closingTime = closingTime_;
    }

    /**
     * @return the crowdsale opening time.
     */
    function openingTime() public view returns (uint256) {
        return _openingTime;
    }

    /**
     * @return the crowdsale closing time.
     */
    function closingTime() public view returns (uint256) {
        return _closingTime;
    }

    /**
     * @return true if the crowdsale is open, false otherwise.
     */
    function isOpen() public view returns (bool) {
        // solhint-disable-next-line not-rely-on-time
        return (_openingTime == 0 && _closingTime == 0) || 
               (block.timestamp >= _openingTime && block.timestamp <= _closingTime);
    }

    /**
     * @dev Checks whether the period in which the crowdsale is open has already elapsed.
     * @return Whether crowdsale period has elapsed
     */
    function hasClosed() public view returns (bool) {
        // solhint-disable-next-line not-rely-on-time
        return block.timestamp > _closingTime;
    }

    /**
     * @dev Extend parent behavior requiring to be within contributing period.
     * @param beneficiary Token purchaser
     * @param weiAmount Amount of wei contributed
     */
    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal override virtual onlyWhileOpen view {
        super._preValidatePurchase(beneficiary, weiAmount);
    }

 }

 /**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
 library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev Give an account access to this role.
     */
    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    /**
     * @dev Remove an account's access to this role.
     */
    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    /**
     * @dev Check if an account has this role.
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero address");
        return role.bearer[account];
    }
 }

 /**
 * @title WhitelistAdminRole
 * @dev WhitelistAdmins are responsible for assigning and removing Whitelisted accounts.
 */
 contract WhitelistAdminRole is Context {
    using Roles for Roles.Role;

    event WhitelistAdminAdded(address indexed account);
    event WhitelistAdminRemoved(address indexed account);

    Roles.Role private _whitelistAdmins;

    constructor() {
        _addWhitelistAdmin(_msgSender());
    }

    modifier onlyWhitelistAdmin() {
        require(isWhitelistAdmin(_msgSender()), "WhitelistAdminRole: caller does not have the WhitelistAdmin role");
        _;
    }

    function isWhitelistAdmin(address account) public view returns (bool) {
        return _whitelistAdmins.has(account);
    }

    function addWhitelistAdmin(address account) public onlyWhitelistAdmin {
        _addWhitelistAdmin(account);
    }

    function renounceWhitelistAdmin() public {
        _removeWhitelistAdmin(_msgSender());
    }

    function _addWhitelistAdmin(address account) internal {
        _whitelistAdmins.add(account);
        emit WhitelistAdminAdded(account);
    }

    function _removeWhitelistAdmin(address account) internal {
        _whitelistAdmins.remove(account);
        emit WhitelistAdminRemoved(account);
    }
 }

 /**
 * @title WhitelistedRole
 * @dev Whitelisted accounts are approved by a WhitelistAdmin to perform certain actions, such as participating in a crowdsale.
 * Only WhitelistAdmins can add or remove Whitelisted accounts, and Whitelisted accounts cannot modify their own status.
 */
 contract WhitelistedRole is Context, WhitelistAdminRole {
    using Roles for Roles.Role;

    // Events emitted when an account is added or removed from the whitelist
    event WhitelistedAdded(address indexed account);
    event WhitelistedRemoved(address indexed account);

    // The set of whitelisted accounts
    Roles.Role private _whitelisteds;

    /**
     * @dev Modifier to make a function callable only by whitelisted accounts.
     * Reverts if the caller is not whitelisted.
     */
    modifier onlyWhitelisted() {
        require(isWhitelisted(_msgSender()), "WhitelistedRole: caller does not have the Whitelisted role");
        _;
    }

    /**
     * @dev Checks if an account is whitelisted.
     * @param account The account to check
     * @return True if the account is whitelisted, false otherwise
     */
    function isWhitelisted(address account) public view returns (bool) {
        return _whitelisteds.has(account);
    }

    /**
     * @dev Adds an account to the whitelist. Only callable by a WhitelistAdmin.
     * @param account The account to add
     */
    function addWhitelisted(address account) public onlyWhitelistAdmin {
        _addWhitelisted(account);
    }

    /**
     * @dev Removes an account from the whitelist. Only callable by a WhitelistAdmin.
     * @param account The account to remove
     */
    function removeWhitelisted(address account) public onlyWhitelistAdmin {
        _removeWhitelisted(account);
    }

    /**
     * @dev Batch adds multiple accounts to the whitelist. Only callable by a WhitelistAdmin.
     * @param accounts The array of accounts to add
     */
    function addWhitelistedBatch(address[] memory accounts) public onlyWhitelistAdmin {
        for (uint256 index = 0; index < accounts.length; index++) {
            _addWhitelisted(accounts[index]);
        }
    }

    /**
     * @dev Batch removes multiple accounts from the whitelist. Only callable by a WhitelistAdmin.
     * @param accounts The array of accounts to remove
     */
    function removeWhitelistedBatch(address[] memory accounts) public onlyWhitelistAdmin {
        for (uint256 index = 0; index < accounts.length; index++) {
            _removeWhitelisted(accounts[index]);
        }
    }

    /**
     * @dev Allows a whitelisted account to renounce its role. This can only be called by the account itself.
     */
    function renounceWhitelisted() public {
        _removeWhitelisted(_msgSender());
    }

    /**
     * @dev Internal function to add an account to the whitelist.
     * Emits a WhitelistedAdded event.
     * @param account The account to add
     */
    function _addWhitelisted(address account) internal {
        _whitelisteds.add(account);
        emit WhitelistedAdded(account);
    }

    /**
     * @dev Internal function to remove an account from the whitelist.
     * Emits a WhitelistedRemoved event.
     * @param account The account to remove
     */
    function _removeWhitelisted(address account) internal {
        _whitelisteds.remove(account);
        emit WhitelistedRemoved(account);
    }
 }

 /**
 * @title FinalizableCrowdsale
 * @dev Extension of TimedCrowdsale with a one-off finalization action, where one
 * can do extra work after finishing.
 */
 contract FinalizableCrowdsale is TimedCrowdsale {

    bool private _finalized;

    event CrowdsaleFinalized();

    constructor (
        uint256 rate_,
        address payable wallet_,
        IERC20Metadata token_,
        address distributionWallet_,
        address owner_,
        uint256 openingTime_,
        uint256 closingTime_
    ) TimedCrowdsale(rate_, wallet_, token_, distributionWallet_, owner_, openingTime_, closingTime_) {
        _finalized = false;
    }

    /**
     * @return true if the crowdsale is finalized, false otherwise.
     */
    function finalized() public view returns (bool) {
        return _finalized;
    }

    /**
     * @dev Must be called after crowdsale ends, to do some extra finalization
     * work. Calls the contract's finalization function.
     */
    function finalize() public onlyOwner() {
        require(!_finalized, "FinalizableCrowdsale: already finalized");
        require(hasClosed(), "FinalizableCrowdsale: not closed");

        _finalized = true;

        _finalization();
        emit CrowdsaleFinalized();
    }

    /**
     * @dev Can be overridden to add finalization logic. The overriding function
     * should call super._finalization() to ensure the chain of finalization is
     * executed entirely.
     */
    function _finalization() internal {
        // solhint-disable-previous-line no-empty-blocks
    }

    /**
     * @dev Extend parent behavior requiring to be within contributing period.
     * @param openingTime_ Crowdsale opening time
     * @param closingTime_ Crowdsale closing time
     */
    function setTimes(uint256 openingTime_, uint256 closingTime_) public override onlyOwner() {
        require(!finalized(), "FinalizableCrowdsale: finalized");
        super.setTimes(openingTime_, closingTime_);
    }

 }

 interface IStakeUbe {
    function asset() external returns (IERC20);
    function startFor(address _account, uint256 _value) external;
 }

 /**
 * @title PostDeliveryCrowdsale
 * @dev This contract implements a crowdsale that locks tokens from withdrawal until the crowdsale ends.
 * It supports post-delivery withdrawal or batch distribution of tokens.
 */
 contract PostDeliveryCrowdsale is FinalizableCrowdsale {

    // Mapping to store the token balances of contributors
    mapping(address => uint256) internal _balances;

    // Array to keep track of contributors for batch token distribution
    address[] public contributors;

    // Address of the staking contract, if used
    address public stakingContract;

    // Token vault to hold tokens until they are delivered
    TokenVault internal _vault;

    /**
     * @dev Flag indicating how tokens should be delivered post-sale.
     * 0: No post-delivery, tokens are delivered immediately
     * 1: Contributors can withdraw tokens after the sale ends
     * 2: Tokens are distributed manually by the owner after the sale ends
     */
    uint8 public usePostDelivery;

    /**
     * @dev Constructor to initialize the PostDeliveryCrowdsale contract.
     * @param usePostDelivery_ Post delivery setting: 0 for disabled, 1 for contributor withdraw, 2 for manual distribution
     * @param rate_ Token rate (tokens per wei)
     * @param wallet_ Address that receives the collected funds
     * @param token_ Token being sold
     * @param distributionWallet_ Address used for token distribution
     * @param openingTime_ Start time for the crowdsale
     * @param closingTime_ End time for the crowdsale
     * @param owner_ Owner of the contract
     */
    constructor (
        uint8 usePostDelivery_,
        uint256 rate_,
        address payable wallet_,
        IERC20Metadata token_,
        address distributionWallet_,
        uint256 openingTime_,
        uint256 closingTime_,
        address owner_
    ) FinalizableCrowdsale(rate_, wallet_, token_, distributionWallet_, owner_, openingTime_, closingTime_) {
        _vault = new TokenVault(); // Initialize the token vault
        usePostDelivery = usePostDelivery_; // Set the post-delivery setting
    }

    /**
     * @dev Transfers tokens to the appropriate recipient (contributor or staking contract).
     * @param contributor Address of the contributor receiving the tokens
     * @param amount Amount of tokens to transfer
     */
    function transferTokens(address contributor, uint256 amount) internal {
        _balances[contributor] = 0;  // Reset contributor's balance to 0
        if (stakingContract == address(0)) {
            _vault.transfer(token, contributor, amount);  // Transfer directly to the contributor
        } else {
            _vault.transfer(token, address(this), amount);  // Transfer tokens to this contract
            token.approve(stakingContract, amount);  // Approve staking contract to spend the tokens
            IStakeUbe(stakingContract).startFor(contributor, amount);  // Start staking for the contributor
        }
    }

    /**
     * @dev Allows contributors to withdraw their tokens after the crowdsale ends.
     * Only available if post-delivery is set to 1 (contributor withdrawal).
     * @param beneficiary Address whose tokens will be withdrawn
     */
    function withdrawTokens(address beneficiary) public {
        require(usePostDelivery == 1, "PostDeliveryCrowdsale: not activated or no withdrawal available");
        require(finalized(), "PostDeliveryCrowdsale: crowdsale not finalized");
        uint256 amount = _balances[beneficiary];
        require(amount > 0, "PostDeliveryCrowdsale: no tokens due for this beneficiary");
        transferTokens(beneficiary, amount);  // Transfer tokens to the beneficiary
    }

    /**
     * @dev Sets the staking contract for token staking.
     * Can only be called by the owner.
     * @param stakes_ Address of the staking contract
     */
    function setStakingContract(address stakes_) external onlyOwner {
        require(IStakeUbe(stakes_).asset() == token, "PostDeliveryCrowdsale: token addresses don't match");
        stakingContract = stakes_;  // Set the staking contract address
    }

    /**
     * @dev Distributes tokens to multiple contributors in batches.
     * Reserved for the owner. Uses LIFO for gas efficiency.
     * @param n Number of contributors to distribute to in this batch
     */
    function distributeTokens(uint256 n) external onlyOwner {
        require(n <= contributors.length, "PostDeliveryCrowdsale: index out of bounds or no distribution available");
        require(finalized(), "PostDeliveryCrowdsale: crowdsale not finalized");

        for (uint i = 0; i < n; i++) {
            address contributor = contributors[contributors.length - 1];
            uint256 amount = _balances[contributor];
            if (amount > 0) {
                transferTokens(contributor, amount);  // Transfer tokens to the contributor
            }
            contributors.pop();  // Remove the contributor from the list
        }
    }

    /**
     * @dev Returns the token balance of an account.
     * @param account Address to query the balance of
     * @return Balance of the account
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev Processes the purchase by storing the balance or transferring tokens directly.
     * Overrides the parent function to handle post-delivery logic.
     * @param beneficiary Address of the token purchaser
     * @param tokenAmount Amount of tokens purchased
     */
    function _processPurchase(address beneficiary, uint256 tokenAmount) override virtual internal {
        if (usePostDelivery != 0) {
            if (usePostDelivery == 2 && _balances[beneficiary] == 0) {
                contributors.push(beneficiary);  // Add to contributors list if using batch distribution
            }
            _balances[beneficiary] += tokenAmount;  // Store the token balance
            _deliverTokens(address(_vault), tokenAmount);  // Deliver tokens to the vault
        } else {
            super._deliverTokens(beneficiary, tokenAmount);  // Deliver tokens directly if no post-delivery
        }
    }

    /**
     * @dev Returns the number of contributors.
     * @return Number of contributors
     */
    function contributorsLength() external view returns (uint256) {
        return contributors.length;
    }

 }

 /**
 * @dev Secondary contract that can only be used by the account that created it.
 * Provides functionality for token transfers in the PostDeliveryCrowdsale.
 */
 contract Secondary is Context {
    address private _primary;

    /**
     * @dev Emitted when the primary account is transferred to a new address.
     * @param recipient New primary account address
     */
    event PrimaryTransferred(address recipient);

    /**
     * @dev Constructor that sets the primary account to the contract creator.
     */
    constructor() {
        address msgSender = _msgSender();
        _primary = msgSender;
        emit PrimaryTransferred(msgSender);  // Emit event for primary account setup
    }

    /**
     * @dev Modifier that ensures the function is called only by the primary account.
     */
    modifier onlyPrimary() {
        require(_msgSender() == _primary, "Secondary: caller is not the primary account");
        _;
    }

    /**
     * @return Address of the primary account
     */
    function primary() public view returns (address) {
        return _primary;
    }

    /**
     * @dev Transfers the primary account role to a new address.
     * @param recipient Address of the new primary account
     */
    function transferPrimary(address recipient) public onlyPrimary {
        require(recipient != address(0), "Secondary: new primary is the zero address");
        _primary = recipient;  // Transfer the primary account role
        emit PrimaryTransferred(recipient);  // Emit event for primary transfer
    }
 }

 /**
 * @title TokenVault
 * @dev A helper contract for PostDeliveryCrowdsale, used to hold and transfer tokens.
 * This vault can only be accessed by the primary account (PostDeliveryCrowdsale contract).
 */
 contract TokenVault is Secondary {
    /**
     * @dev Transfers tokens from the vault to a specified address.
     * Only callable by the primary account.
     * @param token Token to transfer
     * @param to Recipient of the tokens
     * @param amount Amount of tokens to transfer
     */
    function transfer(IERC20 token, address to, uint256 amount) public onlyPrimary {
        token.transfer(to, amount);  // Transfer tokens from the vault
    }
 }

 /**
 *
 * @title CaramelCrowdsale
 * @dev This contract inherits functionality from WhitelistedRole and PostDeliveryCrowdsale to manage a crowdsale that includes
 * several key features:
 *
 * Features:
 * - WhitelistedRole: Allows only approved accounts (whitelisted) to participate in the crowdsale.
 * - PostDeliveryCrowdsale: Ensures token delivery happens after the crowdsale has finished.
 * - Configurable token rates and contribution limits for multiple tokens, where different tokens can be used as a form of payment.
 * - Ether contributions with minimum and maximum limits.
 * - A dynamic whitelist that can be enabled or disabled by the owner.
 * - The owner has full control to set or change the rate, ether and token-specific limits, and contribution settings during the crowdsale.
 *
 */
 contract CaramelCrowdsale is WhitelistedRole, PostDeliveryCrowdsale {

    using SafeERC20 for IERC20Metadata;

    // Event emitted when the whitelist setting is updated
    event WhitelistSetting(bool useWhitelist);

    /**
     * @dev Event emitted when the token rate is changed.
     * @param rate the new token rate
     */
    event TokenRateChanged(uint256 rate);

    /**
     * @dev Event emitted when the token minimum contribution is changed.
     * @param min the new token minimum contribution
     */
    event TokenMinChanged(uint256 min);

    /**
     * @dev Event emitted when the token maximum contribution is changed.
     * @param max the new token maximum contribution
     */
    event TokenMaxChanged(uint256 max);

    /**
     * @dev Event emitted when the ether minimum contribution is changed.
     * @param min the new ether minimum contribution
     */
    event EtherMinChanged(uint256 min);

    /**
     * @dev Event emitted when the ether maximum contribution is changed.
     * @param max the new ether maximum contribution
     */
    event EtherMaxChanged(uint256 max);

    /**
     * @dev Event emitted when tokens are purchased with tokens
     * @param purchaser Address of the user who purchased tokens
     * @param paymentToken Address of the payment token
     * @param beneficiary Address where purchased tokens were sent
     * @param value Amount of ether paid for purchase
     * @param amount Amount of tokens purchased
     */
    event TokensPurchasedWithTokens(address indexed purchaser, address indexed paymentToken, address indexed beneficiary, uint256 value, uint256 amount);

    /**
     * @dev Flag indicating if the crowdsale should enforce whitelist checks.
     */
    bool public useWhitelist;

    /**
     * @dev Minimum Ether contribution allowed for the crowdsale.
     */
    uint256 public minEtherContribution;

    /**
     * @dev Maximum Ether contribution allowed for the crowdsale.
     */
    uint256 public maxEtherContribution;

    /**
     * @dev Rates per token's smallest unit (similar to wei for ETH) for each token accepted as a form of payment.
     * This rate does not account for token decimals, which should be handled by the interface.
     * If the rate is zero, it means that the token is not available for payments.
     * If maxContribution is zero it means it is unlimited.
     */
    mapping (address => TokenData) public tokenData;

    /**
     * @dev Struct to hold data related to each token, including the rate and contribution limits.
     */
    struct TokenData {
        uint256 rate; // Rate per token's smallest unit. It has the same trailing zeros as the buying token
        uint256 minContribution; // Minimum token contribution allowed
        uint256 maxContribution; // Maximum token contribution allowed
    }

    /**
     * @dev Contribution ledger for each ether/token and contributor
     * For ether the first address is 0x0
     */
    mapping (address => mapping (address => uint256)) public contributionsLog;

    /**
     * @dev List of tokens that are available for payments.
     */
    address[] public paymentTokens;

    /**
     * @dev The amount of tokens raised in the crowdsale
     */
    mapping(address => uint256) public tokensRaised;

    /**
     * @dev Constructor that initializes the CaramelCrowdsale contract.
     * It sets whether to use the whitelist, and initializes the other crowdsale parameters.
     * Adds the owner as a WhitelistAdmin and a whitelisted account.
     * @param usePostDelivery_ Determines if post-delivery should be used and how
     * @param useWhitelist_ Determines if the whitelist should be enforced
     * @param rate_ The rate of tokens per wei
     * @param wallet_ The wallet that will receive the funds
     * @param token_ The token being sold
     * @param distributionWallet_ The wallet for distributing tokens
     * @param openingTime_ The crowdsale start time
     * @param closingTime_ The crowdsale end time
     * @param owner_ The owner of the crowdsale contract
     */
    constructor (
        uint8 usePostDelivery_,
        bool useWhitelist_,
        uint256 rate_,
        address payable wallet_,
        IERC20Metadata token_,
        address distributionWallet_,
        uint256 openingTime_,
        uint256 closingTime_,
        address owner_
    ) PostDeliveryCrowdsale(usePostDelivery_, rate_, wallet_, token_, distributionWallet_, openingTime_, closingTime_, owner_) {
        useWhitelist = useWhitelist_;  // Set the initial whitelist flag
        emit WhitelistSetting(useWhitelist_);  // Emit event for whitelist setting

        _addWhitelistAdmin(owner_);  // Add owner as whitelist admin
        _addWhitelisted(owner_);  // Add owner to the whitelist
    }

    /**
     * @dev Overrides the parent behavior to require the beneficiary to be whitelisted if the whitelist is enforced.
     * Also checks if the crowdsale is finalized before allowing purchases.
     * @param _beneficiary The address receiving the tokens
     * @param _weiAmount The amount of wei contributed
     */
    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal override view {

        // Whitelist validations
        if (useWhitelist) {
            require(isWhitelisted(_beneficiary), "WhitelistCrowdsale: beneficiary doesn't have the Whitelisted role");
        }
        require(!finalized(), "CaramelCrowdsale: crowdsale is finalized");  // Ensure crowdsale is not finalized

        // Contribution limits validations
        require(rate > 0, "CaramelCrowdsale: ether contribution not enabled");  // Ensure rate is set

        if (maxEtherContribution > 0) {
            // Check the contributions in ether for the user
            uint256 totalContributions = contributionsLog[address(0)][msg.sender] + _weiAmount;
            require(totalContributions >= minEtherContribution && totalContributions <= maxEtherContribution, "CaramelCrowdsale: contribution is out of bounds");  // Check contribution limits

            // Check the contributions in ether for the beneficiary
            if (_beneficiary != msg.sender) {
                totalContributions = contributionsLog[address(0)][_beneficiary] + _weiAmount;
                require(totalContributions >= minEtherContribution && totalContributions <= maxEtherContribution, "CaramelCrowdsale: contributions to the beneficiary is out of bounds");  // Check contribution limits
            }
        }

        super._preValidatePurchase(_beneficiary, _weiAmount);  // Call parent validation
    }

    /**
     * @dev Overrides parent by storing total contributions in ether
     * @param beneficiary Token purchaser
     * @param tokenAmount Amount of tokens purchased
     */
    function _processPurchase(address beneficiary, uint256 tokenAmount) override virtual internal {
        contributionsLog[address(0)][msg.sender] += msg.value;
        super._processPurchase(beneficiary, tokenAmount);
    }

    /**
     * @dev Allows the owner to enable or disable the whitelist enforcement for the crowdsale.
     * @param useWhitelist_ Boolean flag to enable or disable the whitelist
     */
    function setWhitelist(bool useWhitelist_) external onlyOwner() {
        emit WhitelistSetting(useWhitelist_);  // Emit event for whitelist update
        useWhitelist = useWhitelist_;  // Update whitelist setting
    }

    /**
     * @dev Owner can change the rate.
     * @param rate_ Number of token units a buyer gets per wei
     */
    function setRate(uint256 rate_) public override onlyOwner() {
        emit RateChanged(rate_);  // Emit event for rate change
        rate = rate_;  // Set the new rate
    }

    /**
     * @dev Set token-specific data such as rate, minimum, and maximum contribution limits.
     * @param token_ The token for which the data is being set
     * @param rate_ The rate of tokens per wei for the specified token
     * @param min_ Minimum contribution allowed for the token
     * @param max_ Maximum contribution allowed for the token
     */
    function setTokenData(address token_, uint256 rate_, uint256 min_, uint256 max_) public onlyOwner() {
        require(min_ < max_ || (min_ == 0 && max_ == 0), "Invalid minimum and maximum range");  // Validate contribution limits
        tokenData[token_].rate = rate_;  // Set the rate
        tokenData[token_].minContribution = min_;  // Set the minimum contribution
        tokenData[token_].maxContribution = max_;  // Set the maximum contribution

        // Emit events for token data changes
        emit TokenRateChanged(rate_);
        emit TokenMinChanged(min_);
        emit TokenMaxChanged(max_);
    }

    /**
     * @dev Set Ether contribution limits.
     * @param min_ Minimum Ether contribution allowed
     * @param max_ Maximum Ether contribution allowed
     */
    function setEtherContributions(uint256 min_, uint256 max_) external onlyOwner() {
        require(min_ < max_ || (min_ == 0 && max_ == 0), "CaramelCrowdsale: invalid minimum and maximum range");  // Validate Ether contribution limits
        minEtherContribution = min_;  // Set the minimum Ether contribution
        maxEtherContribution = max_;  // Set the maximum Ether contribution

        // Emit events for Ether contribution changes
        emit EtherMinChanged(min_);
        emit EtherMaxChanged(max_);
    }

    /**
     * @dev Returns the length of the payment token array.
     * @return length The number of accepted payment tokens.
     */
    function paymentTokenLength() external view returns(uint256 length) {
        return paymentTokens.length;  // Return the number of accepted payment tokens.
    }

    /**
     * @dev Add a payment token if it's not already in the array.
     * This function allows the contract owner to add a new payment token to the list of accepted tokens,
     * along with its associated rate and contribution limits.
     * @param token_ The token to be added to the list of accepted tokens
     * @param rate_ The rate of tokens per wei for the specified token
     * @param min_ Minimum contribution allowed for the token
     * @param max_ Maximum contribution allowed for the token
     */
    function addPaymentToken(address token_, uint256 rate_, uint256 min_, uint256 max_) external onlyOwner() {
        require(token_ != address(0), "Invalid token address");  // Ensure valid token address
        
        // Check if the token is already in the paymentTokens array
        if (!_isTokenInArray(token_)) {
            paymentTokens.push(token_);  // Add token to the array if it's not already included.
        }

        // Set the token data
        setTokenData(token_, rate_, min_, max_);  // Configure the token's rate and contribution limits.
    }

    /**
     * @dev Remove a payment token by swapping it with the last element for efficient removal.
     * This function allows the contract owner to remove an accepted payment token from the array.
     * @param index The token index to be removed from the list of accepted tokens
     */
    function removePaymentToken(uint256 index) external onlyOwner() {
        if (index < paymentTokens.length) {
            paymentTokens[index] = paymentTokens[paymentTokens.length - 1];  // Swap the token to be removed with the last element.
            paymentTokens.pop();  // Remove the last element from the array.
        }
    }

    /**
     * @dev Helper function to check if a token exists in the array.
     * This function checks if a given token address is already included in the accepted payment tokens array.
     * @param token_ The token address to check
     * @return bool True if the token exists, false otherwise
     */
    function _isTokenInArray(address token_) internal view returns (bool) {
        for (uint256 i = 0; i < paymentTokens.length; i++) {
            if (paymentTokens[i] == token_) {
                return true;  // Return true if the token is found in the array.
            }
        }
        return false;  // Return false if the token is not found.
    }

    /**
     * @dev Calculate the number of tokens that can be purchased with a specified amount of tokens.
     * This function provides a conversion mechanism for converting the ERC-20 smallest unit into tokens bought
     * based on the current rate and the number of decimal places in both tokens.
     * @param paymentToken The ERC-20 token address used for payment to buy tokens
     * @param paymentTokenAmount The amount of tokens paid in paymentToken
     * @return uint256 The amount of tokens that can be purchased.
     */
    function getTokenAmountWithToken(IERC20Metadata paymentToken, uint256 paymentTokenAmount) public view returns (uint256) {
        // Calculate the number of tokens using the formula:
        // (paymentTokenAmount * paymentTokenRate) / 10^payingTokenDecimals
        return (paymentTokenAmount * tokenData[address(paymentToken)].rate) / 10**paymentToken.decimals();
    }

    /**
     * @dev Low-level token purchase with tokens.
     * Allows users to purchase tokens with whitelisted ERC-20 tokens.
     * This function has a non-reentrancy guard, so it shouldn't be called by
     * another `nonReentrant` function.
     * @param paymentToken The ERC-20 payment token address
     * @param paymentTokenAmount The amount of the payment token paid (in the smallest unit)
     * @param beneficiary Address where purchased tokens will be sent
     */
    function buyTokensWithTokens(address paymentToken, uint256 paymentTokenAmount, address beneficiary) public virtual nonReentrant payable {

        require(paymentToken != address(0), "CaramelCrowdsale: payment token is the zero address");  // Ensure valid payment token address
        require(beneficiary != address(0), "CaramelCrowdsale: beneficiary is the zero address");  // Ensure valid beneficiary address
        require(paymentTokenAmount != 0, "CaramelCrowdsale: paymentTokenAmount is 0");  // Ensure a non-zero payment token amount
        require(tokenData[paymentToken].rate > 0, "CaramelCrowdsale: payment token is not available");  // Check if payment token is valid

        // Whitelist validation if applicable
        if (useWhitelist) {
            require(isWhitelisted(beneficiary), "WhitelistCrowdsale: beneficiary doesn't have the Whitelisted role");  // Ensure beneficiary is whitelisted.
        }
        
        require(!finalized(), "CaramelCrowdsale: crowdsale is finalized");  // Ensure crowdsale is not finalized

        // Check contribution limits for the token
        if (tokenData[paymentToken].maxContribution > 0) {
            // Check the contributions in the token for the user
            uint256 totalContributions = contributionsLog[paymentToken][msg.sender] + paymentTokenAmount;
            require(totalContributions >= tokenData[paymentToken].minContribution && totalContributions <= tokenData[paymentToken].maxContribution, "CaramelCrowdsale: token contribution is out of bounds");  // Check contribution limits

            // Check the contributions for the beneficiary if different from msg.sender
            if (beneficiary != msg.sender) {
                totalContributions = contributionsLog[paymentToken][beneficiary] + paymentTokenAmount;
                require(totalContributions >= tokenData[paymentToken].minContribution && totalContributions <= tokenData[paymentToken].maxContribution, "CaramelCrowdsale: token contribution is out of bounds");  // Check contribution limits
            }
        }

        // Calculate the number of tokens to be issued
        uint256 tokens = getTokenAmountWithToken(IERC20Metadata(paymentToken), paymentTokenAmount);
        require(tokens != 0, "Crowdsale: cannot buy 0 tokens");  // Ensure that at least one token is purchased

        // Update state with raised tokens
        tokensRaised[paymentToken] += paymentTokenAmount;  // Track total tokens raised in payment tokens

        // Process the purchase and assign tokens to the beneficiary
        _processPurchase(beneficiary, tokens);

        // Emit event for tokens purchased with tokens
        emit TokensPurchasedWithTokens(_msgSender(), paymentToken, beneficiary, paymentTokenAmount, tokens);

        // Transfer the token payment to the wallet
        IERC20Metadata(paymentToken).safeTransferFrom(msg.sender, wallet, paymentTokenAmount);  // Transfer the payment to the wallet.
    }

 }
No results found