// File: contracts/Presale.sol



//SPDX-License-Identifier: MIT

pragma solidity 0.8.2;

import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

interface Aggregator {
   function latestRoundData() external view returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);
}

contract Presale is Ownable{
    using SafeERC20 for IERC20;
	
	uint256 public totalTokensSold;
	uint256 public totalTokensToClaim;
    uint256 public usdRaised;
	uint256 public currentRound;
	uint256 public claimStartTime;
	uint256 public monthlyRelease;
	uint256 public roundStartTime;
	
    address public paymentWallet;
	address public INVESTA;
	address public USDT;
	address public USDC;
	Aggregator public aggregatorInterface;
	
	bool public claimStatus;
	bool public preSaleStatus;
	
	uint256[5] public maxAllocation;
	uint256[5] public tokenAmount;
	uint256[5] public tokenPrice;
	uint256[5] public remainingAmount;
	
	struct buyTokenInfo {
	  uint256 usdPaid;
	  uint256 tokenFromBuy; 
	  uint256 tokenFromReferral; 
	  uint256 tokenFromIncentive;
	  uint256 tokenClaimed;
	  string  referralCode;
	  string  sponsorCode;
    }
	
	mapping(address => buyTokenInfo) public mapBuyTokenInfo;
	mapping(string  => address) public referralAddress;
	mapping(string  => uint256) public fundRaisedByReferralCode;
	mapping(address => mapping(uint256 => uint256)) public mapAllocation;
	
    event TokensBought(address user, uint256 tokens, uint256 amount, uint256 timestamp);
    event TokensClaimed(address user, uint256 amount, uint256 timestamp);
	event PreSaleStatusUpdated(bool status);
    event ClaimStatusUpdated(bool status);
	event PaymentWalletUpdated(address newWallet);
	event RoundPriceUpdated(uint256 round, uint256 price);
	
    constructor(address owner, address payment) {
	   USDC = address(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48);
	   USDT = address(0xdAC17F958D2ee523a2206206994597C13D831ec7);
	   INVESTA = address(0x1067C056303ab509823118f1816cd7925f3F72d3);
	   
	   tokenAmount = [4000000 ether, 4000000 ether, 6000000 ether, 6000000 ether, 5000000 ether];
	   remainingAmount = [4000000 ether, 4000000 ether, 6000000 ether, 6000000 ether, 5000000 ether];
	   tokenPrice = [4 * 10**4, 8 * 10**4, 12 * 10**4, 16 * 10**4, 20 * 10**4];
	   maxAllocation = [20000 * 10**6, 20000 * 10**6, 720000 * 10**6, 960000 * 10**6, 1000000 * 10**6];
	   
	   monthlyRelease = 1500000 * 10**18;
	   aggregatorInterface = Aggregator(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
	   paymentWallet = address(payment);
	   _transferOwnership(address(owner));
	}
	
	function buyWithUSDT(uint256 amount, string memory rcode, string memory myrcode) external {
	   require(address(msg.sender).code.length == 0, "Only EOA address allowed");
	   require(amount > 0, "Amount must be greater than zero");
	   require(preSaleStatus, "Presale not start yet");
	   require(referralAddress[rcode] != address(msg.sender), "Sponser and sender wallet can't be same");
	   require(IERC20(USDT).balanceOf(address(msg.sender)) >= amount, "USDT amount not available to buy tokens");
	   require(IERC20(USDT).allowance(address(msg.sender), address(this)) >= amount, "Make sure to add enough USDT allowance");
	   require(maxAllocation[currentRound] - mapAllocation[address(msg.sender)][currentRound] >= amount, "Buy limit not available on this stage");
	   
	   uint256 price = tokenPrice[currentRound];
	   uint256 availableToken = remainingAmount[currentRound];
	   uint256 tokens = amount * (10**18) / price;
	   
	   if(tokens > availableToken)
	   {
	       amount = availableToken * price / 10**18;
		   IERC20(USDT).safeTransferFrom(address(msg.sender), address(paymentWallet), amount);
           _buytokens(amount, availableToken, address(msg.sender), rcode, myrcode);		  
	   } 
	   else
	   {
	       IERC20(USDT).safeTransferFrom(address(msg.sender), address(paymentWallet), amount);
		   _buytokens(amount, tokens, address(msg.sender), rcode, myrcode);
	   }
	   emit TokensBought(address(msg.sender), tokens, amount, block.timestamp);
    }
	
	function buyWithUSDC(uint256 amount, string memory rcode, string memory myrcode) external {
	   require(address(msg.sender).code.length == 0, "Only EOA address allowed");
	   require(amount > 0, "Amount must be greater than zero");
	   require(preSaleStatus, "Presale not start yet");
	   require(referralAddress[rcode] != address(msg.sender), "Sponser and sender wallet can't be same");
	   require(IERC20(USDC).balanceOf(address(msg.sender)) >= amount, "USDC amount not available to buy tokens");
	   require(IERC20(USDC).allowance(address(msg.sender), address(this)) >= amount, "Make sure to add enough USDC allowance");
	   require(maxAllocation[currentRound] - mapAllocation[address(msg.sender)][currentRound] >= amount, "Buy limit not available on this stage");
	   
	   uint256 price = tokenPrice[currentRound];
	   uint256 availableToken = remainingAmount[currentRound];
	   uint256 tokens = amount * (10**18) / price;
	   
	   if(tokens > availableToken)
	   {
	       amount = availableToken * price / 10**18;
		   IERC20(USDC).safeTransferFrom(address(msg.sender), address(paymentWallet), amount);
           _buytokens(amount, availableToken, address(msg.sender), rcode, myrcode);		  
	   } 
	   else
	   {
	       IERC20(USDC).safeTransferFrom(address(msg.sender), address(paymentWallet), amount);
		   _buytokens(amount, tokens, address(msg.sender), rcode, myrcode);
	   }
	   emit TokensBought(address(msg.sender), tokens, amount, block.timestamp);
    }
	
	function buyWithETH(string memory rcode, string memory myrcode) external payable {
	   uint256 amount = (getLatestPrice() * msg.value) / (10**30);
	   
	   require(address(msg.sender).code.length == 0, "Only EOA address allowed");
	   require(referralAddress[rcode] != address(msg.sender), "Sponser and sender wallet can't be same");
	   require(amount > 0, "Amount must be greater than zero");
	   require(preSaleStatus, "Presale not start yet");
	   require(maxAllocation[currentRound] - mapAllocation[address(msg.sender)][currentRound] >= amount, "Buy limit not available on this stage");
	   
	   uint256 price = tokenPrice[currentRound];
	   uint256 availableToken = remainingAmount[currentRound];
	   uint256 tokens = amount * (10**18) / price;
	   
	   if(tokens > availableToken)
	   {
	       amount = availableToken * price / 10**18;
		   (bool success, ) = address(paymentWallet).call{value: address(this).balance}("");
           require(success, "ETH Payment failed");
           _buytokens(amount, availableToken, address(msg.sender), rcode, myrcode);		  
	   } 
	   else
	   {
           (bool success, ) = address(paymentWallet).call{value: address(this).balance}("");
           require(success, "ETH Payment failed");
		   _buytokens(amount, tokens, address(msg.sender), rcode, myrcode);
	   }
	   emit TokensBought(address(msg.sender), tokens, amount, block.timestamp);
    }
	
	function buyWithUSD(uint256 tokens, address buyer, string memory rcode, string memory myrcode) external onlyOwner{
	   require(tokens > 0, "Tokens must be greater than zero");
	   require(remainingAmount[currentRound] >= tokens, "Buy limit not available on this stage");
	   require(referralAddress[rcode] != address(msg.sender), "Sponser and sender wallet can't be same");
	   
	   uint256 price = tokenPrice[currentRound];
	   uint256 amount = tokens * price / 10**18;
	   
	   _buytokens(amount, tokens, address(buyer), rcode, myrcode);
	   emit TokensBought(address(buyer), tokens, amount, block.timestamp);
    }
	
	
	function _buytokens(uint256 amount, uint256 tokens, address buyer, string memory rcode, string memory myrcode) internal {
	     
		if(referralAddress[myrcode] == address(0) && bytes(mapBuyTokenInfo[address(buyer)].referralCode).length == 0) 
		{
		   referralAddress[myrcode] = address(buyer);
		   mapBuyTokenInfo[address(buyer)].referralCode = myrcode;
		}
		
		usdRaised += amount; 
		remainingAmount[currentRound] -= tokens;
		totalTokensSold += tokens;
		totalTokensToClaim += tokens;
		
		currentRound = remainingAmount[currentRound] == 0 ? (currentRound + 1) : currentRound;
		if(remainingAmount[currentRound] == 0 && currentRound != 4)
		{
		   currentRound = currentRound + 1;
		   roundStartTime = block.timestamp;
		}
		
		mapBuyTokenInfo[address(buyer)].usdPaid += amount;
		mapBuyTokenInfo[address(buyer)].tokenFromBuy += tokens;
		mapAllocation[address(buyer)][currentRound] += amount;
		
		if(bytes(mapBuyTokenInfo[address(buyer)].sponsorCode).length != 0)
		{
		    uint256 bonus = tokens * 5 / 100;
			mapBuyTokenInfo[referralAddress[mapBuyTokenInfo[address(buyer)].sponsorCode]].tokenFromReferral += bonus;
			mapBuyTokenInfo[address(buyer)].tokenFromIncentive += bonus;
			totalTokensToClaim += bonus + bonus;
			fundRaisedByReferralCode[mapBuyTokenInfo[address(buyer)].sponsorCode] += amount;
		}
		else if(referralAddress[rcode] != address(0))
		{
			uint256 bonus = tokens * 5 / 100;
			mapBuyTokenInfo[referralAddress[rcode]].tokenFromReferral += bonus;
			mapBuyTokenInfo[address(buyer)].sponsorCode = rcode;
			mapBuyTokenInfo[address(buyer)].tokenFromIncentive += bonus;
			totalTokensToClaim += bonus + bonus;
			fundRaisedByReferralCode[rcode] += amount;
		}
	}
	
    function _tokenAvailableToClaim() internal view returns(uint256 tokens) {
	   tokens = ((block.timestamp - claimStartTime) / 30 days) * monthlyRelease; 
	   tokens = tokens > totalTokensToClaim ? totalTokensToClaim : tokens;
	}
	
	function claimToken() external{
		require(claimStatus, "Claim not start yet");
		require(address(msg.sender).code.length == 0, "Only EOA address allowed");
		
		uint256 pending = pendingToClaim(address(msg.sender));
		if(pending > 0) 
		{
		    mapBuyTokenInfo[address(msg.sender)].tokenClaimed += pending;
		    IERC20(INVESTA).safeTransfer(address(msg.sender), pending);
		    emit TokensClaimed(address(msg.sender), pending, block.timestamp);
		}
		else
		{
		    emit TokensClaimed(msg.sender, 0, block.timestamp);
		}
    }
	
	function pendingToClaim(address user) public view returns (uint256) {
	   if(mapBuyTokenInfo[user].tokenFromBuy > 0 && claimStatus) 
	   {
	       uint256 available = _tokenAvailableToClaim();
		   if(available == totalTokensToClaim)
		   {
		       uint256 pending = (mapBuyTokenInfo[user].tokenFromBuy + mapBuyTokenInfo[user].tokenFromReferral + mapBuyTokenInfo[user].tokenFromIncentive) - mapBuyTokenInfo[user].tokenClaimed;
		       return pending;
		   }
		   else
		   {
		      uint256 pending = ((available * (mapBuyTokenInfo[user].tokenFromBuy + mapBuyTokenInfo[user].tokenFromReferral + mapBuyTokenInfo[user].tokenFromIncentive)) / totalTokensToClaim) - mapBuyTokenInfo[user].tokenClaimed;
		      return pending;
		   }
	   }
       else
	   {
	      return 0;
	   } 
    }
	
    function changePaymentWallet(address newPWallet) external onlyOwner {
       require(newPWallet != address(0), "address cannot be zero");
	   
       paymentWallet = newPWallet;
	   emit PaymentWalletUpdated(newPWallet);
    }
	
	function changeRoundPrice(uint256 round, uint256 price) external onlyOwner {
       require(tokenPrice.length > round, "Incorrect token round");
	   
       tokenPrice[round] = price;
	   emit RoundPriceUpdated(round, price);
    }
	
	function updatePreSaleStatus(bool status) external onlyOwner{
        require(preSaleStatus != status, "Presale is already set to that value");
		if(status)
		{
		   roundStartTime = block.timestamp;
		   require(!claimStatus, "Stop the claim to start the presale");
		}
        preSaleStatus = status;
		emit PreSaleStatusUpdated(status);
    }
	
	function startClaim() external onlyOwner {
        require(!claimStatus, "Claim is already set to that value");
		require(!preSaleStatus, "Stop the presale to start the claim");
		
		claimStartTime = block.timestamp + 30 days;
		claimStatus = true;
		require(IERC20(INVESTA).balanceOf(address(this)) >= totalTokensToClaim, "Tokens is not available to claim");
		emit ClaimStatusUpdated(true);
    }
	
	function getLatestPrice() public view returns (uint256) {
       (, int256 price, , , ) = aggregatorInterface.latestRoundData();
       price = (price * (10 ** 10));
       return uint256(price);
    }
}
// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @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;

    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 Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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 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() 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);
    }
}

// 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: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [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 Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @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-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // 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);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/utils/Context.sol



// 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;
    }
}