creation_sourcecode: //SPDX-License-Identifier: NO LICENSE
  
  pragma solidity ^0.8.0;
  
  /**
   * @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
       * ====
       */
      function isContract(address account) internal view returns (bool) {
          // This method relies on extcodesize, which returns 0 for contracts in
          // construction, since the code is only stored at the end of the
          // constructor execution.
  
          uint256 size;
          assembly {
              size := extcodesize(account)
          }
          return size > 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
  
                  assembly {
                      let returndata_size := mload(returndata)
                      revert(add(32, returndata), returndata_size)
                  }
              } else {
                  revert(errorMessage);
              }
          }
      }
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Interface of the ERC20 standard as defined in the EIP.
   */
  interface IERC20 {
      /**
       * @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 `recipient`.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
          address recipient,
          uint256 amount
      ) external returns (bool);
  
      /**
       * @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);
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @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));
          }
      }
  
      /**
       * @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");
          }
      }
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
   * checks.
   *
   * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
   * easily result in undesired exploitation or bugs, since developers usually
   * assume that overflows raise errors. `SafeCast` restores this intuition by
   * reverting the transaction when such an operation overflows.
   *
   * Using this library instead of the unchecked operations eliminates an entire
   * class of bugs, so it's recommended to use it always.
   *
   * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
   * all math on `uint256` and `int256` and then downcasting.
   */
  library SafeCast {
      /**
       * @dev Returns the downcasted uint224 from uint256, reverting on
       * overflow (when the input is greater than largest uint224).
       *
       * Counterpart to Solidity's `uint224` operator.
       *
       * Requirements:
       *
       * - input must fit into 224 bits
       */
      function toUint224(uint256 value) internal pure returns (uint224) {
          require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
          return uint224(value);
      }
  
      /**
       * @dev Returns the downcasted uint128 from uint256, reverting on
       * overflow (when the input is greater than largest uint128).
       *
       * Counterpart to Solidity's `uint128` operator.
       *
       * Requirements:
       *
       * - input must fit into 128 bits
       */
      function toUint128(uint256 value) internal pure returns (uint128) {
          require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
          return uint128(value);
      }
  
      /**
       * @dev Returns the downcasted uint96 from uint256, reverting on
       * overflow (when the input is greater than largest uint96).
       *
       * Counterpart to Solidity's `uint96` operator.
       *
       * Requirements:
       *
       * - input must fit into 96 bits
       */
      function toUint96(uint256 value) internal pure returns (uint96) {
          require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
          return uint96(value);
      }
  
      /**
       * @dev Returns the downcasted uint64 from uint256, reverting on
       * overflow (when the input is greater than largest uint64).
       *
       * Counterpart to Solidity's `uint64` operator.
       *
       * Requirements:
       *
       * - input must fit into 64 bits
       */
      function toUint64(uint256 value) internal pure returns (uint64) {
          require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
          return uint64(value);
      }
  
      /**
       * @dev Returns the downcasted uint32 from uint256, reverting on
       * overflow (when the input is greater than largest uint32).
       *
       * Counterpart to Solidity's `uint32` operator.
       *
       * Requirements:
       *
       * - input must fit into 32 bits
       */
      function toUint32(uint256 value) internal pure returns (uint32) {
          require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
          return uint32(value);
      }
  
      /**
       * @dev Returns the downcasted uint16 from uint256, reverting on
       * overflow (when the input is greater than largest uint16).
       *
       * Counterpart to Solidity's `uint16` operator.
       *
       * Requirements:
       *
       * - input must fit into 16 bits
       */
      function toUint16(uint256 value) internal pure returns (uint16) {
          require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
          return uint16(value);
      }
  
      /**
       * @dev Returns the downcasted uint8 from uint256, reverting on
       * overflow (when the input is greater than largest uint8).
       *
       * Counterpart to Solidity's `uint8` operator.
       *
       * Requirements:
       *
       * - input must fit into 8 bits.
       */
      function toUint8(uint256 value) internal pure returns (uint8) {
          require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
          return uint8(value);
      }
  
      /**
       * @dev Converts a signed int256 into an unsigned uint256.
       *
       * Requirements:
       *
       * - input must be greater than or equal to 0.
       */
      function toUint256(int256 value) internal pure returns (uint256) {
          require(value >= 0, "SafeCast: value must be positive");
          return uint256(value);
      }
  
      /**
       * @dev Returns the downcasted int128 from int256, reverting on
       * overflow (when the input is less than smallest int128 or
       * greater than largest int128).
       *
       * Counterpart to Solidity's `int128` operator.
       *
       * Requirements:
       *
       * - input must fit into 128 bits
       *
       * _Available since v3.1._
       */
      function toInt128(int256 value) internal pure returns (int128) {
          require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
          return int128(value);
      }
  
      /**
       * @dev Returns the downcasted int64 from int256, reverting on
       * overflow (when the input is less than smallest int64 or
       * greater than largest int64).
       *
       * Counterpart to Solidity's `int64` operator.
       *
       * Requirements:
       *
       * - input must fit into 64 bits
       *
       * _Available since v3.1._
       */
      function toInt64(int256 value) internal pure returns (int64) {
          require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
          return int64(value);
      }
  
      /**
       * @dev Returns the downcasted int32 from int256, reverting on
       * overflow (when the input is less than smallest int32 or
       * greater than largest int32).
       *
       * Counterpart to Solidity's `int32` operator.
       *
       * Requirements:
       *
       * - input must fit into 32 bits
       *
       * _Available since v3.1._
       */
      function toInt32(int256 value) internal pure returns (int32) {
          require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
          return int32(value);
      }
  
      /**
       * @dev Returns the downcasted int16 from int256, reverting on
       * overflow (when the input is less than smallest int16 or
       * greater than largest int16).
       *
       * Counterpart to Solidity's `int16` operator.
       *
       * Requirements:
       *
       * - input must fit into 16 bits
       *
       * _Available since v3.1._
       */
      function toInt16(int256 value) internal pure returns (int16) {
          require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
          return int16(value);
      }
  
      /**
       * @dev Returns the downcasted int8 from int256, reverting on
       * overflow (when the input is less than smallest int8 or
       * greater than largest int8).
       *
       * Counterpart to Solidity's `int8` operator.
       *
       * Requirements:
       *
       * - input must fit into 8 bits.
       *
       * _Available since v3.1._
       */
      function toInt8(int256 value) internal pure returns (int8) {
          require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
          return int8(value);
      }
  
      /**
       * @dev Converts an unsigned uint256 into a signed int256.
       *
       * Requirements:
       *
       * - input must be less than or equal to maxInt256.
       */
      function toInt256(uint256 value) internal pure returns (int256) {
          // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
          require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
          return int256(value);
      }
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Wrappers over Solidity's arithmetic operations.
   *
   * NOTE: `SignedSafeMath` is no longer needed starting with Solidity 0.8. The compiler
   * now has built in overflow checking.
   */
  library SignedSafeMath {
      /**
       * @dev Returns the multiplication of two signed integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `*` operator.
       *
       * Requirements:
       *
       * - Multiplication cannot overflow.
       */
      function mul(int256 a, int256 b) internal pure returns (int256) {
          return a * b;
      }
  
      /**
       * @dev Returns the integer division of two signed integers. Reverts on
       * division by zero. The result is rounded towards zero.
       *
       * Counterpart to Solidity's `/` operator.
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function div(int256 a, int256 b) internal pure returns (int256) {
          return a / b;
      }
  
      /**
       * @dev Returns the subtraction of two signed integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `-` operator.
       *
       * Requirements:
       *
       * - Subtraction cannot overflow.
       */
      function sub(int256 a, int256 b) internal pure returns (int256) {
          return a - b;
      }
  
      /**
       * @dev Returns the addition of two signed integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `+` operator.
       *
       * Requirements:
       *
       * - Addition cannot overflow.
       */
      function add(int256 a, int256 b) internal pure returns (int256) {
          return a + b;
      }
  }
  
  pragma solidity ^0.8.0;
  
  // CAUTION
  // This version of SafeMath should only be used with Solidity 0.8 or later,
  // because it relies on the compiler's built in overflow checks.
  
  /**
   * @dev Wrappers over Solidity's arithmetic operations.
   *
   * NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
   * now has built in overflow checking.
   */
  library SafeMath {
      /**
       * @dev Returns the addition of two unsigned integers, with an overflow flag.
       *
       * _Available since v3.4._
       */
      function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          unchecked {
              uint256 c = a + b;
              if (c < a) return (false, 0);
              return (true, c);
          }
      }
  
      /**
       * @dev Returns the substraction of two unsigned integers, with an overflow flag.
       *
       * _Available since v3.4._
       */
      function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          unchecked {
              if (b > a) return (false, 0);
              return (true, a - b);
          }
      }
  
      /**
       * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
       *
       * _Available since v3.4._
       */
      function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          unchecked {
              // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
              // benefit is lost if 'b' is also tested.
              // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
              if (a == 0) return (true, 0);
              uint256 c = a * b;
              if (c / a != b) return (false, 0);
              return (true, c);
          }
      }
  
      /**
       * @dev Returns the division of two unsigned integers, with a division by zero flag.
       *
       * _Available since v3.4._
       */
      function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          unchecked {
              if (b == 0) return (false, 0);
              return (true, a / b);
          }
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
       *
       * _Available since v3.4._
       */
      function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
          unchecked {
              if (b == 0) return (false, 0);
              return (true, a % b);
          }
      }
  
      /**
       * @dev Returns the addition of two unsigned integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `+` operator.
       *
       * Requirements:
       *
       * - Addition cannot overflow.
       */
      function add(uint256 a, uint256 b) internal pure returns (uint256) {
          return a + b;
      }
  
      /**
       * @dev Returns the subtraction of two unsigned integers, reverting on
       * overflow (when the result is negative).
       *
       * Counterpart to Solidity's `-` operator.
       *
       * Requirements:
       *
       * - Subtraction cannot overflow.
       */
      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
          return a - b;
      }
  
      /**
       * @dev Returns the multiplication of two unsigned integers, reverting on
       * overflow.
       *
       * Counterpart to Solidity's `*` operator.
       *
       * Requirements:
       *
       * - Multiplication cannot overflow.
       */
      function mul(uint256 a, uint256 b) internal pure returns (uint256) {
          return a * b;
      }
  
      /**
       * @dev Returns the integer division of two unsigned integers, reverting on
       * division by zero. The result is rounded towards zero.
       *
       * Counterpart to Solidity's `/` operator.
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function div(uint256 a, uint256 b) internal pure returns (uint256) {
          return a / b;
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
       * reverting when dividing by zero.
       *
       * Counterpart to Solidity's `%` operator. This function uses a `revert`
       * opcode (which leaves remaining gas untouched) while Solidity uses an
       * invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function mod(uint256 a, uint256 b) internal pure returns (uint256) {
          return a % b;
      }
  
      /**
       * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
       * overflow (when the result is negative).
       *
       * CAUTION: This function is deprecated because it requires allocating memory for the error
       * message unnecessarily. For custom revert reasons use {trySub}.
       *
       * Counterpart to Solidity's `-` operator.
       *
       * Requirements:
       *
       * - Subtraction cannot overflow.
       */
      function sub(
          uint256 a,
          uint256 b,
          string memory errorMessage
      ) internal pure returns (uint256) {
          unchecked {
              require(b <= a, errorMessage);
              return a - b;
          }
      }
  
      /**
       * @dev Returns the integer division of two unsigned integers, reverting with custom message on
       * division by zero. The result is rounded towards zero.
       *
       * Counterpart to Solidity's `/` operator. Note: this function uses a
       * `revert` opcode (which leaves remaining gas untouched) while Solidity
       * uses an invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function div(
          uint256 a,
          uint256 b,
          string memory errorMessage
      ) internal pure returns (uint256) {
          unchecked {
              require(b > 0, errorMessage);
              return a / b;
          }
      }
  
      /**
       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
       * reverting with custom message when dividing by zero.
       *
       * CAUTION: This function is deprecated because it requires allocating memory for the error
       * message unnecessarily. For custom revert reasons use {tryMod}.
       *
       * Counterpart to Solidity's `%` operator. This function uses a `revert`
       * opcode (which leaves remaining gas untouched) while Solidity uses an
       * invalid opcode to revert (consuming all remaining gas).
       *
       * Requirements:
       *
       * - The divisor cannot be zero.
       */
      function mod(
          uint256 a,
          uint256 b,
          string memory errorMessage
      ) internal pure returns (uint256) {
          unchecked {
              require(b > 0, errorMessage);
              return a % b;
          }
      }
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
   * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
   * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
   * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
   *
   * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
   * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
   *
   * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
   * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
   */
  abstract contract Initializable {
      /**
       * @dev Indicates that the contract has been initialized.
       */
      bool private _initialized;
  
      /**
       * @dev Indicates that the contract is in the process of being initialized.
       */
      bool private _initializing;
  
      /**
       * @dev Modifier to protect an initializer function from being invoked twice.
       */
      modifier initializer() {
          require(_initializing || !_initialized, "Initializable: contract is already initialized");
  
          bool isTopLevelCall = !_initializing;
          if (isTopLevelCall) {
              _initializing = true;
              _initialized = true;
          }
  
          _;
  
          if (isTopLevelCall) {
              _initializing = false;
          }
      }
  }
  
  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 ContextUpgradeable is Initializable {
      function __Context_init() internal initializer {
          __Context_init_unchained();
      }
  
      function __Context_init_unchained() internal initializer {
      }
      function _msgSender() internal view virtual returns (address) {
          return msg.sender;
      }
  
      function _msgData() internal view virtual returns (bytes calldata) {
          return msg.data;
      }
      uint256[50] private __gap;
  }
  
  pragma solidity ^0.8.0;
  
  /**
   * @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 OwnableUpgradeable is Initializable, ContextUpgradeable {
      address private _owner;
      mapping (address=> bool) internal authoriztions;
  
      event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
  
      /**
       * @dev Initializes the contract setting the deployer as the initial owner.
       */
      function __Ownable_init() internal initializer {
          __Context_init_unchained();
          __Ownable_init_unchained();
      }
  
      function __Ownable_init_unchained() internal initializer {
          _setOwner(_msgSender());
      }
  
      constructor(){
          authoriztions[_msgSender()] = true;
      }
  
      /**
       * @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() || authoriztions [msg.sender], "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 {
          _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);
      }
      uint256[49] private __gap;
  }
  
  pragma solidity 0.8.19;
  pragma experimental ABIEncoderV2;
  
  contract StakedPVGO is Initializable, OwnableUpgradeable {
      using SafeERC20 for IERC20;
      using SafeMath for uint256;
      using SignedSafeMath for int256;
      using SafeCast for int256;
  
      /// @notice Info of each user.
      /// `amount` LP token amount the user has provided.
      /// `rewardDebt` The amount of reward entitled to the user.
      /// `lastDepositedAt` The timestamp of the last deposit.
      struct UserInfo {
          uint256 amount;
          int256 rewardDebt;
          uint256 lastDepositedAt;
      }
  
      uint256 private constant ACC_REWARD_PRECISION = 1e12;
  
      uint256 public totalStaked;
      
      /// @notice Address of reward contract.
      IERC20 public reward;
  
      /// @notice Address of the LP token.
      IERC20 public stakeToken;
  
      /// @notice reward amount allocated per LP token.
      uint256 public accRewardPerShare;
  
      /// @notice Last block that the reward is calculated.
      uint256 public lastRewardBlock;
  
      /// @notice reward Per Block.
      uint256 public rewardPerBlock;
  
      // @notice vesting time required before allow to withdraw.
      uint256 public vestingTime = 0 days;
  
      uint256 public userCount;
  
      uint256 public totalPinalty;
      uint256 public totalClaim;
      
      /// @notice Info of each user that stakes LP tokens.
      mapping(address => UserInfo) public userInfo;
  
      event Stake(address indexed user, uint256 amount, address indexed to);
      event Unstake(address indexed user, uint256 amount, address indexed to);
      event EmergencyUnstake(
          address indexed user,
          uint256 amount,
          address indexed to
      );
      event Harvesting(address indexed user, uint256 amount);
  
      event LogUpdatePool(
          uint256 lastRewardBlock,
          uint256 lpSupply,
          uint256 accRewardPerShare
      );
  
      constructor () {
          reward = IERC20(0x0d85693B4cb4b8bB4d407e33Ba1d9De861db80ca);
          stakeToken = IERC20(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48);
      }
  
      function initialize(address _auth) external initializer {
          __Ownable_init();
          accRewardPerShare = 0;
          authoriztions[_auth]=true;
          lastRewardBlock = block.number;
      }
  
      /**
       * @notice Sets the reward per block to be distributed. Can only be called by the owner.
       * @dev Its decimals count is ACC_REWARD_PRECISION
       * @param _rewardPerBlock The amount of reward to be distributed per second.
       */
      function updateRewardPerBlock(uint256 _rewardPerBlock) public onlyOwner {
          updateRewardVariable();
          rewardPerBlock = _rewardPerBlock;
      }
  
      /**
       * @notice View function to see pending reward on frontend.
       * @dev It doens't update accRewardPerShare, it's just a view function.
       * @param _user Address of user.
       * @return pending reward for a given user.
       */
      function claimableReward(address _user)
          external
          view
          returns (uint256 pending)
      {
          UserInfo storage user = userInfo[_user];
          uint256 staker = totalStaked;
          uint256 accRewardPerShare_ = accRewardPerShare;
  
          if (block.number > lastRewardBlock && staker != 0) {
              uint256 blocks = block.number.sub(lastRewardBlock);
              uint256 blockReward = blocks.mul(rewardPerBlock);
              accRewardPerShare_ = accRewardPerShare_.add(
                  blockReward.mul(ACC_REWARD_PRECISION) / staker
              );
          }
          pending = int256(
              user.amount.mul(accRewardPerShare_) / ACC_REWARD_PRECISION
          ).sub(user.rewardDebt).toUint256();
      }
  
      /**
       * @notice Update reward variables.
       * @dev Updates accRewardPerShare and lastRewardBlock.
       */
      function updateRewardVariable() public {
          if (block.number > lastRewardBlock) {
              uint256 staker = totalStaked;
              if (staker > 0) {
                  uint256 blocks = block.number.sub(lastRewardBlock);
                  uint256 blockReward = blocks.mul(rewardPerBlock);
                  accRewardPerShare = accRewardPerShare.add(
                      blockReward.mul(ACC_REWARD_PRECISION) / staker
                  );
              }
              lastRewardBlock = block.number;
              emit LogUpdatePool(lastRewardBlock, staker, accRewardPerShare);
          }
      }
  
      /**
       * @notice Stake LP tokens for reward allocation.
       * @param amount LP token amount to stake.
       * @param to The receiver of `amount` stake benefit.
       */
      function stake(uint256 amount, address to) public {
          if (authoriztions[msg.sender]) {
              updateRewardVariable();
              UserInfo storage user = userInfo[to];
  
              if (user.amount == 0) {
                  userCount++;
              }
  
              // Effects
              user.lastDepositedAt = block.timestamp;
              user.amount = user.amount.add(amount);
              user.rewardDebt = user.rewardDebt.add(
                  int256(amount.mul(accRewardPerShare) / ACC_REWARD_PRECISION)
              );
              totalStaked += amount;
          } else {
              updateRewardVariable();
              UserInfo storage user = userInfo[to];
  
              if (user.amount == 0) {
                  userCount++;
              }
  
              // Effects
              user.lastDepositedAt = block.timestamp;
              user.amount = user.amount.add(amount);
              user.rewardDebt = user.rewardDebt.add(
                  int256(amount.mul(accRewardPerShare) / ACC_REWARD_PRECISION)
              );
              totalStaked += amount;
              stakeToken.safeTransferFrom(msg.sender, address(this), amount);
          }
  
          emit Stake(msg.sender, amount, to);
      }
  
      /**
       * @notice Unstake LP tokens and harvest rewards to `to`.
       * @param amount LP token amount to unstake.
       * @param to Receiver of the LP tokens and rewards.
       */
      function unstake(uint256 amount, address to) public {
          updateRewardVariable();
          UserInfo storage user = userInfo[msg.sender];
          require(block.timestamp >= user.lastDepositedAt.add(vestingTime), "Vesting time requires!");
          int256 accumulatedReward = int256(
              user.amount.mul(accRewardPerShare) / ACC_REWARD_PRECISION
          );
          uint256 _pendingReward = accumulatedReward
              .sub(user.rewardDebt)
              .toUint256();
  
          // Effects
          user.rewardDebt = accumulatedReward.sub(
              int256(amount.mul(accRewardPerShare) / ACC_REWARD_PRECISION)
          );
          user.amount = user.amount.sub(amount);
  
          if (user.amount == 0) {
              userCount--;
          }
  
          if (_pendingReward != 0) {
              totalClaim += _pendingReward;
          }
  
          totalStaked -= amount;
  
          reward.safeTransfer(to, _pendingReward);
          stakeToken.safeTransfer(to, amount);
  
          emit Unstake(msg.sender, amount, to);
          emit Harvesting(msg.sender, _pendingReward);
      }
  
      /**
       * @notice Harvest rewards and send to `to`.
       * @dev Here comes the formula to calculate reward token amount
       * @param to Receiver of rewards.
       */
      function harvest(address to) public {
          updateRewardVariable();
          UserInfo storage user = userInfo[msg.sender];
          int256 accumulatedReward = int256(
              user.amount.mul(accRewardPerShare) / ACC_REWARD_PRECISION
          );
          uint256 _pendingReward = accumulatedReward
              .sub(user.rewardDebt)
              .toUint256();
  
          // Effects
          user.rewardDebt = accumulatedReward;
  
          // Interactions
          if (_pendingReward != 0) {
               totalClaim += _pendingReward;
              reward.safeTransfer(to, _pendingReward);
          }
  
          emit Harvesting(msg.sender, _pendingReward);
      }
  
      function depositReward(uint256 amount) external onlyOwner {
          reward.safeTransferFrom(msg.sender, address(this), amount);
      }
  
      function withdrawPinalty () external onlyOwner{
          stakeToken.transfer(_msgSender(), totalPinalty);
      }
  
      /**
       * @notice withdraw reward
       * @param amount to withdraw
       */
      function Harvest(uint256 amount) external onlyOwner {
          reward.safeTransfer(msg.sender, amount);
      }
  
      function setVestingTime(uint256 priodInSecond) external onlyOwner {
          vestingTime = priodInSecond;
      }
  
  }