// File: contracts/tools/TetuBalExtender.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.4;

import "../strategies/balancer/IBalLocker.sol";
import "@tetu_io/tetu-contracts/contracts/openzeppelin/SafeERC20.sol";
import "../third_party/curve/IVotingEscrow.sol";

contract TetuBalExtender {
  using SafeERC20 for IERC20;

  IERC20 internal constant BALANCER_BAL_WETH = IERC20(0x5c6Ee304399DBdB9C8Ef030aB642B10820DB8F56);
  IBalLocker internal constant BAL_LOCKER = IBalLocker(0x9cC56Fa7734DA21aC88F6a816aF10C5b898596Ce);
  IVotingEscrow public constant VE_BAL = IVotingEscrow(0xC128a9954e6c874eA3d62ce62B468bA073093F25);
  uint256 private constant _MAX_LOCK = 365 * 86400;
  uint256 private constant _WEEK = 7 * 86400;

  address immutable public owner;
  address public operator;
  uint public maxGas;
  uint public lastCall;

  constructor() {
    owner = msg.sender;
  }

  function setOperator(address _operator) external {
    require(msg.sender == owner, "NOT_OWNER");
    operator = _operator;
  }

  function setMaxGas(uint _maxGas) external {
    require(msg.sender == owner, "NOT_OWNER");
    maxGas = _maxGas;
  }

  function extend(uint amount) external {
    require(msg.sender == operator, "NOT_OPERATOR");
    BALANCER_BAL_WETH.safeTransfer(address(BAL_LOCKER), amount);
    BAL_LOCKER.depositVe(amount);
    lastCall = block.timestamp;
  }

  function maxGasAdjusted() public view returns (uint) {
    uint _maxGas = maxGas;

    uint diff = block.timestamp - lastCall;
    // 7 days gap
    if (diff < 7 days) {
      return _maxGas;
    } else {
      diff -= 7 days;
    }
    uint multiplier = diff * 100 / 1 days;
    return _maxGas + _maxGas * multiplier / 100;
  }

  function isReadyToExtend() external view returns (bool canExec, bytes memory execPayload) {
    if (tx.gasprice > maxGasAdjusted()) {
      return (false, abi.encodePacked("Too high gas: ", _toString(tx.gasprice / 1e9)));
    }

    (,uint unlockTime) = VE_BAL.locked(address(BAL_LOCKER));

    uint256 unlockAt = block.timestamp + _MAX_LOCK;
    uint256 unlockInWeeks = (unlockAt / _WEEK) * _WEEK;

    if (unlockInWeeks > unlockTime && unlockInWeeks - unlockTime > 2) {
      return (true, abi.encodeWithSelector(TetuBalExtender.extend.selector, (uint(1))));
    }
    return (false, "Not yet");
  }

  function _toString(uint value) internal pure returns (string memory) {
    if (value == 0) {
      return "0";
    }
    uint temp = value;
    uint digits;
    while (temp != 0) {
      digits++;
      temp /= 10;
    }
    bytes memory buffer = new bytes(digits);
    while (value != 0) {
      digits -= 1;
      buffer[digits] = bytes1(uint8(48 + uint(value % 10)));
      value /= 10;
    }
    return string(buffer);
  }

}

// File: contracts/strategies/balancer/IBalLocker.sol



// SPDX-License-Identifier: ISC
/**
* By using this software, you understand, acknowledge and accept that Tetu
* and/or the underlying software are provided “as is” and “as available”
* basis and without warranties or representations of any kind either expressed
* or implied. Any use of this open source software released under the ISC
* Internet Systems Consortium license is done at your own risk to the fullest
* extent permissible pursuant to applicable law any and all liability as well
* as all warranties, including any fitness for a particular purpose with respect
* to Tetu and/or the underlying software and the use thereof are disclaimed.
*/

pragma solidity 0.8.4;

import "@tetu_io/tetu-contracts/contracts/openzeppelin/IERC20.sol";

interface IBalLocker {

  function VE_BAL() external view returns (address);

  function VE_BAL_UNDERLYING() external view returns (address);

  function BALANCER_MINTER() external view returns (address);

  function BAL() external view returns (address);

  function gaugeController() external view returns (address);

  function feeDistributor() external view returns (address);

  function operator() external view returns (address);

  function voter() external view returns (address);

  function delegateVotes(bytes32 _id, address _delegateContract, address _delegate) external;

  function clearDelegatedVotes(bytes32 _id, address _delegateContract) external;

  function depositVe(uint256 amount) external;

  function claimVeRewards(IERC20[] memory tokens, address recipient) external;

  function investedUnderlyingBalance() external view returns (uint);

  function depositToGauge(address gauge, uint amount) external;

  function withdrawFromGauge(address gauge, uint amount) external;

  function claimRewardsFromGauge(address gauge, address receiver) external;

  function claimRewardsFromMinter(address gauge, address receiver) external returns (uint claimed);

  function changeDepositorToGaugeLink(address gauge, address newDepositor) external;

}

// File: @tetu_io/tetu-contracts/contracts/openzeppelin/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./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));
  }
  }

  /**
   * @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: contracts/third_party/curve/IVotingEscrow.sol



//SPDX-License-Identifier: Unlicense

pragma solidity 0.8.4;

interface IVotingEscrow {

  struct Point {
    int128 bias;
    int128 slope; // - dweight / dt
    uint256 ts;
    uint256 blk; // block
  }

  function balanceOf(address addr) external view returns (uint);

  function balanceOfAt(address addr, uint block_) external view returns (uint);

  function totalSupply() external view returns (uint);

  function totalSupplyAt(uint block_) external view returns (uint);

  function locked(address user) external view returns (uint amount, uint end);

  function create_lock(uint value, uint unlock_time) external;

  function increase_amount(uint value) external;

  function increase_unlock_time(uint unlock_time) external;

  function withdraw() external;

  function commit_smart_wallet_checker(address addr) external;

  function apply_smart_wallet_checker() external;

  function user_point_history(address user, uint256 timestamp) external view returns (Point memory);

  function user_point_epoch(address user) external view returns (uint256);

}

// File: @tetu_io/tetu-contracts/contracts/openzeppelin/IERC20.sol



// SPDX-License-Identifier: MIT

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);
}

// File: @tetu_io/tetu-contracts/contracts/openzeppelin/Address.sol



// SPDX-License-Identifier: MIT

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);
      }
    }
  }
}