// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
/**
 * @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);
}// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import {IERC20} from "./IERC20.sol";
interface IERC20Detailed is IERC20 {
    function name() external view returns(string memory);
    function symbol() external view returns(string memory);
    function decimals() external view returns(uint8);
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
interface ITransferHook {
    function onTransfer(address from, address to, uint256 amount) external;
}pragma solidity ^0.6.2;
/**
 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
    /**
     * @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");
        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}pragma solidity ^0.6.0;
import './UpgradeabilityProxy.sol';
/**
 * @title BaseAdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract BaseAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
  event AdminChanged(address previousAdmin, address newAdmin);
  /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
   * validated in the constructor.
   */
  bytes32 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
  /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
  modifier ifAdmin() {
    if (msg.sender == _admin()) {
      _;
    } else {
      _fallback();
    }
  }
  /**
   * @return The address of the proxy admin.
   */
  function admin() external ifAdmin returns (address) {
    return _admin();
  }
  /**
   * @return The address of the implementation.
   */
  function implementation() external ifAdmin returns (address) {
    return _implementation();
  }
  /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeAdmin(address newAdmin) external ifAdmin {
    require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
    emit AdminChanged(_admin(), newAdmin);
    _setAdmin(newAdmin);
  }
  /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
  function upgradeTo(address newImplementation) external ifAdmin {
    _upgradeTo(newImplementation);
  }
  /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeToAndCall(address newImplementation, bytes calldata data) payable external ifAdmin {
    _upgradeTo(newImplementation);
    (bool success,) = newImplementation.delegatecall(data);
    require(success);
  }
  /**
   * @return adm The admin slot.
   */
  function _admin() internal view returns (address adm) {
    bytes32 slot = ADMIN_SLOT;
    assembly {
      adm := sload(slot)
    }
  }
  /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
  function _setAdmin(address newAdmin) internal {
    bytes32 slot = ADMIN_SLOT;
    assembly {
      sstore(slot, newAdmin)
    }
  }
  /**
   * @dev Only fall back when the sender is not the admin.
   */
  function _willFallback() internal override virtual {
    require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
    super._willFallback();
  }
}pragma solidity ^0.6.0;
import './BaseUpgradeabilityProxy.sol';
/**
 * @title UpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with a constructor for initializing
 * implementation and init data.
 */
contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract constructor.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, bytes memory _data) public payable {
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if(_data.length > 0) {
      (bool success,) = _logic.delegatecall(_data);
      require(success);
    }
  }  
}pragma solidity ^0.6.0;
import './Proxy.sol';
import './Address.sol';
/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address indexed implementation);
  /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
   * validated in the constructor.
   */
  bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
  /**
   * @dev Returns the current implementation.
   * @return impl Address of the current implementation
   */
  function _implementation() internal override view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      impl := sload(slot)
    }
  }
  /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
  function _upgradeTo(address newImplementation) internal {
    _setImplementation(newImplementation);
    emit Upgraded(newImplementation);
  }
  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) internal {
    require(Address.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      sstore(slot, newImplementation)
    }
  }
}pragma solidity ^0.6.0;
/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
abstract contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  fallback () payable external {
    _fallback();
  }
  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal virtual view returns (address);
  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize())
      // Call the implementation.
      // out and outsize are 0 because we don't know the size yet.
      let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
      // Copy the returned data.
      returndatacopy(0, 0, returndatasize())
      switch result
      // delegatecall returns 0 on error.
      case 0 { revert(0, returndatasize()) }
      default { return(0, returndatasize()) }
    }
  }
  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal virtual {
  }
  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/*
 * @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 GSN 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 payable) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "./Context.sol";
import "../interfaces/IERC20.sol";
import "./SafeMath.sol";
import "./Address.sol";
/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;
    using Address for address;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string internal _name;
    string internal _symbol;
    uint8 private _decimals;
    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 18;
    }
    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }
    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }
    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }
    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }
    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }
    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }
    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }
    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }
    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        _beforeTokenTransfer(sender, recipient, amount);
        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }
    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");
        _beforeTokenTransfer(address(0), account, amount);
        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }
    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");
        _beforeTokenTransfer(account, address(0), amount);
        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }
    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }
    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}pragma solidity ^0.6.0;
/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when 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.
 */
library SafeMath {
    /**
     * @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) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }
    /**
     * @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 sub(a, b, "SafeMath: subtraction overflow");
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    /**
     * @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) {
        // 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 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts 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) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts 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) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts 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 mod(a, b, "SafeMath: modulo by zero");
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.6.10;
import "./BaseAdminUpgradeabilityProxy.sol";
import "./InitializableUpgradeabilityProxy.sol";
/**
 * @title InitializableAdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for 
 * initializing the implementation, admin, and init data.
 */
contract InitializableAdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, InitializableUpgradeabilityProxy {
    /**
   * Contract initializer.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    function initialize(address _logic, address _admin, bytes memory _data) public payable {
        require(_implementation() == address(0));
        InitializableUpgradeabilityProxy.initialize(_logic, _data);
        assert(ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(_admin);
    }
    /**
    * @dev Only fall back when the sender is not the admin.
    */
    function _willFallback() internal override(BaseAdminUpgradeabilityProxy, Proxy) {
        BaseAdminUpgradeabilityProxy._willFallback();
    }
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.6.10;
import "./BaseUpgradeabilityProxy.sol";
/**
 * @title InitializableUpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with an initializer for initializing
 * implementation and init data.
 */
contract InitializableUpgradeabilityProxy is BaseUpgradeabilityProxy {
    /**
   * @dev Contract initializer.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    function initialize(address _logic, bytes memory _data) public payable {
        require(_implementation() == address(0));
        assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if (_data.length > 0) {
            (bool success, ) = _logic.delegatecall(_data);
            require(success);
        }
    }
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import {ERC20} from "../open-zeppelin/ERC20.sol";
import {ITransferHook} from "../interfaces/ITransferHook.sol";
import {VersionedInitializable} from "../utils/VersionedInitializable.sol";
/**
* @notice implementation of the AAVE token contract
* @author Aave
*/
contract AaveToken is ERC20, VersionedInitializable {
    /// @dev snapshot of a value on a specific block, used for balances
    struct Snapshot {
        uint128 blockNumber;
        uint128 value;
    }
    string internal constant NAME = "Aave Token";
    string internal constant SYMBOL = "AAVE";
    uint8 internal constant DECIMALS = 18;
    /// @dev the amount being distributed for the LEND -> AAVE migration
    uint256 internal constant MIGRATION_AMOUNT = 13000000 ether;
    /// @dev the amount being distributed for the PSI and PEI
    uint256 internal constant DISTRIBUTION_AMOUNT = 3000000 ether;
    uint256 public constant REVISION = 1;
    /// @dev owner => next valid nonce to submit with permit()
    mapping (address => uint256) public _nonces;
    mapping (address => mapping (uint256 => Snapshot)) public _snapshots;
    mapping (address => uint256) public _countsSnapshots;
    /// @dev reference to the Aave governance contract to call (if initialized) on _beforeTokenTransfer
    /// !!! IMPORTANT The Aave governance is considered a trustable contract, being its responsibility
    /// to control all potential reentrancies by calling back the AaveToken
    ITransferHook public _aaveGovernance;
    bytes32 public DOMAIN_SEPARATOR;
    bytes public constant EIP712_REVISION = bytes("1");
    bytes32 internal constant EIP712_DOMAIN = keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
    bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    event SnapshotDone(address owner, uint128 oldValue, uint128 newValue);
    constructor() ERC20(NAME, SYMBOL) public {}
    /**
    * @dev initializes the contract upon assignment to the InitializableAdminUpgradeabilityProxy
    * @param migrator the address of the LEND -> AAVE migration contract
    * @param distributor the address of the AAVE distribution contract
    */
    function initialize(
        address migrator,
        address distributor,
        ITransferHook aaveGovernance
    ) external initializer {
        uint256 chainId;
        //solium-disable-next-line
        assembly {
            chainId := chainid()
        }
        DOMAIN_SEPARATOR = keccak256(abi.encode(
            EIP712_DOMAIN,
            keccak256(bytes(NAME)),
            keccak256(EIP712_REVISION),
            chainId,
            address(this)
        ));
        _name = NAME;
        _symbol = SYMBOL;
        _setupDecimals(DECIMALS);
        _aaveGovernance = aaveGovernance;
        _mint(migrator, MIGRATION_AMOUNT);
        _mint(distributor, DISTRIBUTION_AMOUNT);
    }
    /**
    * @dev implements the permit function as for https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
    * @param owner the owner of the funds
    * @param spender the spender
    * @param value the amount
    * @param deadline the deadline timestamp, type(uint256).max for no deadline
    * @param v signature param
    * @param s signature param
    * @param r signature param
    */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        require(owner != address(0), "INVALID_OWNER");
        //solium-disable-next-line
        require(block.timestamp <= deadline, "INVALID_EXPIRATION");
        uint256 currentValidNonce = _nonces[owner];
        bytes32 digest = keccak256(
                abi.encodePacked(
                    "\\x19\\x01",
                    DOMAIN_SEPARATOR,
                    keccak256(
                        abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
                    )
        );
        require(owner == ecrecover(digest, v, r, s), "INVALID_SIGNATURE");
        _nonces[owner] = currentValidNonce.add(1);
        _approve(owner, spender, value);
    }
    /**
    * @dev returns the revision of the implementation contract
    */
    function getRevision() internal pure override returns (uint256) {
        return REVISION;
    }
    /**
    * @dev Writes a snapshot for an owner of tokens
    * @param owner The owner of the tokens
    * @param oldValue The value before the operation that is gonna be executed after the snapshot
    * @param newValue The value after the operation
    */
    function _writeSnapshot(address owner, uint128 oldValue, uint128 newValue) internal {
        uint128 currentBlock = uint128(block.number);
        uint256 ownerCountOfSnapshots = _countsSnapshots[owner];
        mapping (uint256 => Snapshot) storage snapshotsOwner = _snapshots[owner];
        // Doing multiple operations in the same block
        if (ownerCountOfSnapshots != 0 && snapshotsOwner[ownerCountOfSnapshots.sub(1)].blockNumber == currentBlock) {
            snapshotsOwner[ownerCountOfSnapshots.sub(1)].value = newValue;
        } else {
            snapshotsOwner[ownerCountOfSnapshots] = Snapshot(currentBlock, newValue);
            _countsSnapshots[owner] = ownerCountOfSnapshots.add(1);
        }
        emit SnapshotDone(owner, oldValue, newValue);
    }
    /**
    * @dev Writes a snapshot before any operation involving transfer of value: _transfer, _mint and _burn
    * - On _transfer, it writes snapshots for both "from" and "to"
    * - On _mint, only for _to
    * - On _burn, only for _from
    * @param from the from address
    * @param to the to address
    * @param amount the amount to transfer
    */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal override {
        if (from == to) {
            return;
        }
        if (from != address(0)) {
            uint256 fromBalance = balanceOf(from);
            _writeSnapshot(from, uint128(fromBalance), uint128(fromBalance.sub(amount)));
        }
        if (to != address(0)) {
            uint256 toBalance = balanceOf(to);
            _writeSnapshot(to, uint128(toBalance), uint128(toBalance.add(amount)));
        }
        // caching the aave governance address to avoid multiple state loads
        ITransferHook aaveGovernance = _aaveGovernance;
        if (aaveGovernance != ITransferHook(0)) {
            aaveGovernance.onTransfer(from, to, amount);
        }
    }
}// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
/**
 * @title VersionedInitializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 *
 * @author Aave, inspired by the OpenZeppelin Initializable contract
 */
abstract contract VersionedInitializable {
    /**
   * @dev Indicates that the contract has been initialized.
   */
    uint256 internal lastInitializedRevision = 0;
   /**
   * @dev Modifier to use in the initializer function of a contract.
   */
    modifier initializer() {
        uint256 revision = getRevision();
        require(revision > lastInitializedRevision, "Contract instance has already been initialized");
        lastInitializedRevision = revision;
        _;
    }
    /// @dev returns the revision number of the contract.
    /// Needs to be defined in the inherited class as a constant.
    function getRevision() internal pure virtual returns(uint256);
    // Reserved storage space to allow for layout changes in the future.
    uint256[50] private ______gap;
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import {IERC20} from "../interfaces/IERC20.sol";
import {SafeMath} from "../open-zeppelin/SafeMath.sol";
import {VersionedInitializable} from "../utils/VersionedInitializable.sol";
/**
* @title LendToAaveMigrator
* @notice This contract implements the migration from LEND to AAVE token
* @author Aave 
*/
contract LendToAaveMigrator is VersionedInitializable {
    using SafeMath for uint256;
    IERC20 public immutable AAVE;
    IERC20 public immutable LEND;
    uint256 public immutable LEND_AAVE_RATIO;
    uint256 public constant REVISION = 1;
    
    uint256 public _totalLendMigrated;
    /**
    * @dev emitted on migration
    * @param sender the caller of the migration
    * @param amount the amount being migrated
    */
    event LendMigrated(address indexed sender, uint256 indexed amount);
    /**
    * @param aave the address of the AAVE token
    * @param lend the address of the LEND token
    * @param lendAaveRatio the exchange rate between LEND and AAVE 
     */
    constructor(IERC20 aave, IERC20 lend, uint256 lendAaveRatio) public {
        AAVE = aave;
        LEND = lend;
        LEND_AAVE_RATIO = lendAaveRatio;
    }
    /**
    * @dev initializes the implementation
    */
    function initialize() public initializer {
    }
    /**
    * @dev returns true if the migration started
    */
    function migrationStarted() external view returns(bool) {
        return lastInitializedRevision != 0;
    }
    /**
    * @dev executes the migration from LEND to AAVE. Users need to give allowance to this contract to transfer LEND before executing
    * this transaction.
    * @param amount the amount of LEND to be migrated
    */
    function migrateFromLEND(uint256 amount) external {
        require(lastInitializedRevision != 0, "MIGRATION_NOT_STARTED");
        _totalLendMigrated = _totalLendMigrated.add(amount);
        LEND.transferFrom(msg.sender, address(this), amount);
        AAVE.transfer(msg.sender, amount.div(LEND_AAVE_RATIO));
        emit LendMigrated(msg.sender, amount);
    }
    /**
    * @dev returns the implementation revision
    * @return the implementation revision
    */
    function getRevision() internal pure override returns (uint256) {
        return REVISION;
    }
}// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import "../interfaces/IERC20.sol";
contract DoubleTransferHelper {
    IERC20 public immutable AAVE;
    constructor(IERC20 aave) public {
        AAVE = aave;
    }
    function doubleSend(address to, uint256 amount1, uint256 amount2) external {
        AAVE.transfer(to, amount1);
        AAVE.transfer(to, amount2);
    }
}// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import "../open-zeppelin/ERC20.sol";
/**
 * @title ERC20Mintable
 * @dev ERC20 minting logic
 */
contract MintableErc20 is ERC20 {
    constructor(string memory name, string memory symbol, uint8 decimals) ERC20(name, symbol) public {
        _setupDecimals(decimals);
    }
    /**
     * @dev Function to mint tokens
     * @param value The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(uint256 value) public returns (bool) {
        _mint(msg.sender, value);
        return true;
    }
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.10;
import {ITransferHook} from "../interfaces/ITransferHook.sol";
contract MockTransferHook is ITransferHook {
    event MockHookEvent();
    function onTransfer(address from, address to, uint256 amount) external override {
        emit MockHookEvent();
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {BaseAaveTokenV2} from './BaseAaveTokenV2.sol';
import {BaseDelegation} from './BaseDelegation.sol';
contract AaveTokenV3 is BaseAaveTokenV2, BaseDelegation {
  /**
   * @dev initializes the contract upon assignment to the InitializableAdminUpgradeabilityProxy
   */
  function initialize() external virtual initializer {}
  function _afterTokenTransfer(
    address from,
    address to,
    uint256 fromBalanceBefore,
    uint256 toBalanceBefore,
    uint256 amount
  ) internal override {
    _delegationChangeOnTransfer(from, to, fromBalanceBefore, toBalanceBefore, amount);
  }
  function _getDelegationState(address user)
    internal
    view
    override
    returns (DelegationState memory)
  {
    DelegationAwareBalance memory userState = _balances[user];
    return
      DelegationState({
        delegatedPropositionBalance: userState.delegatedPropositionBalance,
        delegatedVotingBalance: userState.delegatedVotingBalance,
        delegationMode: userState.delegationMode
      });
  }
  function _getBalance(address user) internal view override returns (uint256) {
    return _balances[user].balance;
  }
  function _setDelegationState(address user, DelegationState memory delegationState)
    internal
    override
  {
    DelegationAwareBalance storage userState = _balances[user];
    userState.delegatedPropositionBalance = delegationState.delegatedPropositionBalance;
    userState.delegatedVotingBalance = delegationState.delegatedVotingBalance;
    userState.delegationMode = delegationState.delegationMode;
  }
  function _incrementNonces(address user) internal override returns (uint256) {
    unchecked {
      // Does not make sense to check because it's not realistic to reach uint256.max in nonce
      return _nonces[user]++;
    }
  }
  function _getDomainSeparator() internal view override returns (bytes32) {
    return DOMAIN_SEPARATOR();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {ECDSA} from 'openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol';
import {VersionedInitializable} from './utils/VersionedInitializable.sol';
import {EIP712} from './utils/EIP712.sol';
import {BaseAaveToken} from './BaseAaveToken.sol';
abstract contract BaseAaveTokenV2 is BaseAaveToken, VersionedInitializable, EIP712 {
  /// @dev owner => next valid nonce to submit with permit()
  mapping(address => uint256) public _nonces;
  ///////// @dev DEPRECATED from AaveToken v1  //////////////////////////
  //////// kept for backwards compatibility with old storage layout ////
  uint256[3] private ______DEPRECATED_FROM_AAVE_V1;
  ///////// @dev END OF DEPRECATED from AaveToken v1  //////////////////////////
  // deprecated in favor to OZ EIP712
  bytes32 private __DEPRECATED_DOMAIN_SEPARATOR;
  ///////// @dev DEPRECATED from AaveToken v2  //////////////////////////
  //////// kept for backwards compatibility with old storage layout ////
  uint256[4] private ______DEPRECATED_FROM_AAVE_V2;
  ///////// @dev END OF DEPRECATED from AaveToken v2  //////////////////////////
  bytes32 public constant PERMIT_TYPEHASH =
    keccak256('Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)');
  uint256 public constant REVISION = 4;
  constructor() EIP712('Aave token V3', '2') {}
  function DOMAIN_SEPARATOR() public view returns (bytes32) {
    return _domainSeparatorV4();
  }
  /**
   * @dev implements the permit function as for https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param owner the owner of the funds
   * @param spender the spender
   * @param value the amount
   * @param deadline the deadline timestamp, type(uint256).max for no deadline
   * @param v signature param
   * @param s signature param
   * @param r signature param
   */
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external {
    require(owner != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    uint256 currentValidNonce = _nonces[owner];
    bytes32 digest = _hashTypedDataV4(
      keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
    );
    require(owner == ECDSA.recover(digest, v, r, s), 'INVALID_SIGNATURE');
    unchecked {
      // does not make sense to check because it's not realistic to reach uint256.max in nonce
      _nonces[owner] = currentValidNonce + 1;
    }
    _approve(owner, spender, value);
  }
  /**
   * @dev returns the revision of the implementation contract
   */
  function getRevision() internal pure override returns (uint256) {
    return REVISION;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {ECDSA} from 'openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol';
import {SafeCast72} from './utils/SafeCast72.sol';
import {IGovernancePowerDelegationToken} from './interfaces/IGovernancePowerDelegationToken.sol';
import {DelegationMode} from './DelegationAwareBalance.sol';
/**
 * @notice The contract implements generic delegation functionality for the upcoming governance v3
 * @author BGD Labs
 * @dev to make it's pluggable to any exising token it has a set of virtual functions
 *   for simple access to balances and permit functionality
 * @dev ************ IMPORTANT SECURITY CONSIDERATION ************
 *   current version of the token can be used only with asset which has 18 decimals
 *   and possible totalSupply lower then 4722366482869645213696,
 *   otherwise at least POWER_SCALE_FACTOR should be adjusted !!!
 *   *************************************************************
 */
abstract contract BaseDelegation is IGovernancePowerDelegationToken {
  struct DelegationState {
    uint72 delegatedPropositionBalance;
    uint72 delegatedVotingBalance;
    DelegationMode delegationMode;
  }
  mapping(address => address) internal _votingDelegatee;
  mapping(address => address) internal _propositionDelegatee;
  /** @dev we assume that for the governance system delegation with 18 decimals of precision is not needed,
   *   by this constant we reduce it by 10, to 8 decimals.
   *   In case of Aave token this will allow to work with up to 47'223'664'828'696,45213696 total supply
   *   If your token already have less then 10 decimals, please change it to appropriate.
   */
  uint256 public constant POWER_SCALE_FACTOR = 1e10;
  bytes32 public constant DELEGATE_BY_TYPE_TYPEHASH =
    keccak256(
      'DelegateByType(address delegator,address delegatee,uint8 delegationType,uint256 nonce,uint256 deadline)'
    );
  bytes32 public constant DELEGATE_TYPEHASH =
    keccak256('Delegate(address delegator,address delegatee,uint256 nonce,uint256 deadline)');
  /**
   * @notice returns eip-2612 compatible domain separator
   * @dev we expect that existing tokens, ie Aave, already have, so we want to reuse
   * @return domain separator
   */
  function _getDomainSeparator() internal view virtual returns (bytes32);
  /**
   * @notice gets the delegation state of a user
   * @param user address
   * @return state of a user's delegation
   */
  function _getDelegationState(address user) internal view virtual returns (DelegationState memory);
  /**
   * @notice returns the token balance of a user
   * @param user address
   * @return current nonce before increase
   */
  function _getBalance(address user) internal view virtual returns (uint256);
  /**
   * @notice increases and return the current nonce of a user
   * @dev should use `return nonce++;` pattern
   * @param user address
   * @return current nonce before increase
   */
  function _incrementNonces(address user) internal virtual returns (uint256);
  /**
   * @notice sets the delegation state of a user
   * @param user address
   * @param delegationState state of a user's delegation
   */
  function _setDelegationState(address user, DelegationState memory delegationState)
    internal
    virtual;
  /// @inheritdoc IGovernancePowerDelegationToken
  function delegateByType(address delegatee, GovernancePowerType delegationType)
    external
    virtual
    override
  {
    _delegateByType(msg.sender, delegatee, delegationType);
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function delegate(address delegatee) external override {
    _delegateByType(msg.sender, delegatee, GovernancePowerType.VOTING);
    _delegateByType(msg.sender, delegatee, GovernancePowerType.PROPOSITION);
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function getDelegateeByType(address delegator, GovernancePowerType delegationType)
    external
    view
    override
    returns (address)
  {
    return _getDelegateeByType(delegator, _getDelegationState(delegator), delegationType);
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function getDelegates(address delegator) external view override returns (address, address) {
    DelegationState memory delegatorBalance = _getDelegationState(delegator);
    return (
      _getDelegateeByType(delegator, delegatorBalance, GovernancePowerType.VOTING),
      _getDelegateeByType(delegator, delegatorBalance, GovernancePowerType.PROPOSITION)
    );
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function getPowerCurrent(address user, GovernancePowerType delegationType)
    public
    view
    virtual
    override
    returns (uint256)
  {
    DelegationState memory userState = _getDelegationState(user);
    uint256 userOwnPower = uint8(userState.delegationMode) & (uint8(delegationType) + 1) == 0
      ? _getBalance(user)
      : 0;
    uint256 userDelegatedPower = _getDelegatedPowerByType(userState, delegationType);
    return userOwnPower + userDelegatedPower;
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function getPowersCurrent(address user) external view override returns (uint256, uint256) {
    return (
      getPowerCurrent(user, GovernancePowerType.VOTING),
      getPowerCurrent(user, GovernancePowerType.PROPOSITION)
    );
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function metaDelegateByType(
    address delegator,
    address delegatee,
    GovernancePowerType delegationType,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    require(delegator != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    bytes32 digest = ECDSA.toTypedDataHash(
      _getDomainSeparator(),
      keccak256(
        abi.encode(
          DELEGATE_BY_TYPE_TYPEHASH,
          delegator,
          delegatee,
          delegationType,
          _incrementNonces(delegator),
          deadline
        )
      )
    );
    require(delegator == ECDSA.recover(digest, v, r, s), 'INVALID_SIGNATURE');
    _delegateByType(delegator, delegatee, delegationType);
  }
  /// @inheritdoc IGovernancePowerDelegationToken
  function metaDelegate(
    address delegator,
    address delegatee,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    require(delegator != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    bytes32 digest = ECDSA.toTypedDataHash(
      _getDomainSeparator(),
      keccak256(
        abi.encode(DELEGATE_TYPEHASH, delegator, delegatee, _incrementNonces(delegator), deadline)
      )
    );
    require(delegator == ECDSA.recover(digest, v, r, s), 'INVALID_SIGNATURE');
    _delegateByType(delegator, delegatee, GovernancePowerType.VOTING);
    _delegateByType(delegator, delegatee, GovernancePowerType.PROPOSITION);
  }
  /**
   * @dev Modifies the delegated power of a `delegatee` account by type (VOTING, PROPOSITION).
   * Passing the impact on the delegation of `delegatee` account before and after to reduce conditionals and not lose
   * any precision.
   * @param impactOnDelegationBefore how much impact a balance of another account had over the delegation of a `delegatee`
   * before an action.
   * For example, if the action is a delegation from one account to another, the impact before the action will be 0.
   * @param impactOnDelegationAfter how much impact a balance of another account will have  over the delegation of a `delegatee`
   * after an action.
   * For example, if the action is a delegation from one account to another, the impact after the action will be the whole balance
   * of the account changing the delegatee.
   * @param delegatee the user whom delegated governance power will be changed
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   **/
  function _governancePowerTransferByType(
    uint256 impactOnDelegationBefore,
    uint256 impactOnDelegationAfter,
    address delegatee,
    GovernancePowerType delegationType
  ) internal {
    if (delegatee == address(0)) return;
    if (impactOnDelegationBefore == impactOnDelegationAfter) return;
    // we use uint72, because this is the most optimal for AaveTokenV3
    // To make delegated balance fit into uint72 we're decreasing precision of delegated balance by POWER_SCALE_FACTOR
    uint72 impactOnDelegationBefore72 = SafeCast72.toUint72(
      impactOnDelegationBefore / POWER_SCALE_FACTOR
    );
    uint72 impactOnDelegationAfter72 = SafeCast72.toUint72(
      impactOnDelegationAfter / POWER_SCALE_FACTOR
    );
    DelegationState memory delegateeState = _getDelegationState(delegatee);
    if (delegationType == GovernancePowerType.VOTING) {
      delegateeState.delegatedVotingBalance =
        delegateeState.delegatedVotingBalance -
        impactOnDelegationBefore72 +
        impactOnDelegationAfter72;
    } else {
      delegateeState.delegatedPropositionBalance =
        delegateeState.delegatedPropositionBalance -
        impactOnDelegationBefore72 +
        impactOnDelegationAfter72;
    }
    _setDelegationState(delegatee, delegateeState);
  }
  /**
   * @dev performs all state changes related delegation changes on transfer
   * @param from token sender
   * @param to token recipient
   * @param fromBalanceBefore balance of the sender before transfer
   * @param toBalanceBefore balance of the recipient before transfer
   * @param amount amount of tokens sent
   **/
  function _delegationChangeOnTransfer(
    address from,
    address to,
    uint256 fromBalanceBefore,
    uint256 toBalanceBefore,
    uint256 amount
  ) internal {
    if (from == to) {
      return;
    }
    if (from != address(0)) {
      DelegationState memory fromUserState = _getDelegationState(from);
      uint256 fromBalanceAfter = fromBalanceBefore - amount;
      if (fromUserState.delegationMode != DelegationMode.NO_DELEGATION) {
        _governancePowerTransferByType(
          fromBalanceBefore,
          fromBalanceAfter,
          _getDelegateeByType(from, fromUserState, GovernancePowerType.VOTING),
          GovernancePowerType.VOTING
        );
        _governancePowerTransferByType(
          fromBalanceBefore,
          fromBalanceAfter,
          _getDelegateeByType(from, fromUserState, GovernancePowerType.PROPOSITION),
          GovernancePowerType.PROPOSITION
        );
      }
    }
    if (to != address(0)) {
      DelegationState memory toUserState = _getDelegationState(to);
      uint256 toBalanceAfter = toBalanceBefore + amount;
      if (toUserState.delegationMode != DelegationMode.NO_DELEGATION) {
        _governancePowerTransferByType(
          toBalanceBefore,
          toBalanceAfter,
          _getDelegateeByType(to, toUserState, GovernancePowerType.VOTING),
          GovernancePowerType.VOTING
        );
        _governancePowerTransferByType(
          toBalanceBefore,
          toBalanceAfter,
          _getDelegateeByType(to, toUserState, GovernancePowerType.PROPOSITION),
          GovernancePowerType.PROPOSITION
        );
      }
    }
  }
  /**
   * @dev Extracts from state and returns delegated governance power (Voting, Proposition)
   * @param userState the current state of a user
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   **/
  function _getDelegatedPowerByType(
    DelegationState memory userState,
    GovernancePowerType delegationType
  ) internal pure returns (uint256) {
    return
      POWER_SCALE_FACTOR *
      (
        delegationType == GovernancePowerType.VOTING
          ? userState.delegatedVotingBalance
          : userState.delegatedPropositionBalance
      );
  }
  /**
   * @dev Extracts from state and returns the delegatee of a delegator by type of governance power (Voting, Proposition)
   * - If the delegator doesn't have any delegatee, returns address(0)
   * @param delegator delegator
   * @param userState the current state of a user
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   **/
  function _getDelegateeByType(
    address delegator,
    DelegationState memory userState,
    GovernancePowerType delegationType
  ) internal view returns (address) {
    if (delegationType == GovernancePowerType.VOTING) {
      return
        /// With the & operation, we cover both VOTING_DELEGATED delegation and FULL_POWER_DELEGATED
        /// as VOTING_DELEGATED is equivalent to 01 in binary and FULL_POWER_DELEGATED is equivalent to 11
        (uint8(userState.delegationMode) & uint8(DelegationMode.VOTING_DELEGATED)) != 0
          ? _votingDelegatee[delegator]
          : address(0);
    }
    return
      userState.delegationMode >= DelegationMode.PROPOSITION_DELEGATED
        ? _propositionDelegatee[delegator]
        : address(0);
  }
  /**
   * @dev Changes user's delegatee address by type of governance power (Voting, Proposition)
   * @param delegator delegator
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   * @param _newDelegatee the new delegatee
   **/
  function _updateDelegateeByType(
    address delegator,
    GovernancePowerType delegationType,
    address _newDelegatee
  ) internal {
    address newDelegatee = _newDelegatee == delegator ? address(0) : _newDelegatee;
    if (delegationType == GovernancePowerType.VOTING) {
      _votingDelegatee[delegator] = newDelegatee;
    } else {
      _propositionDelegatee[delegator] = newDelegatee;
    }
  }
  /**
   * @dev Updates the specific flag which signaling about existence of delegation of governance power (Voting, Proposition)
   * @param userState a user state to change
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   * @param willDelegate next state of delegation
   **/
  function _updateDelegationModeByType(
    DelegationState memory userState,
    GovernancePowerType delegationType,
    bool willDelegate
  ) internal pure returns (DelegationState memory) {
    if (willDelegate) {
      // Because GovernancePowerType starts from 0, we should add 1 first, then we apply bitwise OR
      userState.delegationMode = DelegationMode(
        uint8(userState.delegationMode) | (uint8(delegationType) + 1)
      );
    } else {
      // First bitwise NEGATION, ie was 01, after XOR with 11 will be 10,
      // then bitwise AND, which means it will keep only another delegation type if it exists
      userState.delegationMode = DelegationMode(
        uint8(userState.delegationMode) &
          ((uint8(delegationType) + 1) ^ uint8(DelegationMode.FULL_POWER_DELEGATED))
      );
    }
    return userState;
  }
  /**
   * @dev This is the equivalent of an ERC20 transfer(), but for a power type: an atomic transfer of a balance (power).
   * When needed, it decreases the power of the `delegator` and when needed, it increases the power of the `delegatee`
   * @param delegator delegator
   * @param _delegatee the user which delegated power will change
   * @param delegationType the type of delegation (VOTING, PROPOSITION)
   **/
  function _delegateByType(
    address delegator,
    address _delegatee,
    GovernancePowerType delegationType
  ) internal {
    // Here we unify the property that delegating power to address(0) == delegating power to yourself == no delegation
    // So from now on, not being delegating is (exclusively) that delegatee == address(0)
    address delegatee = _delegatee == delegator ? address(0) : _delegatee;
    // We read the whole struct before validating delegatee, because in the optimistic case
    // (_delegatee != currentDelegatee) we will reuse userState in the rest of the function
    DelegationState memory delegatorState = _getDelegationState(delegator);
    address currentDelegatee = _getDelegateeByType(delegator, delegatorState, delegationType);
    if (delegatee == currentDelegatee) return;
    bool delegatingNow = currentDelegatee != address(0);
    bool willDelegateAfter = delegatee != address(0);
    uint256 delegatorBalance = _getBalance(delegator);
    if (delegatingNow) {
      _governancePowerTransferByType(delegatorBalance, 0, currentDelegatee, delegationType);
    }
    if (willDelegateAfter) {
      _governancePowerTransferByType(0, delegatorBalance, delegatee, delegationType);
    }
    _updateDelegateeByType(delegator, delegationType, delegatee);
    if (willDelegateAfter != delegatingNow) {
      _setDelegationState(
        delegator,
        _updateDelegationModeByType(delegatorState, delegationType, willDelegateAfter)
      );
    }
    emit DelegateChanged(delegator, delegatee, delegationType);
  }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/ECDSA.sol)
pragma solidity ^0.8.0;
import "../Strings.sol";
/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }
    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }
    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }
        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }
        return (signer, RecoverError.NoError);
    }
    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32 message) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, "\\x19Ethereum Signed Message:\
32")
            mstore(0x1c, hash)
            message := keccak256(0x00, 0x3c)
        }
    }
    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
", Strings.toString(s.length), s));
    }
    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 data) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, "\\x19\\x01")
            mstore(add(ptr, 0x02), domainSeparator)
            mstore(add(ptr, 0x22), structHash)
            data := keccak256(ptr, 0x42)
        }
    }
    /**
     * @dev Returns an Ethereum Signed Data with intended validator, created from a
     * `validator` and `data` according to the version 0 of EIP-191.
     *
     * See {recover}.
     */
    function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\\x19\\x00", validator, data));
    }
}
// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;
/**
 * @title VersionedInitializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 *
 * @author Aave, inspired by the OpenZeppelin Initializable contract
 */
abstract contract VersionedInitializable {
  /**
   * @dev Indicates that the contract has been initialized.
   */
  uint256 internal lastInitializedRevision = 0;
  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    uint256 revision = getRevision();
    require(revision > lastInitializedRevision, 'Contract instance has already been initialized');
    lastInitializedRevision = revision;
    _;
  }
  /// @dev returns the revision number of the contract.
  /// Needs to be defined in the inherited class as a constant.
  function getRevision() internal pure virtual returns (uint256);
  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}
// SPDX-License-Identifier: MIT
// Contract modified from OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/EIP712.sol) to remove local
// fallback storage variables, so contract does not affect on existing storage layout. This works as its used on contracts
// that have name and revision < 32 bytes
pragma solidity ^0.8.10;
import {ECDSA} from 'openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol';
import {ShortStrings, ShortString} from 'openzeppelin-contracts/contracts/utils/ShortStrings.sol';
import {IERC5267} from 'openzeppelin-contracts/contracts/interfaces/IERC5267.sol';
/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
 * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
 * they need in their contracts using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 *
 * NOTE: In the upgradeable version of this contract, the cached values will correspond to the address, and the domain
 * separator of the implementation contract. This will cause the `_domainSeparatorV4` function to always rebuild the
 * separator from the immutable values, which is cheaper than accessing a cached version in cold storage.
 *
 * _Available since v3.4._
 *
 * @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
 */
abstract contract EIP712 is IERC5267 {
  using ShortStrings for *;
  bytes32 private constant _TYPE_HASH =
    keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)');
  // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
  // invalidate the cached domain separator if the chain id changes.
  bytes32 private immutable _cachedDomainSeparator;
  uint256 private immutable _cachedChainId;
  address private immutable _cachedThis;
  bytes32 private immutable _hashedName;
  bytes32 private immutable _hashedVersion;
  ShortString private immutable _name;
  ShortString private immutable _version;
  /**
   * @dev Initializes the domain separator and parameter caches.
   *
   * The meaning of `name` and `version` is specified in
   * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
   *
   * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
   * - `version`: the current major version of the signing domain.
   *
   * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
   * contract upgrade].
   */
  /// @dev BGD: removed usage of fallback variables to not modify previous storage layout. As we know that the length of
  ///           name and version will not be bigger than 32 bytes we use toShortString as there is no need to use the fallback system.
  constructor(string memory name, string memory version) {
    _name = name.toShortString();
    _version = version.toShortString();
    _hashedName = keccak256(bytes(name));
    _hashedVersion = keccak256(bytes(version));
    _cachedChainId = block.chainid;
    _cachedDomainSeparator = _buildDomainSeparator();
    _cachedThis = address(this);
  }
  /**
   * @dev Returns the domain separator for the current chain.
   */
  function _domainSeparatorV4() internal view returns (bytes32) {
    if (address(this) == _cachedThis && block.chainid == _cachedChainId) {
      return _cachedDomainSeparator;
    } else {
      return _buildDomainSeparator();
    }
  }
  function _buildDomainSeparator() private view returns (bytes32) {
    return
      keccak256(abi.encode(_TYPE_HASH, _hashedName, _hashedVersion, block.chainid, address(this)));
  }
  /**
   * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
   * function returns the hash of the fully encoded EIP712 message for this domain.
   *
   * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
   *
   * ```solidity
   * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
   *     keccak256("Mail(address to,string contents)"),
   *     mailTo,
   *     keccak256(bytes(mailContents))
   * )));
   * address signer = ECDSA.recover(digest, signature);
   * ```
   */
  function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
    return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);
  }
  /**
   * @dev See {EIP-5267}.
   *
   * _Available since v4.9._
   */
  function eip712Domain()
    public
    view
    virtual
    returns (
      bytes1 fields,
      string memory name,
      string memory version,
      uint256 chainId,
      address verifyingContract,
      bytes32 salt,
      uint256[] memory extensions
    )
  {
    return (
      hex'0f', // 01111
      _EIP712Name(),
      _EIP712Version(),
      block.chainid,
      address(this),
      bytes32(0),
      new uint256[](0)
    );
  }
  /**
   * @dev The name parameter for the EIP712 domain.
   *
   * NOTE: By default this function reads _name which is an immutable value.
   * It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
   *
   * _Available since v5.0._
   */
  /// @dev BGD: we use toString instead of toStringWithFallback as we dont have fallback, to not modify previous storage layout
  // solhint-disable-next-line func-name-mixedcase
  function _EIP712Name() internal view returns (string memory) {
    return _name.toString(); // _name.toStringWithFallback(_nameFallback);
  }
  /**
   * @dev The version parameter for the EIP712 domain.
   *
   * NOTE: By default this function reads _version which is an immutable value.
   * It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
   *
   * _Available since v5.0._
   */
  /// @dev BGD: we use toString instead of toStringWithFallback as we dont have fallback, to not modify previous storage layout
  // solhint-disable-next-line func-name-mixedcase
  function _EIP712Version() internal view returns (string memory) {
    return _version.toString();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Context} from 'openzeppelin-contracts/contracts/utils/Context.sol';
import {IERC20} from 'openzeppelin-contracts/contracts/token/ERC20/IERC20.sol';
import {IERC20Metadata} from 'openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol';
import {DelegationMode} from './DelegationAwareBalance.sol';
// Inspired by OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/ERC20.sol)
abstract contract BaseAaveToken is Context, IERC20Metadata {
  struct DelegationAwareBalance {
    uint104 balance;
    uint72 delegatedPropositionBalance;
    uint72 delegatedVotingBalance;
    DelegationMode delegationMode;
  }
  mapping(address => DelegationAwareBalance) internal _balances;
  mapping(address => mapping(address => uint256)) internal _allowances;
  uint256 internal _totalSupply;
  string internal _name;
  string internal _symbol;
  // @dev DEPRECATED
  // kept for backwards compatibility with old storage layout
  uint8 private ______DEPRECATED_OLD_ERC20_DECIMALS;
  /**
   * @dev Returns the name of the token.
   */
  function name() public view virtual override returns (string memory) {
    return _name;
  }
  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view virtual override returns (string memory) {
    return _symbol;
  }
  function decimals() public view virtual override returns (uint8) {
    return 18;
  }
  function totalSupply() public view virtual override returns (uint256) {
    return _totalSupply;
  }
  function balanceOf(address account) public view virtual override returns (uint256) {
    return _balances[account].balance;
  }
  function transfer(address to, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _transfer(owner, to, amount);
    return true;
  }
  function allowance(address owner, address spender)
    public
    view
    virtual
    override
    returns (uint256)
  {
    return _allowances[owner][spender];
  }
  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, amount);
    return true;
  }
  function transferFrom(
    address from,
    address to,
    uint256 amount
  ) public virtual override returns (bool) {
    address spender = _msgSender();
    _spendAllowance(from, spender, amount);
    _transfer(from, to, amount);
    return true;
  }
  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, _allowances[owner][spender] + addedValue);
    return true;
  }
  function decreaseAllowance(address spender, uint256 subtractedValue)
    public
    virtual
    returns (bool)
  {
    address owner = _msgSender();
    uint256 currentAllowance = _allowances[owner][spender];
    require(currentAllowance >= subtractedValue, 'ERC20: decreased allowance below zero');
    unchecked {
      _approve(owner, spender, currentAllowance - subtractedValue);
    }
    return true;
  }
  function _transfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {
    require(from != address(0), 'ERC20: transfer from the zero address');
    require(to != address(0), 'ERC20: transfer to the zero address');
    if (from != to) {
      uint104 fromBalanceBefore = _balances[from].balance;
      uint104 toBalanceBefore = _balances[to].balance;
      require(fromBalanceBefore >= amount, 'ERC20: transfer amount exceeds balance');
      unchecked {
        _balances[from].balance = fromBalanceBefore - uint104(amount);
      }
      _balances[to].balance = toBalanceBefore + uint104(amount);
      _afterTokenTransfer(from, to, fromBalanceBefore, toBalanceBefore, amount);
    }
    emit Transfer(from, to, amount);
  }
  function _approve(
    address owner,
    address spender,
    uint256 amount
  ) internal virtual {
    require(owner != address(0), 'ERC20: approve from the zero address');
    require(spender != address(0), 'ERC20: approve to the zero address');
    _allowances[owner][spender] = amount;
    emit Approval(owner, spender, amount);
  }
  function _spendAllowance(
    address owner,
    address spender,
    uint256 amount
  ) internal virtual {
    uint256 currentAllowance = allowance(owner, spender);
    if (currentAllowance != type(uint256).max) {
      require(currentAllowance >= amount, 'ERC20: insufficient allowance');
      unchecked {
        _approve(owner, spender, currentAllowance - amount);
      }
    }
  }
  /**
   * @dev after token transfer hook, added for delegation system
   * @param from token sender
   * @param to token recipient
   * @param fromBalanceBefore balance of the sender before transfer
   * @param toBalanceBefore balance of the recipient before transfer
   * @param amount amount of tokens sent
   **/
  function _afterTokenTransfer(
    address from,
    address to,
    uint256 fromBalanceBefore,
    uint256 toBalanceBefore,
    uint256 amount
  ) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/** @notice influenced by OpenZeppelin SafeCast lib, which is missing to uint72 cast
 * @author BGD Labs
 */
library SafeCast72 {
  /**
   * @dev Returns the downcasted uint72 from uint256, reverting on
   * overflow (when the input is greater than largest uint72).
   *
   * Counterpart to Solidity's `uint16` operator.
   *
   * Requirements:
   *
   * - input must fit into 72 bits
   */
  function toUint72(uint256 value) internal pure returns (uint72) {
    require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
    return uint72(value);
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IGovernancePowerDelegationToken {
  enum GovernancePowerType {
    VOTING,
    PROPOSITION
  }
  /**
   * @dev emitted when a user delegates to another
   * @param delegator the user which delegated governance power
   * @param delegatee the delegatee
   * @param delegationType the type of delegation (VOTING, PROPOSITION)
   **/
  event DelegateChanged(
    address indexed delegator,
    address indexed delegatee,
    GovernancePowerType delegationType
  );
  // @dev we removed DelegatedPowerChanged event because to reconstruct the full state of the system,
  // is enough to have Transfer and DelegateChanged TODO: document it
  /**
   * @dev delegates the specific power to a delegatee
   * @param delegatee the user which delegated power will change
   * @param delegationType the type of delegation (VOTING, PROPOSITION)
   **/
  function delegateByType(address delegatee, GovernancePowerType delegationType) external;
  /**
   * @dev delegates all the governance powers to a specific user
   * @param delegatee the user to which the powers will be delegated
   **/
  function delegate(address delegatee) external;
  /**
   * @dev returns the delegatee of an user
   * @param delegator the address of the delegator
   * @param delegationType the type of delegation (VOTING, PROPOSITION)
   * @return address of the specified delegatee
   **/
  function getDelegateeByType(address delegator, GovernancePowerType delegationType)
    external
    view
    returns (address);
  /**
   * @dev returns delegates of an user
   * @param delegator the address of the delegator
   * @return a tuple of addresses the VOTING and PROPOSITION delegatee
   **/
  function getDelegates(address delegator)
    external
    view
    returns (address, address);
  /**
   * @dev returns the current voting or proposition power of a user.
   * @param user the user
   * @param delegationType the type of delegation (VOTING, PROPOSITION)
   * @return the current voting or proposition power of a user
   **/
  function getPowerCurrent(address user, GovernancePowerType delegationType)
    external
    view
    returns (uint256);
  /**
   * @dev returns the current voting or proposition power of a user.
   * @param user the user
   * @return the current voting and proposition power of a user
   **/
  function getPowersCurrent(address user)
    external
    view
    returns (uint256, uint256);
  /**
   * @dev implements the permit function as for https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param delegator the owner of the funds
   * @param delegatee the user to who owner delegates his governance power
   * @param delegationType the type of governance power delegation (VOTING, PROPOSITION)
   * @param deadline the deadline timestamp, type(uint256).max for no deadline
   * @param v signature param
   * @param s signature param
   * @param r signature param
   */
  function metaDelegateByType(
    address delegator,
    address delegatee,
    GovernancePowerType delegationType,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
  /**
   * @dev implements the permit function as for https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param delegator the owner of the funds
   * @param delegatee the user to who delegator delegates his voting and proposition governance power
   * @param deadline the deadline timestamp, type(uint256).max for no deadline
   * @param v signature param
   * @param s signature param
   * @param r signature param
   */
  function metaDelegate(
    address delegator,
    address delegatee,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
enum DelegationMode {
  NO_DELEGATION,
  VOTING_DELEGATED,
  PROPOSITION_DELEGATED,
  FULL_POWER_DELEGATED
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)
pragma solidity ^0.8.0;
import "./math/Math.sol";
import "./math/SignedMath.sol";
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }
    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toString(int256 value) internal pure returns (string memory) {
        return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMath.abs(value))));
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return keccak256(bytes(a)) == keccak256(bytes(b));
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/ShortStrings.sol)
pragma solidity ^0.8.8;
import "./StorageSlot.sol";
// | string  | 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA   |
// | length  | 0x                                                              BB |
type ShortString is bytes32;
/**
 * @dev This library provides functions to convert short memory strings
 * into a `ShortString` type that can be used as an immutable variable.
 *
 * Strings of arbitrary length can be optimized using this library if
 * they are short enough (up to 31 bytes) by packing them with their
 * length (1 byte) in a single EVM word (32 bytes). Additionally, a
 * fallback mechanism can be used for every other case.
 *
 * Usage example:
 *
 * ```solidity
 * contract Named {
 *     using ShortStrings for *;
 *
 *     ShortString private immutable _name;
 *     string private _nameFallback;
 *
 *     constructor(string memory contractName) {
 *         _name = contractName.toShortStringWithFallback(_nameFallback);
 *     }
 *
 *     function name() external view returns (string memory) {
 *         return _name.toStringWithFallback(_nameFallback);
 *     }
 * }
 * ```
 */
library ShortStrings {
    // Used as an identifier for strings longer than 31 bytes.
    bytes32 private constant _FALLBACK_SENTINEL = 0x00000000000000000000000000000000000000000000000000000000000000FF;
    error StringTooLong(string str);
    error InvalidShortString();
    /**
     * @dev Encode a string of at most 31 chars into a `ShortString`.
     *
     * This will trigger a `StringTooLong` error is the input string is too long.
     */
    function toShortString(string memory str) internal pure returns (ShortString) {
        bytes memory bstr = bytes(str);
        if (bstr.length > 31) {
            revert StringTooLong(str);
        }
        return ShortString.wrap(bytes32(uint256(bytes32(bstr)) | bstr.length));
    }
    /**
     * @dev Decode a `ShortString` back to a "normal" string.
     */
    function toString(ShortString sstr) internal pure returns (string memory) {
        uint256 len = byteLength(sstr);
        // using `new string(len)` would work locally but is not memory safe.
        string memory str = new string(32);
        /// @solidity memory-safe-assembly
        assembly {
            mstore(str, len)
            mstore(add(str, 0x20), sstr)
        }
        return str;
    }
    /**
     * @dev Return the length of a `ShortString`.
     */
    function byteLength(ShortString sstr) internal pure returns (uint256) {
        uint256 result = uint256(ShortString.unwrap(sstr)) & 0xFF;
        if (result > 31) {
            revert InvalidShortString();
        }
        return result;
    }
    /**
     * @dev Encode a string into a `ShortString`, or write it to storage if it is too long.
     */
    function toShortStringWithFallback(string memory value, string storage store) internal returns (ShortString) {
        if (bytes(value).length < 32) {
            return toShortString(value);
        } else {
            StorageSlot.getStringSlot(store).value = value;
            return ShortString.wrap(_FALLBACK_SENTINEL);
        }
    }
    /**
     * @dev Decode a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
     */
    function toStringWithFallback(ShortString value, string storage store) internal pure returns (string memory) {
        if (ShortString.unwrap(value) != _FALLBACK_SENTINEL) {
            return toString(value);
        } else {
            return store;
        }
    }
    /**
     * @dev Return the length of a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
     *
     * WARNING: This will return the "byte length" of the string. This may not reflect the actual length in terms of
     * actual characters as the UTF-8 encoding of a single character can span over multiple bytes.
     */
    function byteLengthWithFallback(ShortString value, string storage store) internal view returns (uint256) {
        if (ShortString.unwrap(value) != _FALLBACK_SENTINEL) {
            return byteLength(value);
        } else {
            return bytes(store).length;
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (interfaces/IERC5267.sol)
pragma solidity ^0.8.0;
interface IERC5267 {
    /**
     * @dev MAY be emitted to signal that the domain could have changed.
     */
    event EIP712DomainChanged();
    /**
     * @dev returns the fields and values that describe the domain separator used by this contract for EIP-712
     * signature.
     */
    function eip712Domain()
        external
        view
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        );
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);
    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);
    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);
    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);
    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)
pragma solidity ^0.8.0;
/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }
    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }
    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }
            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }
            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");
            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////
            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)
                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }
            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.
            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)
                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)
                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }
            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;
            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;
            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256
            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }
    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }
    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);
        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }
    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }
    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }
    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }
    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }
    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }
    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }
    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)
pragma solidity ^0.8.0;
/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMath {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }
    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }
    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }
    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.
pragma solidity ^0.8.0;
/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```solidity
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, `uint256`._
 * _Available since v4.9 for `string`, `bytes`._
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }
    struct BooleanSlot {
        bool value;
    }
    struct Bytes32Slot {
        bytes32 value;
    }
    struct Uint256Slot {
        uint256 value;
    }
    struct StringSlot {
        string value;
    }
    struct BytesSlot {
        bytes value;
    }
    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `StringSlot` with member `value` located at `slot`.
     */
    function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `StringSlot` representation of the string storage pointer `store`.
     */
    function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }
    /**
     * @dev Returns an `BytesSlot` with member `value` located at `slot`.
     */
    function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
     */
    function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }
}