// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

library EnumerableSet {
  // To implement this library for multiple types with as little code
  // repetition as possible, we write it in terms of a generic Set type with
  // bytes32 values.
  // The Set implementation uses private functions, and user-facing
  // implementations (such as AddressSet) are just wrappers around the
  // underlying Set.
  // This means that we can only create new EnumerableSets for types that fit
  // in bytes32.
  struct Set {
    // Storage of set values
    bytes32[] _values;
    // Position of the value in the `values` array, plus 1 because index 0
    // means a value is not in the set.
    mapping(bytes32 => uint256) _indexes;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function _add(Set storage set, bytes32 value) private returns (bool) {
    if (!_contains(set, value)) {
      set._values.push(value);
      // The value is stored at length-1, but we add 1 to all indexes
      // and use 0 as a sentinel value
      set._indexes[value] = set._values.length;
      return true;
    } else {
      return false;
    }
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function _remove(Set storage set, bytes32 value) private returns (bool) {
    // We read and store the value's index to prevent multiple reads from the same storage slot
    uint256 valueIndex = set._indexes[value];

    if (valueIndex != 0) {
      // Equivalent to contains(set, value)
      // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
      // the array, and then remove the last element (sometimes called as 'swap and pop').
      // This modifies the order of the array, as noted in {at}.

      uint256 toDeleteIndex = valueIndex - 1;
      uint256 lastIndex = set._values.length - 1;

      // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
      // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

      bytes32 lastvalue = set._values[lastIndex];

      // Move the last value to the index where the value to delete is
      set._values[toDeleteIndex] = lastvalue;
      // Update the index for the moved value
      set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

      // Delete the slot where the moved value was stored
      set._values.pop();

      // Delete the index for the deleted slot
      delete set._indexes[value];

      return true;
    } else {
      return false;
    }
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function _contains(Set storage set, bytes32 value)
    private
    view
    returns (bool)
  {
    return set._indexes[value] != 0;
  }

  /**
   * @dev Returns the number of values on the set. O(1).
   */
  function _length(Set storage set) private view returns (uint256) {
    return set._values.length;
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function _at(Set storage set, uint256 index) private view returns (bytes32) {
    require(set._values.length > index, "EnumerableSet: index out of bounds");
    return set._values[index];
  }

  function _getValues(Set storage set_)
    private
    view
    returns (bytes32[] storage)
  {
    return set_._values;
  }

  // TODO needs insert function that maintains order.
  // TODO needs NatSpec documentation comment.
  /**
   * Inserts new value by moving existing value at provided index to end of array and setting provided value at provided index
   */
  function _insert(
    Set storage set_,
    uint256 index_,
    bytes32 valueToInsert_
  ) private returns (bool) {
    require(set_._values.length > index_);
    require(
      !_contains(set_, valueToInsert_),
      "Remove value you wish to insert if you wish to reorder array."
    );
    bytes32 existingValue_ = _at(set_, index_);
    set_._values[index_] = valueToInsert_;
    return _add(set_, existingValue_);
  }

  struct Bytes4Set {
    Set _inner;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function add(Bytes4Set storage set, bytes4 value) internal returns (bool) {
    return _add(set._inner, value);
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function remove(Bytes4Set storage set, bytes4 value) internal returns (bool) {
    return _remove(set._inner, value);
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function contains(Bytes4Set storage set, bytes4 value)
    internal
    view
    returns (bool)
  {
    return _contains(set._inner, value);
  }

  /**
   * @dev Returns the number of values on the set. O(1).
   */
  function length(Bytes4Set storage set) internal view returns (uint256) {
    return _length(set._inner);
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function at(Bytes4Set storage set, uint256 index)
    internal
    view
    returns (bytes4)
  {
    return bytes4(_at(set._inner, index));
  }

  function getValues(Bytes4Set storage set_)
    internal
    view
    returns (bytes4[] memory)
  {
    bytes4[] memory bytes4Array_;
    for (
      uint256 iteration_ = 0;
      _length(set_._inner) > iteration_;
      iteration_++
    ) {
      bytes4Array_[iteration_] = bytes4(_at(set_._inner, iteration_));
    }
    return bytes4Array_;
  }

  function insert(
    Bytes4Set storage set_,
    uint256 index_,
    bytes4 valueToInsert_
  ) internal returns (bool) {
    return _insert(set_._inner, index_, valueToInsert_);
  }

  struct Bytes32Set {
    Set _inner;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
    return _add(set._inner, value);
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function remove(Bytes32Set storage set, bytes32 value)
    internal
    returns (bool)
  {
    return _remove(set._inner, value);
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function contains(Bytes32Set storage set, bytes32 value)
    internal
    view
    returns (bool)
  {
    return _contains(set._inner, value);
  }

  /**
   * @dev Returns the number of values on the set. O(1).
   */
  function length(Bytes32Set storage set) internal view returns (uint256) {
    return _length(set._inner);
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function at(Bytes32Set storage set, uint256 index)
    internal
    view
    returns (bytes32)
  {
    return _at(set._inner, index);
  }

  function getValues(Bytes32Set storage set_)
    internal
    view
    returns (bytes4[] memory)
  {
    bytes4[] memory bytes4Array_;

    for (
      uint256 iteration_ = 0;
      _length(set_._inner) >= iteration_;
      iteration_++
    ) {
      bytes4Array_[iteration_] = bytes4(at(set_, iteration_));
    }

    return bytes4Array_;
  }

  function insert(
    Bytes32Set storage set_,
    uint256 index_,
    bytes32 valueToInsert_
  ) internal returns (bool) {
    return _insert(set_._inner, index_, valueToInsert_);
  }

  // AddressSet
  struct AddressSet {
    Set _inner;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function add(AddressSet storage set, address value) internal returns (bool) {
    return _add(set._inner, bytes32(uint256(value)));
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function remove(AddressSet storage set, address value)
    internal
    returns (bool)
  {
    return _remove(set._inner, bytes32(uint256(value)));
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function contains(AddressSet storage set, address value)
    internal
    view
    returns (bool)
  {
    return _contains(set._inner, bytes32(uint256(value)));
  }

  /**
   * @dev Returns the number of values in the set. O(1).
   */
  function length(AddressSet storage set) internal view returns (uint256) {
    return _length(set._inner);
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function at(AddressSet storage set, uint256 index)
    internal
    view
    returns (address)
  {
    return address(uint256(_at(set._inner, index)));
  }

  /**
   * TODO Might require explicit conversion of bytes32[] to address[].
   *  Might require iteration.
   */
  function getValues(AddressSet storage set_)
    internal
    view
    returns (address[] memory)
  {
    address[] memory addressArray;

    for (
      uint256 iteration_ = 0;
      _length(set_._inner) >= iteration_;
      iteration_++
    ) {
      addressArray[iteration_] = at(set_, iteration_);
    }

    return addressArray;
  }

  function insert(
    AddressSet storage set_,
    uint256 index_,
    address valueToInsert_
  ) internal returns (bool) {
    return _insert(set_._inner, index_, bytes32(uint256(valueToInsert_)));
  }

  // UintSet

  struct UintSet {
    Set _inner;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function add(UintSet storage set, uint256 value) internal returns (bool) {
    return _add(set._inner, bytes32(value));
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function remove(UintSet storage set, uint256 value) internal returns (bool) {
    return _remove(set._inner, bytes32(value));
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function contains(UintSet storage set, uint256 value)
    internal
    view
    returns (bool)
  {
    return _contains(set._inner, bytes32(value));
  }

  /**
   * @dev Returns the number of values on the set. O(1).
   */
  function length(UintSet storage set) internal view returns (uint256) {
    return _length(set._inner);
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function at(UintSet storage set, uint256 index)
    internal
    view
    returns (uint256)
  {
    return uint256(_at(set._inner, index));
  }

  struct UInt256Set {
    Set _inner;
  }

  /**
   * @dev Add a value to a set. O(1).
   *
   * Returns true if the value was added to the set, that is if it was not
   * already present.
   */
  function add(UInt256Set storage set, uint256 value) internal returns (bool) {
    return _add(set._inner, bytes32(value));
  }

  /**
   * @dev Removes a value from a set. O(1).
   *
   * Returns true if the value was removed from the set, that is if it was
   * present.
   */
  function remove(UInt256Set storage set, uint256 value)
    internal
    returns (bool)
  {
    return _remove(set._inner, bytes32(value));
  }

  /**
   * @dev Returns true if the value is in the set. O(1).
   */
  function contains(UInt256Set storage set, uint256 value)
    internal
    view
    returns (bool)
  {
    return _contains(set._inner, bytes32(value));
  }

  /**
   * @dev Returns the number of values on the set. O(1).
   */
  function length(UInt256Set storage set) internal view returns (uint256) {
    return _length(set._inner);
  }

  /**
   * @dev Returns the value stored at position `index` in the set. O(1).
   *
   * Note that there are no guarantees on the ordering of values inside the
   * array, and it may change when more values are added or removed.
   *
   * Requirements:
   *
   * - `index` must be strictly less than {length}.
   */
  function at(UInt256Set storage set, uint256 index)
    internal
    view
    returns (uint256)
  {
    return uint256(_at(set._inner, index));
  }
}

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);
}

library SafeMath {
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a, "SafeMath: addition overflow");

    return c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    return sub(a, b, "SafeMath: subtraction overflow");
  }

  function sub(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b <= a, errorMessage);
    uint256 c = a - b;

    return c;
  }

  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }

    uint256 c = a * b;
    require(c / a == b, "SafeMath: multiplication overflow");

    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    return div(a, b, "SafeMath: division by zero");
  }

  function div(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    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;
  }

  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    return mod(a, b, "SafeMath: modulo by zero");
  }

  function mod(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b != 0, errorMessage);
    return a % b;
  }

  function sqrrt(uint256 a) internal pure returns (uint256 c) {
    if (a > 3) {
      c = a;
      uint256 b = add(div(a, 2), 1);
      while (b < c) {
        c = b;
        b = div(add(div(a, b), b), 2);
      }
    } else if (a != 0) {
      c = 1;
    }
  }

  function percentageAmount(uint256 total_, uint8 percentage_)
    internal
    pure
    returns (uint256 percentAmount_)
  {
    return div(mul(total_, percentage_), 1000);
  }

  function substractPercentage(uint256 total_, uint8 percentageToSub_)
    internal
    pure
    returns (uint256 result_)
  {
    return sub(total_, div(mul(total_, percentageToSub_), 1000));
  }

  function percentageOfTotal(uint256 part_, uint256 total_)
    internal
    pure
    returns (uint256 percent_)
  {
    return div(mul(part_, 100), total_);
  }

  function average(uint256 a, uint256 b) internal pure returns (uint256) {
    // (a + b) / 2 can overflow, so we distribute
    return (a / 2) + (b / 2) + (((a % 2) + (b % 2)) / 2);
  }

  function quadraticPricing(uint256 payment_, uint256 multiplier_)
    internal
    pure
    returns (uint256)
  {
    return sqrrt(mul(multiplier_, payment_));
  }

  function bondingCurve(uint256 supply_, uint256 multiplier_)
    internal
    pure
    returns (uint256)
  {
    return mul(multiplier_, supply_);
  }
}

abstract contract ERC20 is IERC20 {
  using SafeMath for uint256;

  // TODO comment actual hash value.
  bytes32 private constant ERC20TOKEN_ERC1820_INTERFACE_ID =
    keccak256("ERC20Token");

  // Present in ERC777
  mapping(address => uint256) internal _balances;

  // Present in ERC777
  mapping(address => mapping(address => uint256)) internal _allowances;

  // Present in ERC777
  uint256 internal _totalSupply;

  // Present in ERC777
  string internal _name;

  // Present in ERC777
  string internal _symbol;

  // Present in ERC777
  uint8 internal _decimals;

  constructor(
    string memory name_,
    string memory symbol_,
    uint8 decimals_
  ) {
    _name = name_;
    _symbol = symbol_;
    _decimals = decimals_;
  }

  function name() public view returns (string memory) {
    return _name;
  }

  function symbol() public view returns (string memory) {
    return _symbol;
  }

  function decimals() public view returns (uint8) {
    return _decimals;
  }

  function totalSupply() public view override returns (uint256) {
    return _totalSupply;
  }

  function balanceOf(address account)
    public
    view
    virtual
    override
    returns (uint256)
  {
    return _balances[account];
  }

  function transfer(address recipient, uint256 amount)
    public
    virtual
    override
    returns (bool)
  {
    _transfer(msg.sender, recipient, 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)
  {
    _approve(msg.sender, spender, amount);
    return true;
  }

  function transferFrom(
    address sender,
    address recipient,
    uint256 amount
  ) public virtual override returns (bool) {
    _transfer(sender, recipient, amount);
    _approve(
      sender,
      msg.sender,
      _allowances[sender][msg.sender].sub(
        amount,
        "ERC20: transfer amount exceeds allowance"
      )
    );
    return true;
  }

  function increaseAllowance(address spender, uint256 addedValue)
    public
    virtual
    returns (bool)
  {
    _approve(
      msg.sender,
      spender,
      _allowances[msg.sender][spender].add(addedValue)
    );
    return true;
  }

  function decreaseAllowance(address spender, uint256 subtractedValue)
    public
    virtual
    returns (bool)
  {
    _approve(
      msg.sender,
      spender,
      _allowances[msg.sender][spender].sub(
        subtractedValue,
        "ERC20: decreased allowance below zero"
      )
    );
    return true;
  }

  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);
  }

  function _mint(address account_, uint256 amount_) internal virtual {
    require(account_ != address(0), "ERC20: mint to the zero address");
    _beforeTokenTransfer(address(this), account_, amount_);
    _totalSupply = _totalSupply.add(amount_);
    _balances[account_] = _balances[account_].add(amount_);
    emit Transfer(address(this), account_, amount_);
  }

  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);
  }

  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 _beforeTokenTransfer(
    address from_,
    address to_,
    uint256 amount_
  ) internal virtual {}
}

library Counters {
  using SafeMath for uint256;

  struct Counter {
    uint256 _value; // default: 0
  }

  function current(Counter storage counter) internal view returns (uint256) {
    return counter._value;
  }

  function increment(Counter storage counter) internal {
    counter._value += 1;
  }

  function decrement(Counter storage counter) internal {
    counter._value = counter._value.sub(1);
  }
}

interface IERC2612Permit {
  function permit(
    address owner,
    address spender,
    uint256 amount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

  function nonces(address owner) external view returns (uint256);
}

abstract contract ERC20Permit is ERC20, IERC2612Permit {
  using Counters for Counters.Counter;

  mapping(address => Counters.Counter) private _nonces;

  // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
  bytes32 public constant PERMIT_TYPEHASH =
    0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;

  bytes32 public DOMAIN_SEPARATOR;

  constructor() {
    uint256 chainID;
    assembly {
      chainID := chainid()
    }

    DOMAIN_SEPARATOR = keccak256(
      abi.encode(
        keccak256(
          "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
        ),
        keccak256(bytes(name())),
        keccak256(bytes("1")), // Version
        chainID,
        address(this)
      )
    );
  }

  function permit(
    address owner,
    address spender,
    uint256 amount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) public virtual override {
    require(block.timestamp <= deadline, "Permit: expired deadline");

    bytes32 hashStruct = keccak256(
      abi.encode(
        PERMIT_TYPEHASH,
        owner,
        spender,
        amount,
        _nonces[owner].current(),
        deadline
      )
    );

    bytes32 _hash = keccak256(
      abi.encodePacked(uint16(0x1901), DOMAIN_SEPARATOR, hashStruct)
    );

    address signer = ecrecover(_hash, v, r, s);
    require(
      signer != address(0) && signer == owner,
      "ZeroSwapPermit: Invalid signature"
    );

    _nonces[owner].increment();
    _approve(owner, spender, amount);
  }

  function nonces(address owner) public view override returns (uint256) {
    return _nonces[owner].current();
  }
}

interface IOwnable {
  function owner() external view returns (address);

  function renounceOwnership() external;

  function transferOwnership(address newOwner_) external;
}

contract Ownable is IOwnable {
  address internal _owner;

  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );

  constructor() {
    _owner = msg.sender;
    emit OwnershipTransferred(address(0), _owner);
  }

  function owner() public view override returns (address) {
    return _owner;
  }

  modifier onlyOwner() {
    require(_owner == msg.sender, "Ownable: caller is not the owner");
    _;
  }

  function renounceOwnership() public virtual override onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  function transferOwnership(address newOwner_)
    public
    virtual
    override
    onlyOwner
  {
    require(newOwner_ != address(0), "Ownable: new owner is the zero address");
    emit OwnershipTransferred(_owner, newOwner_);
    _owner = newOwner_;
  }
}

contract VaultOwned is Ownable {
  address internal _vault;

  function setVault(address vault_) external onlyOwner returns (bool) {
    _vault = vault_;

    return true;
  }

  function vault() public view returns (address) {
    return _vault;
  }

  modifier onlyVault() {
    require(_vault == msg.sender, "VaultOwned: caller is not the Vault");
    _;
  }
}

contract LobiERC20 is ERC20Permit, VaultOwned {
  using SafeMath for uint256;

  constructor() ERC20("Lobi", "LOBI", 9) {}

  function mint(address account_, uint256 amount_) external onlyVault {
    _mint(account_, amount_);
  }

  function burn(uint256 amount) public virtual {
    _burn(msg.sender, amount);
  }

  function burnFrom(address account_, uint256 amount_) public virtual {
    _burnFrom(account_, amount_);
  }

  function _burnFrom(address account_, uint256 amount_) public virtual {
    uint256 decreasedAllowance_ = allowance(account_, msg.sender).sub(
      amount_,
      "ERC20: burn amount exceeds allowance"
    );

    _approve(account_, msg.sender, decreasedAllowance_);
    _burn(account_, amount_);
  }
}

{
  "compilationTarget": {
    "LobiERC20.sol": "LobiERC20"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}