Vimverse

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

import "./SafeMath.sol";

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);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

import "../library/Counters.sol";
import "../interfaces/IERC20.sol";

abstract contract ERC20 is IERC20 {

    using SafeMath for uint256;

    // TODO comment actual hash value.
    bytes32 constant private 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_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = decimals_;
    }

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

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

    function decimals() public view override returns (uint256) {
        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 { }
}

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() public {
        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();
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the number of decimals used to get its user representation.
     */
    function decimals() external view returns (uint256);

    /**
     * @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: MIT
pragma solidity 0.6.12;

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 () public {
    _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_;
  }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

/**
 * @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) {
        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;
    }

    function sqrrt(uint256 a) internal pure returns (uint c) {
        if (a > 3) {
            c = a;
            uint 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 min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    function max(uint x, uint y) internal pure returns (uint z) {
        z = x > y ? x : y;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

import "./Ownable.sol";

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" );
    _;
  }

}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

import "./helpers/ERC20Permit.sol";
import "./helpers/VaultOwned.sol";

contract Vim is ERC20Permit, VaultOwned {

    using SafeMath for uint256;

    constructor() ERC20("Vimverse", "Vim", 9) public {
        _vault = msg.sender;
    }

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