Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
import "./IERC721Receiver.sol";
import "./Pausable.sol";
import "./Woolf.sol";
import "./WOOL.sol";
contract Barn is Ownable, IERC721Receiver, Pausable {
// maximum alpha score for a Wolf
uint8 public constant MAX_ALPHA = 8;
// struct to store a stake's token, owner, and earning values
struct Stake {
uint16 tokenId;
uint80 value;
address owner;
}
event TokenStaked(address owner, uint256 tokenId, uint256 value);
event SheepClaimed(uint256 tokenId, uint256 earned, bool unstaked);
event WolfClaimed(uint256 tokenId, uint256 earned, bool unstaked);
// reference to the Woolf NFT contract
Woolf woolf;
// reference to the $WOOL contract for minting $WOOL earnings
WOOL wool;
// maps tokenId to stake
mapping(uint256 => Stake) public barn;
// maps alpha to all Wolf stakes with that alpha
mapping(uint256 => Stake[]) public pack;
// tracks location of each Wolf in Pack
mapping(uint256 => uint256) public packIndices;
// total alpha scores staked
uint256 public totalAlphaStaked = 0;
// any rewards distributed when no wolves are staked
uint256 public unaccountedRewards = 0;
// amount of $WOOL due for each alpha point staked
uint256 public woolPerAlpha = 0;
// sheep earn 10000 $WOOL per day
uint256 public constant DAILY_WOOL_RATE = 10000 ether;
// sheep must have 2 days worth of $WOOL to unstake or else it's too cold
uint256 public constant MINIMUM_TO_EXIT = 2 days;
// wolves take a 20% tax on all $WOOL claimed
uint256 public constant WOOL_CLAIM_TAX_PERCENTAGE = 20;
// there will only ever be (roughly) 2.4 billion $WOOL earned through staking
uint256 public constant MAXIMUM_GLOBAL_WOOL = 2400000000 ether;
// amount of $WOOL earned so far
uint256 public totalWoolEarned;
// number of Sheep staked in the Barn
uint256 public totalSheepStaked;
// the last time $WOOL was claimed
uint256 public lastClaimTimestamp;
// emergency rescue to allow unstaking without any checks but without $WOOL
bool public rescueEnabled = false;
/**
* @param _woolf reference to the Woolf NFT contract
* @param _wool reference to the $WOOL token
*/
constructor(address _woolf, address _wool) {
woolf = Woolf(_woolf);
wool = WOOL(_wool);
}
/** STAKING */
/**
* adds Sheep and Wolves to the Barn and Pack
* @param account the address of the staker
* @param tokenIds the IDs of the Sheep and Wolves to stake
*/
function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external {
require(account == _msgSender() || _msgSender() == address(woolf), "DONT GIVE YOUR TOKENS AWAY");
for (uint i = 0; i < tokenIds.length; i++) {
if (_msgSender() != address(woolf)) { // dont do this step if its a mint + stake
require(woolf.ownerOf(tokenIds[i]) == _msgSender(), "AINT YO TOKEN");
woolf.transferFrom(_msgSender(), address(this), tokenIds[i]);
} else if (tokenIds[i] == 0) {
continue; // there may be gaps in the array for stolen tokens
}
if (isSheep(tokenIds[i]))
_addSheepToBarn(account, tokenIds[i]);
else
_addWolfToPack(account, tokenIds[i]);
}
}
/**
* adds a single Sheep to the Barn
* @param account the address of the staker
* @param tokenId the ID of the Sheep to add to the Barn
*/
function _addSheepToBarn(address account, uint256 tokenId) internal whenNotPaused _updateEarnings {
barn[tokenId] = Stake({
owner: account,
tokenId: uint16(tokenId),
value: uint80(block.timestamp)
});
totalSheepStaked += 1;
emit TokenStaked(account, tokenId, block.timestamp);
}
/**
* adds a single Wolf to the Pack
* @param account the address of the staker
* @param tokenId the ID of the Wolf to add to the Pack
*/
function _addWolfToPack(address account, uint256 tokenId) internal {
uint256 alpha = _alphaForWolf(tokenId);
totalAlphaStaked += alpha; // Portion of earnings ranges from 8 to 5
packIndices[tokenId] = pack[alpha].length; // Store the location of the wolf in the Pack
pack[alpha].push(Stake({
owner: account,
tokenId: uint16(tokenId),
value: uint80(woolPerAlpha)
})); // Add the wolf to the Pack
emit TokenStaked(account, tokenId, woolPerAlpha);
}
/** CLAIMING / UNSTAKING */
/**
* realize $WOOL earnings and optionally unstake tokens from the Barn / Pack
* to unstake a Sheep it will require it has 2 days worth of $WOOL unclaimed
* @param tokenIds the IDs of the tokens to claim earnings from
* @param unstake whether or not to unstake ALL of the tokens listed in tokenIds
*/
function claimManyFromBarnAndPack(uint16[] calldata tokenIds, bool unstake) external whenNotPaused _updateEarnings {
uint256 owed = 0;
for (uint i = 0; i < tokenIds.length; i++) {
if (isSheep(tokenIds[i]))
owed += _claimSheepFromBarn(tokenIds[i], unstake);
else
owed += _claimWolfFromPack(tokenIds[i], unstake);
}
if (owed == 0) return;
wool.mint(_msgSender(), owed);
}
/**
* realize $WOOL earnings for a single Sheep and optionally unstake it
* if not unstaking, pay a 20% tax to the staked Wolves
* if unstaking, there is a 50% chance all $WOOL is stolen
* @param tokenId the ID of the Sheep to claim earnings from
* @param unstake whether or not to unstake the Sheep
* @return owed - the amount of $WOOL earned
*/
function _claimSheepFromBarn(uint256 tokenId, bool unstake) internal returns (uint256 owed) {
Stake memory stake = barn[tokenId];
require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
require(!(unstake && block.timestamp - stake.value < MINIMUM_TO_EXIT), "GONNA BE COLD WITHOUT TWO DAY'S WOOL");
if (totalWoolEarned < MAXIMUM_GLOBAL_WOOL) {
owed = (block.timestamp - stake.value) * DAILY_WOOL_RATE / 1 days;
} else if (stake.value > lastClaimTimestamp) {
owed = 0; // $WOOL production stopped already
} else {
owed = (lastClaimTimestamp - stake.value) * DAILY_WOOL_RATE / 1 days; // stop earning additional $WOOL if it's all been earned
}
if (unstake) {
if (random(tokenId) & 1 == 1) { // 50% chance of all $WOOL stolen
_payWolfTax(owed);
owed = 0;
}
woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // send back Sheep
delete barn[tokenId];
totalSheepStaked -= 1;
} else {
_payWolfTax(owed * WOOL_CLAIM_TAX_PERCENTAGE / 100); // percentage tax to staked wolves
owed = owed * (100 - WOOL_CLAIM_TAX_PERCENTAGE) / 100; // remainder goes to Sheep owner
barn[tokenId] = Stake({
owner: _msgSender(),
tokenId: uint16(tokenId),
value: uint80(block.timestamp)
}); // reset stake
}
emit SheepClaimed(tokenId, owed, unstake);
}
/**
* realize $WOOL earnings for a single Wolf and optionally unstake it
* Wolves earn $WOOL proportional to their Alpha rank
* @param tokenId the ID of the Wolf to claim earnings from
* @param unstake whether or not to unstake the Wolf
* @return owed - the amount of $WOOL earned
*/
function _claimWolfFromPack(uint256 tokenId, bool unstake) internal returns (uint256 owed) {
require(woolf.ownerOf(tokenId) == address(this), "AINT A PART OF THE PACK");
uint256 alpha = _alphaForWolf(tokenId);
Stake memory stake = pack[alpha][packIndices[tokenId]];
require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
owed = (alpha) * (woolPerAlpha - stake.value); // Calculate portion of tokens based on Alpha
if (unstake) {
totalAlphaStaked -= alpha; // Remove Alpha from total staked
woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // Send back Wolf
Stake memory lastStake = pack[alpha][pack[alpha].length - 1];
pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position
packIndices[lastStake.tokenId] = packIndices[tokenId];
pack[alpha].pop(); // Remove duplicate
delete packIndices[tokenId]; // Delete old mapping
} else {
pack[alpha][packIndices[tokenId]] = Stake({
owner: _msgSender(),
tokenId: uint16(tokenId),
value: uint80(woolPerAlpha)
}); // reset stake
}
emit WolfClaimed(tokenId, owed, unstake);
}
/**
* emergency unstake tokens
* @param tokenIds the IDs of the tokens to claim earnings from
*/
function rescue(uint256[] calldata tokenIds) external {
require(rescueEnabled, "RESCUE DISABLED");
uint256 tokenId;
Stake memory stake;
Stake memory lastStake;
uint256 alpha;
for (uint i = 0; i < tokenIds.length; i++) {
tokenId = tokenIds[i];
if (isSheep(tokenId)) {
stake = barn[tokenId];
require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // send back Sheep
delete barn[tokenId];
totalSheepStaked -= 1;
emit SheepClaimed(tokenId, 0, true);
} else {
alpha = _alphaForWolf(tokenId);
stake = pack[alpha][packIndices[tokenId]];
require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
totalAlphaStaked -= alpha; // Remove Alpha from total staked
woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // Send back Wolf
lastStake = pack[alpha][pack[alpha].length - 1];
pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position
packIndices[lastStake.tokenId] = packIndices[tokenId];
pack[alpha].pop(); // Remove duplicate
delete packIndices[tokenId]; // Delete old mapping
emit WolfClaimed(tokenId, 0, true);
}
}
}
/** ACCOUNTING */
/**
* add $WOOL to claimable pot for the Pack
* @param amount $WOOL to add to the pot
*/
function _payWolfTax(uint256 amount) internal {
if (totalAlphaStaked == 0) { // if there's no staked wolves
unaccountedRewards += amount; // keep track of $WOOL due to wolves
return;
}
// makes sure to include any unaccounted $WOOL
woolPerAlpha += (amount + unaccountedRewards) / totalAlphaStaked;
unaccountedRewards = 0;
}
/**
* tracks $WOOL earnings to ensure it stops once 2.4 billion is eclipsed
*/
modifier _updateEarnings() {
if (totalWoolEarned < MAXIMUM_GLOBAL_WOOL) {
totalWoolEarned +=
(block.timestamp - lastClaimTimestamp)
* totalSheepStaked
* DAILY_WOOL_RATE / 1 days;
lastClaimTimestamp = block.timestamp;
}
_;
}
/** ADMIN */
/**
* allows owner to enable "rescue mode"
* simplifies accounting, prioritizes tokens out in emergency
*/
function setRescueEnabled(bool _enabled) external onlyOwner {
rescueEnabled = _enabled;
}
/**
* enables owner to pause / unpause minting
*/
function setPaused(bool _paused) external onlyOwner {
if (_paused) _pause();
else _unpause();
}
/** READ ONLY */
/**
* checks if a token is a Sheep
* @param tokenId the ID of the token to check
* @return sheep - whether or not a token is a Sheep
*/
function isSheep(uint256 tokenId) public view returns (bool sheep) {
(sheep, , , , , , , , , ) = woolf.tokenTraits(tokenId);
}
/**
* gets the alpha score for a Wolf
* @param tokenId the ID of the Wolf to get the alpha score for
* @return the alpha score of the Wolf (5-8)
*/
function _alphaForWolf(uint256 tokenId) internal view returns (uint8) {
( , , , , , , , , , uint8 alphaIndex) = woolf.tokenTraits(tokenId);
return MAX_ALPHA - alphaIndex; // alpha index is 0-3
}
/**
* chooses a random Wolf thief when a newly minted token is stolen
* @param seed a random value to choose a Wolf from
* @return the owner of the randomly selected Wolf thief
*/
function randomWolfOwner(uint256 seed) external view returns (address) {
if (totalAlphaStaked == 0) return address(0x0);
uint256 bucket = (seed & 0xFFFFFFFF) % totalAlphaStaked; // choose a value from 0 to total alpha staked
uint256 cumulative;
seed >>= 32;
// loop through each bucket of Wolves with the same alpha score
for (uint i = MAX_ALPHA - 3; i <= MAX_ALPHA; i++) {
cumulative += pack[i].length * i;
// if the value is not inside of that bucket, keep going
if (bucket >= cumulative) continue;
// get the address of a random Wolf with that alpha score
return pack[i][seed % pack[i].length].owner;
}
return address(0x0);
}
/**
* generates a pseudorandom number
* @param seed a value ensure different outcomes for different sources in the same block
* @return a pseudorandom value
*/
function random(uint256 seed) internal view returns (uint256) {
return uint256(keccak256(abi.encodePacked(
tx.origin,
blockhash(block.number - 1),
block.timestamp,
seed
)));
}
function onERC721Received(
address,
address from,
uint256,
bytes calldata
) external pure override returns (bytes4) {
require(from == address(0x0), "Cannot send tokens to Barn directly");
return IERC721Receiver.onERC721Received.selector;
}
}
// SPDX-License-Identifier: MIT
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
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
* for the additional interface id that will be supported. For example:
*
* ```solidity
* function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
* return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
* }
* ```
*
* Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
*/
abstract contract ERC165 is IERC165 {
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
return interfaceId == type(IERC165).interfaceId;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./IERC20Metadata.sol";
import "./Context.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 Contracts guidelines: functions revert
* instead 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, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @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;
}
/**
* @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 this function is
* overridden;
*
* 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 virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual 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);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
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] + 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) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This 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);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(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:
*
* - `account` 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 += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(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);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This 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 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 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 {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been 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 _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./IERC721Metadata.sol";
import "./Address.sol";
import "./Context.sol";
import "./Strings.sol";
import "./ERC165.sol";
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension, but not including the Enumerable extension, which is available separately as
* {ERC721Enumerable}.
*/
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
using Address for address;
using Strings for uint256;
// Token name
string private _name;
// Token symbol
string private _symbol;
// Mapping from token ID to owner address
mapping(uint256 => address) private _owners;
// Mapping owner address to token count
mapping(address => uint256) private _balances;
// Mapping from token ID to approved address
mapping(uint256 => address) private _tokenApprovals;
// Mapping from owner to operator approvals
mapping(address => mapping(address => bool)) private _operatorApprovals;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
return
interfaceId == type(IERC721).interfaceId ||
interfaceId == type(IERC721Metadata).interfaceId ||
super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721-balanceOf}.
*/
function balanceOf(address owner) public view virtual override returns (uint256) {
require(owner != address(0), "ERC721: balance query for the zero address");
return _balances[owner];
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view virtual override returns (address) {
address owner = _owners[tokenId];
require(owner != address(0), "ERC721: owner query for nonexistent token");
return owner;
}
/**
* @dev See {IERC721Metadata-name}.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
string memory baseURI = _baseURI();
return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
}
/**
* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
* token will be the concatenation of the `baseURI` and the `tokenId`. Empty
* by default, can be overriden in child contracts.
*/
function _baseURI() internal view virtual returns (string memory) {
return "";
}
/**
* @dev See {IERC721-approve}.
*/
function approve(address to, uint256 tokenId) public virtual override {
address owner = ERC721.ownerOf(tokenId);
require(to != owner, "ERC721: approval to current owner");
require(
_msgSender() == owner || isApprovedForAll(owner, _msgSender()),
"ERC721: approve caller is not owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view virtual override returns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
require(operator != _msgSender(), "ERC721: approve to caller");
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
//solhint-disable-next-line max-line-length
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes memory _data
) public virtual override {
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_safeTransfer(from, to, tokenId, _data);
}
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* `_data` is additional data, it has no specified format and it is sent in call to `to`.
*
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
* implement alternative mechanisms to perform token transfer, such as signature-based.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeTransfer(
address from,
address to,
uint256 tokenId,
bytes memory _data
) internal virtual {
_transfer(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Returns whether `tokenId` exists.
*
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
*
* Tokens start existing when they are minted (`_mint`),
* and stop existing when they are burned (`_burn`).
*/
function _exists(uint256 tokenId) internal view virtual returns (bool) {
return _owners[tokenId] != address(0);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
}
/**
* @dev Safely mints `tokenId` and transfers it to `to`.
*
* Requirements:
*
* - `tokenId` must not exist.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeMint(address to, uint256 tokenId) internal virtual {
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/
function _safeMint(
address to,
uint256 tokenId,
bytes memory _data
) internal virtual {
_mint(to, tokenId);
require(
_checkOnERC721Received(address(0), to, tokenId, _data),
"ERC721: transfer to non ERC721Receiver implementer"
);
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/
function _mint(address to, uint256 tokenId) internal virtual {
require(to != address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_balances[to] += 1;
_owners[tokenId] = to;
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId) internal virtual {
address owner = ERC721.ownerOf(tokenId);
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
_balances[owner] -= 1;
delete _owners[tokenId];
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/
function _transfer(
address from,
address to,
uint256 tokenId
) internal virtual {
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
require(to != address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_balances[from] -= 1;
_balances[to] += 1;
_owners[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/
function _approve(address to, uint256 tokenId) internal virtual {
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
* The call is not executed if the target address is not a contract.
*
* @param from address representing the previous owner of the given token ID
* @param to target address that will receive the tokens
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return bool whether the call correctly returned the expected magic value
*/
function _checkOnERC721Received(
address from,
address to,
uint256 tokenId,
bytes memory _data
) private returns (bool) {
if (to.isContract()) {
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
return retval == IERC721Receiver.onERC721Received.selector;
} catch (bytes memory reason) {
if (reason.length == 0) {
revert("ERC721: transfer to non ERC721Receiver implementer");
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
return true;
}
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` 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 tokenId
) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ERC721.sol";
import "./IERC721Enumerable.sol";
/**
* @dev This implements an optional extension of {ERC721} defined in the EIP that adds
* enumerability of all the token ids in the contract as well as all token ids owned by each
* account.
*/
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
// Mapping from owner to list of owned token IDs
mapping(address => mapping(uint256 => uint256)) private _ownedTokens;
// Mapping from token ID to index of the owner tokens list
mapping(uint256 => uint256) private _ownedTokensIndex;
// Array with all token ids, used for enumeration
uint256[] private _allTokens;
// Mapping from token id to position in the allTokens array
mapping(uint256 => uint256) private _allTokensIndex;
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
return _ownedTokens[owner][index];
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _allTokens.length;
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/
function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
return _allTokens[index];
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 tokenId
) internal virtual override {
super._beforeTokenTransfer(from, to, tokenId);
if (from == address(0)) {
_addTokenToAllTokensEnumeration(tokenId);
} else if (from != to) {
_removeTokenFromOwnerEnumeration(from, tokenId);
}
if (to == address(0)) {
_removeTokenFromAllTokensEnumeration(tokenId);
} else if (to != from) {
_addTokenToOwnerEnumeration(to, tokenId);
}
}
/**
* @dev Private function to add a token to this extension's ownership-tracking data structures.
* @param to address representing the new owner of the given token ID
* @param tokenId uint256 ID of the token to be added to the tokens list of the given address
*/
function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
uint256 length = ERC721.balanceOf(to);
_ownedTokens[to][length] = tokenId;
_ownedTokensIndex[tokenId] = length;
}
/**
* @dev Private function to add a token to this extension's token tracking data structures.
* @param tokenId uint256 ID of the token to be added to the tokens list
*/
function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
_allTokensIndex[tokenId] = _allTokens.length;
_allTokens.push(tokenId);
}
/**
* @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
* while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
* gas optimizations e.g. when performing a transfer operation (avoiding double writes).
* This has O(1) time complexity, but alters the order of the _ownedTokens array.
* @param from address representing the previous owner of the given token ID
* @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
*/
function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
// To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
// then delete the last slot (swap and pop).
uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
uint256 tokenIndex = _ownedTokensIndex[tokenId];
// When the token to delete is the last token, the swap operation is unnecessary
if (tokenIndex != lastTokenIndex) {
uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
_ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
_ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
}
// This also deletes the contents at the last position of the array
delete _ownedTokensIndex[tokenId];
delete _ownedTokens[from][lastTokenIndex];
}
/**
* @dev Private function to remove a token from this extension's token tracking data structures.
* This has O(1) time complexity, but alters the order of the _allTokens array.
* @param tokenId uint256 ID of the token to be removed from the tokens list
*/
function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
// To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
// then delete the last slot (swap and pop).
uint256 lastTokenIndex = _allTokens.length - 1;
uint256 tokenIndex = _allTokensIndex[tokenId];
// When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
// rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
// an 'if' statement (like in _removeTokenFromOwnerEnumeration)
uint256 lastTokenId = _allTokens[lastTokenIndex];
_allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
_allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
// This also deletes the contents at the last position of the array
delete _allTokensIndex[tokenId];
_allTokens.pop();
}
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
interface IBarn {
function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external;
function randomWolfOwner(uint256 seed) external view returns (address);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
interface IERC165 {
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
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
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/
interface IERC721 is IERC165 {
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/
function approve(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator) external view returns (bool);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes calldata data
) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Enumerable is IERC721 {
/**
* @dev Returns the total amount of tokens stored by the contract.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns a token ID owned by `owner` at a given `index` of its token list.
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);
/**
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
* Use along with {totalSupply} to enumerate all tokens.
*/
function tokenByIndex(uint256 index) external view returns (uint256);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Metadata is IERC721 {
/**
* @dev Returns the token collection name.
*/
function name() external view returns (string memory);
/**
* @dev Returns the token collection symbol.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/
function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/
interface IERC721Receiver {
/**
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
* by `operator` from `from`, this function is called.
*
* It must return its Solidity selector to confirm the token transfer.
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
*
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
*/
function onERC721Received(
address operator,
address from,
uint256 tokenId,
bytes calldata data
) external returns (bytes4);
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
interface ITraits {
function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
interface IWoolf {
// struct to store each token's traits
struct SheepWolf {
bool isSheep;
uint8 fur;
uint8 head;
uint8 ears;
uint8 eyes;
uint8 nose;
uint8 mouth;
uint8 neck;
uint8 feet;
uint8 alphaIndex;
}
function getPaidTokens() external view returns (uint256);
function getTokenTraits(uint256 tokenId) external view returns (SheepWolf memory);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_setOwner(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_setOwner(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./Context.sol";
/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/
abstract contract Pausable is Context {
/**
* @dev Emitted when the pause is triggered by `account`.
*/
event Paused(address account);
/**
* @dev Emitted when the pause is lifted by `account`.
*/
event Unpaused(address account);
bool private _paused;
/**
* @dev Initializes the contract in unpaused state.
*/
constructor() {
_paused = false;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/
function paused() public view virtual returns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/
modifier whenNotPaused() {
require(!paused(), "Pausable: paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/
modifier whenPaused() {
require(paused(), "Pausable: not paused");
_;
}
/**
* @dev Triggers stopped state.
*
* Requirements:
*
* - The contract must not be paused.
*/
function _pause() internal virtual whenNotPaused {
_paused = true;
emit Paused(_msgSender());
}
/**
* @dev Returns to normal state.
*
* Requirements:
*
* - The contract must be paused.
*/
function _unpause() internal virtual whenPaused {
_paused = false;
emit Unpaused(_msgSender());
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT licence
// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
if (value == 0) {
return "0";
}
uint256 temp = value;
uint256 digits;
while (temp != 0) {
digits++;
temp /= 10;
}
bytes memory buffer = new bytes(digits);
while (value != 0) {
digits -= 1;
buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
value /= 10;
}
return string(buffer);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/
function toHexString(uint256 value) internal pure returns (string memory) {
if (value == 0) {
return "0x00";
}
uint256 temp = value;
uint256 length = 0;
while (temp != 0) {
length++;
temp >>= 8;
}
return toHexString(value, length);
}
/**
* @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] = _HEX_SYMBOLS[value & 0xf];
value >>= 4;
}
require(value == 0, "Strings: hex length insufficient");
return string(buffer);
}
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
import "./Ownable.sol";
import "./Strings.sol";
import "./ITraits.sol";
import "./IWoolf.sol";
contract Traits is Ownable, ITraits {
using Strings for uint256;
// struct to store each trait's data for metadata and rendering
struct Trait {
string name;
string png;
}
// mapping from trait type (index) to its name
string[9] _traitTypes = [
"Fur",
"Head",
"Ears",
"Eyes",
"Nose",
"Mouth",
"Neck",
"Feet",
"Alpha"
];
// storage of each traits name and base64 PNG data
mapping(uint8 => mapping(uint8 => Trait)) public traitData;
// mapping from alphaIndex to its score
string[4] _alphas = [
"8",
"7",
"6",
"5"
];
IWoolf public woolf;
constructor() {}
/** ADMIN */
function setWoolf(address _woolf) external onlyOwner {
woolf = IWoolf(_woolf);
}
/**
* administrative to upload the names and images associated with each trait
* @param traitType the trait type to upload the traits for (see traitTypes for a mapping)
* @param traits the names and base64 encoded PNGs for each trait
*/
function uploadTraits(uint8 traitType, uint8[] calldata traitIds, Trait[] calldata traits) external onlyOwner {
require(traitIds.length == traits.length, "Mismatched inputs");
for (uint i = 0; i < traits.length; i++) {
traitData[traitType][traitIds[i]] = Trait(
traits[i].name,
traits[i].png
);
}
}
/** RENDER */
/**
* generates an <image> element using base64 encoded PNGs
* @param trait the trait storing the PNG data
* @return the <image> element
*/
function drawTrait(Trait memory trait) internal pure returns (string memory) {
return string(abi.encodePacked(
'<image x="4" y="4" width="32" height="32" image-rendering="pixelated" preserveAspectRatio="xMidYMid" xlink:href="data:image/png;base64,',
trait.png,
'"/>'
));
}
/**
* generates an entire SVG by composing multiple <image> elements of PNGs
* @param tokenId the ID of the token to generate an SVG for
* @return a valid SVG of the Sheep / Wolf
*/
function drawSVG(uint256 tokenId) public view returns (string memory) {
IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);
uint8 shift = s.isSheep ? 0 : 9;
string memory svgString = string(abi.encodePacked(
drawTrait(traitData[0 + shift][s.fur]),
s.isSheep ? drawTrait(traitData[1 + shift][s.head]) : drawTrait(traitData[1 + shift][s.alphaIndex]),
s.isSheep ? drawTrait(traitData[2 + shift][s.ears]) : '',
drawTrait(traitData[3 + shift][s.eyes]),
s.isSheep ? drawTrait(traitData[4 + shift][s.nose]) : '',
drawTrait(traitData[5 + shift][s.mouth]),
s.isSheep ? '' : drawTrait(traitData[6 + shift][s.neck]),
s.isSheep ? drawTrait(traitData[7 + shift][s.feet]) : ''
));
return string(abi.encodePacked(
'<svg id="woolf" width="100%" height="100%" version="1.1" viewBox="0 0 40 40" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">',
svgString,
"</svg>"
));
}
/**
* generates an attribute for the attributes array in the ERC721 metadata standard
* @param traitType the trait type to reference as the metadata key
* @param value the token's trait associated with the key
* @return a JSON dictionary for the single attribute
*/
function attributeForTypeAndValue(string memory traitType, string memory value) internal pure returns (string memory) {
return string(abi.encodePacked(
'{"trait_type":"',
traitType,
'","value":"',
value,
'"}'
));
}
/**
* generates an array composed of all the individual traits and values
* @param tokenId the ID of the token to compose the metadata for
* @return a JSON array of all of the attributes for given token ID
*/
function compileAttributes(uint256 tokenId) public view returns (string memory) {
IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);
string memory traits;
if (s.isSheep) {
traits = string(abi.encodePacked(
attributeForTypeAndValue(_traitTypes[0], traitData[0][s.fur].name),',',
attributeForTypeAndValue(_traitTypes[1], traitData[1][s.head].name),',',
attributeForTypeAndValue(_traitTypes[2], traitData[2][s.ears].name),',',
attributeForTypeAndValue(_traitTypes[3], traitData[3][s.eyes].name),',',
attributeForTypeAndValue(_traitTypes[4], traitData[4][s.nose].name),',',
attributeForTypeAndValue(_traitTypes[5], traitData[5][s.mouth].name),',',
attributeForTypeAndValue(_traitTypes[7], traitData[7][s.feet].name),','
));
} else {
traits = string(abi.encodePacked(
attributeForTypeAndValue(_traitTypes[0], traitData[9][s.fur].name),',',
attributeForTypeAndValue(_traitTypes[1], traitData[10][s.alphaIndex].name),',',
attributeForTypeAndValue(_traitTypes[3], traitData[12][s.eyes].name),',',
attributeForTypeAndValue(_traitTypes[5], traitData[14][s.mouth].name),',',
attributeForTypeAndValue(_traitTypes[6], traitData[15][s.neck].name),',',
attributeForTypeAndValue("Alpha Score", _alphas[s.alphaIndex]),','
));
}
return string(abi.encodePacked(
'[',
traits,
'{"trait_type":"Generation","value":',
tokenId <= woolf.getPaidTokens() ? '"Gen 0"' : '"Gen 1"',
'},{"trait_type":"Type","value":',
s.isSheep ? '"Sheep"' : '"Wolf"',
'}]'
));
}
/**
* generates a base64 encoded metadata response without referencing off-chain content
* @param tokenId the ID of the token to generate the metadata for
* @return a base64 encoded JSON dictionary of the token's metadata and SVG
*/
function tokenURI(uint256 tokenId) public view override returns (string memory) {
IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);
string memory metadata = string(abi.encodePacked(
'{"name": "',
s.isSheep ? 'Sheep #' : 'Wolf #',
tokenId.toString(),
'", "description": "Thousands of Sheep and Wolves compete on a farm in the metaverse. A tempting prize of $WOOL awaits, with deadly high stakes. All the metadata and images are generated and stored 100% on-chain. No IPFS. NO API. Just the Ethereum blockchain.", "image": "data:image/svg+xml;base64,',
base64(bytes(drawSVG(tokenId))),
'", "attributes":',
compileAttributes(tokenId),
"}"
));
return string(abi.encodePacked(
"data:application/json;base64,",
base64(bytes(metadata))
));
}
/** BASE 64 - Written by Brech Devos */
string internal constant TABLE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
function base64(bytes memory data) internal pure returns (string memory) {
if (data.length == 0) return '';
// load the table into memory
string memory table = TABLE;
// multiply by 4/3 rounded up
uint256 encodedLen = 4 * ((data.length + 2) / 3);
// add some extra buffer at the end required for the writing
string memory result = new string(encodedLen + 32);
assembly {
// set the actual output length
mstore(result, encodedLen)
// prepare the lookup table
let tablePtr := add(table, 1)
// input ptr
let dataPtr := data
let endPtr := add(dataPtr, mload(data))
// result ptr, jump over length
let resultPtr := add(result, 32)
// run over the input, 3 bytes at a time
for {} lt(dataPtr, endPtr) {}
{
dataPtr := add(dataPtr, 3)
// read 3 bytes
let input := mload(dataPtr)
// write 4 characters
mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(18, input), 0x3F)))))
resultPtr := add(resultPtr, 1)
mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(12, input), 0x3F)))))
resultPtr := add(resultPtr, 1)
mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr( 6, input), 0x3F)))))
resultPtr := add(resultPtr, 1)
mstore(resultPtr, shl(248, mload(add(tablePtr, and( input, 0x3F)))))
resultPtr := add(resultPtr, 1)
}
// padding with '='
switch mod(mload(data), 3)
case 1 { mstore(sub(resultPtr, 2), shl(240, 0x3d3d)) }
case 2 { mstore(sub(resultPtr, 1), shl(248, 0x3d)) }
}
return result;
}
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
import "./ERC20.sol";
import "./Ownable.sol";
contract WOOL is ERC20, Ownable {
// a mapping from an address to whether or not it can mint / burn
mapping(address => bool) controllers;
constructor() ERC20("WOOL", "WOOL") { }
/**
* mints $WOOL to a recipient
* @param to the recipient of the $WOOL
* @param amount the amount of $WOOL to mint
*/
function mint(address to, uint256 amount) external {
require(controllers[msg.sender], "Only controllers can mint");
_mint(to, amount);
}
/**
* burns $WOOL from a holder
* @param from the holder of the $WOOL
* @param amount the amount of $WOOL to burn
*/
function burn(address from, uint256 amount) external {
require(controllers[msg.sender], "Only controllers can burn");
_burn(from, amount);
}
/**
* enables an address to mint / burn
* @param controller the address to enable
*/
function addController(address controller) external onlyOwner {
controllers[controller] = true;
}
/**
* disables an address from minting / burning
* @param controller the address to disbale
*/
function removeController(address controller) external onlyOwner {
controllers[controller] = false;
}
}
// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;
import "./Ownable.sol";
import "./Pausable.sol";
import "./ERC721Enumerable.sol";
import "./IWoolf.sol";
import "./IBarn.sol";
import "./ITraits.sol";
import "./WOOL.sol";
contract Woolf is IWoolf, ERC721Enumerable, Ownable, Pausable {
// mint price
uint256 public constant MINT_PRICE = .069420 ether;
// max number of tokens that can be minted - 50000 in production
uint256 public immutable MAX_TOKENS;
// number of tokens that can be claimed for free - 20% of MAX_TOKENS
uint256 public PAID_TOKENS;
// number of tokens have been minted so far
uint16 public minted;
// mapping from tokenId to a struct containing the token's traits
mapping(uint256 => SheepWolf) public tokenTraits;
// mapping from hashed(tokenTrait) to the tokenId it's associated with
// used to ensure there are no duplicates
mapping(uint256 => uint256) public existingCombinations;
// list of probabilities for each trait type
// 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves
uint8[][18] public rarities;
// list of aliases for Walker's Alias algorithm
// 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves
uint8[][18] public aliases;
// reference to the Barn for choosing random Wolf thieves
IBarn public barn;
// reference to $WOOL for burning on mint
WOOL public wool;
// reference to Traits
ITraits public traits;
/**
* instantiates contract and rarity tables
*/
constructor(address _wool, address _traits, uint256 _maxTokens) ERC721("Wolf Game", 'WGAME') {
wool = WOOL(_wool);
traits = ITraits(_traits);
MAX_TOKENS = _maxTokens;
PAID_TOKENS = _maxTokens / 5;
// I know this looks weird but it saves users gas by making lookup O(1)
// A.J. Walker's Alias Algorithm
// sheep
// fur
rarities[0] = [15, 50, 200, 250, 255];
aliases[0] = [4, 4, 4, 4, 4];
// head
rarities[1] = [190, 215, 240, 100, 110, 135, 160, 185, 80, 210, 235, 240, 80, 80, 100, 100, 100, 245, 250, 255];
aliases[1] = [1, 2, 4, 0, 5, 6, 7, 9, 0, 10, 11, 17, 0, 0, 0, 0, 4, 18, 19, 19];
// ears
rarities[2] = [255, 30, 60, 60, 150, 156];
aliases[2] = [0, 0, 0, 0, 0, 0];
// eyes
rarities[3] = [221, 100, 181, 140, 224, 147, 84, 228, 140, 224, 250, 160, 241, 207, 173, 84, 254, 220, 196, 140, 168, 252, 140, 183, 236, 252, 224, 255];
aliases[3] = [1, 2, 5, 0, 1, 7, 1, 10, 5, 10, 11, 12, 13, 14, 16, 11, 17, 23, 13, 14, 17, 23, 23, 24, 27, 27, 27, 27];
// nose
rarities[4] = [175, 100, 40, 250, 115, 100, 185, 175, 180, 255];
aliases[4] = [3, 0, 4, 6, 6, 7, 8, 8, 9, 9];
// mouth
rarities[5] = [80, 225, 227, 228, 112, 240, 64, 160, 167, 217, 171, 64, 240, 126, 80, 255];
aliases[5] = [1, 2, 3, 8, 2, 8, 8, 9, 9, 10, 13, 10, 13, 15, 13, 15];
// neck
rarities[6] = [255];
aliases[6] = [0];
// feet
rarities[7] = [243, 189, 133, 133, 57, 95, 152, 135, 133, 57, 222, 168, 57, 57, 38, 114, 114, 114, 255];
aliases[7] = [1, 7, 0, 0, 0, 0, 0, 10, 0, 0, 11, 18, 0, 0, 0, 1, 7, 11, 18];
// alphaIndex
rarities[8] = [255];
aliases[8] = [0];
// wolves
// fur
rarities[9] = [210, 90, 9, 9, 9, 150, 9, 255, 9];
aliases[9] = [5, 0, 0, 5, 5, 7, 5, 7, 5];
// head
rarities[10] = [255];
aliases[10] = [0];
// ears
rarities[11] = [255];
aliases[11] = [0];
// eyes
rarities[12] = [135, 177, 219, 141, 183, 225, 147, 189, 231, 135, 135, 135, 135, 246, 150, 150, 156, 165, 171, 180, 186, 195, 201, 210, 243, 252, 255];
aliases[12] = [1, 2, 3, 4, 5, 6, 7, 8, 13, 3, 6, 14, 15, 16, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 26, 26];
// nose
rarities[13] = [255];
aliases[13] = [0];
// mouth
rarities[14] = [239, 244, 249, 234, 234, 234, 234, 234, 234, 234, 130, 255, 247];
aliases[14] = [1, 2, 11, 0, 11, 11, 11, 11, 11, 11, 11, 11, 11];
// neck
rarities[15] = [75, 180, 165, 120, 60, 150, 105, 195, 45, 225, 75, 45, 195, 120, 255];
aliases[15] = [1, 9, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 14, 12, 14];
// feet
rarities[16] = [255];
aliases[16] = [0];
// alphaIndex
rarities[17] = [8, 160, 73, 255];
aliases[17] = [2, 3, 3, 3];
}
/** EXTERNAL */
/**
* mint a token - 90% Sheep, 10% Wolves
* The first 20% are free to claim, the remaining cost $WOOL
*/
function mint(uint256 amount, bool stake) external payable whenNotPaused {
require(tx.origin == _msgSender(), "Only EOA");
require(minted + amount <= MAX_TOKENS, "All tokens minted");
require(amount > 0 && amount <= 10, "Invalid mint amount");
if (minted < PAID_TOKENS) {
require(minted + amount <= PAID_TOKENS, "All tokens on-sale already sold");
require(amount * MINT_PRICE == msg.value, "Invalid payment amount");
} else {
require(msg.value == 0);
}
uint256 totalWoolCost = 0;
uint16[] memory tokenIds = stake ? new uint16[](amount) : new uint16[](0);
uint256 seed;
for (uint i = 0; i < amount; i++) {
minted++;
seed = random(minted);
generate(minted, seed);
address recipient = selectRecipient(seed);
if (!stake || recipient != _msgSender()) {
_safeMint(recipient, minted);
} else {
_safeMint(address(barn), minted);
tokenIds[i] = minted;
}
totalWoolCost += mintCost(minted);
}
if (totalWoolCost > 0) wool.burn(_msgSender(), totalWoolCost);
if (stake) barn.addManyToBarnAndPack(_msgSender(), tokenIds);
}
/**
* the first 20% are paid in ETH
* the next 20% are 20000 $WOOL
* the next 40% are 40000 $WOOL
* the final 20% are 80000 $WOOL
* @param tokenId the ID to check the cost of to mint
* @return the cost of the given token ID
*/
function mintCost(uint256 tokenId) public view returns (uint256) {
if (tokenId <= PAID_TOKENS) return 0;
if (tokenId <= MAX_TOKENS * 2 / 5) return 20000 ether;
if (tokenId <= MAX_TOKENS * 4 / 5) return 40000 ether;
return 80000 ether;
}
function transferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
// Hardcode the Barn's approval so that users don't have to waste gas approving
if (_msgSender() != address(barn))
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/** INTERNAL */
/**
* generates traits for a specific token, checking to make sure it's unique
* @param tokenId the id of the token to generate traits for
* @param seed a pseudorandom 256 bit number to derive traits from
* @return t - a struct of traits for the given token ID
*/
function generate(uint256 tokenId, uint256 seed) internal returns (SheepWolf memory t) {
t = selectTraits(seed);
if (existingCombinations[structToHash(t)] == 0) {
tokenTraits[tokenId] = t;
existingCombinations[structToHash(t)] = tokenId;
return t;
}
return generate(tokenId, random(seed));
}
/**
* uses A.J. Walker's Alias algorithm for O(1) rarity table lookup
* ensuring O(1) instead of O(n) reduces mint cost by more than 50%
* probability & alias tables are generated off-chain beforehand
* @param seed portion of the 256 bit seed to remove trait correlation
* @param traitType the trait type to select a trait for
* @return the ID of the randomly selected trait
*/
function selectTrait(uint16 seed, uint8 traitType) internal view returns (uint8) {
uint8 trait = uint8(seed) % uint8(rarities[traitType].length);
if (seed >> 8 < rarities[traitType][trait]) return trait;
return aliases[traitType][trait];
}
/**
* the first 20% (ETH purchases) go to the minter
* the remaining 80% have a 10% chance to be given to a random staked wolf
* @param seed a random value to select a recipient from
* @return the address of the recipient (either the minter or the Wolf thief's owner)
*/
function selectRecipient(uint256 seed) internal view returns (address) {
if (minted <= PAID_TOKENS || ((seed >> 245) % 10) != 0) return _msgSender(); // top 10 bits haven't been used
address thief = barn.randomWolfOwner(seed >> 144); // 144 bits reserved for trait selection
if (thief == address(0x0)) return _msgSender();
return thief;
}
/**
* selects the species and all of its traits based on the seed value
* @param seed a pseudorandom 256 bit number to derive traits from
* @return t - a struct of randomly selected traits
*/
function selectTraits(uint256 seed) internal view returns (SheepWolf memory t) {
t.isSheep = (seed & 0xFFFF) % 10 != 0;
uint8 shift = t.isSheep ? 0 : 9;
seed >>= 16;
t.fur = selectTrait(uint16(seed & 0xFFFF), 0 + shift);
seed >>= 16;
t.head = selectTrait(uint16(seed & 0xFFFF), 1 + shift);
seed >>= 16;
t.ears = selectTrait(uint16(seed & 0xFFFF), 2 + shift);
seed >>= 16;
t.eyes = selectTrait(uint16(seed & 0xFFFF), 3 + shift);
seed >>= 16;
t.nose = selectTrait(uint16(seed & 0xFFFF), 4 + shift);
seed >>= 16;
t.mouth = selectTrait(uint16(seed & 0xFFFF), 5 + shift);
seed >>= 16;
t.neck = selectTrait(uint16(seed & 0xFFFF), 6 + shift);
seed >>= 16;
t.feet = selectTrait(uint16(seed & 0xFFFF), 7 + shift);
seed >>= 16;
t.alphaIndex = selectTrait(uint16(seed & 0xFFFF), 8 + shift);
}
/**
* converts a struct to a 256 bit hash to check for uniqueness
* @param s the struct to pack into a hash
* @return the 256 bit hash of the struct
*/
function structToHash(SheepWolf memory s) internal pure returns (uint256) {
return uint256(bytes32(
abi.encodePacked(
s.isSheep,
s.fur,
s.head,
s.eyes,
s.mouth,
s.neck,
s.ears,
s.feet,
s.alphaIndex
)
));
}
/**
* generates a pseudorandom number
* @param seed a value ensure different outcomes for different sources in the same block
* @return a pseudorandom value
*/
function random(uint256 seed) internal view returns (uint256) {
return uint256(keccak256(abi.encodePacked(
tx.origin,
blockhash(block.number - 1),
block.timestamp,
seed
)));
}
/** READ */
function getTokenTraits(uint256 tokenId) external view override returns (SheepWolf memory) {
return tokenTraits[tokenId];
}
function getPaidTokens() external view override returns (uint256) {
return PAID_TOKENS;
}
/** ADMIN */
/**
* called after deployment so that the contract can get random wolf thieves
* @param _barn the address of the Barn
*/
function setBarn(address _barn) external onlyOwner {
barn = IBarn(_barn);
}
/**
* allows owner to withdraw funds from minting
*/
function withdraw() external onlyOwner {
payable(owner()).transfer(address(this).balance);
}
/**
* updates the number of tokens for sale
*/
function setPaidTokens(uint256 _paidTokens) external onlyOwner {
PAID_TOKENS = _paidTokens;
}
/**
* enables owner to pause / unpause minting
*/
function setPaused(bool _paused) external onlyOwner {
if (_paused) _pause();
else _unpause();
}
/** RENDER */
function tokenURI(uint256 tokenId) public view override returns (string memory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
return traits.tokenURI(tokenId);
}
}