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@Phineas
Created March 20, 2021 19:40
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contract WaifuEnhancementToken is Context, IERC20 {
using SafeMath for uint256;
// Constants
uint256 public SECONDS_IN_A_DAY = 86400;
uint256 public constant INITIAL_ALLOTMENT = 1830 * (10 ** 18);
uint256 public constant PRE_REVEAL_MULTIPLIER = 1;
// Public variables
uint256 public emissionStart;
uint256 public emissionEnd;
uint256 public emissionPerDay = 10 * (10 ** 18);
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
mapping(uint256 => uint256) private _lastClaim;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
address private _waifusAddress;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18. Also initalizes {emissionStart}
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name, string memory symbol, uint256 emissionStartTimestamp) {
_name = name;
_symbol = symbol;
_decimals = 18;
emissionStart = emissionStartTimestamp;
emissionEnd = emissionStartTimestamp + (86400 * 365 * 10);
}
/**
* @dev Returns the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
/**
* @dev When accumulated NCTs have last been claimed for a Hashmask index
*/
function lastClaim(uint256 tokenIndex) public view returns (uint256) {
require(IWaifus(_waifusAddress).ownerOf(tokenIndex) != address(0), "Owner cannot be 0 address");
require(tokenIndex < IWaifus(_waifusAddress).totalSupply(), "NFT at index has not been minted yet");
uint256 lastClaimed = uint256(_lastClaim[tokenIndex]) != 0 ? uint256(_lastClaim[tokenIndex]) : emissionStart;
return lastClaimed;
}
/**
* @dev Accumulated NCT tokens for a Hashmask token index.
*/
function accumulated(uint256 tokenIndex) public view returns (uint256) {
require(block.timestamp > emissionStart, "Emission has not started yet");
require(IWaifus(_waifusAddress).ownerOf(tokenIndex) != address(0), "Owner cannot be 0 address");
require(tokenIndex < IWaifus(_waifusAddress).totalSupply(), "NFT at index has not been minted yet");
uint256 lastClaimed = lastClaim(tokenIndex);
// Sanity check if last claim was on or after emission end
if (lastClaimed >= emissionEnd) return 0;
uint256 accumulationPeriod = block.timestamp < emissionEnd ? block.timestamp : emissionEnd; // Getting the min value of both
uint256 totalAccumulated = accumulationPeriod.sub(lastClaimed).mul(emissionPerDay).div(SECONDS_IN_A_DAY);
// If claim hasn't been done before for the index, add initial allotment (plus prereveal multiplier if applicable)
if (lastClaimed == emissionStart) {
uint256 initialAllotment = IWaifus(_waifusAddress).isMintedBeforeReveal(tokenIndex) == true ? INITIAL_ALLOTMENT.mul(PRE_REVEAL_MULTIPLIER) : INITIAL_ALLOTMENT;
totalAccumulated = totalAccumulated.add(initialAllotment);
}
return totalAccumulated;
}
/**
* @dev Permissioning not added because it is only callable once. It is set right after deployment and verified.
*/
function setWaifusAddress(address waifusAddress) public {
require(_waifusAddress == address(0), "Already set");
_waifusAddress = waifusAddress;
}
/**
* @dev Claim mints NCTs and supports multiple Hashmask token indices at once.
*/
function claim(uint256[] memory tokenIndices) public returns (uint256) {
require(block.timestamp > emissionStart, "Emission has not started yet");
uint256 totalClaimQty = 0;
for (uint i = 0; i < tokenIndices.length; i++) {
// Sanity check for non-minted index
require(tokenIndices[i] < IWaifus(_waifusAddress).totalSupply(), "NFT at index has not been minted yet");
// Duplicate token index check
for (uint j = i + 1; j < tokenIndices.length; j++) {
require(tokenIndices[i] != tokenIndices[j], "Duplicate token index");
}
uint tokenIndex = tokenIndices[i];
require(IWaifus(_waifusAddress).ownerOf(tokenIndex) == msg.sender, "Sender is not the owner");
uint256 claimQty = accumulated(tokenIndex);
if (claimQty != 0) {
totalClaimQty = totalClaimQty.add(claimQty);
_lastClaim[tokenIndex] = block.timestamp;
}
}
require(totalClaimQty != 0, "No accumulated NCT");
_mint(msg.sender, totalClaimQty);
return totalClaimQty;
}
/**
* @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);
// Approval check is skipped if the caller of transferFrom is the Waifus contract. For better UX.
if (msg.sender != _waifusAddress) {
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
}
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
// ++
/**
* @dev Burns a quantity of tokens held by the caller.
*
* Emits an {Transfer} event to 0 address
*
*/
function burn(uint256 burnQuantity) public virtual override returns (bool) {
_burn(msg.sender, burnQuantity);
return true;
}
// ++
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
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