Endemic Exchange

Endemic Exchange contract enables trading on Endemic.

There are several types of trading that are supported in our system:

1. Auction
   • Dutch
   • Reserve
   • Fixed
   • Private
2. Offer

The Dutch auction is a mechanism in which the auctioneer begins with a high asking price in the case of selling and lowers it until some participant accepts the price, or it reaches a predetermined reserve price. NFT will stay listed at the reserve price until the seller cancels the listing.

Unlike the dutch auction where the price of the NFT is decreased as time passes, in a reserve auction, the price can go up as bidders bid and try to outbid each other. Also, while listing seller needs to specify the minimum price that is asked for the auctioned NFT. When listed, for the auction to start it needs to be bid at least one time, and after that bidders try to outbid each other until the auction is finished. The highest bidder at the end gets the right to claim auction NFT.

Fixed auction is a type of auction where the auctioneer sets a fixed price for the NFT. The price will remain the same until NFT is sold or the auctioneer decides to update the listing of the auctioned NFT.

A private auction is for those who want their auction to remain private and hidden from the rest of the marketplace. During the private listing, the auctioneer needs to provide the wallet address of the specific buyer to whom he wants to sell his NFT. After listing, it will only be visible to the seller and buyer.

Offer trade mechanism enables trading beside auction. Offer makers can create offers with any amount of funds. Nevertheless, if NFT is already auctioned, the offer will still be shown on the seller's profile and he will be able to accept the offer and conclude the sale. The offer maker if wanted can also cancel his offer and retrieve the funds he deposited for the offer.

Auction methods

createDutchAuction

function createDutchAuction(
        address nftContract,
        uint256 tokenId,
        uint256 startingPrice,
        uint256 endingPrice,
        uint256 duration,
        uint256 amount,
        address paymentErc20TokenAddress,
        bytes4 assetClass
    ) external nonReentrant

Method used to create an dutch auction in the marketplace.

Parameters

Name	Type	Description
nftContract	address	address of the collection
tokenId	uint256	token id to auction
startingPrice	uint256	starting price of the auction, in wei
endingPrice	uint256	ending price of the auction must be less or equal to starting price, in wei
duration	uint256	duration of the auction, greater than 1 minute
amount	uint256	amount of tokens to auction, 1 for ERC-721, multiple for ERC-1155
paymentErc20TokenAddress	address	address of the ERC20 token that the auction is listed in
assetClass	bytes4	ERC721 or ERC1155 identifiers

If auction is listed in ether, paymentErc20TokenAddress will be Ethereum's default zero address.

Asset classes

    bytes4 public constant ERC721_ASSET_CLASS = bytes4(keccak256("ERC721"));
    bytes4 public constant ERC1155_ASSET_CLASS = bytes4(keccak256("ERC1155"));

createReserveAuction

function createReserveAuction(
        address nftContract,
        uint256 tokenId,
        uint256 reservePrice,
        address paymentErc20TokenAddress
    )
        external
        nonReentrant
        onlySupportedERC20Payments(paymentErc20TokenAddress)

The method used to create a reserve auction in the marketplace.

Parameters

Name	Type	Description
nftContract	address	address of the collection
tokenId	uint256	token id to auction
reservePrice	uint256	minimum price sellers asks for the NFT
paymentErc20TokenAddress	address	address of the ERC20 token that the auction is listed in

If auction is listed in ether, paymentErc20TokenAddress will be Ethereum's default zero address.

createFixedDutchAuction

function createFixedDutchAuction(
        address nftContract,
        uint256 tokenId,
        uint256 price,
        uint256 amount,
        address paymentErc20TokenAddress,
        bytes4 assetClass
    ) external nonReentrant

The method used to create an fixed auction in the marketplace.

Parameters

Name	Type	Description
nftContract	address	address of the collection
tokenId	uint256	token id to auction
price	uint256	fixed price of the auction, in wei
amount	uint256	amount of tokens to auction, 1 for ERC-721, multiple for ERC-1155
paymentErc20TokenAddress	address	address of the ERC20 token that the auction is listed in
assetClass	bytes4	ERC721 or ERC1155 identifiers

If auction is listed in ether, paymentErc20TokenAddress will be Ethereum's default zero address.

Asset classes

    bytes4 public constant ERC721_ASSET_CLASS = bytes4(keccak256("ERC721"));
    bytes4 public constant ERC1155_ASSET_CLASS = bytes4(keccak256("ERC1155"));

bidForDutchAuction

function bidForDutchAuction(bytes32 id, uint256 tokenAmount)
        external
        payable
        nonReentrant

Method to complete the auction. It requires ether to be sent or sufficient allowance if auction is listed in ERC-20.

Parameters

Name	Type	Description
id	bytes32	auction id
tokenAmount	uint256	amount of token to buy, 1 for ERC-721, multiple for ERC-1155

bidForReserveAuctionInErc20

function bidForReserveAuctionInErc20(bytes32 id, uint256 bidPriceWithFees)
        external
        nonReentrant

Method bids for the reserve auction in ERC-20. It requires sufficient in ERC-20 that auction is listed in.

Parameters

Name	Type	Description
id	bytes32	auction id
bidPriceWithFees	uint256	bid amount including fees

buyFromPrivateSale

function buyFromPrivateSale(
        address paymentErc20TokenAddress,
        address nftContract,
        uint256 tokenId,
        uint256 price,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external payable nonReentrant

The method to complete private auction.

Parameters

Name	Type	Description
paymentErc20TokenAddress	address	address of the ERC20 token that the auction is listed in
nftContract	address	address of the collection
tokenId	uint256	token id of the NFT privately auctioned
price	uint256	price of the auction
deadline	uint256	timestamp when private auction expires
v	uint8	last byte of the digital signature
r	bytes32	first 32 bytes of digital signature
s	bytes32	second 32 bytes of digital signature

If auction is privately listed in ether, paymentErc20TokenAddress will be Ethereum's default zero address.

Digital signature

EIP-721 Signature is used in private auctions to ensure the seller's identity. R, S, V are cryptographic parts of the ECDSA digital signature that the seller created for the privately auction NFT.

finalizeReserveAuction

function finalizeReserveAuction(bytes32 id) external nonReentrant

The method to complete the reserve auction. It can be called by either seller or highest bidder. Auction must finish before this method can be called.

Parameters

Name	Type	Description
id	bytes32	auction id

getHighestBidder

function getHighestBidder(bytes32 id) external view returns (address)

The method returns address of the highest bidder for provided auction id. Auction must be listed as reserve.

Parameters

Name	Type	Description
id	bytes32	auction id

getCurrentPrice

function getCurrentPrice(bytes32 id) external view returns (uint256)

The method calculates and returns current price of the auction.

Parameters

Name	Type	Description
id	bytes32	auction id

Returns

The price of the auction in certain moment. In case of dutch auction where price is lowered as the time passes, price will be different between the method calls.

cancelAuction

function cancelAuction(bytes32 id) external

Cancel auction with provided id. Only seller of auction is able to do the cancelation.

Parameters

Name	Type	Description
id	bytes32	auction id

getAuction

function getAuction(bytes32 id)
        external
        view
        returns (
            address seller,
            address paymentErc20TokenAddress,
            uint256 startingPrice,
            uint256 endingPrice,
            uint256 startedAt,
            uint256 endingAt,
            uint256 amount
        )

Parameters

Name	Type	Description
id	bytes32	auction id

Returns

Name	Type	Description
seller	address	seller of the NFT
paymentErc20TokenAddress	address	address of the ERC20 token that the auction is listed in
startingPrice	uint256	starting price of the auction, in wei
endingPrice	uint256	ending price of the auction in wei
startedAt	uint256	timestamp when auction started
endingAt	uint256	timestamp when auction will end
amount	uint256	amount of tokens on sale, 1 for ERC-721, multiple for ERC-1155

createAuctionId

 function createAuctionId(address nftContract, uint256 tokenId, address seller) public pure returns (bytes32)

Parameters

Name	Type	Description
nftContract	address	address of the collection
tokenId	uint256	token id for auction
seller	address	seller of the auction

Returns

Type	Description
bytes32	auction id

Offer methods

placeNftOffer

function placeNftOffer(
        address nftContract,
        uint256 tokenId,
        uint256 duration
    ) external payable nonReentrant

The method places an offer in ether for an NFT.

Parameters

Name	Type	Description
nftContract	address	address of the collection
tokenId	uint256	tokenId to offer
duration	address	timestamp when offer expires

placeNftOfferInErc20

function placeNftOfferInErc20(
        address nftContract,
        address paymentErc20TokenAddress,
        uint256 offerInErc20,
        uint256 tokenId,
        uint256 duration
    )
        external
        nonReentrant
        onlySupportedERC20Payments(paymentErc20TokenAddress)

The method places an offer in ERC-20 for a NFT.

Parameters

Name	Type	Description
nftContract	address	address of the collection
paymentErc20TokenAddress	address	address of the ERC20 token that the offer is given in
offerInErc20	uint256	offer amount given in ERC20
tokenId	address	tokenId to offer
duration	address	timestamp when offer expires

Modifiers

 onlySupportedERC20Payments(paymentErc20TokenAddress)

The method accepts only offers in supported ERC20 payment methods.

placeCollectionOffer

function placeCollectionOffer(address nftContract, uint256 duration)
        external
        payable
        nonReentrant

The method places an offer in ether for a collection.

Parameters

Name	Type	Description
nftContract	address	address of the collection
duration	address	timestamp when offer expires

placeCollectionOfferInErc20

function placeCollectionOfferInErc20(
        address nftContract,
        address paymentErc20TokenAddress,
        uint256 offerInErc20,
        uint256 duration
    )
        external
        nonReentrant
        onlySupportedERC20Payments(paymentErc20TokenAddress)

Th method places an offer in ERC-20 for a collection.

Parameters

Name	Type	Description
nftContract	address	address of the collection
paymentErc20TokenAddress	address	address of the ERC20 token that the offer is given in
offerInErc20	uint256	offer amount given in ERC20
duration	address	timestamp when offer expires

Modifiers

 onlySupportedERC20Payments(paymentErc20TokenAddress)

The method accepts only offers in supported ERC20 payment methods.

cancelOffer

function cancelOffer(uint256 offerId) external nonReentrant

The method cancels offer.

Parameters

Name	Type	Description
offerId	address	id of the offer to cancel

cancelOffers

function cancelOffers(uint256[] calldata offerIds) external nonReentrant

The method cancels array of offers.

Parameters

Name	Type	Description
offerIds	uint256[]	ids of the offers to cancel

adminCancelOffers

function adminCancelOffers(uint256[] calldata offerIds)
        external
        onlyOwner
        nonReentrant

The method cancels array of offers with administrator permission.

Parameters

Name	Type	Description
offerIds	uint256[]	ids of the offers to cancel

acceptNftOffer

function acceptNftOffer(uint256 offerId) external nonReentrant

The method accepts given NFT offer.

Parameters

Name	Type	Description
offerId	uint256	id of the offer to accept

acceptCollectionOffer

function acceptCollectionOffer(uint256 offerId, uint256 tokenId)
        external
        nonReentrant

The method accepts given collection offer.

Parameters

Name	Type	Description
offerId	uint256	id of the offer to accept
tokenId	uint256	token id of the NFT to accept offer

getOffer

function getOffer(uint256 offerId) external view returns (Offer memory)

Parameters

Name	Type	Description
offerId	bytes32	offer id

Returns

Name	Type	Description
id	uint256	offer id
nftContract	address	address of the collection
paymentErc20TokenAddress	address	address of the ERC20 token that the offer is given in
bidder	address	address of the offer maker
tokenId	uint256	token id of the NFT to offer
price	uint256	amount bidded
priceWithTakerFee	uint256	amount bidded including fees
expiresAt	uint256	timestamp when offer expires
isForCollection	bool	flag if offer is for collection or for an NFT

If offer is given in ether, paymentErc20TokenAddress will be Ethereum's default zero address.