// SPDX-License-Identifier: Unlicense import FungibleToken from 0xf233dcee88fe0abe import NonFungibleToken from 0x1d7e57aa55817448 pub contract StoreFrontAuction { // The total amount of AuctionItems that have been created pub var totalAuctions: UInt64 /// Path where the public capability for the `Collection` is available pub let collectionPublicPath: PublicPath /// Path where the `Collection` is stored pub let collectionStoragePath: StoragePath // Events pub event AuctionItemsCreated(auctionId: UInt64, nftID: UInt64, startPrice: UFix64, seller: Address?) pub event AuctionBidCreated(auctionId: UInt64, bidPrice: UFix64, buyer: Address?) pub event AuctionSettled(auctionId: UInt64, price: UFix64) pub event AuctionCanceled(auctionId: UInt64) // AuctionItem contains the Resources and metadata for a single auction pub resource AuctionItem { pub(set) var NFT: @NonFungibleToken.NFT? pub let bidVault: @FungibleToken.Vault pub(set) var meta: ItemMeta init( NFT: @NonFungibleToken.NFT, bidVault: @FungibleToken.Vault, meta: ItemMeta ) { self.NFT <- NFT self.bidVault <- bidVault self.meta = meta StoreFrontAuction.totalAuctions = StoreFrontAuction.totalAuctions + UInt64(1) } // depositBidTokens deposits the bidder's tokens into the AuctionItem's Vault pub fun depositBidTokens(vault: @FungibleToken.Vault) { self.bidVault.deposit(from: <-vault) } // withdrawNFT removes the NFT from the AuctionItem and returns it to the caller pub fun withdrawNFT(): @NonFungibleToken.NFT { let NFT <- self.NFT <- nil return <- NFT! } // updateRecipientVaultCap updates the bidder's Vault capability, providing the // us with a way to return their FungibleTokens access(contract) fun updateRecipientVaultCap(cap: Capability<&{FungibleToken.Receiver}>) { let meta = self.meta meta.recipientVaultCap = cap self.meta = meta } // sendNFT sends the NFT to the Collection belonging to the provided Capability access(contract) fun sendNFT(_ capability: Capability<&{NonFungibleToken.CollectionPublic}>) { // borrow a reference to the owner's NFT receiver if let collectionRef = capability.borrow() { let NFT <- self.withdrawNFT() // deposit the token into the owner's collection collectionRef.deposit(token: <-NFT) } else { panic("Unable to borrow collection reference") } } // sendBidTokens sends the bid tokens to the Vault Receiver belonging to the provided Capability access(contract) fun sendBidTokens(_ capability: Capability<&{FungibleToken.Receiver}>) { // borrow a reference to the owner's NFT receiver if let vaultRef = capability.borrow() { let bidVaultRef = &self.bidVault as &FungibleToken.Vault vaultRef.deposit(from: <-bidVaultRef.withdraw(amount: bidVaultRef.balance)) } else { panic("Couldn't get vault reference") } } destroy() { // send the NFT back to auction owner self.sendNFT(self.meta.ownerCollectionCap) // if there's a bidder... if let vaultCap = self.meta.recipientVaultCap { // ...send the bid tokens back to the bidder self.sendBidTokens(vaultCap) } destroy self.NFT destroy self.bidVault } } // ItemMeta contains the metadata for an AuctionItem pub struct ItemMeta { // Auction Settings pub let auctionID: UInt64 pub let minimumBidIncrement: UFix64 // Auction State pub var startPrice: UFix64 pub(set) var currentPrice: UFix64 pub(set) var auctionCompleted: Bool pub let finishAtTimestamp: UFix64 // Recipient's Receiver Capabilities pub(set) var recipientCollectionCap: Capability<&{NonFungibleToken.CollectionPublic}> pub(set) var recipientVaultCap: Capability<&{FungibleToken.Receiver}>? // Owner's Receiver Capabilities pub let ownerCollectionCap: Capability<&{NonFungibleToken.CollectionPublic}> pub let ownerVaultCap: Capability<&{FungibleToken.Receiver}> init( minimumBidIncrement: UFix64, startPrice: UFix64, ownerCollectionCap: Capability<&{NonFungibleToken.CollectionPublic}>, ownerVaultCap: Capability<&{FungibleToken.Receiver}>, finishAtTimestamp: UFix64 ) { self.auctionID = StoreFrontAuction.totalAuctions + UInt64(1) self.minimumBidIncrement = minimumBidIncrement self.startPrice = startPrice self.currentPrice = startPrice self.auctionCompleted = false self.recipientCollectionCap = ownerCollectionCap self.recipientVaultCap = ownerVaultCap self.ownerCollectionCap = ownerCollectionCap self.ownerVaultCap = ownerVaultCap self.finishAtTimestamp = finishAtTimestamp } } // AuctionPublic is a resource interface that restricts users to // retreiving the auction price list and placing bids pub resource interface AuctionPublic { pub fun getAuctionPrices(): {UInt64: UFix64} pub fun placeBid( id: UInt64, bidTokens: @FungibleToken.Vault, vaultCap: Capability<&{FungibleToken.Receiver}>, collectionCap: Capability<&{NonFungibleToken.CollectionPublic}> ) } // AuctionCollection contains a dictionary of AuctionItems and provides // methods for manipulating the AuctionItems pub resource AuctionCollection: AuctionPublic { // Auction Items pub var auctionItems: @{UInt64: AuctionItem} init() { self.auctionItems <- {} } // addTokenToauctionItems adds an NFT to the auction items and sets the meta data // for the auction item pub fun addTokenToAuctionItems(token: @NonFungibleToken.NFT, minimumBidIncrement: UFix64, startPrice: UFix64, bidVault: @FungibleToken.Vault, collectionCap: Capability<&{NonFungibleToken.CollectionPublic}>, vaultCap: Capability<&{FungibleToken.Receiver}>, finishAtTimestamp: UFix64) { // create a new auction meta resource let meta = ItemMeta( minimumBidIncrement: minimumBidIncrement, startPrice: startPrice, ownerCollectionCap: collectionCap, ownerVaultCap: vaultCap, finishAtTimestamp: finishAtTimestamp ) let nftID = token.id // create a new auction items resource container let item <- create AuctionItem( NFT: <-token, bidVault: <-bidVault, meta: meta ) let id = item.meta.auctionID // update the auction items dictionary with the new resources let oldItem <- self.auctionItems[id] <- item destroy oldItem emit AuctionItemsCreated(auctionId: id, nftID: nftID, startPrice: startPrice, seller: collectionCap.borrow()!.owner?.address) } // getAuctionPrices returns a dictionary of available NFT IDs with their current price pub fun getAuctionPrices(): {UInt64: UFix64} { pre { self.auctionItems.keys.length > 0: "There are no auction items" } let priceList: {UInt64: UFix64} = {} for id in self.auctionItems.keys { let itemRef = (&self.auctionItems[id] as? &AuctionItem?)! if itemRef.meta.auctionCompleted == false { priceList[id] = itemRef.meta.currentPrice } } return priceList } // settleAuction sends the auction item to the highest bidder // and deposits the FungibleTokens into the auction owner's account pub fun settleAuction(_ id: UInt64) { let itemRef = (&self.auctionItems[id] as &AuctionItem?)! let itemMeta = itemRef.meta if itemMeta.auctionCompleted { panic("This auction is already settled") } if itemRef.NFT == nil { panic("Auction doesn't exist") } // return if there are no bids to settle if itemMeta.currentPrice == itemMeta.startPrice { self.returnAuctionItemToOwner(id) log("No bids. Nothing to settle") return } self.exchangeTokens(id) itemMeta.auctionCompleted = true emit AuctionSettled(auctionId: id, price: itemMeta.currentPrice) if let item <- self.auctionItems.remove(key: id) { item.meta = itemMeta self.auctionItems[id] <-! item } } // exchangeTokens sends the purchased NFT to the buyer and the bidTokens to the seller pub fun exchangeTokens(_ id: UInt64) { let itemRef = (&self.auctionItems[id] as &AuctionItem?)! if itemRef.NFT == nil { panic("Auction doesn't exist") } let itemMeta = itemRef.meta itemRef.sendNFT(itemMeta.recipientCollectionCap) itemRef.sendBidTokens(itemMeta.ownerVaultCap) } // placeBid sends the bidder's tokens to the bid vault and updates the // currentPrice of the current auction item pub fun placeBid(id: UInt64, bidTokens: @FungibleToken.Vault, vaultCap: Capability<&{FungibleToken.Receiver}>, collectionCap: Capability<&{NonFungibleToken.CollectionPublic}>) { pre { self.auctionItems[id] != nil: "NFT doesn't exist" } // Get the auction item resources let itemRef = (&self.auctionItems[id] as &AuctionItem?)! let itemMeta = itemRef.meta if itemMeta.auctionCompleted { panic("auction has already completed") } if (bidTokens.balance - itemMeta.currentPrice) < itemMeta.minimumBidIncrement { panic("bid amount be larger than minimum bid increment") } if itemMeta.finishAtTimestamp < getCurrentBlock().timestamp { panic("auction is not available") } if itemRef.bidVault.balance != UFix64(0) { if let vaultCap = itemMeta.recipientVaultCap { itemRef.sendBidTokens(itemMeta.recipientVaultCap!) } else { panic("unable to get recipient Vault capability") } } // Update the auction item itemRef.depositBidTokens(vault: <-bidTokens) itemRef.updateRecipientVaultCap(cap: vaultCap) // Update the current price of the token itemMeta.currentPrice = itemRef.bidVault.balance // Add the bidder's Vault and NFT receiver references itemMeta.recipientCollectionCap = collectionCap itemRef.meta = itemMeta emit AuctionBidCreated(auctionId: id, bidPrice: itemMeta.currentPrice, buyer: collectionCap.borrow()!.owner?.address) } // releasePreviousBid returns the outbid user's tokens to // their vault receiver pub fun releasePreviousBid(_ id: UInt64) { // get a reference to the auction items resources let itemRef = (&self.auctionItems[id] as &AuctionItem?)! let itemMeta = itemRef.meta // release the bidTokens from the vault back to the bidder if let vaultCap = itemMeta.recipientVaultCap { itemRef.sendBidTokens(itemMeta.recipientVaultCap!) } else { log("unable to get vault capability") } } // returnAuctionItemToOwner releases any bids and returns the NFT // to the owner's Collection pub fun returnAuctionItemToOwner(_ id: UInt64) { let itemRef = (&self.auctionItems[id] as &AuctionItem?)! let itemMeta = itemRef.meta // release the bidder's tokens self.releasePreviousBid(id) // clear the NFT's meta data let oldItem <- self.auctionItems[id] <- nil destroy oldItem } // cancel auction and returns the NFT to the owner's Collection pub fun cancelAndReturnAuctionItemToOwner(_ id: UInt64) { self.returnAuctionItemToOwner(id) emit AuctionCanceled(auctionId: id) } destroy() { for id in self.auctionItems.keys { self.returnAuctionItemToOwner(id) } // destroy the empty resources destroy self.auctionItems } } // createAuctionCollection returns a new AuctionCollection resource to the caller pub fun createAuctionCollection(): @AuctionCollection { let auctionCollection <- create AuctionCollection() return <- auctionCollection } init() { self.totalAuctions = UInt64(0) self.collectionPublicPath = /public/StoreFrontAuctionCollection self.collectionStoragePath = /storage/StoreFrontAuctionCollection } }

Contract

Contract