import FungibleToken from 0xf233dcee88fe0abe import ZelosAccountingToken from 0xc38aea683c0c4d38 import Eternal from 0xc38aea683c0c4d38 import Market from 0xc38aea683c0c4d38 import FlowStorageFees from 0xe467b9dd11fa00df import FlowToken from 0x1654653399040a61 // This transaction is for a user to purchase a moment that another user // has for sale in their sale collection // Parameters // // sellerAddress: the Flow address of the account issuing the sale of a moment // tokenID: the ID of the moment being purchased // purchaseAmount: the amount for which the user is paying for the moment; must not be less than the moment's price transaction(sellerAddress: Address, tokenID: UInt64, purchaseAmount: UFix64) { // Local variables for the eternal collection object and token provider let collectionRef: &Eternal.Collection let providerRef: &ZelosAccountingToken.Vault{FungibleToken.Provider} let vaultRef: &FlowToken.Vault let userAcct: AuthAccount prepare(acct: AuthAccount, admin: AuthAccount) { // borrow a reference to the signer's collection self.collectionRef = acct.borrow<&Eternal.Collection>(from: /storage/EternalMomentCollection) ?? panic("Could not borrow reference to the Moment Collection") // borrow a reference to the signer's fungible token Vault self.providerRef = acct.borrow<&ZelosAccountingToken.Vault{FungibleToken.Provider}>(from: /storage/zelosAccountingTokenVault)! // borrow a reference to the admins flow token vault self.vaultRef = admin.borrow<&FlowToken.Vault>(from: /storage/flowTokenVault) ?? panic("failed to borrow reference to admin vault") self.userAcct = acct } execute { // withdraw tokens from the signer's vault let tokens <- self.providerRef.withdraw(amount: purchaseAmount) as! @ZelosAccountingToken.Vault // get the seller's public account object let seller = getAccount(sellerAddress) // borrow a public reference to the seller's sale collection let eternalSaleCollection = seller.getCapability(/public/eternalSaleCollection) .borrow<&{Market.SalePublic}>() ?? panic("Could not borrow public sale reference") // purchase the moment let purchasedToken <- eternalSaleCollection.purchase(tokenID: tokenID, buyTokens: <-tokens) // deposit the purchased moment into the signer's collection self.collectionRef.deposit(token: <-purchasedToken) // Used to determine whether signer needs more storage fun returnFlowFromStorage(_ storage: UInt64): UFix64 { // safe convert UInt64 to UFix64 (without overflow) let f = UFix64(storage % 100000000 as UInt64) * 0.00000001 as UFix64 + UFix64(storage / 100000000 as UInt64) // decimal point correction. Megabytes to bytes have a conversion of 10^-6 while UFix64 minimum value is 10^-8 let storageMb = f * 100.0 as UFix64 let storage = FlowStorageFees.storageCapacityToFlow(storageMb) return storage } // Determine Storage Used by user and Total Capacity in their account var storageUsed = returnFlowFromStorage(self.userAcct.storageUsed) var storageTotal = returnFlowFromStorage(self.userAcct.storageCapacity) // if user has used more than their total capacity, increase total capacity if (storageUsed > storageTotal) { let difference = storageUsed - storageTotal // Withdraw storage fee let sentVault <- self.vaultRef.withdraw(amount: difference) // Deposit storage fee to recipient let receiver = self.userAcct.getCapability(/public/flowTokenReceiver) .borrow<&{FungibleToken.Receiver}>() ?? panic("failed to borrow reference to recipient vault") receiver.deposit(from: <-sentVault) } } }

Transaction

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