特邀文章：在Cadence中实施Bored Ape Yacht Club智能合约

import NonFungibleToken from "./utility/NonFungibleToken.cdc"

pub contract BoredApeYachtClub: NonFungibleToken {

    pub var totalSupply: UInt64

    // events
    pub event ContractInitialized()
    pub event Withdraw(id: UInt64, from: Address?)
    pub event Deposit(id: UInt64, to: Address?)

    // paths
    pub let CollectionStoragePath: StoragePath
    pub let CollectionPublicPath: PublicPath

    pub resource NFT: NonFungibleToken.INFT {
        pub let id: UInt64
        init() {
            self.id = self.uuid
            BoredApeYachtClub.totalSupply = BoredApeYachtClub.totalSupply + 1
        }
    }

    pub resource interface CollectionPublic {
        pub fun borrowApeNFT(id: UInt64): &NFT?
    }
    pub resource Collection: NonFungibleToken.Provider, NonFungibleToken.Receiver, NonFungibleToken.CollectionPublic, CollectionPublic {
        pub var ownedNFTs: @{UInt64: NonFungibleToken.NFT}

        pub fun withdraw(withdrawID: UInt64): @NonFungibleToken.NFT {
            let token <- self.ownedNFTs.remove(key: withdrawID)!
            emit Withdraw(id: token.id, from: self.owner?.address)
            return <-token
        }

        pub fun deposit(token: @NonFungibleToken.NFT) {
            let token <- token as! @NFT
            let id: UInt64 = token.id
            self.ownedNFTs[id] <-! token
            emit Deposit(id: id, to: self.owner?.address)
        }

        pub fun getIDs(): [UInt64] {
            return self.ownedNFTs.keys
        }

        pub fun borrowNFT(id: UInt64): &NonFungibleToken.NFT {
            return (&self.ownedNFTs[id] as &NonFungibleToken.NFT?)!
        }

        pub fun borrowApeNFT(id: UInt64): &NFT? {
            let token = &self.ownedNFTs[id] as auth &NonFungibleToken.NFT?
            return token as! &NFT?
        }

        init() {
            self.ownedNFTs <- {}
        }

        destroy() {
            destroy self.ownedNFTs
        }
    }

    pub fun createEmptyCollection(): @Collection {
        return <- create Collection()
    }

    init() {
        self.totalSupply = 0
        self.CollectionStoragePath = /storage/BAYCCollection
        self.CollectionPublicPath = /public/BAYCCollection
    }
}

BoredApeYachtClub.totalSupply=BoredApeYachtClub.totalSupply+ 1

function mintApe(uint numberOfTokens) public payable {
    require(saleIsActive, "Sale must be active to mint Ape");
    require(numberOfTokens <= maxApePurchase, "Can only mint 20 tokens at a time");
    require(totalSupply().add(numberOfTokens) <= MAX_APES, "Purchase would exceed max supply of Apes");
    require(apePrice.mul(numberOfTokens) <= msg.value, "Ether value sent is not correct");
   
    for(uint i = 0; i < numberOfTokens; i++) {
        uint mintIndex = totalSupply();
        if (totalSupply() < MAX_APES) {
            _safeMint(msg.sender, mintIndex);
        }
    }
}

// custom variables
pub let apePrice: UFix64
pub let maxApePurchase: UInt64
pub var maxApes: UInt64
pub var saleIsActive: Bool

pub fun mintApe(
    numberOfTokens: UInt64,
    payment: @FlowToken.Vault,
    recipientVault: &Collection{NonFungibleToken.Receiver}
) {
    pre {
        BoredApeYachtClub.saleIsActive: "Sale must be active to mint Ape"
        numberOfTokens <= BoredApeYachtClub.maxApePurchase: "Can only mint 20 tokens at a time"
        BoredApeYachtClub.totalSupply + numberOfTokens <= BoredApeYachtClub.maxApes: "Purchase would exceed max supply of Apes"
        BoredApeYachtClub.apePrice * UFix64(numberOfTokens) == payment.balance: "$FLOW value sent is not correct"
    }

    var i: UInt64 = 0
    while i < numberOfTokens {
        recipientVault.deposit(token: <- create NFT())
        i = i + 1
    }

    // deposit the payment to the contract owner
    let ownerVault = BoredApeYachtClub.account.getCapability(/public/flowTokenReceiver)
        .borrow<&FlowToken.Vault{FungibleToken.Receiver}>()
        ?? panic("Could not get the Flow Token Vault from the Owner of this contract.")
    ownerVault.deposit(from: <- payment)
}

init(maxNftSupply: UInt64) {
    self.apePrice = 0.08 // $FLOW
    self.maxApePurchase = 20
    self.maxApes = maxNftSupply
    self.saleIsActive = false
}

uint256public constant apePrice = 80000000000000000;//0.08 ETH
uintpublic constant maxApePurchase = 20；
uint256public MAX_APES;//传递到构造函数中
boolpublic saleIsActive = false；

pub struct Template {
    // let's assume this is a `cid` for IPFS
    pub let image: String
    pub let attributes: {String: String}

    init(image: String, attributes: {String: String}) {
        self.image = image
        self.attributes = attributes
    }
}

// maps serial -> Template
access(self) let templates: {UInt64: Template}

pub resource Owner {
    pub fun flipSaleState() {
        BoredApeYachtClub.saleIsActive = !BoredApeYachtClub.saleIsActive
    }

    pub fun fulfillMetadata(templateId: UInt64, image: String, attributes: {String: String}) {
        BoredApeYachtClub.templates[templateId] = Template(image: image, attributes: attributes)
    }
}

self.account.save(<- create Owner(), to: /storage/BAYCOwner)