TopShot_08.cdc

// NFT 代表的就是一個 moment，也就是一張卡片
// 它實作官方 NFT contract 裡的 INFT interface
// 以及 MetadataViews.Resolver interface
pub resource NFT: NonFungibleToken.INFT, MetadataViews.Resolver {
    // 每一張卡片都有獨特的 ID 代表，
    // 並且這也是實作 NonFungibleToken.INFT 必須要有的
    pub let id: UInt64
    pub let data: MomentData
    
    // 創建 struct 時候的初始化 function
    // 在這裡就是卡片被 mint 出來的時候，
    // 主要就是初始化上述提到的那些 variables
    // 並且發出 mint 出新卡片的 event
    init(serialNumber: UInt32, playID: UInt32, setID: UInt32) {
        // 將總供應量 +1
        TopShot.totalSupply = TopShot.totalSupply + UInt64(1)
        self.id = TopShot.totalSupply
        self.data = MomentData(setID: setID, playID: playID, serialNumber: serialNumber)
        emit MomentMinted(momentID: self.id, playID: playID, setID: self.data.setID, serialNumber: self.data.serialNumber)
    }
    
    // 卡片被銷毀時候會發出某張卡片被銷毀的 event
    destroy() {
        emit MomentDestroyed(id: self.id)
    }
    
    pub fun name(): String {
        let fullName: String = TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "FullName") ?? ""
        let playType: String = TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "PlayType") ?? ""
        return fullName
            .concat(" ")
            .concat(playType)
    }
    
    pub fun description(): String {
        let setName: String = TopShot.getSetName(setID: self.data.setID) ?? ""
        let serialNumber: String = self.data.serialNumber.toString()
        let seriesNumber: String = TopShot.getSetSeries(setID: self.data.setID)?.toString() ?? ""
        return "A series "
            .concat(seriesNumber)
            .concat(" ")
            .concat(setName)
            .concat(" moment with serial number ")
            .concat(serialNumber)
    }
    
    // 這是 MetadataViews.Resolver 必須的實作 function，
    // 代表 metadata 可以有幾種 view type，也就是 metadata 的資料結構，
    // 第一個當然是原本 MetadataViews 內建的 Display type，會儲存 name, description
    // 第二個就是本合約自己定義的 TopShotMomentMetadataView Type 則是儲存上面提到的那些卡片資訊
    pub fun getViews(): [Type] {
        return [
            Type<MetadataViews.Display>(),
            Type<TopShotMomentMetadataView>()
        ]
    }
    
    // 這也是 MetadataViews.Resolver 必須的實作 function，
    // 目的是讓外部能夠傳入 view type 來存取到想要的 metadata 形式，
    // 所以下面可以看到如果是傳入預設的 MetadataViews.Display type ，就會回傳 name, description, thumbnail
    // 而如果是傳入 TopShotMomentMetadataView Type 就會回傳球員名字、所屬隊伍等等卡片資訊
    pub fun resolveView(_ view: Type): AnyStruct? {
        switch view {
            case Type<MetadataViews.Display>():
                return MetadataViews.Display(
                    name: self.name(),
                    description: self.description(),
                    thumbnail: MetadataViews.HTTPFile("")
                )
            case Type<TopShotMomentMetadataView>():
                return TopShotMomentMetadataView(
                    fullName: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "FullName"),
                    firstName: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "FirstName"),
                    lastName: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "LastName"),
                    birthdate: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "Birthdate"),
                    birthplace: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "Birthplace"),
                    jerseyNumber: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "JerseyNumber"),
                    draftTeam: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "DraftTeam"),
                    draftYear: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "DraftYear"),
                    draftSelection: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "DraftSelection"),
                    draftRound: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "DraftRound"),
                    teamAtMomentNBAID: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "TeamAtMomentNBAID"),
                    teamAtMoment: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "TeamAtMoment"),
                    primaryPosition: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "PrimaryPosition"),
                    height: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "Height"),
                    weight: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "Weight"),
                    totalYearsExperience: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "TotalYearsExperience"),
                    nbaSeason: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "NbaSeason"),
                    dateOfMoment: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "DateOfMoment"),
                    playCategory: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "PlayCategory"),
                    playType: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "PlayType"),
                    homeTeamName: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "HomeTeamName"),
                    awayTeamName: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "AwayTeamName"),
                    homeTeamScore: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "HomeTeamScore"),
                    awayTeamScore: TopShot.getPlayMetaDataByField(playID: self.data.playID, field: "AwayTeamScore"),
                    seriesNumber: TopShot.getSetSeries(setID: self.data.setID),
                    setName: TopShot.getSetName(setID: self.data.setID),
                    serialNumber: self.data.serialNumber,
                    playID: self.data.playID,
                    setID: self.data.setID,
                    numMomentsInEdition: TopShot.getNumMomentsInEdition(setID: self.data.setID, playID: self.data.playID)
                )
        }
        return nil
    }
}