Cocoa練習帳

モデルのHandをDataTypeプロトコル適用ということにして、項目名をCardから汎用的なItemに変更する。

protocol DataType {
    var numberOfItems: Int {get}
    func addNewItem(at index: Int) -> Self
    func deleteItem(at index: Int) -> Self
    func moveItem(fromIndex: Int, toIndex: Int) -> Self
}

struct Hand: DataType {
    private var deck = Deck()
    private var cards = [Card]()
    
    public init() {
    }
    
    public init(deck: Deck, cards: [Card]) {
        self.deck = deck
        self.cards = cards
    }
    
    public var numberOfItems: Int {
        return cards.count
    }
    
    public func addNewItem(at index: Int) -> Hand {
        return insertCard(card: deck.nextCard(), at: index)
    }
    
    private func insertCard(card: Card, at index: Int) -> Hand {
        var mutableCards = cards
        mutableCards.insert(card, at: index)
        return Hand(deck: deck, cards: mutableCards)
    }
    
    public func deleteItem(at index: Int) -> Hand {
        var mutableCards = cards
        mutableCards.remove(at: index)
        return Hand(deck: deck, cards: mutableCards)
    }
    
    public func moveItem(fromIndex: Int, toIndex: Int) -> Hand {
        return deleteItem(at: fromIndex).insertCard(card: cards[fromIndex], at: toIndex)
    }
    
    subscript(index: Int) -> Card {
        return cards[index]
    }
}

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