final class IAPManager: NSObject, SKProductsRequestDelegate, SKPaymentTransactionObserver {
    static let shared = IAPManager()

    private var products = [SKProduct]()

    private var productBeingPurchased: SKProduct?

    enum Product: String, CaseIterable {
        case removeAds = "JokesRUs.RemoveAds"
        case summerIcon = "JokesRUs.Icons.Summer"
        case tacoIcon = "JokesRUs.Icons.Taco"
        case pizzaIcon = "JokesRUs.Icons.Pizza"
        case hotdogIcon = "JokesRUs.Icons.HotDog"
        case hamburgerIcon = "JokesRUs.Icons.Hamburger"
        case doughnutIcon = "JokesRUs.Icons.Doughnut"
    }
    let group = DispatchGroup()
    
    public func fetchProducts() {
        let request = SKProductsRequest(productIdentifiers: Set(Product.allCases.compactMap(({ $0.rawValue }))))
        request.delegate = self
        request.start()
    }
    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        products = response.products
    }
    func request(_ request: SKRequest, didFailWithError error: Error) {
        guard request is SKProductsRequest else {
            return
        }

        print("Product fetch request failed")
    }
    public func purchase(product: Product, completion: @escaping () -> Void) {
        guard SKPaymentQueue.canMakePayments() else {
            return
        }
        guard let storeKitProduct = products.first(where: { $0.productIdentifier == product.rawValue }) else {
            return
        }
        Utilities.purchaseFailed = Bool()
        let paymentRequest = SKPayment(product: storeKitProduct)
        SKPaymentQueue.default().add(self)
        SKPaymentQueue.default().add(paymentRequest)
        completion()
    }
    public func restore() {
        print("start restore")
        Utilities.restoredPurchases = false
        SKPaymentQueue.default().restoreCompletedTransactions()
    }
    
    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        transactions.forEach({ transaction in
            switch transaction.transactionState {
            case .purchasing:
                //No op
                print("purchasing")
                break
            case .purchased:
                handlePurchase(transaction.payment.productIdentifier)
                Utilities.purchaseFailed = false
                break
            case .failed:
                print("purchase failed")
                Utilities.purchaseFailed = true
                Utilities.restoredPurchases = false
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "checkFailedPurchase"), object: nil)
                break
            case .restored:
                print("purchases restored")
                handlePurchase(transaction.payment.productIdentifier)
                Utilities.restoredPurchases = true
                print("finish restore")
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "checkRestored"), object: nil)
                SKPaymentQueue.default().finishTransaction(transaction)
                break
            case .deferred:
                print("deferred")
                break
            @unknown default:
                print("default")
                break
            }
        })
}
    private func handlePurchase(_ id: String) {
        print("Pass on Icon = \(IconChange.passOnIcon)")
        UserDefaults.standard.setValue(true, forKey: id)
        print("id = \(id)")
        Utilities.purchaseID = id
        
        if id == "JokesRUs.RemoveAds" {
            Utilities.ShowAds = false
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "AdsRemoved"), object: nil)
        }
        if id == "JokesRUs.Icons.Summer" {
            print("summer bought")
            IconChange.setIconPurchased = true
            IconChange.summerIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "summerIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
        if id == "JokesRUs.Icons.Taco" {
            print("taco bought")
            IconChange.setIconPurchased = true
            IconChange.tacoIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "tacoIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
        if id == "JokesRUs.Icons.Pizza" {
            print("pizza bought")
            IconChange.setIconPurchased = true
            IconChange.pizzaIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "pizzaIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
        if id == "JokesRUs.Icons.HotDog" {
            print("hotdog bought")
            IconChange.setIconPurchased = true
            IconChange.hotdogIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "hotdogIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
        if id == "JokesRUs.Icons.Hamburger" {
            print("hamburger bought")
            IconChange.setIconPurchased = true
            IconChange.hamburgerIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "hamburgerIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
        if id == "JokesRUs.Icons.Doughnut" {
            print("doughnut bought")
            IconChange.setIconPurchased = true
            IconChange.doughnutIconUnlocked = true
            IconChange.numUnlocked = IconChange.numUnlocked + 1
            UserDefaults.standard.setValue(IconChange.numUnlocked + 1, forKey: "numUnlocked")
            UserDefaults.standard.setValue(true, forKey: "doughnutIconUnlocked")
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "setIcon"), object: nil)
        }
    }
}