IAPService.swift

//
//  IAPService.swift
//  Remelo
//
//  Created by Hassan El Desouky on 2/23/20.
//  Copyright © 2020 Hassan El Desouky. All rights reserved.
//

import Foundation
import StoreKit

enum IAPProduct: String {
  case monthlyAutoRenewableSubscription = ""
  case yearlyAutoRenewwableSubscription = ""
}


class IAPService: NSObject {
  private override init() { }
  static let shared = IAPService()
  
  var products = [SKProduct]()
  let paymentQueue = SKPaymentQueue.default()
  
  func getProducts() {
    let products: Set = [IAPProduct.monthlyAutoRenewableSubscription.rawValue,
                         IAPProduct.yearlyAutoRenewwableSubscription.rawValue]
    let request = SKProductsRequest(productIdentifiers: products)
    request.delegate = self
    request.start()
    paymentQueue.add(self)
  }
  
  func purchase(product: IAPProduct) {
    guard let productToPurchace = products.filter({ $0.productIdentifier == product.rawValue }).first else { return }
    let payment = SKPayment(product: productToPurchace)
    paymentQueue.add(payment)
  }
  
  func restorePurchases() {
    print("Restored")
    paymentQueue.restoreCompletedTransactions()
  }
 }

extension IAPService: SKProductsRequestDelegate {
  func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
    self.products = response.products
    for product in products {
      print(product.localizedTitle)
    }
  }
}

extension IAPService: SKPaymentTransactionObserver {
  func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
    for transaction in transactions {
      print(transaction.transactionState.status(), transaction.payment.productIdentifier)
      if transaction.transactionState == .purchasing {
        break
      } else {
        queue.finishTransaction(transaction)
      }
    }
  }
}

extension SKPaymentTransactionState {
  func status() -> String {
    switch self {
    case .deferred:
      return "deferred"
    case .purchased:
      return "purchased"
    case .failed:
      return "failed"
    case .purchasing:
      return "purchasing"
    case .restored:
      return "restored"
    @unknown default:
      return ""
    }
  }
}