#import 
#import 

@interface ViewController : UIViewController<
SKProductsRequestDelegate,SKPaymentTransactionObserver> {
   SKProductsRequest *productsRequest;
   NSArray *validProducts;
   UIActivityIndicatorView *activityIndicatorView;
   IBOutlet UILabel *productTitleLabel;
   IBOutlet UILabel *productDescriptionLabel;
   IBOutlet UILabel *productPriceLabel;
   IBOutlet UIButton *purchaseButton;
}

- (void)fetchAvailableProducts;
- (BOOL)canMakePurchases;
- (void)purchaseMyProduct:(SKProduct*)product;
- (IBAction)purchase:(id)sender;

@end

#import "ViewController.h"
#define kTutorialPointProductID 
@"com.tutorialPoints.testApp.testProduct"

@interface ViewController ()
@end

@implementation ViewController

- (void)viewDidLoad {
   [super viewDidLoad];
   
   // Adding activity indicator
   activityIndicatorView = [[UIActivityIndicatorView alloc]
   initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
   activityIndicatorView.center = self.view.center;
   [activityIndicatorView hidesWhenStopped];
   [self.view addSubview:activityIndicatorView];
   [activityIndicatorView startAnimating];
   
   //Hide purchase button initially
   purchaseButton.hidden = YES;
   [self fetchAvailableProducts];
}

- (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
   // Dispose of any resources that can be recreated.
}

-(void)fetchAvailableProducts {
   NSSet *productIdentifiers = [NSSet 
   setWithObjects:kTutorialPointProductID,nil];
   productsRequest = [[SKProductsRequest alloc] 
   initWithProductIdentifiers:productIdentifiers];
   productsRequest.delegate = self;
   [productsRequest start];
}

- (BOOL)canMakePurchases {
   return [SKPaymentQueue canMakePayments];
}

- (void)purchaseMyProduct:(SKProduct*)product {
   if ([self canMakePurchases]) {
      SKPayment *payment = [SKPayment paymentWithProduct:product];
      [[SKPaymentQueue defaultQueue] addTransactionObserver:self];
      [[SKPaymentQueue defaultQueue] addPayment:payment];
   } else {
      UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:
      @"Purchases are disabled in your device" message:nil delegate:
      self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
      [alertView show];
   }
}
-(IBAction)purchase:(id)sender {
   [self purchaseMyProduct:[validProducts objectAtIndex:0]];
   purchaseButton.enabled = NO; 
}

#pragma mark StoreKit Delegate

-(void)paymentQueue:(SKPaymentQueue *)queue 
updatedTransactions:(NSArray *)transactions {
   for (SKPaymentTransaction *transaction in transactions) {
      switch (transaction.transactionState) {
         case SKPaymentTransactionStatePurchasing:
            NSLog(@"Purchasing");
         break;
         
         case SKPaymentTransactionStatePurchased:
            if ([transaction.payment.productIdentifier 
            isEqualToString:kTutorialPointProductID]) {
               NSLog(@"Purchased ");
               UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:
               @"Purchase is completed succesfully" message:nil delegate:
               self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
               [alertView show];
            }
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
         break;
            
         case SKPaymentTransactionStateRestored:
            NSLog(@"Restored ");
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
         break;
            
         case SKPaymentTransactionStateFailed:
            NSLog(@"Purchase failed ");
         break
         default:
         break;
      }
   }
}

-(void)productsRequest:(SKProductsRequest *)request 
didReceiveResponse:(SKProductsResponse *)response {
   SKProduct *validProduct = nil;
   int count = [response.products count];
   
   if (count>0) {
      validProducts = response.products;
      validProduct = [response.products objectAtIndex:0];
      
      if ([validProduct.productIdentifier 
         isEqualToString:kTutorialPointProductID]) {
         [productTitleLabel setText:[NSString stringWithFormat:
            @"Product Title: %@",validProduct.localizedTitle]];
         [productDescriptionLabel setText:[NSString stringWithFormat:
            @"Product Desc: %@",validProduct.localizedDescription]];
         [productPriceLabel setText:[NSString stringWithFormat:
            @"Product Price: %@",validProduct.price]];
      }
   } else {
      UIAlertView *tmp = [[UIAlertView alloc]
         initWithTitle:@"Not Available"
         message:@"No products to purchase"
         delegate:self
         cancelButtonTitle:nil
         otherButtonTitles:@"Ok", nil];
         [tmp show];
   }
   
   [activityIndicatorView stopAnimating];
   purchaseButton.hidden = NO;
}
@end