import VSStoreKit

// 1. Create an instance conforming to PurchasedProductsProtocol 
let puchasedProducts: PurchasedProductsProtocol = PurchasedProducts()

// 2. Provide StoreAccess purchaseCompletionHandler so it can mark products as purchased
let storeAccess = StoreAccess.shared
storeAccess.purchaseCompletionHandler = { purchasedProductIdentifier in
    puchasedProducts.markProductAsPurchased(purchasedProductIdentifier)
}

// 3. Create an instance conforming to LocalProductsDataSource with your products (in-app purchases)
let localProducts: LocalProductsDataSource = LocalProducts()

// 4. Request products from the store
storeAccess.requestProductsWithIdentifiers(localProducts.productIdentifiers)

// 5. Instantiate ProductsDataSource object that you will use to populate your UITableView, UICollectionView or whatever with products (in-app purchases)
let productsDataSource = ProductsDataSource(localProducts: localProducts, storeProducts: storeAccess)

// 6. Buy product
let productIdentifier = productsDataSource.identifierForProductAtIndex(index)
storeAccess.purchaseProductWithIdentifier(productIdentifier)

// 7. Observe StoreAccess state change with help of StoreAccessObserver by providing it optional handlers for the states you are interested in
let storeAccessObserver = StoreAccessObserver()
storeAccessObserver.receivedProductsStateHandler = {
    // reload your products presentation
}
storeAccessObserver.purchasedStateHandler = {
    // reload your products presentation
}