//
//  AccountServiceIAPManager.swift
//  Wallet
//
//  Created by Saveliy Stavitsky on 4/12/21.
//  Copyright © 2021 AM. All rights reserved.
//

import Foundation
import StoreKit

extension AccountOnboarding.Service {
    class IAP: NSObject {

        private let newAccountProducatIAPID = "life.malinka.wallet.newaccount"

        var products: [SKProduct] = []
        var transactions = SKPaymentQueue.default().transactions

        var onReceiveProductsHandler: ((Result<[SKProduct], IAPManagerError>) -> Void)?
        var onBuyProductHandler: ((Result<SKPaymentTransaction, Error>) -> Void)?

        static let shared = IAP()

        private override init() {
            super.init()
        }

        func getProducts(withHandler productsReceiveHandler: ((_ result: Result<[SKProduct], IAPManagerError>) -> Void)? = nil) {
            onReceiveProductsHandler = productsReceiveHandler
            let request = SKProductsRequest(productIdentifiers: Set([newAccountProducatIAPID]))
            request.delegate = self
            request.start()
        }

        enum IAPManagerError: Error {
            case noProductIDsFound
            case noProductsFound
            case paymentWasCancelled
            case productRequestFailed
        }

        func canMakePayments() -> Bool {
            return SKPaymentQueue.canMakePayments()
        }

        func startObserving() {
            SKPaymentQueue.default().add(self)
        }

        func stopObserving() {
            SKPaymentQueue.default().remove(self)
        }

        func buy(product: SKProduct, withHandler handler: @escaping ((_ result: Result<SKPaymentTransaction, Error>) -> Void)) {
            let payment = SKPayment(product: product)
            SKPaymentQueue.default().add(payment)
            onBuyProductHandler = handler
        }

        func getAppStoreReceipt() -> String? {
            
            if let appStoreReceiptURL = Bundle.main.appStoreReceiptURL,
                FileManager.default.fileExists(atPath: appStoreReceiptURL.path) {
                do {
                    let receiptData = try Data(contentsOf: appStoreReceiptURL, options: .alwaysMapped)
                    print(receiptData)
                    let receiptString = receiptData.base64EncodedString(options: [])
                    return receiptString
                } catch {
                    print("Couldn't read receipt data with error: " + error.localizedDescription)
                    return nil
                }
            }
            return nil
        }
        
        func finishTransaction(transaction: SKPaymentTransaction) {
            SKPaymentQueue.default().finishTransaction(transaction)
        }
    }
}

extension AccountOnboarding.Service.IAP.IAPManagerError: LocalizedError {
    var errorDescription: String? {
        switch self {
        case .noProductIDsFound: return "No In-App Purchase product identifiers were found."
        case .noProductsFound: return "No In-App Purchases were found."
        case .productRequestFailed: return "Unable to fetch available In-App Purchase products at the moment."
        case .paymentWasCancelled: return "In-App Purchase process was cancelled."
        }
    }
}

extension AccountOnboarding.Service.IAP: SKProductsRequestDelegate {

    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        products = response.products
        if products.count > 0 {
            onReceiveProductsHandler?(.success(products))
        } else {
            onReceiveProductsHandler?(.failure(.noProductsFound))
        }
    }

    func request(_ request: SKRequest, didFailWithError error: Error) {
        onReceiveProductsHandler?(.failure(.productRequestFailed))
    }

    func requestDidFinish(_ request: SKRequest) {
    }
}

extension AccountOnboarding.Service.IAP: SKPaymentTransactionObserver {

    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        transactions.forEach { (transaction) in
            switch transaction.transactionState {
            case .purchased:
                onBuyProductHandler?(.success(transaction))
//                SKPaymentQueue.default().finishTransaction(transaction)
            case .restored:
                break
            case .failed:
                if let error = transaction.error as? SKError {
                    if error.code != .paymentCancelled {
                        onBuyProductHandler?(.failure(error))
                    } else {
                        onBuyProductHandler?(.failure(IAPManagerError.paymentWasCancelled))
                    }
                    print("IAP Error:", error.localizedDescription)
                }
                SKPaymentQueue.default().finishTransaction(transaction)
            case .deferred, .purchasing: break
            @unknown default: break
            }
        }
    }
}

extension SKProduct {
    public func localizedPrice() -> String? {
        let formatter = NumberFormatter()
        formatter.numberStyle = .currency
        formatter.locale = self.priceLocale
        return formatter.string(from: self.price)
    }
}