//
//  TopicsViewController.swift
//  AeroBuddy
//
//  Created by Luke Collister on 26/09/2019.
//  Copyright © 2019 Luke Collister. All rights reserved.
//

/* This class should display the relevant topics only, based on the selection of subject from the previous TBVC */

import UIKit
import StoreKit

class TopicsViewController: UITableViewController, SKProductsRequestDelegate, SKPaymentTransactionObserver, TopicCellDelegate {

    // MARK: - Declarations
    var subjectVar: Subject?
    var productsSet = Set<String>()
    var displayTopics = [Topic]()
    var allTopics = [Topic]()
    var ownedTopics = [Topic]()
    var mytopic: Topic!
    let workingDG = DispatchGroup()



    // MARK: - Buy Button Methods
    func cellButtonTapped(cell: TopicCell) {
        // Trigger an alert to buy the subject
        let alert = UIAlertController(title: "Purchase Topic?", message: "You do not own this topic. Do you wish to purchase it?", preferredStyle: .alert)

        // Add the topic product identifier to the set
        let buttonPosition: CGPoint = cell.convert(CGPoint.zero, to: self.tableView)
        let indexPath = self.tableView.indexPathForRow(at: buttonPosition)
        productsSet.insert(displayTopics[indexPath!.row].product_identifier!)
        print("PRODUCTS SET: ", productsSet)

        // Yes option
        alert.addAction(UIAlertAction(title: "Yes", style: .default, handler: { action in
           // IAP Code Here
           if (SKPaymentQueue.canMakePayments()) {
               let productsRequest:SKProductsRequest = SKProductsRequest(productIdentifiers: self.productsSet)
               productsRequest.delegate = self
               productsRequest.start()
               print("Fetching Products")
           } else {
               print("Can't make purchases")
           }
        }))
        // No option
        alert.addAction(UIAlertAction(title: "No", style: .cancel, handler: { action in
            self.productsSet.removeAll()
        }))

        self.present(alert, animated: true)
        print("The topic with product identifier ", productsSet, " was selected!")
    }



    // MARK: - IAP Methods
    var product_identifier: String?

    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        let count: Int = response.products.count
        if (count > 0) {
            let validProduct: SKProduct = response.products[0] as SKProduct
            print(validProduct.localizedTitle)
            print(validProduct.localizedDescription)
            print(validProduct.price)
            buyProduct(product: validProduct)
        } else {
            print("nothing")
        }
    }

    func buyProduct(product: SKProduct) {
        print("Sending the Payment Request to Apple")
        let payment = SKPayment(product: product)
        SKPaymentQueue.default().add(payment)
    }

    func request(_ request: SKRequest, didFailWithError error: Error) {
        print("Error Fetching product information")
    }

    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        print("Received Payment Transaction Response from Apple")

        print("Transactions: ", transactions)

        for transaction: AnyObject in transactions {
            if let trans:SKPaymentTransaction = transaction as? SKPaymentTransaction {
                switch trans.transactionState {
                case .purchased:
                    print("Product Purchased")
                    SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
                    // Handle the purchase
                    UserDefaults.standard.set(true , forKey: "purchased")
                    // Get the receipt if it's available
                    if let appStoreReceiptURL = Bundle.main.appStoreReceiptURL, FileManager.default.fileExists(atPath: appStoreReceiptURL.path) {

                        do {
                            let receiptData = try Data(contentsOf: appStoreReceiptURL, options: .alwaysMapped)
                            print("RECEIPT DATA: ", receiptData)

                            let receiptString = receiptData.base64EncodedString(options: [])
                            print("RECEIPT STRING: ", receiptString)

                            // Read receiptData
                            // Create POST request
                            let url = URL(string: "http://fe01.kilosierracharlie.me/verifypayment")!
                            var request = URLRequest(url: url)
                            request.httpMethod = "POST"
                            request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
                            let parameters: [String: Any] = [
                                "receipt": receiptString
                            ]
                            request.httpBody = parameters.percentEncoded()

                            // Send the data
                            print("Before URLSession")
                            let task = URLSession.shared.dataTask(with: request) { data, response, error in
                                guard let data = data, error == nil else {
                                    print(error?.localizedDescription ?? "No data")
                                    print("No data could be sent to the server. Please contact us.")
                                    return
                                }
                                let responseJSON = try? JSONSerialization.jsonObject(with: data, options: [])
                                if let responseJSON = responseJSON as? [String: Any] {
                                    print(responseJSON)
                                    //TO DO: Refresh if error false, else throw error
                                }
                                print("DATA: ", data)
                            }
                            print("Here")
                            task.resume()
                        }
                        catch {
                            print("Couldn't read receipt data with error: " + error.localizedDescription)
                        }
                    }
                    break;

                case .failed:
                    print("Purchased Failed")
                    SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
                    break;

                case .restored:
                    print("Already Purchased")
                    SKPaymentQueue.default().restoreCompletedTransactions()

                    // Handle the purchase
                    UserDefaults.standard.set(true , forKey: "purchased")
                    //adView.hidden = true
                    break;
                default:
                    print("In default")
                    break;
                }
            }
        }
    }



    // MARK: - UITableViewMethods
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
       return self.displayTopics.count
    }


    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
       let cell = tableView.dequeueReusableCell(withIdentifier: "TopicCell", for: indexPath) as! TopicCell
       cell.topic = displayTopics[indexPath.row]
       if (cell.topic?.owned == false) {
           cell.backgroundColor = UIColor(red: 90/255, green: 90/255, blue: 90/255, alpha: 1)
       } else {
           //cell.backgroundColor = default
       }
       cell.delegate = self
       return cell
    }


    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "topicToContentSegue" {
            if let destinationVC = segue.destination as? ContentViewController {
                destinationVC.topic = mytopic
                destinationVC.setup()
            }
        }
    }


    // When the cell is pressed
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        // Determine which Topic was selected
        let selectedTopic = displayTopics[indexPath.row]
        mytopic = selectedTopic
        print("Selected subject: ", displayTopics[indexPath.row])

        // If owned, load the topic
        if (mytopic.owned == true) {
            print("My topic is owned, go to segue")
            performSegue(withIdentifier: "topicToContentSegue", sender: self)
        } else {
            print("My topic is not owned, show alert")
            let alert = UIAlertController(title: "Locked Content", message: "You must purchase this topic to be able to view its content.", preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "Return", style: .cancel, handler: { action in

            }))
            self.present(alert, animated: true)
        }
    }




    // MARK: - Default Methods
    override func viewDidLoad() {
        super.viewDidLoad()

        // Clear all arrays
        displayTopics.removeAll()
        allTopics.removeAll()
        ownedTopics.removeAll()

        // Set the title based to the selected Course
        self.title = subjectVar?.title

        // Get owned Topics
        DispatchQueue.global(qos: .background).async {
            self.workingDG.enter()
            self.getAllTopics(endpoint: "topics")
            self.workingDG.enter()
            self.getAllTopics(endpoint: "topics/my")

            self.workingDG.notify(queue: .main) {
                for i in 0 ..< self.ownedTopics.count {
                    self.ownedTopics[i].owned = true
                }

                var idArray = [Int]()
                for topic in self.ownedTopics {
                    idArray.append(topic.id)
                }
                for var topic in self.allTopics {
                    topic.owned = idArray.contains(topic.id)
                    // Display topics only in the selected subject
                    if var topics = self.subjectVar!.topics {
                        for top in topics {
                            self.displayTopics.append(top)
                        }
                    }
                }
                self.tableView.reloadData()
            }
        }
        SKPaymentQueue.default().add(self)
    }



    // MARK: - JSON Methods
    func getAllTopics(endpoint: String) {
       let url = URL(string: "\(ServHandler.connectProtocol)://\(ServHandler.baseURL)/\(endpoint)")
       let task = URLSession.shared.dataTask(with: url!) {(data, response, error) in
           guard error == nil else {
               print("Error!")
               return
           }
           guard let content = data else {
               print("There is no data!")
               return
           }

           let decoder = JSONDecoder()
           do {
               for var topic in try decoder.decode([Topic].self, from: content) {
                   if (endpoint == "topics") {
                       topic.product_identifier = "com.aerobuddy.topic.\(topic.id)"
                       self.allTopics.append(topic)
                   }
                   else {
                       self.ownedTopics.append(topic)
                   }
               }
               self.workingDG.leave()
               return
           }
           catch {
               print(error.localizedDescription)
               print(error)
               return
           }
       }
       task.resume()
    }
}