//
//  AllCoursesViewController.swift
//  AeroBuddy
//
//  Created by Luke Collister on 01/09/2019.
//  Copyright © 2019 Luke Collister. All rights reserved.
//

import UIKit
import StoreKit

class AllCoursesViewController: UITableViewController, SKProductsRequestDelegate, SKPaymentTransactionObserver, CourseCellDelegate {

    // MARK: - Variable Declarations
    var tempData = [Course]()

    var allCourses = [Course]()
    var ownedCourses = [Course]()
    var displayCourses = [Course]()
    var products = [String: SKProduct]()
    var mycourse: Course!

    var hasFinishedLoading = true

    let workingDG = DispatchGroup()

    var productsSet = Set<String>()


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

    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        for validProduct in response.products{

            products[validProduct.productIdentifier] = validProduct

            for course in displayCourses {
                if( course.product_identifier! == validProduct.productIdentifier ){
                    course.price = validProduct.regularPrice
                }
            }
        }
        DispatchQueue.main.async {
            self.tableView.reloadData()
        }
    }

    func buyProduct(product: SKProduct) {
        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]) {

        for transaction: AnyObject in transactions {
            if let trans:SKPaymentTransaction = transaction as? SKPaymentTransaction {
                switch trans.transactionState {
                case .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)

                            let receiptString = receiptData.base64EncodedString(options: [])

                            // 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
                            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 (responseJSON as? [String: Any]) != nil {
                                    //TO DO: Refresh if error false, else throw error
                                }
                            }
                            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)
                    print( transaction.error.debugDescription )
                    break;

                case .restored:
                    SKPaymentQueue.default().restoreCompletedTransactions()

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

    @objc func userActReload(){

        if( hasFinishedLoading ){

            hasFinishedLoading = false

            displayCourses.removeAll()
            ownedCourses.removeAll()
            allCourses.removeAll()
            self.tableView.reloadData()


            let activityIndicator = MyIndicator(frame: CGRect(x: UIScreen.main.bounds.size.width/2 - 75, y: UIScreen.main.bounds.size.height/2 - 150, width: 150, height: 150), image: UIImage(named: "LOADING.png")!)
            view.addSubview(activityIndicator)
            activityIndicator.startAnimating()

            DispatchQueue.global(qos: .background).async {
                APIHandler.load( endpoint: .AllCourses, completion: {( data ) in
                    for e in data {
                        let tc : Course = e as! Course
                        self.productsSet.insert( tc.product_identifier! )
                        forOwned:
                        for sub in tc.subjects! {
                            if (sub.owned ?? false) {
                                tc.partOwned = true
                                break
                            }
                            for top in sub.topics! {
                                if (top.owned ?? false) {
                                    tc.partOwned = true
                                    break forOwned
                                }
                            }
                        }
                        self.displayCourses.append( tc )
                    }

                    APIHandler.load( endpoint: .OwnedCourses, completion: {( data ) in
                        for e in data {
                            let tc : Course = e as! Course
                            for o in self.displayCourses {
                                if o.id == tc.id {
                                    o.owned = true
                                }
                            }
                        }

                        let productsRequest: SKProductsRequest = SKProductsRequest(productIdentifiers: self.productsSet)
                        productsRequest.delegate = self
                        productsRequest.start()

                        DispatchQueue.main.async {
                            self.tableView.reloadData()
                            activityIndicator.stopAnimating()
                            self.hasFinishedLoading = true
                        }
                    })
                })
            }
        }
    }

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

        // Provide an empty backBarButton to hide the 'Back' text present by default in the back button.
        self.navigationItem.setHidesBackButton(true, animated:true)

        // Add a right navigation bar button to allow refreshing of JSON
        navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "arrow.clockwise"), style: .plain, target: self, action: #selector( userActReload ) )

        // IAP Code
        SKPaymentQueue.default().add(self)

        userActReload()
    }

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


    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CourseCell", for: indexPath) as! CourseCell
        cell.course = displayCourses[indexPath.row]
        if (cell.course?.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
    }


    // When the cell is pressed
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        // Determine which Course was selected
        let selectedCourse = displayCourses[indexPath.row]
        mycourse = selectedCourse

        // Load the subjects for this course
        performSegue(withIdentifier: "courseToSubjectSegue", sender: self)
    }


    func cellButtonTapped(cell: CourseCell) {
        // Trigger an alert to buy the course
        let alert = UIAlertController(title: "Purchase Course?", message: "You do not own this course. Do you wish to purchase it? Pressing \"Yes\" will purchase *all* subjects and topics within the course.", preferredStyle: .alert)

        // Add the course product identifier to the set
        let buttonPosition: CGPoint = cell.convert(CGPoint.zero, to: self.tableView)
        let indexPath = self.tableView.indexPathForRow(at: buttonPosition)

        // Yes option
        alert.addAction(UIAlertAction(title: "Yes", style: .default, handler: { action in
           // IAP Code Here
           if (SKPaymentQueue.canMakePayments()) {
                self.buyProduct(product: self.products[ self.displayCourses[indexPath!.row].product_identifier! ]! )
           } 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)
    }


    // MARK: - Segue Methods
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "courseToSubjectSegue" {
            if let destinationVC = segue.destination as? SubjectsViewController {
                destinationVC.courseVar = mycourse
            }
        }
    }
}


// MARK: - Extensions
extension Dictionary {
    func percentEncoded() -> Data? {
        return map { key, value in
            let escapedKey = "\(key)".addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed) ?? ""
            let escapedValue = "\(value)".addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed) ?? ""
            return escapedKey + "=" + escapedValue
        }
        .joined(separator: "&")
        .data(using: .utf8)
    }
}

extension CharacterSet {
    static let urlQueryValueAllowed: CharacterSet = {
        let generalDelimitersToEncode = ":#[]@" // does not include "?" or "/" due to RFC 3986 - Section 3.4
        let subDelimitersToEncode = "!$&'()*+,;="

        var allowed = CharacterSet.urlQueryAllowed
        allowed.remove(charactersIn: "\(generalDelimitersToEncode)\(subDelimitersToEncode)")
        return allowed
    }()
}

extension SKProduct {

    /// - returns: The cost of the product formatted in the local currency.
    var regularPrice: String? {
        let formatter = NumberFormatter()
        formatter.numberStyle = .currency
        formatter.locale = self.priceLocale
        return formatter.string(from: self.price)
    }

}