//
//  SubscriptionsViewController.swift
//  Earthquake Network
//
//  Created by Busi Andrea on 29/07/2020.
//  Copyright © 2020 Earthquake Network. All rights reserved.
//

import UIKit
import StoreKit
import Shogun


class SubscriptionsViewController: UITableViewController {

    private static let SegueIdentifierSubscriptionDetail = "ShowSubscriptionDetail"
    
    // sezioni
    private enum TableSection: CaseIterable {
        case active
        case description
        case monthly
        case yearly
        case perpetual
        
        var sectionTitle: String? {
            switch self {
            case .monthly: return NSLocalizedString("inapp_monthly_subscriptions", comment: "")
            case .yearly: return NSLocalizedString("inapp_yearly_subscriptions", comment: "")
            case .perpetual: return NSLocalizedString("inapp_lifetime_subscriptions", comment: "")
            default: return nil
            }
        }
    }
    
    private let sections = TableSection.allCases
    
    private var allProducts = [SKProduct]()
    private var monthlyProducts = [SKProduct]()
    private var yearlyProducts = [SKProduct]()
    private var perpetualProducts = [SKProduct]()
    /// Product already bought by the user
    private var subscribedProduct: SKProduct?
    /// Availability for subscriptions
    private var availability: EQNPurchaseAvailability?
    /// Tells if products are loading
    private var isLoading = false
    /// Tells if a restore is in progress
    private var isRestorePurchase = false
    
    // MARK: - View Lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        addObservers()
        configureUI()
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        loadData()
        checkAvailabilities()
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == Self.SegueIdentifierSubscriptionDetail,
            let controller = segue.destination as? SubscriptionDetailViewController,
            let product = sender as? SKProduct {
            controller.product = product
        }
    }
    
    // MARK: - Private
    
    private func addObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(handlePurchaseNotification(_:)),
                                               name: .EQNInAppPurchaseDidComplete,
                                               object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(fail(_:)),
                                               name: .EQNInAppPurchaseDidFail,
                                               object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(handleNoTransactionsNotification(_:)),
                                               name: .EQNInAppPurchaseNoTransactions,
                                               object: nil)
    }
    
    private func configureUI() {
        let restoreButton = UIBarButtonItem(title: NSLocalizedString("purchase_pro_restore", comment: ""),
                                            style: .plain,
                                            target: self,
                                            action: #selector(restoreTapped(_:)))
        navigationItem.rightBarButtonItem = restoreButton

        // if is presented in Simulator, add done button
        if navigationController?.viewControllers.first == self {
            let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(closeTapped(_:)))
            navigationItem.leftBarButtonItem = doneButton
        }
        
        tableView.rowHeight = UITableView.automaticDimension
        tableView.estimatedRowHeight = 600.0
        tableView.registerCell(for: SubscriptionsActiveTableViewCell.self)
        tableView.registerCell(for: SubscriptionsDescriptionTableViewCell.self)
        tableView.registerCell(for: SubscriptionProductTableViewCell.self)
        tableView.registerHeaderFooterView(for: SubscriptionsHeaderTableViewCell.self)
    }
    
    private func updateUI() {
        monthlyProducts.removeAll()
        yearlyProducts.removeAll()
        perpetualProducts.removeAll()
        
        // creates list to show
        let isDiscountAvailable = checkDiscountPrice()
        allProducts.forEach { (product) in
            if isDiscountAvailable {
                if  product.productIdentifier == VersioneProProducts.Identifier.Subscription10kMonthly ||
                    product.productIdentifier == VersioneProProducts.Identifier.Subscription100kMonthly {
                    monthlyProducts.append(product)
                } else if   product.productIdentifier == VersioneProProducts.Identifier.Subscription10kYearlyDiscounted ||
                            product.productIdentifier == VersioneProProducts.Identifier.Subscription100kYearlyDiscounted {
                    yearlyProducts.append(product)
                }
            } else {
                if  product.productIdentifier == VersioneProProducts.Identifier.Subscription10kMonthly ||
                    product.productIdentifier == VersioneProProducts.Identifier.Subscription100kMonthly {
                    monthlyProducts.append(product)
                }
                else if product.productIdentifier == VersioneProProducts.Identifier.Subscription10kYearly ||
                        product.productIdentifier == VersioneProProducts.Identifier.Subscription100kYearly {
                    yearlyProducts.append(product)
                }
            }
            // perpetual scribuscriptions doesn't have discounted version
            if  product.productIdentifier == VersioneProProducts.Identifier.Subscription10kPerpetual ||
                product.productIdentifier == VersioneProProducts.Identifier.Subscription100kPerpetual {
                perpetualProducts.append(product)
            }
        }
        
        tableView.reloadData()
    }
    
    private func loadData() {
        isLoading = true
        
        VersioneProProducts.store.requestProducts{ [weak self] success, products in
            self?.isLoading = false

            guard let self = self, let products = products, success == true else { return }
            
            let purchased = products.filter { (product) -> Bool in
                let isPurchased = VersioneProProducts.store.isProductPurchased(product.productIdentifier)
                let isSubscription = VersioneProProducts.isSubscription(for: product.productIdentifier)
                return isPurchased && isSubscription
            }
            self.subscribedProduct = purchased.first
            self.allProducts = products.sorted(by: { $0.productIdentifier > $1.productIdentifier })
            
            self.updateUI()
        }
    }
    
    private func checkDiscountPrice() -> Bool {
        let downloaded = EQNManager.manager().rete_smartphone?.subscriptionsDiscounted
        return downloaded ?? false
    }
    
    private func checkAvailabilities() {
        EQNPurchaseUtility.availableSubscriptions { (availability) in
            DispatchQueue.main.async {
                self.availability = availability
                self.updateUI()
            }
        }
    }
    
    // MARK: - Actions
    
    @objc func restoreTapped(_ sender: AnyObject) {
        isRestorePurchase = true
        VersioneProProducts.store.restorePurchases()
    }
    
    @objc func closeTapped(_ sender: AnyObject) {
        dismiss(animated: true, completion: nil)
    }
    
    // MARK: - Notifications
    
    @objc func fail(_ notification: Notification){
        VersioneProProducts.store.loadPurchase()
    }
    
    @objc func handlePurchaseNotification(_ notification: Notification) {
        if isRestorePurchase {
            isRestorePurchase = false
            
            var product: String = "unknown"
            if let productIdentifier = notification.object as? String, let productName = resourceNameForProductIdentifier(productIdentifier) {
                product = productName
            }
            
            let message = "\(NSLocalizedString("purchase_pro_restore_alert_message", comment: ""))\n\n(\(product))"
            let alert = UIAlertController(title: NSLocalizedString("purchase_pro_restore_alert_title", comment: ""),
                                          message: message, preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "ok", style: .default, handler: nil))
            present(alert, animated: true, completion: nil)
        }
        
        VersioneProProducts.store.loadPurchase()
        loadData()
    }
    
    @objc func handleNoTransactionsNotification(_ notification: Notification) {
        let alert = UIAlertController(title: NSLocalizedString("attention", comment: ""),
                                      message: NSLocalizedString("purchase_pro_no_subscriptions_alert_message", comment: ""), preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "ok", style: .default, handler: nil))
        present(alert, animated: true, completion: nil)
    }

    // MARK: - Table view data source
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        sections.count
    }
    
    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let tableSection = sections[section]
        let view = tableView.dequeueHeaderFooterView(cellIdentifiable: SubscriptionsHeaderTableViewCell.self)
        view.update(isLoading: isLoading, title: tableSection.sectionTitle)
        return view
    }
    
    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        let tableSection = sections[section]
        if tableSection.sectionTitle != nil {
            return 50
        }
        return 0
    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let tableSection = sections[section]
        switch tableSection {
        case .active: return 1
        case .description: return 1
        case .monthly,
             .yearly,
             .perpetual:
            return availableProducts(for: tableSection).count
        }
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let tableSection = sections[indexPath.section]
        if tableSection == .active {
            let cell = tableView.dequeueReusableCell(cellIdentifiable: SubscriptionsActiveTableViewCell.self, for: indexPath)
            cell.selectionStyle = .none
            cell.update(with: subscribedProduct)
            return cell
        }
        if tableSection == .description {
            let cell = tableView.dequeueReusableCell(cellIdentifiable: SubscriptionsDescriptionTableViewCell.self, for: indexPath)
            cell.selectionStyle = .none
            return cell
        }
        
        let products = availableProducts(for: tableSection)
        let cell = tableView.dequeueReusableCell(cellIdentifiable: SubscriptionProductTableViewCell.self, for: indexPath)
        cell.update(product: products[indexPath.row], availability: availability)
        return cell
    }
    
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        
        let tableSection = sections[indexPath.section]
        let products = availableProducts(for: tableSection)
        if !products.isEmpty {
            performSegue(withIdentifier: Self.SegueIdentifierSubscriptionDetail, sender: products[indexPath.row])
        }
    }
    
    // MARK: - Helpers
    
    private func availableProducts(for section: TableSection) -> [SKProduct] {
        switch section {
        case .monthly: return monthlyProducts
        case .yearly: return yearlyProducts
        case .perpetual: return perpetualProducts
        default: return []
        }
    }
}

extension SubscriptionsViewController: StoryboardInitializable {
    static var storyboardName: String {
        "Main"
    }
    
    static var storyboardControllerId: String {
        "subscriptionsController"
    }
}