//
//  AppDelegate.swift
//  NetNewsWire
//
//  Created by Maurice Parker on 4/8/19.
//  Copyright © 2019 Ranchero Software. All rights reserved.
//

import UIKit
import RSCore
import RSWeb
import Account
import UserNotifications
import os.log

var appDelegate: AppDelegate!

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDelegate, UnreadCountProvider {

	private var backgroundUpdateTask = UIBackgroundTaskIdentifier.invalid
	
	var log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "application")
	var window: UIWindow?

	var faviconDownloader: FaviconDownloader!
	var imageDownloader: ImageDownloader!
	var authorAvatarDownloader: AuthorAvatarDownloader!
	var feedIconDownloader: FeedIconDownloader!

	var unreadCount = 0 {
		didSet {
			if unreadCount != oldValue {
				postUnreadCountDidChangeNotification()
				UIApplication.shared.applicationIconBadgeNumber = unreadCount
			}
		}
	}
	
	override init() {
		
		super.init()
		appDelegate = self
		
		NotificationCenter.default.addObserver(self, selector: #selector(unreadCountDidChange(_:)), name: .UnreadCountDidChange, object: nil)
		NotificationCenter.default.addObserver(self, selector: #selector(accountRefreshDidFinish(_:)), name: .AccountRefreshDidFinish, object: nil)
		NotificationCenter.default.addObserver(self, selector: #selector(userDefaultsDidChange(_:)), name: UserDefaults.didChangeNotification, object: nil)
		
		// Reinitialize the shared state as early as possible
		_ = AccountManager.shared
		
	}

	func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
		
		// Set up the split view
		let splitViewController = window!.rootViewController as! UISplitViewController
		let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as! UINavigationController
		navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem
		splitViewController.delegate = self
		
		AppDefaults.registerDefaults()
		let isFirstRun = AppDefaults.isFirstRun
		if isFirstRun {
			os_log("Is first run.", log: log, type: .info)
		}
		
		let localAccount = AccountManager.shared.defaultAccount
		DefaultFeedsImporter.importIfNeeded(isFirstRun, account: localAccount)
		
		let tempDir = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!
		let faviconsFolderURL = tempDir.appendingPathComponent("Favicons")
		try! FileManager.default.createDirectory(at: faviconsFolderURL, withIntermediateDirectories: true, attributes: nil)
		faviconDownloader = FaviconDownloader(folder: faviconsFolderURL.absoluteString)
		
		let imagesFolderURL = tempDir.appendingPathComponent("Images")
		try! FileManager.default.createDirectory(at: imagesFolderURL, withIntermediateDirectories: true, attributes: nil)
		imageDownloader = ImageDownloader(folder: imagesFolderURL.absoluteString)

		authorAvatarDownloader = AuthorAvatarDownloader(imageDownloader: imageDownloader)
		feedIconDownloader = FeedIconDownloader(imageDownloader: imageDownloader)

		DispatchQueue.main.async {
			self.unreadCount = AccountManager.shared.unreadCount
		}
		
		UNUserNotificationCenter.current().requestAuthorization(options:[.badge, .sound, .alert]) { (granted, error) in
			if granted {
				DispatchQueue.main.async {
					UIApplication.shared.registerForRemoteNotifications()
				}
			}
		}

		updateBackgroundRefreshInterval()

		return true
		
	}

//	func application(_ application: UIApplication, shouldSaveApplicationState coder: NSCoder) -> Bool {
//
//		let versionNumber = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as! String
//		coder.encode(versionNumber, forKey: "VersionNumber")
//
//		return true
//
//	}
//
//	func application(_ application: UIApplication, shouldRestoreApplicationState coder: NSCoder) -> Bool {
//		if let storedVersionNumber = coder.decodeObject(forKey: "VersionNumber") as? String {
//			let versionNumber = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as! String
//			if versionNumber == storedVersionNumber {
//				return true
//			}
//		}
//		return false
//	}
	
	func applicationWillResignActive(_ application: UIApplication) {
		// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
		// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
	}

	func applicationDidEnterBackground(_ application: UIApplication) {
		// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
		// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
	}

	func applicationWillEnterForeground(_ application: UIApplication) {
		// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
	}

	func applicationDidBecomeActive(_ application: UIApplication) {
		
		// If we haven't refreshed the database for 15 minutes, run a refresh automatically
		if let lastRefresh = AppDefaults.lastRefresh {
			if Date() > lastRefresh.addingTimeInterval(15 * 60) {
				AccountManager.shared.refreshAll()
			}
		} else {
			AccountManager.shared.refreshAll()
		}

	}

	func applicationWillTerminate(_ application: UIApplication) {
		// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
	}

	func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
		
		os_log("Woken to perform account refresh.", log: log, type: .info)
		
		var startingUnreadCount = 0
		
		let completeProcessing = { [unowned self] in
			
			UIApplication.shared.endBackgroundTask(self.backgroundUpdateTask)
			self.backgroundUpdateTask = UIBackgroundTaskIdentifier.invalid
			
			if startingUnreadCount < self.unreadCount {
				self.sendReceivedArticlesUserNotification(newArticleCount: self.unreadCount - startingUnreadCount)
				completionHandler(.newData)
			} else {
				completionHandler(.noData)
			}
			
		}
		
		DispatchQueue.global(qos: .background).async { [unowned self] in
			
			self.backgroundUpdateTask = UIApplication.shared.beginBackgroundTask {
				completeProcessing()
				os_log("Accounts refresh processing terminated for running too long.", log: self.log, type: .info)
			}
			
			while(!AccountManager.shared.isUnreadCountsInitialized) {
				os_log("Waiting for unread counts to be initialized...", log: self.log, type: .debug)
				sleep(1)
			}
			
			startingUnreadCount = self.unreadCount
			
			DispatchQueue.main.async {
				AccountManager.shared.refreshAll()
			}
			
			os_log("Accounts requested to begin refresh.", log: self.log, type: .debug)
			
			sleep(1)
			while(!AccountManager.shared.combinedRefreshProgress.isComplete) {
				os_log("Waiting for account refresh processing to complete...", log: self.log, type: .debug)
				sleep(1)
			}
			
			completeProcessing()
			os_log("Accounts completed refresh processing.", log: self.log, type: .info)
			
		}
		
	}
	
	// MARK: - Split view

	func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController:UIViewController, onto primaryViewController:UIViewController) -> Bool {
	    guard let secondaryAsNavController = secondaryViewController as? UINavigationController else { return false }
	    guard let topAsDetailController = secondaryAsNavController.topViewController as? DetailViewController else { return false }
	    if topAsDetailController.navState?.currentArticle == nil {
	        // Return true to indicate that we have handled the collapse by doing nothing; the secondary controller will be discarded.
	        return true
	    }
	    return false
	}

	// MARK: Notifications
	
	@objc func unreadCountDidChange(_ note: Notification) {
		if note.object is AccountManager {
			unreadCount = AccountManager.shared.unreadCount
		}
	}
	
	@objc func userDefaultsDidChange(_ note: Notification) {
		updateBackgroundRefreshInterval()
	}

	@objc func accountRefreshDidFinish(_ note: Notification) {
		AppDefaults.lastRefresh = Date()
	}
	
	// MARK: - API
	
	func logMessage(_ message: String, type: LogItem.ItemType) {
		print("logMessage: \(message) - \(type)")
		
	}
	
	func logDebugMessage(_ message: String) {
		logMessage(message, type: .debug)
	}
	
}

private extension AppDelegate {
	
	func updateBackgroundRefreshInterval() {
		let refreshInterval = AppDefaults.refreshInterval
		if refreshInterval == .manually {
			UIApplication.shared.setMinimumBackgroundFetchInterval(UIApplication.backgroundFetchIntervalNever)
		} else {
			UIApplication.shared.setMinimumBackgroundFetchInterval(AppDefaults.refreshInterval.inSeconds())
		}
	}
	
	func sendReceivedArticlesUserNotification(newArticleCount: Int) {

		let content = UNMutableNotificationContent()
		content.title = NSLocalizedString("Article Download", comment: "New Articles")
		
		let body: String = {
			if newArticleCount == 1 {
				return NSLocalizedString("You have downloaded 1 new article.", comment: "Article Downloaded")
			} else {
				let formatString = NSLocalizedString("You have downloaded %d new articles.", comment: "Articles Downloaded")
				return NSString.localizedStringWithFormat(formatString as NSString, newArticleCount) as String
			}
		}()
		
		content.body = body
		content.sound = UNNotificationSound.default
		
		let request = UNNotificationRequest.init(identifier: "NewArticlesReceived", content: content, trigger: nil)
		UNUserNotificationCenter.current().add(request)
		
	}
	
}