let cellId = "cellId"
var fetchedStatsArray: [NSManagedObject] = []

fileprivate lazy var fetchedResultsController: NSFetchedResultsController<AlarmItem> = {
    //create fetch request
    let fetchRequest: NSFetchRequest<AlarmItem> = AlarmItem.fetchRequest()

    //configure fetch request
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "alarmAttributes", ascending: true)]
    let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

    let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)

    let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

    fetchedResultsController.delegate = self

    return fetchedResultsController
}()

func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
    tableView.beginUpdates()
}

func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
    tableView.endUpdates()
}

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {

    switch(type) {
    case .insert:
        if let indexPath = newIndexPath {
            tableView.insertRows(at: [indexPath], with: .fade)
        }
        break;
    case .delete:
        if let indexPath = indexPath {
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
        break;
    case .update:
        //this is mostlikely where the problem lies
        //self.tableView.reloadData()
        if let indexPath = indexPath, let cell = tableView.cellForRow(at: indexPath) {
            configureCell(cell, at: indexPath)
        }
        break;
    case .move:
        if let indexPath = indexPath {
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
        if let newIndexPath = newIndexPath {
            tableView.insertRows(at: [newIndexPath], with: .fade)
        }
        break;
    @unknown default:
        print("Something odd is happening")
    }
}


override func viewDidLoad() {
    super.viewDidLoad()


override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    do {
        try fetchedResultsController.performFetch()
    } catch let err as NSError {
        print("Failed to fetch items", err)
    }
}

@objc func addAlarmItem(_ sender: AnyObject) {
    let alertController = UIAlertController(title: "Add New Item", message: "Please fill in the blanks", preferredStyle: .alert)
    let saveAction = UIAlertAction(title: "Save", style: .default) { [unowned self] action in

        //combined string of attributes
        let myStrings: [String] = alertController.textFields!.compactMap { $0.text }
        let myText = myStrings.joined(separator: ",")

        self.save(myText)
        self.tableView.reloadData()
    }

    let cancelAction = UIAlertAction(title: "Cancel", style: .destructive, handler: nil)

    alertController.addTextField { (textField) in
        textField.placeholder = "Enter Name of Engineer"
    }
    alertController.addTextField { (textField) in
        textField.placeholder = "Enter Date of Alarm in DD/MM/YYYY"
    }
    alertController.addTextField { (textField) in
        textField.placeholder = "Enter Time of Alarm in 24h (eg: 2300)"
    }
    alertController.addTextField { (textField) in
        textField.placeholder = "Please indicate True/False (type True or False)"
    }
    alertController.addTextField { (textField) in
        textField.placeholder = "Insert comments (if any), or NIL"
    }


    if let popoverController = alertController.popoverPresentationController {
        popoverController.sourceView = self.view;
        popoverController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0.0, height: 0.0)
        popoverController.permittedArrowDirections = []
        popoverController.barButtonItem = self.navigationItem.leftBarButtonItem
    }
    self.present(alertController, animated: true, completion: nil)
}

func save(_ itemName: String) {
    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
    let managedContext = appDelegate.persistentContainer.viewContext
    let entity = NSEntityDescription.entity(forEntityName: "AlarmItem", in: managedContext)!
    let item = NSManagedObject(entity: entity, insertInto: managedContext)
    item.setValue(itemName, forKey: "alarmAttributes")

    do {
        try managedContext.save()
        tableView.reloadData()

    } catch let err as NSError {
        print("Failed to save an item", err)
    }
}

@objc func exportCSV(_ sender: AnyObject) {
    exportDatabase()
}

func exportDatabase() {
    let exportString = createExportString()
    saveAndExport(exportString: exportString)
}

func saveAndExport(exportString: String) {
    let exportFilePath = NSTemporaryDirectory() + "itemlist.csv"
    let exportFileUrl = NSURL(fileURLWithPath: exportFilePath)
    FileManager.default.createFile(atPath: exportFilePath, contents: NSData() as Data, attributes: nil)
    var fileHandle: FileHandle? = nil

    do {
        fileHandle = try FileHandle(forUpdating: exportFileUrl as URL)
    } catch {
        print("filehandle has error")
    }

    if fileHandle != nil {
        fileHandle!.seekToEndOfFile()
        let csvData = exportString.data(using: String.Encoding.utf8, allowLossyConversion: false)
        fileHandle!.write(csvData!)
        fileHandle!.closeFile()

        let firstActivityItem = NSURL(fileURLWithPath: exportFilePath)
        let activityViewController : UIActivityViewController = UIActivityViewController(activityItems: [firstActivityItem], applicationActivities: nil)

        activityViewController.excludedActivityTypes = [
            UIActivity.ActivityType.assignToContact,
            UIActivity.ActivityType.saveToCameraRoll,
            UIActivity.ActivityType.postToFlickr,
            UIActivity.ActivityType.postToVimeo,
            UIActivity.ActivityType.postToTencentWeibo
        ]
        activityViewController.popoverPresentationController?.sourceView = self.view
        activityViewController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection()
        activityViewController.popoverPresentationController?.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
        self.present(activityViewController, animated: true, completion: nil)
    }
}

func createExportString() -> String {
    var alarmAttributes: String?
    var export: String = NSLocalizedString("Engineer Name,Date of Alarm,Time of Alarm,True or False,Engineer Comments n", comment: "")

    for (index, AlarmItem) in fetchedStatsArray.enumerated() {
        if index <= fetchedStatsArray.count - 1 {
            alarmAttributes = AlarmItem.value(forKey: "alarmAttributes") as! String?
            let alarmAttributeStrings = alarmAttributes
            export += "(alarmAttributeStrings ?? "0") n"
        }
    }
    print("the app will now print: (export) ")
    return export
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
    let sectionInfo = fetchedResultsController.sections![section]
    return sectionInfo.numberOfObjects
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath)
    let alarmItem = fetchedResultsController.object(at: indexPath) as NSManagedObject
    cell.textLabel?.text = alarmItem.value(forKeyPath: "alarmAttributes") as? String
    return cell
}

func tableView(_ tableView: UITableView!, canEditRowAtIndexPath indexPath: NSIndexPath!) -> Bool {
    return true
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    tableView.deselectRow(at: indexPath, animated: true)
}

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
    guard editingStyle == .delete else { return }

    //fetch
    let toBeDeleted = fetchedResultsController.object(at: indexPath)

    //delete
    fetchedResultsController.managedObjectContext.delete(toBeDeleted)

    do {
        try fetchedResultsController.managedObjectContext.save()
    } catch let err as NSError {
        print("failed to save item", err)
    }

}

func tableView(_tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "AlarmItem", for: indexPath)
    configureCell(cell, at: indexPath)

    return cell
}

func configureCell(_ cell: UITableViewCell, at indexPath: IndexPath) {
    let alarmItem = fetchedResultsController.object(at: indexPath)

    //configure cell
    cell.textLabel?.text = alarmItem.value(forKeyPath: "alarmAttributes") as? String
}