/*

 Copyright (C) 2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The Data View Controller displays a flag, and controls the 'Reveal' button for showing the answer.

*/

import UIKit

class DataViewController: UIViewController {

    // MARK: Properties

    @IBOutlet weak var answerLabel: UILabel!

    @IBOutlet weak var flagLabel: UILabel!

    @IBOutlet weak var revealButton: UIButton!

    var regionCode: String? {

        didSet {

            if let regionCode = regionCode {

                // Offset for flags range in Unicode.

                flag = ""

                let base: UInt32 = 127397

                for character in regionCode.unicodeScalars {

                    guard let unicodeScalar = UnicodeScalar(base + character.value) else {

                        // `base` + `character.value` is an invalid unicode scalar value.

                        continue

                    }

                    flag?.append(String(unicodeScalar))

                }

            }

            else {

                flag = nil

            }

        }

    }

    private var flag: String?

    // MARK: UIViewController

    override func viewWillAppear(_ animated: Bool) {

        super.viewWillAppear(animated)

        guard let regionCode = regionCode else { fatalError("No region code has been set") }

        answerLabel.text = Locale.current.localizedString(forRegionCode: regionCode)

        flagLabel.text = flag

        answerLabel.isHidden = true

        revealButton.isHidden = false

    }

    @IBAction func revealAnswer(sender: UIButton) {

        answerLabel.isHidden = false

        revealButton.isHidden = true

    }

}