import UIKit

extension UIStoryboard {
    enum Storyboard: String {
        case Main
        // TODO add all the project storyboards here
    }

    convenience init(storyboard: Storyboard, bundle: NSBundle? = nil) {
        self.init(name: storyboard.rawValue, bundle: bundle)
    }

    func instantiateViewController<VC: UIViewController where VC: StoryboardIdentifiable>() -> VC {
        let optionalViewController = self.instantiateViewControllerWithIdentifier(VC.storyboardIdentifier)

        guard let viewController = optionalViewController as? VC  else {
            fatalError("Couldn't instantiate view controller with identifier \(VC.storyboardIdentifier) ")
        }

        return viewController
    }
}

protocol StoryboardIdentifiable {
    static var storyboardIdentifier: String { get }
}

extension StoryboardIdentifiable where Self: UIViewController {
    static var storyboardIdentifier: String {
        return String(self)
    }
}

extension UIViewController : StoryboardIdentifiable { }