import UIKit

class CustomViewController<VM: ViewModel>: UIViewController {
    
    private lazy var leftNavigationAction: () -> Void = {
        self.navigationController?.popViewController(animated: true)
    }
    
    var viewModel: VM! {
        didSet {
            viewModelDidLoad()
        }
    }
    
    lazy var loadingView: LoadingView = {
        return LoadingView()
    }()
    
    lazy var errorView: ErrorView = {
        return ErrorView()
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Create the view model if needed
        if (viewModel == nil) {
            viewModel = VM()
        }
        
//        setTheme()
    }
    
    public func showContentView() {
        dropViews([errorView, loadingView])
    }
    
    public func showLoadingView() {
        dropViews([errorView])
        addViewIfNeeded(loadingView)
    }
    
    public func showErrorView(error: String = .defaultError) {
        dropViews([loadingView])
        addViewIfNeeded(errorView)
        errorView.title = error
    }
    
    private func dropViews(_ views: [UIView]) {
        views.forEach { view in
            view.removeFromSuperview()
        }
    }
    
    private func addViewIfNeeded(_ subview: UIView) {
        if (!view.subviews.contains(subview)) {
            view.addSubviewAndFill(subview)
            view.bringSubviewToFront(subview)
        }
    }
    
    func viewModelDidLoad() {
        // Empty
    }
    
    @objc private func leftAction() {
        leftNavigationAction()
    }
    
    func setLeftNavigationButton(_ icon: UIImage, action: (() -> Void)? = nil) {
        
        // Attach left action
        // Or fallback with a pop
        if let leftAction = action {
            leftNavigationAction = leftAction
        } else {
            leftNavigationAction = {
                self.navigationController?.popViewController(animated: true)
            }
        }
        
        navigationItem.leftBarButtonItem = UIBarButtonItem(
            image: .back,
            style: .plain,
            target: self,
            action: #selector(CustomViewController.leftAction)
        )
    }
    func showAlert(title: String, address: String? =  nil , errorMsg: String? =  nil, description: String? = nil){
        
        let showAlert = UIAlertController(title: title, message: errorMsg, preferredStyle: .alert)
        if let address = address {
            let imageView = UIImageView(frame: CGRect(x: 10, y: 50, width: 250, height: 250))
            imageView.image = generateQRCode(from: address)
            imageView.layer.magnificationFilter = CALayerContentsFilter.nearest
            showAlert.view.addSubview(imageView)
            let height = NSLayoutConstraint(item: showAlert.view as Any, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 400)
            let width = NSLayoutConstraint(item: showAlert.view as Any, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant:250)
            showAlert.view.addConstraint(height)
            showAlert.view.addConstraint(width)
            showAlert.addAction(UIAlertAction(title: "Copy Address", style: .default, handler: { action in
                UIPasteboard.general.string = address
                debugPrint("✅✅ Created Invoice ✅✅", address)
            }))
            
        }
        if let description = description {
            showAlert.message = description
        }
        showAlert.addAction(UIAlertAction(title: "OK", style: .default, handler: { action in
            
        }))
        self.present(showAlert, animated: true, completion: nil)
    }
    func generateQRCode(from string: String) -> UIImage? {
        let data = string.data(using: String.Encoding.ascii)
        if let QRFilter = CIFilter(name: "CIQRCodeGenerator") {
            QRFilter.setValue(data, forKey: "inputMessage")
            guard let QRImage = QRFilter.outputImage else {return nil}
            return UIImage(ciImage: QRImage)
        }
        return nil
    }
}