import UIKit
import Shared

final class SideMenuPresentTransition: NSObject, UIViewControllerAnimatedTransitioning {
    static let fromViewTag = UUID().hashValue

    init(
        dismissInteractor: SideMenuDismissInteracting,
        menuAnimator: SideMenuAnimating,
        viewAnimator: UIViewAnimating.Type
    ) {
        self.dismissInteractor = dismissInteractor
        self.menuAnimator = menuAnimator
        self.viewAnimator = viewAnimator
        super.init()
    }

    let dismissInteractor: SideMenuDismissInteracting
    let menuAnimator: SideMenuAnimating
    let viewAnimator: UIViewAnimating.Type

    // MARK: UIViewControllerAnimatedTransitioning

    func transitionDuration(using context: UIViewControllerContextTransitioning?) -> TimeInterval { 0.25 }

    func animateTransition(using context: UIViewControllerContextTransitioning) {
        guard let fromVC = context.viewController(forKey: .from),
              let fromSnapshot = fromVC.view.snapshotView(afterScreenUpdates: true),
              let toVC = context.viewController(forKey: .to)
        else {
            context.completeTransition(false)
            return
        }

        context.containerView.addSubview(toVC.view)
        toVC.view.frame = context.containerView.bounds

        let fromView = UIView()
        fromView.tag = Self.fromViewTag
        context.containerView.addSubview(fromView)
        fromView.frame = context.containerView.bounds
        fromView.layer.shadowColor = UIColor.black.cgColor
        fromView.layer.shadowOpacity = 1
        fromView.layer.shadowOffset = .zero
        fromView.layer.shadowRadius = 32
        fromView.addSubview(fromSnapshot)
        fromSnapshot.frame = fromView.bounds
        fromSnapshot.layer.cornerRadius = 0
        fromSnapshot.layer.masksToBounds = true

        dismissInteractor.setup(
            view: fromView,
            action: { fromVC.dismiss(animated: true) }
        )

        viewAnimator.animate(
            withDuration: transitionDuration(using: context),
            animations: {
                self.menuAnimator.animate(in: context.containerView, to: 1)
            },
            completion: { _ in
                let isCancelled = context.transitionWasCancelled
                context.completeTransition(isCancelled == false)
            }
        )
    }
}