//
//  FFAnimationTransitioning.swift
//  FFAlert
//
//  Created by FFIB on 2017/11/13.
//  Copyright © 2017年 FFIB. All rights reserved.
//

import UIKit

class FFAnimationTransitioning: NSObject, UIViewControllerAnimatedTransitioning {

    private var isPresentation = false
    private let initialScale: CGFloat = 1.2
    private let springDamping: CGFloat = 45.71
    private let springVelocity: CGFloat = 0

    init(presentation: Bool) {
        self.isPresentation = presentation
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.5
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        guard let fromController = transitionContext.viewController(forKey: .from),
            let toController = transitionContext.viewController(forKey: .to),
            let fromView = fromController.view,
            let toView = toController.view else {
                return
        }

        if isPresentation {
            transitionContext.containerView.addSubview(toView)
        }

        let animatingController = isPresentation ? toController : fromController
        let animatingView = animatingController.view
        animatingView?.frame = transitionContext.finalFrame(for: animatingController)

        if isPresentation {
            animatingView?.transform = CGAffineTransform(scaleX: initialScale, y: initialScale)
            animatingView?.alpha = 0

            animate({
                animatingView?.transform = CGAffineTransform(scaleX: 1, y: 1)
                animatingView?.alpha = 1
            }, context: transitionContext, withCompletion: { (finished) in
                transitionContext.completeTransition(finished)
            })
        } else {
            animate({
                animatingView?.alpha = 0
            }, context: transitionContext, withCompletion: { (finished) in
                fromView.removeFromSuperview()
                transitionContext.completeTransition(finished)
            })
        }
    }

    private func animate(_ animations: @escaping (() -> Void),
                         context: UIViewControllerContextTransitioning,
                         withCompletion completion: @escaping ((Bool) -> Void)) {
        UIView.animate(withDuration: transitionDuration(using: context),
                       delay: 0,
                       usingSpringWithDamping: springDamping,
                       initialSpringVelocity: springVelocity,
                       options: [],
                       animations: animations,
                       completion: completion)
    }

}