Yep/Yep/ViewControllers/Conversation/ConversationMessagePreviewTransitionManager.swift

//
//  ConversationMessagePreviewTransitionManager.swift
//  Yep
//
//  Created by NIX on 15/5/6.
//  Copyright (c) 2015年 Catch Inc. All rights reserved.
//

import UIKit

class ConversationMessagePreviewTransitionManager: NSObject, UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning {

    var frame = CGRectZero
    var transitionView: UIView? {
        didSet {
            if let transitionView = transitionView {
                transitionViewSnapshot = transitionView.snapshotViewAfterScreenUpdates(false)
            }
        }
    }
    var transitionViewSnapshot: UIView?


    var isPresentation = false

    var transitionContext: UIViewControllerContextTransitioning?

    // MARK: UIViewControllerTransitioningDelegate

    func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        isPresentation = true

        return self
    }

    func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        isPresentation = false

        return self
    }

    // MARK: UIViewControllerAnimatedTransitioning

    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return isPresentation ? 0.5 : 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {

        self.transitionContext = transitionContext

        if isPresentation {
            presentTransition(transitionContext)
        } else {
            dismissTransition(transitionContext)
        }
    }


    let largerOffset: CGFloat = 80

    func presentTransition(transitionContext: UIViewControllerContextTransitioning) {
        //let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey) as? ConversationsViewController
        let toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) as? MessageMediaViewController

        //let fromView = transitionContext.viewForKey(UITransitionContextFromViewKey)
        let toView = transitionContext.viewForKey(UITransitionContextToViewKey)

        let containerView = transitionContext.containerView()

        containerView?.addSubview(toView!)

        let animatingVC = toVC!
        let animatingView = toView!

        if let transitionViewSnapshot = transitionViewSnapshot {

            animatingView.addSubview(transitionViewSnapshot)
            transitionViewSnapshot.frame = frame

            animatingVC.view.backgroundColor = UIColor.clearColor()
            animatingVC.mediasCollectionView.alpha = 0
            animatingVC.mediaControlView.alpha = 0

            let fullDuration = transitionDuration(transitionContext)

            UIView.animateKeyframesWithDuration(fullDuration, delay: 0.0, options: .CalculationModeCubic, animations: { () -> Void in

                UIView.addKeyframeWithRelativeStartTime(0, relativeDuration: 0.2, animations: { () -> Void in
                    animatingVC.view.backgroundColor = UIColor.whiteColor()
                })

                UIView.addKeyframeWithRelativeStartTime(0.2, relativeDuration: 0.5, animations: { () -> Void in
                    transitionViewSnapshot.center = animatingView.center
                })


                UIView.addKeyframeWithRelativeStartTime(0.7, relativeDuration: 0.2, animations: { () -> Void in
                    let targetWidth = animatingView.bounds.width + self.largerOffset

                    let dw = targetWidth - transitionViewSnapshot.bounds.width
                    let ratio = targetWidth / transitionViewSnapshot.bounds.width
                    let height = ratio * transitionViewSnapshot.bounds.height
                    let dh = height - transitionViewSnapshot.bounds.height

                    let frame = CGRectInset(transitionViewSnapshot.frame, -dw * 0.5, -dh * 0.5)

                    transitionViewSnapshot.frame = frame
                })

                UIView.addKeyframeWithRelativeStartTime(0.9, relativeDuration: 0.0, animations: { () -> Void in
                    let ratio = (animatingView.bounds.width + self.largerOffset) / animatingView.bounds.width
                    animatingVC.mediasCollectionView.transform = CGAffineTransformMakeScale(ratio, ratio)
                    animatingVC.mediasCollectionView.alpha = 1
                    animatingVC.mediaControlView.alpha = 1
                    
                    transitionViewSnapshot.alpha = 0
                })

                UIView.addKeyframeWithRelativeStartTime(0.9, relativeDuration: 0.1, animations: { () -> Void in
                    animatingVC.mediasCollectionView.transform = CGAffineTransformMakeScale(1.0, 1.0)
                })

            }, completion: { (finished) -> Void in
                transitionViewSnapshot.removeFromSuperview()

                transitionContext.completeTransition(true)
            })

        } else {
            transitionContext.completeTransition(false)
        }
    }

    func dismissTransition(transitionContext: UIViewControllerContextTransitioning) {
        let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey) as? MessageMediaViewController

        let fromView = transitionContext.viewForKey(UITransitionContextFromViewKey)

        let animatingVC = fromVC!
        let animatingView = fromView!

        let fullDuration = transitionDuration(transitionContext)

        if let transitionViewSnapshot = transitionViewSnapshot {

            if let transitionView = self.transitionView {
                transitionView.alpha = 0
            }

            UIView.animateKeyframesWithDuration(fullDuration, delay: 0.0, options: .CalculationModeCubic, animations: { () -> Void in

                UIView.addKeyframeWithRelativeStartTime(0.0, relativeDuration: 0.2, animations: { () -> Void in
                    let ratio = (animatingView.bounds.width + self.largerOffset) / animatingView.bounds.width
                    animatingVC.mediasCollectionView.transform = CGAffineTransformMakeScale(ratio, ratio)
                    animatingVC.mediaControlView.alpha = 0
                })

                UIView.addKeyframeWithRelativeStartTime(0.2, relativeDuration: 0.0, animations: { () -> Void in
                    animatingView.addSubview(transitionViewSnapshot)
                    transitionViewSnapshot.center = animatingView.center
                    transitionViewSnapshot.alpha = 1

                    animatingVC.mediasCollectionView.alpha = 0
                })

                UIView.addKeyframeWithRelativeStartTime(0.2, relativeDuration: 0.6, animations: { () -> Void in
                    transitionViewSnapshot.frame = self.frame
                })

                UIView.addKeyframeWithRelativeStartTime(0.8, relativeDuration: 0.2, animations: { () -> Void in
                    animatingVC.view.backgroundColor = UIColor.clearColor()
                })

            }, completion: { (finished) -> Void in

                if let transitionView = self.transitionView {
                    transitionView.alpha = 1
                }

                transitionViewSnapshot.removeFromSuperview()

                transitionContext.completeTransition(true)
            })

        } else {
            transitionContext.completeTransition(false)
        }
    }
}