//
//  LargeImageShrinkAnimationController.swift
//  Tusker
//
//  Created by Shadowfacts on 9/1/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import UIKit
import Gifu

class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
    
    let interactionController: LargeImageInteractionController?
    
    init(interactionController: LargeImageInteractionController?) {
        self.interactionController = interactionController
    }
    
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.2
    }
    
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        guard let fromVC = transitionContext.viewController(forKey: .from) as? LargeImageViewController,
            let toVC = transitionContext.viewController(forKey: .to),
            let finalFrame = fromVC.originFrame else {
                return
        }
        
        let originalVCFrame = fromVC.view.frame
        
        let containerView = transitionContext.containerView
        let image = fromVC.image!
        let ratio = image.size.width / image.size.height
        let width = originalVCFrame.width
        let height = width / ratio
        let originalFrame = CGRect(x: originalVCFrame.midX - width / 2, y: originalVCFrame.midY - height / 2, width: width, height: height)
        
        let imageView = GIFImageView(frame: originalFrame)
        imageView.image = fromVC.image!
        if let gifData = fromVC.gifData {
            imageView.animate(withGIFData: gifData)
        }
        imageView.contentMode = .scaleAspectFill
        imageView.layer.cornerRadius = 0
        imageView.layer.masksToBounds = true
        
        let blackView = UIView(frame: originalVCFrame)
        blackView.backgroundColor = .black
        blackView.alpha = 1
        
        containerView.addSubview(toVC.view)
        containerView.addSubview(blackView)
        containerView.addSubview(imageView)
        
        let duration = transitionDuration(using: transitionContext)
        UIView.animate(withDuration: duration, animations: {
            imageView.frame = finalFrame
            imageView.layer.cornerRadius = fromVC.originCornerRadius!
            blackView.alpha = 0
        }, completion: { _ in
            blackView.removeFromSuperview()
            imageView.removeFromSuperview()
            if transitionContext.transitionWasCancelled {
                toVC.view.removeFromSuperview()
            }
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        })
    }
    
}