//
//  PopupAnimator.swift
// JiuLaiBao
//
//  Created by SeanXu on 2018/8/5.
//  Copyright © 2018 GuoXiaoMei. All rights reserved.
//

import UIKit
import SnapKit

public protocol PopupViewControllerType {
    var grayView: UIView { get set }
    var contentView: UIView { get set }
    var contentHeight: CGFloat { get set }
}

public enum PopupAnimatorType {
    case present
    case dismiss
}

public class PopupAnimator: NSObject, UIViewControllerAnimatedTransitioning {
    
    public var animatorType: PopupAnimatorType
    
    public init(_ animatorType: PopupAnimatorType) {
        self.animatorType = animatorType
        super.init()
    }
    
    public func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.3
    }
    
    public func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let containerView = transitionContext.containerView
        
        guard let fromViewController = transitionContext.viewController(forKey: .from),
            let toViewController = transitionContext.viewController(forKey: .to),
            let fromView = fromViewController.view,
            let toView = toViewController.view else {
                print("!!! Error: popup animation is not allowed !!!")
                return
        }
        if animatorType == .present {
            guard let popup = toViewController as? PopupViewControllerType else {
                return
            }
            
            let grayView = popup.grayView
            let contentView = popup.contentView
            let duration = transitionDuration(using: transitionContext)
            toView.frame = containerView.frame
            containerView.addSubview(toView)
            toView.layoutIfNeeded()
            
            grayView.alpha = 0
            contentView.snp.updateConstraints { make in
                make.bottom.equalToSuperview()
            }
            toView.setNeedsUpdateConstraints()
            UIView.animate(withDuration: duration, delay: 0, options: [.curveEaseInOut], animations: {
                toView.layoutIfNeeded()
                grayView.alpha = 1.0
            }, completion: { _ in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })
        } else if animatorType == .dismiss {
            guard let popup = fromViewController as? PopupViewControllerType else {
                return
            }
            
            let grayView = popup.grayView
            let contentView = popup.contentView
            let contentHeight = popup.contentHeight
            let duration = transitionDuration(using: transitionContext)
            
            contentView.snp.updateConstraints { make in
                make.bottom.equalTo(contentHeight)
            }
            fromView.setNeedsUpdateConstraints()
            UIView.animate(withDuration: duration, delay: 0, options: [.curveEaseInOut], animations: {
                fromView.layoutIfNeeded()
                grayView.alpha = 0
            }, completion: { _ in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })
        }
    }
    
}