//
//  AccountSwitchingContainerViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 11/11/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import UIKit

class AccountSwitchingContainerViewController: UIViewController {

    private(set) var root: TuskerRootViewController
    
    init(root: TuskerRootViewController) {
        self.root = root
        
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        embedChild(root)
    }
    
    func setRoot(_ newRoot: TuskerRootViewController, animating direction: AnimationDirection) {
        let oldRoot = self.root
        if direction == .none {
            oldRoot.removeViewAndController()
        }
        self.root = newRoot
        embedChild(newRoot)
        
        if direction != .none {
            if UIAccessibility.prefersCrossFadeTransitions {
                newRoot.view.alpha = 0
                
                UIView.animate(withDuration: 0.4, delay: 0, options: .curveEaseInOut) {
                    newRoot.view.alpha = 1
                    oldRoot.view.alpha = 0
                } completion: { (_) in
                    oldRoot.removeViewAndController()
                }
            } else {
                let sign: CGFloat = direction == .downwards ? -1 : 1
                let newInitialOffset = sign * view.bounds.height
                
                newRoot.view.transform = CGAffineTransform(translationX: 0, y: newInitialOffset)
                
                UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseInOut) {
                    newRoot.view.transform = .identity
                    oldRoot.view.transform = CGAffineTransform(translationX: 0, y: -newInitialOffset)
                } completion: { (_) in
                    oldRoot.removeViewAndController()
                }
            }
        }
    }
}

extension AccountSwitchingContainerViewController {
    enum AnimationDirection {
        case none, downwards, upwards
    }
}

extension AccountSwitchingContainerViewController: TuskerRootViewController {
    func presentCompose() {
        root.presentCompose()
    }
    
    func select(tab: MainTabBarViewController.Tab) {
        root.select(tab: tab)
    }
    
    func getTabController(tab: MainTabBarViewController.Tab) -> UIViewController? {
        root.getTabController(tab: tab)
    }
}