//
//  BaseViewController.swift
//  PrivadoVPN
//
//  Created by Zhandos Bolatbekov on 03.06.2021.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import UIKit

class BaseViewController: UIViewController, ReactivelyConstrained {
    
    var portraitConstraints = [NSLayoutConstraint]()
    var landscapeConstraints = [NSLayoutConstraint]()
    var sharedConstraints = [NSLayoutConstraint]()
    
    let layoutEmitter = Emitter<EmitterLayoutChangeType>()
    
    // MARK: - Init
    
    init() {
        super.init(nibName: nil, bundle: nil)
        
        self.layoutEmitter.addReaction { [weak self] isLandscape -> ShouldContinueReceiveNotifications in
            
            guard let self = self else { return false }
            
            if isLandscape {
                NSLayoutConstraint.deactivate(self.portraitConstraints)
                NSLayoutConstraint.activate(self.landscapeConstraints)
            } else {
                NSLayoutConstraint.deactivate(self.landscapeConstraints)
                NSLayoutConstraint.activate(self.portraitConstraints)
            }
            NSLayoutConstraint.activate(self.sharedConstraints)
            
            self.layoutChildren(for: self, isLanscape: isLandscape)
            self.layoutSubViews(for: self.view, isLandscape: isLandscape)
            self.updateViewConstraints()
            return true
        }
    }
    
    func layoutSubViews(for view: UIView, isLandscape: Bool) {
        view.subviews.forEach { view in
            if let view = view as? BaseView {
                view.layoutEmitter.invoke(isLandscape)
                view.layoutIfNeeded()
            }
        }
    }
    func layoutChildren(for controller: BaseViewController, isLanscape: Bool) {
        controller.children.forEach { vc in
            if let vc = vc as? BaseViewController {
                vc.layoutEmitter.invoke(isLanscape)
                vc.updateViewConstraints()
            }
        }
    }
    
    func layoutForCurrentOrientation() {
        let landscape = DeviceInfoProvider.isLandscapeOrienation && self.view.bounds.width * 3 >= UIScreen.main.bounds.width * 2
        self.layoutEmitter.invoke(landscape)
    }
    
    @available(*, unavailable)
    required init?(coder: NSCoder) { nil }
    
    // MARK: - Lifecycle
    
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        
        let isLandscape = DeviceInfoProvider.isLandscapeOrienation && size.width * 3 >= UIScreen.main.bounds.width * 2
        
        self.layoutEmitter.invoke(isLandscape)
        self.view.subviews
            .compactMap { $0 as? ReactivelyConstrained }
            .forEach { $0.layoutEmitter.invoke(isLandscape) }
    }
}