CaseContainerView.swift

//
//  CaseContainerView.swift
//  CaseContainer
//
//  Created by minjuniMac on 25/09/2018.
//  Copyright © 2018 mjun. All rights reserved.
//

import UIKit

open class CaseContainerView: CaseContainerBaseView<CaseContainerViewController> {
    public private(set) var containerScrollView = UIScrollView().then {
        $0.backgroundColor = .red
        $0.showsHorizontalScrollIndicator = false
        $0.showsVerticalScrollIndicator = false
        /// was specified unidirection Scrolling, this direction of scrollView is vertical
        $0.isDirectionalLockEnabled = true
        $0.bounces = true
        
        /// height of scrollView's contentSize is adjusted in iPhoneX' seriess(iPhoneX, iPhone XS, iPhone XR...). I didn't want to this Behavior
        if #available(iOS 11, *) {
            $0.contentInsetAdjustmentBehavior = .never
        }
    }
    
    /**
     This property is containerScrollView's contentView
     */
    lazy public private(set) var verticalCanvasView = UIView().then {
        $0.backgroundColor = .brown
    }
    
    public var tabScrollView = TabScrollView()
    
    public var contentsScrollView = UIScrollView().then {
        $0.bounces = true
        $0.backgroundColor = .purple
        $0.isDirectionalLockEnabled = true
        $0.showsVerticalScrollIndicator = false
        $0.isPagingEnabled = true
    }
    
    /**
     This propery is ContentsScrollView's Content View
     */
    lazy public private(set) var horizonCanvasView = UIView().then {
        let rect = CGRect(
            x: 0, y: 0,
            width: ui.contentsScrollViewContentSize.width,
            height: ui.contentsScrollViewContentSize.height)
        $0.frame = rect
        $0.backgroundColor = .blue
    }
    
    public var tabBarHeight: CGFloat {
        guard let homeIndicator = UIApplication.shared.windows.first,
            let tabBarController = vc.tabBarController else {
                return 0
        }
        let tabBarHeight = tabBarController.tabBar.frame.height
        
        if #available(iOS 11.0, *) {
            let homeIndicatorHeight = homeIndicator.safeAreaInsets.bottom
            return tabBarHeight + homeIndicatorHeight
        } else {
            return tabBarHeight
        }
    }
    
    struct UI {
        var tabScrollViewHeight: CGFloat
        var contentsScrollViewFrameSize: CGSize
        var contentsScrollViewContentSize: CGSize
        var containerScrollViewContentSize: CGSize
        
        init(containerViewController: CaseContainerViewController,
             tabScrollHeaight: CGFloat,
             tabBarHeight: CGFloat) {
            guard containerViewController.viewContorllers.count > 0  else {
                fatalError("you must Implement ChildViewController")
            }
            let numberOfChildVierControlelr: CGFloat = CGFloat(containerViewController.viewContorllers.count)
            tabScrollViewHeight = tabScrollHeaight
            
            contentsScrollViewFrameSize = CGSize(
                width: UIScreen.mainWidth,
                height: UIScreen.mainHeight - (UIApplication.statusBarHeight + tabScrollViewHeight + tabBarHeight))
            
            contentsScrollViewContentSize = CGSize(
                width: UIScreen.mainWidth * numberOfChildVierControlelr,
                height: UIScreen.mainHeight - UIApplication.statusBarHeight )
            
            containerScrollViewContentSize = CGSize(
                width: UIScreen.mainWidth,
                height: tabScrollViewHeight + contentsScrollViewFrameSize.height)
            
        }
    }
    
    lazy var ui = UI(
        containerViewController: vc,
        tabScrollHeaight: vc.appearence.tabScrollHegiht,
        tabBarHeight: tabBarHeight)
    
    
    override func setupUI() {
        backgroundColor = .white
        /*
         ⎮ View
         ⎮ -- containerScrollView
         ⎮ ---- verticalCanvasView
         ⎮ ------ headerView
         ⎮ ------ tabCollectionView
         ⎮ ------ contentsScrollView
         ⎮ -------- horizonCanvasView
         ⎮ ---------- vc.children.view
         ⎮ ---------- vc.children.view1
         ⎮ ----------- ...
         */
        addSubviews([containerScrollView])
        containerScrollView.addSubview(verticalCanvasView)
        contentsScrollView.addSubview(horizonCanvasView)
        verticalCanvasView.addSubviews([tabScrollView, contentsScrollView])
        
        containerScrollView
            .topAnchor(to: layoutMarginsGuide.topAnchor)
            .leadingAnchor(to: leadingAnchor)
            .trailingAnchor(to: trailingAnchor)
            .bottomAnchor(to: bottomAnchor, constant: -tabBarHeight)
            .activateAnchors()
        
        verticalCanvasView
            .topAnchor(to: containerScrollView.topAnchor)
            .bottomAnchor(to: containerScrollView.bottomAnchor)
            .leadingAnchor(to: containerScrollView.leadingAnchor)
            .trailingAnchor(to: containerScrollView.trailingAnchor)
            
            .dimensionAnchors(size: ui.containerScrollViewContentSize)
            .activateAnchors()
        
        tabScrollView
            .topAnchor(to: verticalCanvasView.topAnchor)
            .leadingAnchor(to: verticalCanvasView.leadingAnchor)
            .trailingAnchor(to: verticalCanvasView.trailingAnchor)
            .heightAnchor(constant: ui.tabScrollViewHeight)
            .activateAnchors()
        
        contentsScrollView
            .topAnchor(to: tabScrollView.bottomAnchor)
            .leadingAnchor(to: verticalCanvasView.leadingAnchor)
            .trailingAnchor(to: verticalCanvasView.trailingAnchor)
            .heightAnchor(constant: ui.contentsScrollViewFrameSize.height)
            .activateAnchors()
        
        /// ViewControllers that are added on initilization add parent ViewController's childViewController
        guard vc.viewContorllers.count > 0 else {
            fatalError("You must be to add container view controller's child view controller when it is initializaed")
        }
        
        vc.viewContorllers.forEach {
            guard $0.title != nil else {
                fatalError("You must be to add viewControllers`s title when it is initialized")
            }
        }
        
        setupChildViewController(of: vc.viewContorllers)
    }
    
    override func setupBinding() {
        containerScrollView.contentSize = ui.containerScrollViewContentSize
        contentsScrollView.contentSize = ui.contentsScrollViewContentSize
        
        containerScrollView.delegate = vc
        contentsScrollView.delegate = vc
        tabScrollView.delegate = vc
        
        tabScrollView.setupBinding(parent: vc, ui: ui)
    }
    
    func setupChildViewController(of childViewControllers: [UIViewController]) {
        guard let initialChildVC = childViewControllers.first else {
            return
        }
        // 1. Add child Viewcontroller into ContainerViewControlelr
        vc.addChild(initialChildVC)
        
        // 2. add child ViewController's view into ContainerViewController view
        horizonCanvasView.addSubview(initialChildVC.view)
        
        // 3. determine child View Controller`s view frame
        initialChildVC.view.frame = CGRect(x: 0, y: 0,
                                           width: ui.contentsScrollViewFrameSize.width,
                                           height: ui.contentsScrollViewContentSize.height)
        
        initialChildVC.didMove(toParent: vc)
    }
}