raspberry/iOS/Wallet/Sources/Common/View/CommonViewLoading.swift

//
//  CommonViewLoading.swift
//  Wallet
//
//  Created by Igor on 27.02.2021.
//  Copyright © 2021 AM. All rights reserved.
//

import UIKit

enum Loader {
    
    static func isLoading(in view: UIView) -> Bool { view.subviews.contains(where: { $0 is CommonViewLoading }) }
    
    private static var loaders = [CommonViewLoading]()
    
    private static func popup(_ view: UIView) -> CommonControllerPopup? {
        var ctrl: UIViewController? = view.viewController
        while ctrl != nil && !(ctrl is CommonControllerPopup) {
            ctrl = ctrl?.parent
        }
        return ctrl as? CommonControllerPopup
    }
    
    static func show(in viewController: UIViewController = .topController(), color: UIColor = Asset.snow.color.withAlphaComponent(0.9)) {
        var ctrl: UIViewController? = viewController
        while ctrl != nil && !(ctrl is CommonControllerPopup) {
            ctrl = ctrl?.parent
        }
        if let ctrl = ctrl as? CommonControllerPopup {
            ctrl.view.isUserInteractionEnabled = false
            self.show(
                in: ctrl.contentView,
                color: color,
                frame: .init(x: 0, y: 0, width: ctrl.contentView.frame.width, height: ctrl.contentView.frame.height - ctrl.bottomHeight.constant)
            )
        } else {
            self.show(in: viewController.view, color: color)
        }
    }
    
    static func show(in view: UIView, color: UIColor = Asset.snow.color.withAlphaComponent(0.9), frame: CGRect? = nil) {
        if let loading = view.subviews.compactMap({ $0 as? CommonViewLoading }).first {
            loading.show(in: view, color: color, frame: frame)
        } else {
            let loader = CommonViewLoading()
            self.loaders.append(loader)
            loader.show(in: view, color: color, frame: frame)
        }
    }
    
    static func hide(in viewController: UIViewController = .topController()) {
        var ctrl: UIViewController? = viewController
        while ctrl != nil && !(ctrl is CommonControllerPopup) {
            ctrl = ctrl?.parent
        }
        if let ctrl = ctrl as? CommonControllerPopup {
            ctrl.view.isUserInteractionEnabled = true
            self.hide(in: ctrl.contentView)
        } else {
            self.hide(in: viewController.view)
        }
    }

    static func hide(in view: UIView) {
        let views = view.subviews.compactMap({ $0 as? CommonViewLoading })
        views
            .map { popup($0) }
            .forEach { $0?.view.isUserInteractionEnabled = true }
        views.forEach { view in
            view.hide()
            self.loaders.removeAll(where: { $0 == view })
        }
    }
    
    static func hideAll() {
        self.loaders.compactMap({ $0.superview }).forEach({ hide(in: $0) })
        self.loaders = []
    }
    
}

final class CommonViewLoading: UIView {
    
    private let imgView = UIImageView(frame: .init(x: 0, y: 0, width: 100, height: 100))
    private let alphaView = UIView()
    
    init() {
        super.init(frame: .init(x: 0, y: 0, width: imgView.frame.size.width, height: imgView.frame.size.height))
        self.backgroundColor = .clear
        self.translatesAutoresizingMaskIntoConstraints = true
        self.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        
        self.alphaView.frame = bounds
        self.alphaView.translatesAutoresizingMaskIntoConstraints = true
        self.alphaView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        self.addSubview(alphaView)
        
        self.imgView.translatesAutoresizingMaskIntoConstraints = false
        self.imgView.contentMode = .scaleAspectFit
        self.imgView.loadGif(name: "loader")
        self.imgView.frame.size = .init(width: 100, height: 100)
        self.addSubview(imgView)
    }
    
    convenience init(showImmediatelyWithSize size: CGFloat) {
        self.init()
        self.startAnimation(withSize: size)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func show(in view: UIView, color: UIColor = .clear, frame: CGRect? = nil) {
        self.frame = frame ?? view.bounds
        if superview == nil {
            view.addSubview(self)
            self.alphaView.backgroundColor = color
            self.startAnimation(withSize: 100)
        } else {
            self.layoutIfNeeded()
        }
    }
    
    func hide() {
        UIView.animate(withDuration: Animation.fast) {
            self.alphaView.alpha = 0
        } completion: { _ in
            self.removeFromSuperview()
        }
    }
    
    private func startAnimation(withSize size: CGFloat) {
        self.alphaView.alpha = 0
        
        NSLayoutConstraint.activate([
            self.imgView.widthAnchor.constraint(equalToConstant: size),
            self.imgView.heightAnchor.constraint(equalToConstant: size),
            self.imgView.centerXAnchor.constraint(equalTo: centerXAnchor),
            self.imgView.centerYAnchor.constraint(equalTo: centerYAnchor)
        ])
        
        self.layoutIfNeeded()
        UIView.animate(withDuration: Animation.fast) {
            self.alphaView.alpha = 1
        }
    }
    
}