//
//  ViewProtocol.swift
//  VDS
//
//  Created by Matt Bruce on 7/22/22.
//

import Foundation
import UIKit
import Combine

public protocol ViewProtocol: AnyObject, Initable, Resettable, Enabling, Surfaceable, AccessibilityUpdatable {
    /// Set of Subscribers for any Publishers for this Control.
    var subscribers: Set<AnyCancellable> { get set }
    
    /// Key of whether or not updateView() is called in setNeedsUpdate()
    var shouldUpdateView: Bool { get set }

    /// Used for setting an implementation for the default Accessible Action
    var accessibilityAction: ((Self) -> Void)? { get set }

    /// Called once when a view is initialized and is used to Setup additional UI or other constants and configurations.
    func setup()

    /// Default configurations for values and properties. This is called in the setup() and reset().
    func setDefaults()

    /// Used to make changes to the View based off a change events or from local properties.
    func updateView()
    
    /// Used to update any Accessibility properties.
    func updateAccessibility()
}

extension ViewProtocol {
    
    /// Called when there are changes in a View based off a change events or from local properties.
    public func setNeedsUpdate() {
        if shouldUpdateView {
            shouldUpdateView = false
            
            //see if this is a view that has children
            let parent = self as? any ParentViewProtocol
            let children = parent?.getAllChildren()
            //if so turn off the shouldUpdate to keep UI
            //from blocking
            children?.forEach{ $0.shouldUpdateView = false }
            
            updateView()
            updateAccessibility()
            
            //if so turn on 
            children?.forEach{
                $0.updateView()
                $0.updateAccessibility()
                $0.shouldUpdateView = true
            }
            shouldUpdateView = true
        }
    }
}

extension ViewProtocol where Self: UIView {

    /// Helper method for removing a superview and updating Self.
    public func removeFromSuperview(_ view: UIView){
        if view.superview != nil {
            view.removeFromSuperview()
            setNeedsDisplay()
        }
    }    
}

extension ViewProtocol where Self: UIControl {
    /// Helper method to assign a completion block to a specific UIControl Event using Combine and stored in the subscribers.
    public func addEvent(event: UIControl.Event, block: @escaping (Self)->()) {
        publisher(for: event)
            .sink(receiveValue: { c in
                block(c)
            }).store(in: &subscribers)
    }
}