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

import Foundation
import UIKit
import Combine

internal protocol DispatchQueueViewProtocol: AnyObject {
    var updateWorkItem: DispatchWorkItem? { get set }
}

public protocol ViewProtocol: AnyObject, Initable, Resettable, Enabling, Surfaceable {
    /// Set of Subscribers for any Publishers for this Control.
    var subscribers: Set<AnyCancellable> { get set }
    
    /// Executed on initialization for this View.
    func initialSetup()
    
    /// Called once when a view is initialized and is used to Setup additional UI or other constants and configurations.
    func setup()
    
    /// 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()
    
    /// Called when there are changes in a View based off a change events or from local properties.
    func setNeedsUpdate()
}

extension ViewProtocol {
    private func doUpdate() {
        updateView()
        updateAccessibility()
    }

    public func setNeedsUpdate() {
        guard let dispatchQueueSelf = self as? DispatchQueueViewProtocol else {
            doUpdate()
            return
        }
        dispatchQueueSelf.updateWorkItem?.cancel()
        let workItem = DispatchWorkItem { [weak self] in
            self?.doUpdate()
        }
        DispatchQueue.main.async(execute: workItem)
        dispatchQueueSelf.updateWorkItem = workItem
    }
}

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)
    }
}