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

import Foundation
import Combine
import UIKit

public enum HandlerableUpdateStrategy {
    case immediate
    case delayed
    case alwaysImmediate
}

public protocol Handlerable: AnyObject, Initable, Disabling, Surfaceable {
    var subject: PassthroughSubject<Void, Never> { get set }
    var subscribers: Set<AnyCancellable> { get set }
    var updateStrategy: HandlerableUpdateStrategy { get set }
    func updateView()
}

extension Handlerable {
    public func setupNeedsUpdateEvent() {
        subject
            .debounce(for: .seconds(0), scheduler: RunLoop.main)
            .sink { [weak self] _ in
            self?.updateView()
        }.store(in: &subscribers)
    }
    
    public func setNeedsUpdate() {
        switch updateStrategy {
        case .delayed:
            subject.send()
        case .immediate, .alwaysImmediate:
            updateView()
        }
    }
    
    public func updateIfNeeded<T: Equatable>(_ oldValue: T, _ newValue: T) {
        if oldValue != newValue {
            setNeedsUpdate()
        }
    }
}

extension Handlerable where Self: UIControl {
    public func addEvent(event: UIControl.Event, block: @escaping (Self)->()) {
        publisher(for: event)
            .sink(receiveValue: { c in
                block(c)
            }).store(in: &subscribers)
    }
}