vds_ios/VDS/Protocols/ModelHandlerable.swift

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

import Foundation
import Combine
import UIKit

public protocol ModelHandlerable: AnyObject, Initable {
    associatedtype ModelType: Modelable
    var model: ModelType { get set }
    var modelPublisher: Published<ModelType>.Publisher { get }
    var subscribers: Set<AnyCancellable> { get set }
    init(with model: ModelType)
    func set(with model: ModelType)
    func shouldUpdateView(viewModel: ModelType) -> Bool
    func updateView(viewModel: ModelType)
}

extension ModelHandlerable {
    public init() {
        self.init(with: ModelType())
    }
    
    public func set(with model: ModelType) {
        if shouldUpdateView(viewModel: model){
            updateView(viewModel: model)
            self.model = model
        }
    }
    
    public func shouldUpdateView(viewModel: ModelType) -> Bool {
        model != viewModel
    }
    
    public func setupUpdateView() {
        handlerPublisher()
            .subscribe(on: RunLoop.main)
            .sink { [weak self] viewModel in
                self?.updateView(viewModel: viewModel)
            }
            .store(in: &subscribers)
    }
    
    public func handlerPublisher() -> AnyPublisher<ModelType, Never> {
        modelPublisher
            .debounce(for: .seconds(Constants.ModelStateDebounce), scheduler: RunLoop.main)
            .eraseToAnyPublisher()
    }
}