i//
//  EmbeddedColorWell.swift
//  SwiftUI-Mac
//
//  Created by Sarah Reichelt on 10/11/19.
//  Copyright © 2019 Sarah Reichelt. All rights reserved.
//

import SwiftUI
import Combine

struct EmbeddedColorWell: NSViewRepresentable {
  
  @Binding var selectedColor: NSColor
  
  class Coordinator: NSObject {
    
    var embedded: EmbeddedColorWell
    var subscriptions: [AnyCancellable] = []
    
    init(_ embedded: EmbeddedColorWell) {
      self.embedded = embedded
    }
    
    /// Observe KVO compliant color property on NSColorWell object.
    /// Update the selectedColor property on EmbeddedColorWell as needed.
    /// - Parameter colorWell: The NSColorWell view.
    func changeColor(colorWell: NSColorWell) {
      
      subscriptions.append(colorWell.publisher(for: \.color, options: .new)
        .sink { color in
          // Avoid modifying state during view update
          DispatchQueue.main.async {
            if self.embedded.selectedColor != color {
              self.embedded.selectedColor = color
            }
          }
      })
    }
  }
  
  func makeCoordinator() -> EmbeddedColorWell.Coordinator {
    Coordinator(self)
  }
  
  func makeNSView(context: Context) -> NSColorWell {
    let colorWell = NSColorWell(frame: .zero)
    context.coordinator.changeColor(colorWell: colorWell)
    return colorWell
  }
  
  func updateNSView(_ nsView: NSColorWell, context: Context) {
    nsView.color = selectedColor
  }
  
}