Blueprint+OpenCombine.swift

Blueprint+OpenCombine.swift

import UIKit
import OpenCombine
import BlueprintUI
import BlueprintUICommonControls

typealias Published = OpenCombine.Published

final class CounterViewModel {
    
    @Published var totalCount = 0
    
    func increase() {
        totalCount += 1
    }
    
    func decrease() {
        totalCount -= 1
    }
    
}

class ViewController: UIViewController {

    // Blueprint
    let blueprintView = BlueprintView()
    let viewModel = CounterViewModel()
    lazy var counterView = BlueprintCounterView(viewModel: viewModel)
    var bag = Set<AnyCancellable>()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemGreen
        
        addBlueprintView()
    }
    
    func addBlueprintView() {
        self.view = blueprintView
        viewModel.$totalCount.sink { val in
            print("\(val)")
            self.updateBlueprintUI()
        }.store(in: &bag)
    }
    
    func updateBlueprintUI() {
        blueprintView.element = counterView.element
    }

}

struct BlueprintCounterView {
    
    var viewModel: CounterViewModel
    
    var element: Element {
        Column { col in
            col.horizontalAlignment = .center
            col.add(child: Spacer())
            col.add(child: counterColumn)
            col.add(child: Spacer())
        }
    }
    
    var counterColumn: Element {
        Column { col in
            let label = Label(text: "\(viewModel.totalCount)") {
                $0.color = .black
                $0.font = .systemFont(ofSize: 32)
            }
            col.add(child: label)
            col.add(child: buttonsRow)
        }
        .constrainedTo(width: .absolute(200), height: .absolute(100))
    }
    
    var buttonsRow: Element {
        Row { row in
            let buttonDec = Button(onTap: {viewModel.decrease()}, wrapping:
                                        Label(text: " - "){
                                            $0.font = .systemFont(ofSize: 28)
                                        }
                                    ).box(background: .lightGray, borders: .solid(color: .black, width: 1))
            let buttonInc = Button(onTap: {viewModel.increase()}, wrapping:
                                        Label(text: " + "){
                                            $0.font = .systemFont(ofSize: 28)
                                        }
                                    ).box(background: .lightGray, borders: .solid(color: .black, width: 1))
            row.add(child: buttonDec)
            row.add(child: Spacer().constrainedTo(width: .absolute(20)))
            row.add(child: buttonInc)
        }
    }
    
}