vds_ios/VDS/Components/RadioButton/RadioButtonGroup.swift

//
//  RadioButtonGroup.swift
//  VDS
//
//  Created by Matt Bruce on 8/11/22.
//

import Foundation
import UIKit

public class RadioButtonGroup: Control<DefaultRadioButtonGroupModel>, SelectorGroupHandlerable, Changable {
    public typealias ModelHandlerType = RadioButton
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    public var selectorViews: [ModelHandlerType] = []
    
    @Proxy(\.model.selectedModel)
    public var selectedModel: ModelHandlerType.ModelType? {
        didSet{
            if hasError, selectedModel != nil {
                hasError = false
            }
        }
    }
    
    public var hasError: Bool {
        get { model.hasError }
        set {
            var newHasError = newValue
            if selectedModel != nil, newHasError {
                newHasError = false
            }
            let selectors = model.selectors.compactMap { existing in
                return existing.copyWith {
                    $0.hasError = newHasError
                }
            }
            model.hasError = newHasError
            model.selectors = selectors
        }
    }
    
    
    public var onChange: Blocks.ActionBlock?
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var mainStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.alignment = .top
            $0.axis = .vertical
            $0.spacing = 10
        }
    }()
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    override public var disabled: Bool {
        didSet {
            updateSelectors()
        }
    }
    
    override public var surface: Surface {
        didSet {
            updateSelectors()
        }
    }

    open override func setup() {
        super.setup()
        
        isAccessibilityElement = true
        accessibilityTraits = .button
        addSubview(mainStackView)
        
        mainStackView.topAnchor.constraint(equalTo: topAnchor).isActive = true
        mainStackView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
        mainStackView.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
        mainStackView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
    }
    
    open override func shouldUpdateView(viewModel: ModelType) -> Bool {
        let update = viewModel.selectedModel?.id != model.selectedModel?.id
        || viewModel.selectors.count != model.selectors.count
        || viewModel.hasError != model.hasError
        || viewModel.surface != model.surface
        || viewModel.disabled != model.disabled
        return update
    }

    open override func updateView(viewModel: ModelType) {
        func findSelectorView(id: UUID) -> ModelHandlerType? {
            return selectorViews.first(where: { existingSelectorView in
                return existingSelectorView.model.id == id
            })
        }
        
        for selectorModel in viewModel.selectors {
            //see if view is there for the model
            if let foundSelectorView = findSelectorView(id: selectorModel.id) {
                foundSelectorView.set(with: selectorModel)
            } else {
                
                //create view
                let newSelectorView = ModelHandlerType(with: selectorModel)
                
                //add the selectedPublisher for the change
                newSelectorView.publisher(for: .valueChanged)
                    .sink(receiveValue: { [weak self] control in
                        guard self?.model.selectors.count ?? 0 > 0 else { return }
                        self?.didSelect(selector: control.model)
                    })
                    .store(in: &subscribers)
                
                //add model update to the subscribers
                newSelectorView.handlerPublisher()
                    .sink { [weak self] model in
                        if let cached = self?.getCachedSelector(viewModel: model), newSelectorView.shouldUpdateView(viewModel: cached) {
                            self?.replace(viewModel: model)
                        }
                    }
                    .store(in: &subscribers)
                
                self.selectorViews.append(newSelectorView)
                mainStackView.addArrangedSubview(newSelectorView)
            }
        }
    }

    open func didSelect(selector: ModelHandlerType.ModelType) {
        if var oldSelectedModel = selectedModel {
            oldSelectedModel.selected = false
            replace(viewModel: oldSelectedModel)
        }
        
        //only select is selected
        if selector.selected {
            var newSelectedModel = selector
            newSelectedModel.selected = true
            replace(viewModel: newSelectedModel)
            selectedModel = newSelectedModel
        } else {
            //ensure current value is removed
            selectedModel = nil
        }
    }
}