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

import Foundation
import UIKit
import Combine

open class SelectorGroupBase<SelectorType, SelectorGroupType: SelectorGroupModel, SelectorHandlerType: SelectorBase<SelectorType>>: View<SelectorGroupType>, Changable where SelectorType == SelectorGroupType.SelectorType {
    
    public var selectorViews: [SelectorHandlerType] = []
        
    public var onChange: Blocks.ActionBlock?
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var mainStackView: UIStackView = {
        let stackView = UIStackView()
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.alignment = .top
        stackView.axis = .vertical
        stackView.spacing = 10
        return stackView
    }()
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    override public var disabled: Bool {
        didSet {
            updateSelectors()
        }
    }
    
    override public var surface: Surface {
        didSet {
            updateSelectors()
        }
    }
    
    private func updateSelectors(){
        let selectors = model.selectors.compactMap { existing in
            return existing.with {
                $0.disabled = disabled
                $0.surface = surface
            }
        }
        model.selectors = selectors
    }
    
    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: SelectorGroupType) -> Bool {
        let update = 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) {
        //print("Selector Group update:")
        func findSelectorView(id: UUID) -> SelectorHandlerType? {
            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 = SelectorHandlerType(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)
            }
        }
        
    }
    
    public func getCachedSelector(viewModel: SelectorType) -> SelectorType? {
        if let  index = model.selectors.firstIndex(where: { element in
            return element.id == viewModel.id
        }) {
            return model.selectors[index]
        } else {
            return nil
        }
    }
    
    public func replace(viewModel: SelectorType){
        if let  index = model.selectors.firstIndex(where: { element in
            return element.id == viewModel.id
        }) {
            model.selectors[index] = viewModel
        }
    }
    
    open func didSelect(selector: SelectorType) { }
    
}