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

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

open class SelectorBase<ModelType: SelectorModel>: Control<ModelType>, Changable {

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var mainStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.alignment = .top
            $0.axis = .vertical
        }
    }()
    
    private var selectorStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.alignment = .top
            $0.axis = .horizontal
        }
    }()
    
    private var selectorLabelStackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .vertical
        }
    }()
    
    private var primaryLabel = Label()
    
    private var secondaryLabel = Label()
    
    private var errorLabel = Label()
            
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    public var selectorView: UIView = {
        return  UIView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
        }
    }()

    public var onChange: Blocks.ActionBlock?
        
    @Proxy(\.model.id)
    open var id: UUID

    //can't bind to @Proxy
    open override var isSelected: Bool {
        get { model.selected }
        set {
            if model.selected != newValue {
                model.selected = newValue
            }
        }
    }
   
    @Proxy(\.model.labelText)
    open var labelText: String?

    @Proxy(\.model.childText)
    open var childText: String?

    @Proxy(\.model.hasError)
    open var hasError: Bool
    
    @Proxy(\.model.errorText)
    open var errorText: String?

    @Proxy(\.model.inputId)
    open var inputId: String?

    @Proxy(\.model.value)
    open var value: AnyHashable?
    
    @Proxy(\.model.dataAnalyticsTrack)
    open var dataAnalyticsTrack: String?

    @Proxy(\.model.dataClickStream)
    open var dataClickStream: String?

    @Proxy(\.model.dataTrack)
    open var dataTrack: String?

    @Proxy(\.model.accessibilityHintEnabled)
    open var accessibilityHintEnabled: String?
    
    @Proxy(\.model.accessibilityHintDisabled)
    open var accessibilityHintDisabled: String?
    
    @Proxy(\.model.accessibilityValueEnabled)
    open var accessibilityValueEnabled: String?
    
    @Proxy(\.model.accessibilityValueDisabled)
    open var accessibilityValueDisabled: String?
    
    @Proxy(\.model.accessibilityLabelEnabled)
    open var accessibilityLabelEnabled: String?
    
    @Proxy(\.model.accessibilityLabelDisabled)
    open var accessibilityLabelDisabled: String?
           
    //--------------------------------------------------
    // MARK: - Constraints
    //--------------------------------------------------
    
    private var knobLeadingConstraint: NSLayoutConstraint?
    private var knobTrailingConstraint: NSLayoutConstraint?
    private var knobHeightConstraint: NSLayoutConstraint?
    private var knobWidthConstraint: NSLayoutConstraint?
    private var selectorHeightConstraint: NSLayoutConstraint?
    private var selectorWidthConstraint: NSLayoutConstraint?
    
    //functions
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
  
    open override func setup() {
        super.setup()
        addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(Self.tap)))

        isAccessibilityElement = true
        accessibilityTraits = .button
        addSubview(mainStackView)
        
        mainStackView.addArrangedSubview(selectorStackView)
        mainStackView.addArrangedSubview(errorLabel)
        selectorStackView.addArrangedSubview(selectorView)
        selectorStackView.addArrangedSubview(selectorLabelStackView)
        selectorLabelStackView.addArrangedSubview(primaryLabel)
        selectorLabelStackView.addArrangedSubview(secondaryLabel)

        let selectorSize = getSelectorSize()
        selectorHeightConstraint = selectorView.heightAnchor.constraint(equalToConstant: selectorSize.height)
        selectorHeightConstraint?.isActive = true
        
        selectorWidthConstraint = selectorView.widthAnchor.constraint(equalToConstant: selectorSize.width)
        selectorWidthConstraint?.isActive = true

        updateSelector(model)
        
        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

    }
    
    func updateLabels(_ viewModel: ModelType) {

        //deal with labels
        if viewModel.shouldShowLabels {
            //add the stackview to hold the 2 labels
            //top label
            if let labelModel = viewModel.labelModel {
                primaryLabel.set(with: labelModel)
                primaryLabel.isHidden = false
            } else {
                primaryLabel.isHidden = true
            }
            
            //bottom label
            if let childModel = viewModel.childModel {
                secondaryLabel.set(with: childModel)
                secondaryLabel.isHidden = false
            } else {
                secondaryLabel.isHidden = true
            }
            selectorStackView.spacing = 12
            selectorLabelStackView.spacing = 4
            selectorLabelStackView.isHidden = false
            
        } else {
            selectorStackView.spacing = 0
            selectorLabelStackView.spacing = 0
            selectorLabelStackView.isHidden = true
        }
        
        //either add/remove the error from the main stack
        if let errorModel = model.errorModel, model.shouldShowError {
            errorLabel.set(with: errorModel)
            mainStackView.spacing = 8
            errorLabel.isHidden = false
        } else {
            mainStackView.spacing = 0
            errorLabel.isHidden = true
        }
        
    }
    
    public override func reset() {
        super.reset()
        updateSelector(model)
        setAccessibilityLabel()
        onChange = nil
    }
    
    //--------------------------------------------------
    // MARK: - Selector View
    //--------------------------------------------------
    open func getSelectorSize() -> CGSize {
        fatalError("must override")
    }
    
    open func updateSelector(_ viewModel: ModelType) {
    }
        
    //--------------------------------------------------
    // MARK: - Actions
    //--------------------------------------------------
    open override func sendActions(for controlEvents: UIControl.Event) {
        super.sendActions(for: controlEvents)
        if controlEvents.contains(.touchUpInside) {
            toggle()
        }
    }
    
    @objc func tap() {
        sendActions(for: .touchUpInside)

    }
    
    /// This will checkbox the state of the Selector and execute the actionBlock if provided.
    open func toggle() {
        //removed error
        if hasError && isSelected == false {
            hasError.toggle()
        }
        isSelected.toggle()
        sendActions(for: .valueChanged)
        onChange?()
    }
        
    override open func accessibilityActivate() -> Bool {
        // Hold state in case User wanted isAnimated to remain off.
        guard isUserInteractionEnabled else { return false }
        sendActions(for: .touchUpInside)
        return true
    }

    //--------------------------------------------------
    // MARK: - State
    //--------------------------------------------------
    /// Follow the SwiftUI View paradigm
    /// - Parameter viewModel: state
    open override func shouldUpdateView(viewModel: ModelType) -> Bool {
        let update = viewModel.selected != model.selected
        || viewModel.labelText != model.labelText
        || viewModel.childText != model.childText
        || viewModel.hasError != model.hasError
        || viewModel.surface != model.surface
        || viewModel.disabled != model.disabled
        return update
    }
    
    open override func updateView(viewModel: ModelType) {
        let enabled = !viewModel.disabled

        updateLabels(viewModel)
        updateSelector(viewModel)
        setAccessibilityHint(enabled)
        setAccessibilityValue(viewModel.selected)
        setAccessibilityLabel(viewModel.selected)
        isUserInteractionEnabled = !viewModel.disabled
        setNeedsLayout()
        layoutIfNeeded()
    }
}