//
//  SelectorItemBase.swift
//  VDS
//
//  Created by Matt Bruce on 6/5/23.
//

import Foundation
import UIKit
import Combine
import VDSTokens

/// Base Class used to build out a SelectorControlable control.
open class SelectorItemBase<Selector: SelectorControlable>: Control, Errorable, Changeable {
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var shouldShowError: Bool {
        guard showError && isEnabled && errorText?.isEmpty == false else { return false }
        return true
    }
    
    private var shouldShowLabels: Bool {
        guard labelText?.isEmpty == false || childText?.isEmpty == false || labelAttributedText?.string.isEmpty == false || childAttributedText?.string.isEmpty == false else { return false }
        return true
    }
    
    private var mainStackView = UIStackView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.alignment = .top
        $0.axis = .vertical
    }
    
    private var selectorStackView = UIStackView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.alignment = .top
        $0.axis = .horizontal
    }
    
    private var selectorLabelStackView = UIStackView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.axis = .vertical
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    open var onChangeSubscriber: AnyCancellable? 
    
    /// Label used to render labelText.
    open var label = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .boldBodyLarge
    }
    
    /// Label used to render childText.
    open var childLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .bodyLarge
    }
    
    /// Label used to render errorText.
    open var errorLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textStyle = .bodyMedium
    }
    
    /// Generic Object used to allow the user to 'Select'.
    open var selectorView = Selector()
    
    open override var isSelected: Bool { didSet { setNeedsUpdate() } }
    
    /// Text shown in the label.
    open var labelText: String? { didSet { setNeedsUpdate() } }
    
    /// Array of LabelAttributeModel objects used in rendering the labelText.
    open var labelTextAttributes: [any LabelAttributeModel]? { didSet { setNeedsUpdate() } }
    
    /// Instead of use labelText and labelTextAttirbutes, this is a fully baked NSAttributedString with both text and attributes.
    open var labelAttributedText: NSAttributedString? {
        didSet {
            label.attributedText = labelAttributedText
            setNeedsUpdate()
        }
    }
    
    /// Text shown in the childLabel.
    open var childText: String? { didSet { setNeedsUpdate() } }
    
    /// Array of LabelAttributeModel objects used in rendering the childText.
    open var childTextAttributes: [any LabelAttributeModel]? { didSet { setNeedsUpdate() } }
    
    /// Instead of use childText and childTextAttirbutes, this is a fully baked NSAttributedString with both text and attributes.
    open var childAttributedText: NSAttributedString? {
        didSet {
            childLabel.attributedText = childAttributedText
            setNeedsUpdate()
        }
    }
    
    /// Override UIControl state to add the .error state if showError is true.
    open override var state: UIControl.State {
        get {
            var state = super.state
            if showError {
                state.insert(.error)
            }
            return state
        }
    }
    
    var _showError: Bool = false
    
    open var showError: Bool {
        get { _showError }
        set {
            if !isSelected && _showError != newValue {
                _showError = newValue
                setNeedsUpdate()
            }
        }
    }

    open var errorText: String? { didSet { setNeedsUpdate() } }

    open var inputId: String? { didSet { setNeedsUpdate() } }

    open var value: AnyHashable? { hiddenValue }
        
    open var hiddenValue: AnyHashable? { didSet { setNeedsUpdate() } }
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    /// Executed on initialization for this View.
    open override func initialSetup() {
        super.initialSetup()
        onClick = { control in
            control.toggle()
        }
    }

    /// Called once when a view is initialized and is used to Setup additional UI or other constants and configurations.
    open override func setup() {
        super.setup()

        isAccessibilityElement = true
        accessibilityTraits = .button
        addSubview(mainStackView)
        mainStackView.isUserInteractionEnabled = false
        
        mainStackView.addArrangedSubview(selectorStackView)
        mainStackView.addArrangedSubview(errorLabel)
        selectorStackView.addArrangedSubview(selectorView)
        selectorStackView.addArrangedSubview(selectorLabelStackView)
        selectorLabelStackView.addArrangedSubview(label)
        selectorLabelStackView.addArrangedSubview(childLabel)
        mainStackView
            .pinTop()
            .pinLeading()
            .pinTrailing()
            .pinBottom(0, .defaultHigh)
    }
            
    /// Used to make changes to the View based off a change events or from local properties.
    open override func updateView() {
        super.updateView()
        updateLabels()
        selectorView.showError = showError
        selectorView.isSelected = isSelected
        selectorView.isHighlighted = isHighlighted
        selectorView.isEnabled = isEnabled
        selectorView.surface = surface
    }

    /// Used to update any Accessibility properties.
    open override func updateAccessibility() {
        super.updateAccessibility()
        setAccessibilityLabel(for: [selectorView, label, childLabel, errorLabel])
    }
        
    /// Resets to default settings.
    open override func reset() {
        super.reset()
        shouldUpdateView = false
        label.reset()
        childLabel.reset()
        errorLabel.reset()
        
        label.textStyle = .boldBodyLarge
        childLabel.textStyle = .bodyLarge
        errorLabel.textStyle = .bodyMedium
        
        labelText = nil
        labelTextAttributes = nil
        labelAttributedText = nil
        childText = nil
        childTextAttributes = nil
        childAttributedText = nil
        showError = false
        errorText = nil
        inputId = nil
        isSelected = false
        
        onChange = nil
        shouldUpdateView = true
        setNeedsUpdate()
    }
    
    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------
       /// Update all labels with Text as well as adding and removing the labels.
    func updateLabels() {

        //deal with labels
        if shouldShowLabels {
            //add the stackview to hold the 2 labels
            //top label
            if let labelText {
                label.surface = surface
                label.isEnabled = isEnabled
                label.attributes = labelTextAttributes
                label.text = labelText
                label.isHidden = false
            } else if labelAttributedText != nil {
                label.isHidden = false

            } else {
                label.isHidden = true
            }
            
            //bottom label
            if let childText {
                childLabel.text = childText
                childLabel.surface = surface
                childLabel.isEnabled = isEnabled
                childLabel.attributes = childTextAttributes
                childLabel.isHidden = false
                
            } else if childAttributedText != nil {
                childLabel.isHidden = false

            } else {
                childLabel.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 errorText, shouldShowError {
            errorLabel.text = errorText
            errorLabel.surface = surface
            errorLabel.isEnabled = isEnabled
            mainStackView.spacing = 8
            errorLabel.isHidden = false
        } else {
            mainStackView.spacing = 0
            errorLabel.isHidden = true
        }
    }

    /// This will change to state of the Selector.
    open func toggle() {}

}