//
//  Checkbox.swift
//  VDS
//
//  Created by Matt Bruce on 7/22/22.
//

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

/// Checkboxes are a multi-select component through which a customer indicates a choice. If a binary choice, the component is a checkbox. If the choice has multiple options, the component is a ``CheckboxGroup``.
@objc(VDSCheckbox)
public class Checkbox: CheckboxBase{}

@objc(VDSSoloCheckbox)
public class SoloCheckbox: CheckboxBase{
    public override func initialSetup() {
        super.initialSetup()
        publisher(for: .touchUpInside)
            .sink { control in
                control.toggle()
            }.store(in: &subscribers)
    }
}

@objc(VDSCheckboxBase)
open class CheckboxBase: Control, Errorable {
    //--------------------------------------------------
    // 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 && !disabled && 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 label = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textPosition = .left
        $0.textStyle = .boldBodyLarge
    }
    
    open var childLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textPosition = .left
        $0.textStyle = .bodyLarge
    }
    
    open var errorLabel = Label().with {
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.textPosition = .left
        $0.textStyle = .bodyMedium
    }
            
    open var selectorView = UIView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
    }
        
    open var isAnimated: Bool = true { didSet { didChange() }}
    
    open override var isSelected: Bool { didSet { didChange() }}
   
    open var labelText: String? { didSet { didChange() }}

    open var labelTextAttributes: [any LabelAttributeModel]? { didSet { didChange() }}
    
    open var labelAttributedText: NSAttributedString? {
        didSet {
            label.useAttributedText = !(labelAttributedText?.string.isEmpty ?? true)
            label.attributedText = labelAttributedText
            didChange()
        }
    }
    
    open var childText: String? { didSet { didChange() }}
    
    open var childTextAttributes: [any LabelAttributeModel]? { didSet { didChange() }}
    
    open var childAttributedText: NSAttributedString? {
        didSet {
            childLabel.useAttributedText =  !(childAttributedText?.string.isEmpty ?? true)
            childLabel.attributedText = childAttributedText
            didChange()
        }
    }

    var _showError: Bool = false
    open var showError: Bool {
        get { _showError }
        set {
            if !isSelected && _showError != newValue {
                _showError = newValue
                didChange()
            }
        }
    }
    
    open override var state: UIControl.State {
        get {
            var state = super.state
            if showError {
                state.insert(.error)
            }
            return state
        }
    }

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

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

    open var value: AnyHashable? { didSet { didChange() }}
    
    //--------------------------------------------------
    // MARK: - Constraints
    //--------------------------------------------------
    
    private var selectorHeightConstraint: NSLayoutConstraint?
    private var selectorWidthConstraint: NSLayoutConstraint?
    
    //functions
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
    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)

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

        updateSelector()
        
        mainStackView.pinToSuperView()

    }
    
    func updateLabels() {

        //deal with labels
        if shouldShowLabels {
            //add the stackview to hold the 2 labels
            //top label
            if let labelText {
                label.surface = surface
                label.disabled = disabled
                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.disabled = disabled
                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.disabled = disabled
            mainStackView.spacing = 8
            errorLabel.isHidden = false
        } else {
            mainStackView.spacing = 0
            errorLabel.isHidden = true
        }
    }
    
    open override func reset() {
        super.reset()
        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
        value = nil
        isSelected = false
        
        updateSelector()
    }
    
    /// This will checkbox the state of the Selector and execute the actionBlock if provided.
    open func toggle() {
        //removed error
        if showError && isSelected == false {
            showError.toggle()
        }
        isSelected.toggle()
        sendActions(for: .valueChanged)
    }
        
    //--------------------------------------------------
    // MARK: - State
    //--------------------------------------------------    
    open override func updateView() {
        updateLabels()
        updateSelector()
    }

    
    //--------------------------------------------------
    // MARK: - Configuration Properties
    //--------------------------------------------------
    public let checkboxSize = CGSize(width: 20, height: 20)
    
    private var backgroundColorConfig = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: .selected)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: [.selected,.highlighted])
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forState: [.selected, .disabled])
        $0.setSurfaceColors(VDSColor.feedbackErrorBackgroundOnlight, VDSColor.feedbackErrorBackgroundOndark, forState: .error)
    }

    private var borderColorConfig = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSFormControlsColor.borderOnlight, VDSFormControlsColor.borderOndark, forState: .normal)
        $0.setSurfaceColors(VDSColor.interactiveDisabledOnlight, VDSColor.interactiveDisabledOndark, forState: .disabled)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: .highlighted)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark, forState: .selected)
        $0.setSurfaceColors(VDSColor.feedbackErrorOnlight, VDSColor.feedbackErrorOndark, forState: .error)
    }

    private var checkColorConfig = ControlColorConfiguration().with {
        $0.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOnlight, forState: .selected)
        $0.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOnlight, forState: [.selected, .disabled])
        $0.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOnlight, forState: [.selected, .highlighted])
    }

    //--------------------------------------------------
    // MARK: - Checkbox View
    //--------------------------------------------------
    /// Manages the appearance of the checkbox.
    private var shapeLayer: CAShapeLayer?
    
    open func getSelectorSize() -> CGSize {
        return checkboxSize
    }
    
    open func updateSelector() {
        //get the colors
        let backgroundColor = backgroundColorConfig.getColor(self)
        let borderColor = borderColorConfig.getColor(self)
        let checkColor = checkColorConfig.getColor(self)

        if let shapeLayer = shapeLayer, let sublayers = layer.sublayers, sublayers.contains(shapeLayer) {
            shapeLayer.removeFromSuperlayer()
            self.shapeLayer = nil
        }

        selectorView.layer.cornerRadius = VDSFormControls.borderradius
        selectorView.layer.borderWidth = VDSFormControls.widthBorder

        if shapeLayer == nil {
            let bounds = selectorView.bounds
            let length = max(bounds.size.height, bounds.size.width)
            guard length > 0.0, shapeLayer == nil else { return }
            
            //draw the checkmark layer
            let xInsetLeft = length * 0.25
            let yInsetTop = length * 0.3
            let innerWidth = length - (xInsetLeft + length * 0.25) // + Right X Inset
            let innerHeight = length - (yInsetTop + length * 0.35) // + Bottom Y Inset
            
            let startPoint = CGPoint(x: xInsetLeft, y: yInsetTop + (innerHeight / 2))
            let pivotOffSet = CGPoint(x: xInsetLeft + (innerWidth * 0.33), y: yInsetTop + innerHeight)
            let endOffset = CGPoint(x: xInsetLeft + innerWidth, y: yInsetTop)
            
            let bezierPath = UIBezierPath()
            bezierPath.move(to: startPoint)
            bezierPath.addLine(to: pivotOffSet)
            bezierPath.addLine(to: endOffset)

            let shapeLayer = CAShapeLayer()
            self.shapeLayer = shapeLayer
            shapeLayer.frame = bounds
            layer.addSublayer(shapeLayer)
            shapeLayer.strokeColor = checkColor.cgColor
            shapeLayer.fillColor = UIColor.clear.cgColor
            shapeLayer.path = bezierPath.cgPath
            shapeLayer.lineJoin = .miter
            shapeLayer.lineWidth = 2
            CATransaction.withDisabledAnimations {
                shapeLayer.strokeEnd = isSelected ? 1 : 0
            }
        }
        
        shapeLayer?.removeAllAnimations()
        
        if isAnimated {
            let animateStrokeEnd = CABasicAnimation(keyPath: "strokeEnd")
            animateStrokeEnd.timingFunction = CAMediaTimingFunction(name: .linear)
            animateStrokeEnd.duration = 0.3
            animateStrokeEnd.fillMode = .both
            animateStrokeEnd.isRemovedOnCompletion = false
            animateStrokeEnd.fromValue = !isSelected ? 1 : 0
            animateStrokeEnd.toValue = isSelected ? 1 : 0
            self.shapeLayer?.add(animateStrokeEnd, forKey: "strokeEnd")
            
            UIView.animate(withDuration: 0.2, delay: 0.1, options: .curveEaseOut, animations: {
                self.selectorView.backgroundColor = backgroundColor
                self.selectorView.layer.borderColor = borderColor.cgColor
            })
        } else {
            CATransaction.withDisabledAnimations {
                self.shapeLayer?.strokeEnd = isSelected ? 1 : 0
            }
            
            selectorView.backgroundColor = backgroundColor
            selectorView.layer.borderColor = borderColor.cgColor
        }
    }
}