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

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

public class Checkbox: CheckboxBase<DefaultCheckboxModel>{}

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

open class CheckboxBase<ModelType: CheckboxModel>: 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?
        
    //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 selectorHeightConstraint: NSLayoutConstraint?
    private var selectorWidthConstraint: NSLayoutConstraint?
    
    //functions
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
  
    open override func setup() {
        super.setup()
        
        //add tapGesture to self
        publisher(for: UITapGestureRecognizer()).sink { [weak self] _ in
            self?.sendActions(for: .touchUpInside)
        }.store(in: &subscribers)
        
        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
    }
    
    /// 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?()
    }
        
    //--------------------------------------------------
    // 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)
        setNeedsLayout()
        layoutIfNeeded()
    }

    
    //--------------------------------------------------
    // MARK: - Configuration Properties
    //--------------------------------------------------
    public let checkboxSize = CGSize(width: 20, height: 20)
    
    private var checkboxBackgroundColorConfiguration: CheckboxErrorColorConfiguration = {
        return CheckboxErrorColorConfiguration().with {
            $0.forTrue.enabled.lightColor = VDSColor.elementsPrimaryOnlight
            $0.forTrue.enabled.darkColor = VDSColor.elementsPrimaryOndark
            $0.forTrue.disabled.lightColor = VDSColor.interactiveDisabledOnlight
            $0.forTrue.disabled.darkColor = VDSColor.interactiveDisabledOndark
            //error doesn't care enabled/disable
            $0.error.forTrue.lightColor = VDSColor.elementsPrimaryOnlight
            $0.error.forTrue.darkColor = VDSColor.elementsPrimaryOndark
            $0.error.forFalse.lightColor = VDSColor.feedbackErrorBackgroundOnlight
            $0.error.forFalse.darkColor = VDSColor.feedbackErrorBackgroundOndark
        }
    }()
    
    private var checkboxBorderColorConfiguration: CheckboxErrorColorConfiguration = {
        return CheckboxErrorColorConfiguration().with {
            $0.forTrue.enabled.lightColor = VDSColor.elementsPrimaryOnlight
            $0.forTrue.enabled.darkColor = VDSColor.elementsPrimaryOndark
            $0.forFalse.enabled.lightColor = VDSFormControlsColor.borderOnlight
            $0.forFalse.enabled.darkColor = VDSFormControlsColor.borderOndark
            $0.forTrue.disabled.lightColor = VDSColor.interactiveDisabledOnlight
            $0.forTrue.disabled.darkColor = VDSColor.interactiveDisabledOndark
            $0.forFalse.disabled.lightColor = VDSColor.interactiveDisabledOnlight
            $0.forFalse.disabled.darkColor = VDSColor.interactiveDisabledOndark
            //error doesn't care enabled/disable
            $0.error.forTrue.lightColor = VDSColor.elementsPrimaryOnlight
            $0.error.forTrue.darkColor = VDSColor.elementsPrimaryOndark
            $0.error.forFalse.lightColor = VDSColor.feedbackErrorOnlight
            $0.error.forFalse.darkColor = VDSColor.feedbackErrorOndark
        }
    }()

    private var checkboxCheckColorConfiguration: BinarySurfaceColorConfiguration<ModelType> = {
        return BinarySurfaceColorConfiguration<ModelType>().with {
            $0.forTrue.lightColor = VDSColor.elementsPrimaryOndark
            $0.forTrue.darkColor = VDSColor.elementsPrimaryOnlight
        }
    }()
        
    //--------------------------------------------------
    // MARK: - Checkbox View
    //--------------------------------------------------
    /// Manages the appearance of the checkbox.
    private var shapeLayer: CAShapeLayer?
    
    open func getSelectorSize() -> CGSize {
        return checkboxSize
    }
    
    open func updateSelector(_ viewModel: ModelType) {
        //get the colors
        let backgroundColor = checkboxBackgroundColorConfiguration.getColor(viewModel)
        let borderColor = checkboxBorderColorConfiguration.getColor(viewModel)
        let checkColor = checkboxCheckColorConfiguration.getColor(viewModel)

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

        selectorView.backgroundColor = backgroundColor
        selectorView.layer.borderColor = borderColor.cgColor
        selectorView.layer.cornerRadius = 2.0
        selectorView.layer.borderWidth = 1.0

        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 = model.selected ? 1 : 0
            }
        }
    }
    
    //--------------------------------------------------
    // MARK: - Color Class Configurations
    //--------------------------------------------------
    private class CheckboxErrorColorConfiguration: BinaryDisabledSurfaceColorConfiguration<ModelType> {
        public let error = BinarySurfaceColorConfiguration<ModelType>()
        override func getColor(_ viewModel: ModelType) -> UIColor {
            //only show error is enabled and showError == true
            let showErrorColor = !viewModel.disabled && viewModel.hasError
            
            if showErrorColor {
                return error.getColor(viewModel)
            } else {
                return super.getColor(viewModel)
            }
        }
    }
        
}