//
//  TileContainer.swift
//  VDS
//
//  Created by Matt Bruce on 12/16/22.
//

import Foundation
import VDSCoreTokens
import UIKit
import Combine

@objc(VDSTileContainer)
open class TileContainer: TileContainerBase<TileContainer.Padding> {
        
    /// Enum used to describe the padding choices used for this component.
    public enum Padding: DefaultValuing {
        case padding3X
        case padding4X
        case padding6X
        case padding8X
        case padding12X
        case custom(CGFloat)
        
        public static var defaultValue: Self { .padding4X }
        
        public var value: CGFloat {
            switch self {
            case .padding3X:
                return VDSLayout.space3X
            case .padding4X:
                return VDSLayout.space4X
            case .padding6X:
                return VDSLayout.space6X
            case .padding8X:
                return VDSLayout.space8X
            case .padding12X:
                return VDSLayout.space12X
            case .custom(let padding):
                return padding
            }
        }
    }
}

open class TileContainerBase<PaddingType: DefaultValuing>: Control where PaddingType.ValueType == CGFloat  {
    //--------------------------------------------------
    // 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: - Enums
    //--------------------------------------------------
    /// Enum used to describe the background color choices used for this component.
    public enum BackgroundColor: Equatable {
        
        case primary
        case secondary
        case white
        case black
        case token(UIColor.VDSColor)
        case custom(UIColor)
        
        private var reflectedValue: String { String(reflecting: self) }

        public static func == (lhs: Self, rhs: Self) -> Bool {
            lhs.reflectedValue == rhs.reflectedValue
        }
    }
    
    /// Enum used to describe the background effect choices used for this component.
    public enum BackgroundEffect {
        case transparency
        case gradient(UIColor, UIColor)
        case none
    }
       
    /// Enum used to describe the aspect ratios used for this component.
    public enum AspectRatio: String, CaseIterable {
        case ratio1x1 = "1:1"
        case ratio3x4 = "3:4"
        case ratio4x3 = "4:3"
        case ratio2x3 = "2:3"
        case ratio3x2 = "3:2"
        case ratio9x16 = "9:16"
        case ratio16x9 = "16:9"
        case ratio1x2 = "1:2"
        case ratio2x1 = "2:1"
        case none
    }
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var backgroundImageView = UIImageView().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.contentMode = .scaleAspectFill
        $0.clipsToBounds = true
    }

    internal var containerView = View()

    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    /// This takes an image source url and applies it as a background image.
    open var backgroundImage: UIImage? { didSet {  setNeedsUpdate() } }
    
    /// This is the container in which views will be pinned.
    open var contentView = View()

    ///  This is the view used to show the high light color for a onClick.
    open var highlightView = View().with {
        $0.isUserInteractionEnabled = false
    }

    /// This controls the aspect ratio for the component.
    open var aspectRatio: AspectRatio = .ratio1x1 { didSet {  setNeedsUpdate() } }

    /// Sets the background color for the component.
    open var color: BackgroundColor? { didSet {  setNeedsUpdate() } }
    
    /// Sets the background effect for the component.
    open var backgroundEffect: BackgroundEffect = .none { didSet {  setNeedsUpdate() } }

    /// Sets the inside padding for the component
    open var padding: PaddingType = PaddingType.defaultValue { didSet {  setNeedsUpdate() } }
    
    /// Applies a background color if backgroundImage prop fails or has trouble loading.
    open var imageFallbackColor: Surface = .light { didSet {  setNeedsUpdate() } }

    private var _width: CGFloat?
    /// Sets the width for the component. Accepts a pixel value.
    open var width: CGFloat? {
        get { return _width }
        set {
            if let newValue, newValue > 100 {
                _width = newValue
            } else {
                _width = nil
            }
            setNeedsUpdate()
        }
    }
        
    private var _height: CGFloat?
    /// Sets the height for the component. Accepts a pixel value.
    open var height: CGFloat? {
        get { return _height }
        set {
            if let newValue, newValue > 44 {
                _height = newValue
            } else {
                _height = nil
            }
            setNeedsUpdate()
        }
    }
    
    /// If true, a border is rendered around the container.
    open var showBorder: Bool = false { didSet {  setNeedsUpdate() } }
    
    /// Determines if there is a drop shadow or not.
    open var showDropShadow: Bool = false { didSet {  setNeedsUpdate() } }
        
    //--------------------------------------------------
    // MARK: - Constraints
    //--------------------------------------------------
    internal var widthConstraint: NSLayoutConstraint?
    internal var heightConstraint: NSLayoutConstraint?
    internal var heightGreaterThanConstraint: NSLayoutConstraint?
    internal var containerTopConstraint: NSLayoutConstraint?
    internal var containerBottomConstraint: NSLayoutConstraint?
    internal var containerLeadingConstraint: NSLayoutConstraint?
    internal var containerTrailingConstraint: NSLayoutConstraint?
        
    //--------------------------------------------------
    // MARK: - Configuration
    //--------------------------------------------------
    private let cornerRadius = VDSLayout.shapeCornerradiusTiles
    internal var backgroundColorConfiguration = BackgroundColorConfiguration()
    private let dropShadowConfiguration = DropShadowConfiguration().with {
        $0.shadowColorConfiguration = SurfaceColorConfiguration().with {
            $0.lightColor = VDSColor.elementsPrimaryOnlight
        }.eraseToAnyColorable()
        $0.shadowOffsetConfiguration = .init(.init(width: 0, height: 6), .zero)
        $0.shadowRadiusConfiguration = .init(8.0, 0.0)
        $0.shadowOpacityConfiguration = .init(0.1, 0.0)
    }
    
    private var borderColorConfiguration = SurfaceColorConfiguration().with {
        $0.lightColor = VDSColor.elementsLowcontrastOnlight
        $0.darkColor = VDSColor.elementsLowcontrastOndark
    }
    
    private var imageFallbackColorConfiguration = SurfaceColorConfiguration().with {
        $0.lightColor = VDSColor.backgroundPrimaryLight
        $0.darkColor = VDSColor.backgroundPrimaryDark
    }
    
    private var hightLightViewColorConfiguration = SurfaceColorConfiguration().with {
        $0.lightColor = VDSColor.paletteWhite.withAlphaComponent(0.3)
        $0.darkColor = VDSColor.paletteBlack.withAlphaComponent(0.3)
    }
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    /// 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 = false
        
        let layoutGuide = UILayoutGuide()
        addLayoutGuide(layoutGuide)
        layoutGuide
            .pinTop()
            .pinLeading()
            .pinTrailing(0, .defaultHigh)
            .pinBottom(0, .defaultHigh)
        addSubview(backgroundImageView)
        addSubview(containerView)
        containerView.addSubview(contentView)
        addSubview(highlightView)
            
        containerView.pinToSuperView()
        
        widthConstraint = layoutGuide.widthAnchor.constraint(equalToConstant: 0)

        heightGreaterThanConstraint = layoutGuide.heightAnchor.constraint(greaterThanOrEqualToConstant: 44.0)
        heightGreaterThanConstraint?.isActive = false

        heightConstraint = layoutGuide.heightAnchor.constraint(equalToConstant: 0)

        backgroundImageView.pinToSuperView()
        
        backgroundImageView.setContentHuggingPriority(.defaultLow, for: .horizontal)
        backgroundImageView.setContentHuggingPriority(.defaultLow, for: .vertical)
        backgroundImageView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        backgroundImageView.setContentCompressionResistancePriority(.defaultLow, for: .vertical)
        backgroundImageView.isUserInteractionEnabled = false
        backgroundImageView.isHidden = true
        
        containerTopConstraint = contentView.pinTop(anchor: layoutGuide.topAnchor, constant: padding.value)
        containerBottomConstraint = layoutGuide.pinBottom(anchor: contentView.bottomAnchor, constant: padding.value)
        containerLeadingConstraint = contentView.pinLeading(anchor: layoutGuide.leadingAnchor, constant: padding.value)
        containerTrailingConstraint = layoutGuide.pinTrailing(anchor: contentView.trailingAnchor, constant: padding.value)

        highlightView.pin(layoutGuide)
        highlightView.isHidden = true
        highlightView.backgroundColor = .clear
        
        //corner radius
        layer.cornerRadius = cornerRadius
        backgroundImageView.layer.cornerRadius = cornerRadius
        highlightView.layer.cornerRadius = cornerRadius
        clipsToBounds = true
    }
    
    /// Overriden to take the hit if there is an onClickSubscriber and the view is not a UIControl
    open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let view = super.hitTest(point, with: event)
        guard let _ = onClickSubscriber else { return view }
        guard view is UIControl else { return self }
        return view
    }
    
    /// Resets to default settings.
    open override func reset() {
        super.reset()
        shouldUpdateView = false
        color = .white
        aspectRatio = .ratio1x1
        imageFallbackColor = .light
        width = nil
        height = nil
        showBorder = false
        showDropShadow = false
        shouldUpdateView = true
        setNeedsUpdate()
    }
        
    /// Used to make changes to the View based off a change events or from local properties.
    open override func updateView() {
        super.updateView()
        
        highlightView.backgroundColor = hightLightViewColorConfiguration.getColor(self)
        highlightView.isHidden = !isHighlighted
        
        layer.borderColor = borderColorConfiguration.getColor(self).cgColor
        layer.borderWidth = showBorder ? VDSFormControls.borderWidth : 0

        containerTopConstraint?.constant = padding.value
        containerLeadingConstraint?.constant = padding.value
        containerBottomConstraint?.constant = padding.value
        containerTrailingConstraint?.constant = padding.value

        if let width, aspectRatio == .none && height == nil{
            widthConstraint?.constant = width
            widthConstraint?.isActive = true
            heightConstraint?.isActive = false
            heightGreaterThanConstraint?.isActive = true
        } else if let height, let width {
            widthConstraint?.constant = width
            heightConstraint?.constant = height
            heightConstraint?.isActive = true
            widthConstraint?.isActive = true
            heightGreaterThanConstraint?.isActive = false
        } else if let width  {
            let size = ratioSize(for: width)
            widthConstraint?.constant = size.width
            heightConstraint?.constant = size.height
            widthConstraint?.isActive = true
            heightConstraint?.isActive = true
            heightGreaterThanConstraint?.isActive = false
        } else {
            widthConstraint?.isActive = false
            heightConstraint?.isActive = false
        }

        applyBackgroundEffects()
        
        if showDropShadow, surface == .light {
            addDropShadow(dropShadowConfiguration)
        } else {
            removeDropShadows()
        }
    }
    
    open override func updateAccessibility() {
        super.updateAccessibility()
        containerView.isAccessibilityElement = onClickSubscriber != nil
        containerView.accessibilityHint = "Double tap to open."
        containerView.accessibilityLabel = nil
    }
    
    open override var accessibilityElements: [Any]? {
        get {
            var items = [Any]()
            if containerView.isAccessibilityElement {
                if !accessibilityTraits.contains(.button) && !accessibilityTraits.contains(.link) {
                    containerView.accessibilityTraits = .button
                } else {
                    containerView.accessibilityTraits = accessibilityTraits
                }
                items.append(containerView)
            }
            
            let elements = gatherAccessibilityElements(from: contentView)
            let views = elements.compactMap({ $0 as? UIView })
            
            //update accessibilityLabel
            containerView.setAccessibilityLabel(for: views)
            
            //append all children that are accessible
            items.append(contentsOf: elements)
           
            return items
        }
        set {}
    }
    
    /// Used to update frames for the added CAlayers to our view
    open override func layoutSubviews() {
        super.layoutSubviews()
        dropShadowLayers?.forEach { $0.frame = bounds }
        gradientLayers?.forEach { $0.frame = bounds }
    }
    
    //--------------------------------------------------
    // MARK: - Public Methods
    //--------------------------------------------------

    /// This will place a view within the contentView of this component.
    public func addContentView(_ view: UIView, shouldPin: Bool = true) {
        view.removeFromSuperview()
        contentView.addSubview(view)
        if shouldPin {
            view.pinToSuperView()
        }
    }

    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------
    
    private func applyBackgroundEffects() {
        let color = backgroundColorConfiguration.getColor(self)
        var alphaConfiguration: CGFloat = 1.0
        let imageFallbackColor = imageFallbackColorConfiguration.getColor(self)
        switch backgroundEffect {
        case .transparency:
            alphaConfiguration = 0.8
            removeGradientLayer()
        case .gradient(let firstColor, let secondColor):
            alphaConfiguration = 1.0
            addGradientLayer(with: firstColor, secondColor: secondColor)
            backgroundImageView.isHidden = true
            backgroundImageView.alpha = 1.0
        case .none:
            alphaConfiguration = 1.0
            removeGradientLayer()
        }
        if let backgroundImage {
            backgroundImageView.image = backgroundImage
            backgroundImageView.isHidden = false
            backgroundImageView.alpha = alphaConfiguration
            backgroundColor = imageFallbackColor.withAlphaComponent(alphaConfiguration)
        } else {
            backgroundImageView.isHidden = true
            backgroundImageView.alpha = 1.0
            backgroundColor = color.withAlphaComponent(alphaConfiguration)
        }
    }
    
    private func ratioSize(for width: CGFloat) -> CGSize {
        var height: CGFloat = width
        
        switch aspectRatio {
        case .ratio1x1:
            break;
        case .ratio3x4:
            height = (4 / 3) * width
        case .ratio4x3:
            height = (3 / 4) * width
        case .ratio2x3:
            height = (3 / 2) * width
        case .ratio3x2:
            height = (2 / 3) * width
        case .ratio9x16:
            height = (16 / 9) * width
        case .ratio16x9:
            height = (9 / 16) * width
        case .ratio1x2:
            height = (2 / 1) * width
        case .ratio2x1:
            height = (1 / 2) * width
        
        default:
            break
        }
        
        return CGSize(width: width, height: height)
    }

}

extension TileContainerBase {
    
    final class BackgroundColorConfiguration: ObjectColorable {
        
        typealias ObjectType = TileContainerBase
        
        let primaryColorConfig = SurfaceColorConfiguration(VDSColor.backgroundPrimaryLight, VDSColor.backgroundPrimaryDark)
        let secondaryColorConfig = SurfaceColorConfiguration(VDSColor.backgroundSecondaryLight, VDSColor.backgroundSecondaryDark)
        let grayColorConfig = SurfaceColorConfiguration(VDSColor.backgroundSecondaryLight, VDSColor.backgroundSecondaryDark)
        let whiteColorConfig = SurfaceColorConfiguration(VDSColor.paletteWhite, VDSColor.paletteWhite)
        let blackColorConfig = SurfaceColorConfiguration(VDSColor.paletteBlack, VDSColor.paletteBlack)
        
        required init() { }
        
        func getColor(_ object: ObjectType) -> UIColor {
            guard let color = object.color else {
                let config = object.surface == .light ? blackColorConfig : whiteColorConfig
                return config.getColor(object.surface)
            }
            
            switch color {
            case .primary:
                return primaryColorConfig.getColor(object.surface)
            case .secondary:
                return secondaryColorConfig.getColor(object.surface)
            case .white:
                return whiteColorConfig.getColor(object.surface)
            case .black:
                return blackColorConfig.getColor(object.surface)
            case .token(let vdsColor):
                return vdsColor.uiColor
            case .custom(let color):
                return color
            }
        }
    }
}