//
//  DropShadowable.swift
//  VDS
//
//  Created by Bandaru, Krishna Kishore on 16/02/24.
//

import Foundation
import UIKit

/**
 DropShadowable protocol helps with the configuration values for adding drop shadows for light & dark surfaces.
*/
protocol DropShadowable {
    ///Shadow Color configuration for light and dark surfaces
    var shadowColorConfiguration: AnyColorable { get set }
    ///Shadow Opacity configuration for light and dark surfaces
    var shadowOpacityConfiguration: SurfaceConfigurationValue<CGFloat> { get set }
    ///Shadow Offset configuration for light and dark surfaces
    var shadowOffsetConfiguration: SurfaceConfigurationValue<CGSize> { get set }
    ///Shadow Radius configuration for light and dark surfaces
    var shadowRadiusConfiguration: SurfaceConfigurationValue<CGFloat> { get set }
}

/**
 DropShadowableConfiguration protocol helps with multiple drop shadows configurations can be added to a view.
 */
protocol DropShadowableConfiguration {
    
    ///Configurations are the DropShadowable list, these are applied on the view
    var configurations: [DropShadowable] { get }
}

/**
 Extension on ViewProtocol for adding drop shadows & gradient layer on view.
 */
extension ViewProtocol where Self: UIView {
    
    func addDropShadow(_ config: DropShadowable) {
        addDropShadows([config])
    }
    
    func addDropShadows(_ configs: [DropShadowable]) {
        removeDropShadows()
        layer.backgroundColor = backgroundColor?.cgColor
        layer.masksToBounds = false
        for config in configs {
            let shadowPath = UIBezierPath(roundedRect: bounds, cornerRadius: layer.cornerRadius)
            let shadowLayer = CALayer()
            shadowLayer.shadowPath = shadowPath.cgPath
            shadowLayer.frame = bounds
            shadowLayer.position = .init(x: bounds.midX, y: bounds.midY)
            shadowLayer.backgroundColor = backgroundColor?.cgColor
            shadowLayer.cornerRadius = layer.cornerRadius
            shadowLayer.shadowColor =  config.shadowColorConfiguration.getColor(self).cgColor
            shadowLayer.shadowOpacity = Float(config.shadowOpacityConfiguration.value(for: self))
            shadowLayer.shadowOffset =  config.shadowOffsetConfiguration.value(for: self)
            shadowLayer.shadowRadius = config.shadowRadiusConfiguration.value(for: self)
            shadowLayer.name = "dropShadowLayer"
            shadowLayer.shouldRasterize = true
            shadowLayer.rasterizationScale = UIScreen.main.scale
            layer.insertSublayer(shadowLayer, at: 0)
        }
    }
    
    func removeDropShadows() {
        layer.sublayers?.removeAll { $0.name == "dropShadowLayer" }
    }
    
    func addGradientLayer(with firstColor: UIColor, secondColor: UIColor) {
        removeGradientLayer()
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = bounds
        gradientLayer.startPoint = CGPoint(x: 0, y: 1)
        gradientLayer.endPoint = CGPoint(x: 1, y: 0)
        gradientLayer.position = center
        gradientLayer.shouldRasterize = true
        gradientLayer.backgroundColor = UIColor.clear.cgColor
        gradientLayer.rasterizationScale = UIScreen.main.scale
        gradientLayer.cornerRadius = layer.cornerRadius
        gradientLayer.colors = [firstColor.cgColor, secondColor.cgColor]
        gradientLayer.name = "gradientLayer"
        layer.insertSublayer(gradientLayer, at: 0)
    }
    
    func removeGradientLayer() {
        layer.sublayers?.removeAll { $0.name == "gradientLayer" }
    }
}