//
//  UIColor+Gradient.swift
//  BlockEQ
//
//  Created by Satraj Bambra on 2018-03-09.
//  Copyright © 2018 Satraj Bambra. All rights reserved.
//
import UIKit

extension UIColor {
    convenience init(_ hex: UInt) {
        self.init(
            red: CGFloat((hex & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((hex & 0x00FF00) >> 8) / 255.0,
            blue: CGFloat(hex & 0x0000FF) / 255.0,
            alpha: CGFloat(1.0)
        )
    }
}

typealias GradientType = (x: CGPoint, y: CGPoint)

enum GradientPoint {
    case leftRight
    case rightLeft
    case topBottom
    case bottomTop
    case topLeftBottomRight
    case bottomRightTopLeft
    case topRightBottomLeft
    case bottomLeftTopRight
    
    func draw() -> GradientType {
        switch self {
        case .leftRight:
            return (x: CGPoint(x: 0, y: 0.5), y: CGPoint(x: 1, y: 0.5))
        case .rightLeft:
            return (x: CGPoint(x: 1, y: 0.5), y: CGPoint(x: 0, y: 0.5))
        case .topBottom:
            return (x: CGPoint(x: 0.5, y: 0), y: CGPoint(x: 0.5, y: 1))
        case .bottomTop:
            return (x: CGPoint(x: 0.5, y: 1), y: CGPoint(x: 0.5, y: 0))
        case .topLeftBottomRight:
            return (x: CGPoint(x: 0, y: 0), y: CGPoint(x: 1, y: 1))
        case .bottomRightTopLeft:
            return (x: CGPoint(x: 1, y: 1), y: CGPoint(x: 0, y: 0))
        case .topRightBottomLeft:
            return (x: CGPoint(x: 1, y: 0), y: CGPoint(x: 0, y: 1))
        case .bottomLeftTopRight:
            return (x: CGPoint(x: 0, y: 1), y: CGPoint(x: 1, y: 0))
        }
    }
}

class GradientLayer : CAGradientLayer {
    var gradient: GradientType? {
        didSet {
            startPoint = gradient?.x ?? CGPoint.zero
            endPoint = gradient?.y ?? CGPoint.zero
        }
    }
}

class GradientView: UIView {
    override public class var layerClass: Swift.AnyClass {
        get {
            return GradientLayer.self
        }
    }
}

protocol GradientViewProvider {
    associatedtype GradientViewType
}

extension GradientViewProvider where Self: UIView {
    var gradientLayer: GradientViewType { return layer as! GradientViewType }
}

extension UIView: GradientViewProvider {
    typealias GradientViewType = GradientLayer
}