//
//  UIButton+Extension.swift
//  dinoGo
//
//  Created by osell on 2022/12/7.
//  Copyright © 2022 dino. All rights reserved.
//

import Foundation

extension  UIButton {
    
    /// 设置图片的居中边位置，需要在setImage和setTitle之后调用才生效，且button大小大于图片+文字+间距
    /// - Parameters:
    ///   - edge: 仅有image时相对于button，都有时上左下相对于button，右相对于title, 仅有title时相对于button，都有时上右下相对于button，左相对于image
    ///   - spacing: 距离
    public func setImageEdge(_ edge: UIRectEdge, spacing: CGFloat) {
        let imageSize = imageView?.image?.size ?? .zero
        let labelSize = titleLabel?.intrinsicContentSize ?? .zero
        
        switch edge {
        case .left:
            imageEdgeInsets = UIEdgeInsets(top: 0, left: -spacing / 2.0, bottom: 0, right: spacing / 2.0)
            titleEdgeInsets = UIEdgeInsets(top: 0, left: spacing / 2.0, bottom: 0, right: -spacing / 2.0)
        case .right:
            imageEdgeInsets = UIEdgeInsets(top: 0, left: labelSize.width + spacing / 2.0, bottom: 0, right: -labelSize.width - spacing / 2.0)
            titleEdgeInsets = UIEdgeInsets(top: 0, left: -imageSize.width - spacing / 2.0, bottom: 0, right: imageSize.width + spacing / 2.0)
        case .top:
            imageEdgeInsets = UIEdgeInsets(top: -labelSize.height - spacing / 2.0, left: 0, bottom: spacing / 2.0, right: -labelSize.width)
            titleEdgeInsets = UIEdgeInsets(top: spacing / 2.0, left: -imageSize.width, bottom: -imageSize.height - spacing / 2.0, right: 0)
        case .bottom:
            imageEdgeInsets = UIEdgeInsets(top: spacing / 2.0, left: 0, bottom: -labelSize.height - spacing / 2.0, right: -labelSize.width)
            titleEdgeInsets = UIEdgeInsets(top: -imageSize.height - spacing / 2.0, left: -imageSize.width, bottom: spacing / 2.0, right: 0)
        default:
            break
        }
    }
    
    /// 设置按钮背景颜色
    /// - Parameters:
    ///   - backgroundColor: 颜色
    ///   - state: 状态
    public func setBackgroundColor(_ backgroundColor: UIColor, for state: UIControl.State) {
        var image: UIImage?
        let rect = CGRect(origin: .zero, size: CGSize(width: 1, height: 1))
        UIGraphicsBeginImageContextWithOptions(rect.size, false, 0)
        if let context = UIGraphicsGetCurrentContext() {
            context.setFillColor(backgroundColor.cgColor)
            context.fill(rect)
            image = UIGraphicsGetImageFromCurrentImageContext()
        }
        UIGraphicsEndImageContext()
        setBackgroundImage(image, for: state)
    }
}

// MARK: - 扩大按钮点击区域
extension UIButton {
    /// 设置此属性即可扩大响应范围, 分别对应上左下右
    /// 优势：与Auto-Layout无缝配合
    /// 劣势：View Debugger 查看不到增加的响应区域有多大，
    private static var ExtendEdgeInsetsKey = "ExtendEdgeInsetsKey"
    
    var extendEdgeInsets: UIEdgeInsets {
        get {
            return objc_getAssociatedObject(self, &UIButton.ExtendEdgeInsetsKey) as? UIEdgeInsets ?? UIEdgeInsets.zero
        }
        set {
            objc_setAssociatedObject(self, &UIButton.ExtendEdgeInsetsKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }

    override open func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        if UIEdgeInsetsEqualToEdgeInsets(extendEdgeInsets, .zero) || !self.isEnabled || self.isHidden || self.alpha < 0.01 {
            return super.point(inside: point, with: event)
        }
        let newRect = extendRect(bounds, extendEdgeInsets)
        return newRect.contains(point)
    }

    private func extendRect(_ rect: CGRect, _ edgeInsets: UIEdgeInsets) -> CGRect {
        let x = rect.minX - edgeInsets.left
        let y = rect.minY - edgeInsets.top
        let w = rect.width + edgeInsets.left + edgeInsets.right
        let h = rect.height + edgeInsets.top + edgeInsets.bottom
        return CGRect(x: x, y: y, width: w, height: h)
    }
}