//
//  SPFadeEdgeImageView.swift
//  MoviaBox
//
//  Created by 佳尔 on 2025/4/28.
//

import UIKit

class SPFadeEdgeImageView: UIImageView {
    
    override var image: UIImage? {
        didSet {
            applyBlurAndEdgeFadeEffect()
        }
    }
    
    private var blurredImage: UIImage?
    
    override func layoutSubviews() {
        super.layoutSubviews()
        applyBlurAndEdgeFadeEffect()
    }
    
    private func applyBlurAndEdgeFadeEffect() {
        if blurredImage != nil, blurredImage == image {
            return
        }
        // 1. 添加高斯模糊效果到图片
        let context = CIContext(options: nil)
        guard let image = self.image else { return }
        guard let ciImage = CIImage(image: image) else { return }
        
        let filter = CIFilter(name: "CIGaussianBlur")
        filter?.setValue(ciImage, forKey: kCIInputImageKey)
        filter?.setValue(50, forKey: kCIInputRadiusKey)  // 调整模糊半径
        guard let outputImage = filter?.outputImage else { return }
        
        if let cgImage = context.createCGImage(outputImage, from: outputImage.extent) {
            let blurredImage = UIImage(cgImage: cgImage)
            self.blurredImage = blurredImage
            self.image = blurredImage
        }
        
        // 2. 创建渐变蒙版（四周虚化）
        let maskLayer = CAShapeLayer()
        maskLayer.frame = bounds
        
        // 画一个圆形的反向路径，中心完全显示，四周渐变透明
        let path = UIBezierPath(rect: bounds)
        let insetRect = bounds.insetBy(dx: bounds.width * 0.1, dy: bounds.height * 0.1)
        let innerPath = UIBezierPath(roundedRect: insetRect, cornerRadius: 20)
        path.append(innerPath)
        path.usesEvenOddFillRule = true
        
        maskLayer.path = path.cgPath
        maskLayer.fillRule = .evenOdd
        
        // 3. 创建径向渐变图层
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = bounds
        gradientLayer.colors = [
            UIColor.black.withAlphaComponent(1).cgColor,
            UIColor.black.withAlphaComponent(0).cgColor
        ]
        gradientLayer.startPoint = CGPoint(x: 0.5, y: 0.5)
        gradientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)
        gradientLayer.locations = [0.5, 1]
        gradientLayer.type = .radial
        
        // 4. 添加渐变蒙版到图片
        let containerLayer = CALayer()
        containerLayer.frame = bounds
        containerLayer.addSublayer(gradientLayer)
        containerLayer.mask = maskLayer
        
        self.layer.mask = containerLayer
    }
    
}