//
//  UIImage+Placeholder.swift
//  SwiftBilibili
//
//  Created by 罗文 on 2021/1/19.
//  Copyright © 2021年 罗文. All rights reserved.
//

import UIKit

import SwiftyImage

extension UIImage {
    
   class func placeholderImage(bgColor:UIColor = .db_gray,bgSize:CGSize) -> UIImage? {
    
       if bgSize == .zero {
          return nil
       }
    
       let bgImage = UIImage.size(bgSize).color(bgColor).image
       let centerImage = NYImage.Home.default_img!
       let placeholderImage = bgImage + centerImage
       return placeholderImage
   }
   
   class func resizeImage(image:UIImage?,newSize:CGSize) -> UIImage? {
        
        guard let image = image else {
            return nil
        }
        
        UIGraphicsBeginImageContext(newSize)
        image.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }
    
    class func generateQRCode(from jsonString: String, size: CGSize) -> UIImage? {
        // 将 JSON 字符串转换为二进制数据
        guard let jsonData = jsonString.data(using: .utf8) else {
            return nil
        }
        
        // 创建 CIFilter 对象，使用 "CIQRCodeGenerator" 过滤器生成二维码
        guard let filter = CIFilter(name: "CIQRCodeGenerator") else {
            return nil
        }
        
        // 设置输入数据
        filter.setValue(jsonData, forKey: "inputMessage")
        
        // 设置纠错级别，默认为 "L" (低)
        filter.setValue("M", forKey: "inputCorrectionLevel")
        
        // 获取生成的 CIImage
        guard let ciImage = filter.outputImage else {
            return nil
        }
        
        // 对 CIImage 进行缩放，以适应目标大小
        let scaleX = size.width / ciImage.extent.size.width
        let scaleY = size.height / ciImage.extent.size.height
        let transformedImage = ciImage.transformed(by: CGAffineTransform(scaleX: scaleX, y: scaleY))
        
        // 将 CIImage 转换为 UIImage
        let context = CIContext()
        guard let cgImage = context.createCGImage(transformedImage, from: transformedImage.extent) else {
            return nil
        }
        let qrCodeImage = UIImage(cgImage: cgImage)
        
        return qrCodeImage
    }
    
}