import SwiftUI
import CoreImage.CIFilterBuiltins

struct QRCodeImage: View {
    let content: String
    var size: CGFloat = 180

    var body: some View {
        if let image = Self.generate(content: content) {
            Image(uiImage: image)
                .interpolation(.none)
                .resizable()
                .scaledToFit()
                .frame(width: size, height: size)
                .accessibilityLabel("二维码")
        } else {
            RoundedRectangle(cornerRadius: 8)
                .fill(Color.secondary.opacity(0.2))
                .frame(width: size, height: size)
                .overlay(Text("QR 不可用").font(.caption))
        }
    }

    private static func generate(content: String) -> UIImage? {
        let context = CIContext()
        let filter = CIFilter.qrCodeGenerator()
        filter.message = Data(content.utf8)
        filter.correctionLevel = "M"
        guard let output = filter.outputImage else { return nil }
        let scaled = output.transformed(by: CGAffineTransform(scaleX: 10, y: 10))
        guard let cg = context.createCGImage(scaled, from: scaled.extent) else { return nil }
        return UIImage(cgImage: cg)
    }
}