import Foundation
import Vision

public struct QRCodeDecoder: Sendable {
    public init() {}
    public func detect(in data: Data) throws -> [String] {
        let request = VNDetectBarcodesRequest()
        request.symbologies = [.qr]
        try VNImageRequestHandler(data: data).perform([request])
        var seen = Set<String>()
        return (request.results ?? []).compactMap(\.payloadStringValue).filter { seen.insert($0).inserted }
    }
}