Composing Mail in SwiftUI

////  MailView.swift//  sky-earth-human////  Source: https://stackoverflow.com/a/58693164/9568307//
import MessageUIimport SwiftUIimport UIKit
struct MailView: UIViewControllerRepresentable {  @Environment(\.presentationMode) var presentation  @Binding var result: Result<MFMailComposeResult, Error>?
  class Coordinator: NSObject, MFMailComposeViewControllerDelegate {    @Binding var presentation: PresentationMode    @Binding var result: Result<MFMailComposeResult, Error>?
    init(presentation: Binding<PresentationMode>,         result: Binding<Result<MFMailComposeResult, Error>?>)    {      _presentation = presentation      _result = result    }
    func mailComposeController(_: MFMailComposeViewController,                               didFinishWith result: MFMailComposeResult,                               error: Error?)    {      defer {        $presentation.wrappedValue.dismiss()      }      guard error == nil else {        self.result = .failure(error!)        return      }      self.result = .success(result)    }  }
  func makeCoordinator() -> Coordinator {    return Coordinator(presentation: presentation,                       result: $result)  }
  func makeUIViewController(context: UIViewControllerRepresentableContext<MailView>) -> MFMailComposeViewController {    let vc = MFMailComposeViewController()    vc.setToRecipients(["hey@cho.sh"])    vc.setSubject("하늘땅사람 관련 문의")    vc.setMessageBody("""
    문의 내용을 여기에 입력해주세요.
    --------------------
    하늘땅사람 버전: ((Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String)!)    iOS 버전: (UIDevice.current.systemVersion)    기기: (UIDevice.current.model)
    """, isHTML: false)    vc.mailComposeDelegate = context.coordinator    return vc  }
  func updateUIViewController(_: MFMailComposeViewController,                              context _: UIViewControllerRepresentableContext<MailView>) {}}

Button(action: {self.isShowingMailView.toggle()}) {  Image(systemName: "paperplane.fill").frame(alignment: .center)  Text("버그 제보 및 기능 제안하기")}  .disabled(!MFMailComposeViewController.canSendMail())  .sheet(isPresented: $isShowingMailView) {    MailView(result: self.$result)  }