desc "Build and submit to TestFlight"
lane :submit_testflight do

  # 1) Create a keychain

  keychain_name = "certs"
  create_keychain(
    name: keychain_name,
    default_keychain: false,
    timeout: 3600,
    password: SecureRandom.base64,
    unlock: true
  )

  # 2) Import distribution certificate

  import_certificate(
    certificate_path: "/path/to/your/certificate",
    certificate_password: ENV["KEY_PASSWORD"],
    keychain_name: keychain_name
  )

  # 3) Download provisioning profile

  sigh(
    username: "your_apple_id_username",
    provisioning_name: "your_provisioning_profile_name",
    team_id: "your_team_id",
    cert_id: "your_cert_id"
  )

  # 4) Increment the build number

  increment_build_number(
    build_number: Time.now.to_i
  )

  # 5) Build the app

  gym(
    clean: true,
    workspace: "/path/to/your/workspace",
    output_name: "VTS.ipa",
    scheme: "VTS App Store",
    codesigning_identity: "your_codesigning_identity",
    xcargs:  "PROVISIONING_PROFILE_SPECIFIER='your_provisioning_prof'"
  )

  # 6) Release to TestFlight

  pilot(username: "your_app_id_username")
end