export const enum EmailHeaderKey {
  MessageId = "Message-ID",
  References = "References",
  ThreadIndex = "Thread-Index",
  XMailer = "X-Mailer",
  XPriority = "X-Priority",
  XMSMailPriority = "X-MSMail-Priority",
  MIMEVersion = "MIME-Version",
  AuthenticationResults = "Authentication-Results",
  XAutoResponseSuppress = "X-Auto-Response-Suppress",
  XEntityID = "X-Entity-ID",
  Precedence = "Precedence",
  ListUnsubscribePost = "List-Unsubscribe-Post",
  ListUnsubscribe = "List-Unsubscribe",
  ListId = "List-Id",
  XSpamStatus = "X-Spam-Status",
  XSpamScore = "X-Spam-Score",
  XFeedbackID = "X-Feedback-ID",
  XEntityRefID = "X-Entity-Ref-ID",
  InReplyTo = "In-Reply-To",
  XGmailThreadBreak = "X-Gmail-Thread-Break",
  ThreadTopic = "Thread-Topic",
  XTransactionID = "X-Transaction-ID",
  XCategory = "X-Category",
  Importance = "Importance",
  XCampaignID = "X-Campaign-ID",
  XMarketingEmail = "X-Marketing-Email",
  // Image-related anti-spam headers
  XImageSource = "X-Image-Source",
  XContentSecurity = "X-Content-Security",
  XImageValidation = "X-Image-Validation",
  XOriginVerified = "X-Origin-Verified",
  XImageCount = "X-Image-Count",
  XTrustedSources = "X-Trusted-Sources",
}

export enum Priority {
  High = "high",
  Normal = "normal",
  Low = "low",
}