chore: import upstream snapshot with attribution

apps/sim/lib/messaging/email/prepare.ts

@@ -0,0 +1,107 @@
+import { getBaseUrl } from '@/lib/core/utils/urls'
+import type { EmailOptions, EmailType, ProcessedEmailData } from '@/lib/messaging/email/types'
+import { generateUnsubscribeToken, isUnsubscribed } from '@/lib/messaging/email/unsubscribe'
+import { getFromEmailAddress, hasEmailHeaderControlChars } from '@/lib/messaging/email/utils'
+
+function sanitizeEmailSubject(subject: string): string {
+  return subject.replace(/[\r\n]+/g, ' ').trim()
+}
+
+interface UnsubscribeInjection {
+  headers: Record<string, string>
+  html?: string
+  text?: string
+}
+
+function buildUnsubscribeInjection(
+  recipientEmail: string,
+  emailType: EmailType,
+  html?: string,
+  text?: string
+): UnsubscribeInjection {
+  const token = generateUnsubscribeToken(recipientEmail, emailType)
+  const baseUrl = getBaseUrl()
+  const encodedEmail = encodeURIComponent(recipientEmail)
+  const unsubscribeUrl = `${baseUrl}/unsubscribe?token=${token}&email=${encodedEmail}`
+
+  return {
+    headers: {
+      'List-Unsubscribe': `<${unsubscribeUrl}>`,
+      'List-Unsubscribe-Post': 'List-Unsubscribe=One-Click',
+    },
+    html: html
+      ?.replace(/\{\{UNSUBSCRIBE_TOKEN\}\}/g, token)
+      .replace(/\{\{UNSUBSCRIBE_EMAIL\}\}/g, encodedEmail),
+    text: text
+      ?.replace(/\{\{UNSUBSCRIBE_TOKEN\}\}/g, token)
+      .replace(/\{\{UNSUBSCRIBE_EMAIL\}\}/g, encodedEmail),
+  }
+}
+
+function validateAndSanitize(options: EmailOptions): {
+  senderEmail: string
+  subject: string
+  replyTo?: string
+} {
+  const senderEmail = options.from || getFromEmailAddress()
+  const recipients = Array.isArray(options.to) ? options.to : [options.to]
+
+  if (recipients.some(hasEmailHeaderControlChars)) {
+    throw new Error('Invalid recipient email header')
+  }
+  if (hasEmailHeaderControlChars(senderEmail)) {
+    throw new Error('Invalid from email header')
+  }
+  if (options.replyTo && hasEmailHeaderControlChars(options.replyTo)) {
+    throw new Error('Invalid reply-to email header')
+  }
+
+  const subject = sanitizeEmailSubject(options.subject)
+  if (subject.length === 0) {
+    throw new Error('Email subject cannot be empty')
+  }
+
+  return { senderEmail, subject, replyTo: options.replyTo }
+}
+
+export function processEmailData(options: EmailOptions): ProcessedEmailData {
+  const { senderEmail, subject, replyTo } = validateAndSanitize(options)
+  const {
+    to,
+    html,
+    text,
+    emailType = 'transactional',
+    includeUnsubscribe = true,
+    attachments,
+  } = options
+
+  let finalHtml = html
+  let finalText = text
+  let headers: Record<string, string> = {}
+
+  if (includeUnsubscribe && emailType !== 'transactional') {
+    const primaryEmail = Array.isArray(to) ? to[0] : to
+    const injection = buildUnsubscribeInjection(primaryEmail, emailType, html, text)
+    headers = injection.headers
+    finalHtml = injection.html
+    finalText = injection.text
+  }
+
+  return {
+    to,
+    subject,
+    html: finalHtml,
+    text: finalText,
+    senderEmail,
+    headers,
+    attachments,
+    replyTo,
+  }
+}
+
+export async function shouldSkipForUnsubscribe(options: EmailOptions): Promise<boolean> {
+  const { emailType = 'transactional', to } = options
+  if (emailType === 'transactional') return false
+  const primaryEmail = Array.isArray(to) ? to[0] : to
+  return isUnsubscribed(primaryEmail, emailType)
+}