Email queue + async sending; legal settings and placeholders

- Add in-memory email queue with rate limiting (MAX_EMAILS_PER_HOUR)
- Bulk send to event attendees now queues and returns immediately
- Frontend shows 'Emails are being sent in the background'
- Legal pages, settings, and placeholders updates

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/lib/email.ts

@@ -10,6 +10,7 @@ import {
   defaultTemplates,
   type DefaultTemplate 
 } from './emailTemplates.js';
+import { enqueueBulkEmails, type TemplateEmailJobParams } from './emailQueue.js';
 import nodemailer from 'nodemailer';
 import type { Transporter } from 'nodemailer';
 
@@ -1173,6 +1174,100 @@ export const emailService = {
       errors,
     };
   },
+
+  /**
+   * Queue emails for event attendees (non-blocking).
+   * Adds all matching recipients to the background email queue and returns immediately.
+   * Rate limiting and actual sending is handled by the email queue.
+   */
+  async queueEventEmails(params: {
+    eventId: string;
+    templateSlug: string;
+    customVariables?: Record<string, any>;
+    recipientFilter?: 'all' | 'confirmed' | 'pending' | 'checked_in';
+    sentBy: string;
+  }): Promise<{ success: boolean; queuedCount: number; error?: string }> {
+    const { eventId, templateSlug, customVariables = {}, recipientFilter = 'confirmed', sentBy } = params;
+
+    // Validate event exists
+    const event = await dbGet<any>(
+      (db as any)
+        .select()
+        .from(events)
+        .where(eq((events as any).id, eventId))
+    );
+
+    if (!event) {
+      return { success: false, queuedCount: 0, error: 'Event not found' };
+    }
+
+    // Validate template exists
+    const template = await this.getTemplate(templateSlug);
+    if (!template) {
+      return { success: false, queuedCount: 0, error: `Template "${templateSlug}" not found` };
+    }
+
+    // Get tickets based on filter
+    let ticketQuery = (db as any)
+      .select()
+      .from(tickets)
+      .where(eq((tickets as any).eventId, eventId));
+
+    if (recipientFilter !== 'all') {
+      ticketQuery = ticketQuery.where(
+        and(
+          eq((tickets as any).eventId, eventId),
+          eq((tickets as any).status, recipientFilter)
+        )
+      );
+    }
+
+    const eventTickets = await dbAll<any>(ticketQuery);
+
+    if (eventTickets.length === 0) {
+      return { success: true, queuedCount: 0, error: 'No recipients found' };
+    }
+
+    // Get site timezone for proper date/time formatting
+    const timezone = await this.getSiteTimezone();
+
+    // Build individual email jobs for the queue
+    const jobs: TemplateEmailJobParams[] = eventTickets.map((ticket: any) => {
+      const locale = ticket.preferredLanguage || 'en';
+      const eventTitle = locale === 'es' && event.titleEs ? event.titleEs : event.title;
+      const fullName = `${ticket.attendeeFirstName} ${ticket.attendeeLastName || ''}`.trim();
+
+      return {
+        templateSlug,
+        to: ticket.attendeeEmail,
+        toName: fullName,
+        locale,
+        eventId: event.id,
+        sentBy,
+        variables: {
+          attendeeName: fullName,
+          attendeeEmail: ticket.attendeeEmail,
+          ticketId: ticket.id,
+          eventTitle,
+          eventDate: this.formatDate(event.startDatetime, locale, timezone),
+          eventTime: this.formatTime(event.startDatetime, locale, timezone),
+          eventLocation: event.location,
+          eventLocationUrl: event.locationUrl || '',
+          ...customVariables,
+        },
+      };
+    });
+
+    // Enqueue all emails for background processing
+    enqueueBulkEmails(jobs);
+
+    console.log(`[Email] Queued ${jobs.length} emails for event "${event.title}" (filter: ${recipientFilter})`);
+
+    return {
+      success: true,
+      queuedCount: jobs.length,
+    };
+  },
   
   /**
    * Send a custom email (not from template)
@@ -1183,10 +1278,11 @@ export const emailService = {
     subject: string;
     bodyHtml: string;
     bodyText?: string;
+    replyTo?: string;
     eventId?: string;
-    sentBy: string;
+    sentBy?: string | null;
   }): Promise<{ success: boolean; logId?: string; error?: string }> {
-    const { to, toName, subject, bodyHtml, bodyText, eventId, sentBy } = params;
+    const { to, toName, subject, bodyHtml, bodyText, replyTo, eventId, sentBy = null } = params;
     
     const allVariables = {
       ...this.getCommonVariables(),
@@ -1208,7 +1304,7 @@ export const emailService = {
       subject,
       bodyHtml: finalBodyHtml,
       status: 'pending',
-      sentBy,
+      sentBy: sentBy || null,
       createdAt: now,
     });
     
@@ -1218,6 +1314,7 @@ export const emailService = {
       subject,
       html: finalBodyHtml,
       text: bodyText,
+      replyTo,
     });
     
     // Update log

backend/src/lib/emailQueue.ts

@@ -0,0 +1,194 @@
+// In-memory email queue with rate limiting
+// Processes emails asynchronously in the background without blocking the request thread
+
+import { generateId } from './utils.js';
+
+// ==================== Types ====================
+
+export interface EmailJob {
+  id: string;
+  type: 'template';
+  params: TemplateEmailJobParams;
+  addedAt: number;
+}
+
+export interface TemplateEmailJobParams {
+  templateSlug: string;
+  to: string;
+  toName?: string;
+  variables: Record<string, any>;
+  locale?: string;
+  eventId?: string;
+  sentBy?: string;
+}
+
+export interface QueueStatus {
+  queued: number;
+  processing: boolean;
+  sentInLastHour: number;
+  maxPerHour: number;
+}
+
+// ==================== Queue State ====================
+
+const queue: EmailJob[] = [];
+const sentTimestamps: number[] = [];
+let processing = false;
+let processTimer: ReturnType<typeof setTimeout> | null = null;
+
+// Lazy reference to emailService to avoid circular imports
+let _emailService: any = null;
+
+function getEmailService() {
+  if (!_emailService) {
+    // Dynamic import to avoid circular dependency
+    throw new Error('[EmailQueue] Email service not initialized. Call initEmailQueue() first.');
+  }
+  return _emailService;
+}
+
+/**
+ * Initialize the email queue with a reference to the email service.
+ * Must be called once at startup.
+ */
+export function initEmailQueue(emailService: any): void {
+  _emailService = emailService;
+  console.log('[EmailQueue] Initialized');
+}
+
+// ==================== Rate Limiting ====================
+
+function getMaxPerHour(): number {
+  return parseInt(process.env.MAX_EMAILS_PER_HOUR || '30', 10);
+}
+
+/**
+ * Clean up timestamps older than 1 hour
+ */
+function cleanOldTimestamps(): void {
+  const oneHourAgo = Date.now() - 3_600_000;
+  while (sentTimestamps.length > 0 && sentTimestamps[0] <= oneHourAgo) {
+    sentTimestamps.shift();
+  }
+}
+
+// ==================== Queue Operations ====================
+
+/**
+ * Add a single email job to the queue.
+ * Returns the job ID.
+ */
+export function enqueueEmail(params: TemplateEmailJobParams): string {
+  const id = generateId();
+  queue.push({
+    id,
+    type: 'template',
+    params,
+    addedAt: Date.now(),
+  });
+  scheduleProcessing();
+  return id;
+}
+
+/**
+ * Add multiple email jobs to the queue at once.
+ * Returns array of job IDs.
+ */
+export function enqueueBulkEmails(paramsList: TemplateEmailJobParams[]): string[] {
+  const ids: string[] = [];
+  for (const params of paramsList) {
+    const id = generateId();
+    queue.push({
+      id,
+      type: 'template',
+      params,
+      addedAt: Date.now(),
+    });
+    ids.push(id);
+  }
+  if (ids.length > 0) {
+    console.log(`[EmailQueue] Queued ${ids.length} emails for background processing`);
+    scheduleProcessing();
+  }
+  return ids;
+}
+
+/**
+ * Get current queue status
+ */
+export function getQueueStatus(): QueueStatus {
+  cleanOldTimestamps();
+  return {
+    queued: queue.length,
+    processing,
+    sentInLastHour: sentTimestamps.length,
+    maxPerHour: getMaxPerHour(),
+  };
+}
+
+// ==================== Processing ====================
+
+function scheduleProcessing(): void {
+  if (processing) return;
+  processing = true;
+  // Start processing on next tick to not block the caller
+  setImmediate(() => processNext());
+}
+
+async function processNext(): Promise<void> {
+  if (queue.length === 0) {
+    processing = false;
+    console.log('[EmailQueue] Queue empty. Processing stopped.');
+    return;
+  }
+
+  // Rate limit check
+  cleanOldTimestamps();
+  const maxPerHour = getMaxPerHour();
+
+  if (sentTimestamps.length >= maxPerHour) {
+    // Calculate when the oldest timestamp in the window expires
+    const waitMs = sentTimestamps[0] + 3_600_000 - Date.now() + 500; // 500ms buffer
+    console.log(
+      `[EmailQueue] Rate limit reached (${maxPerHour}/hr). ` +
+      `Pausing for ${Math.ceil(waitMs / 1000)}s. ${queue.length} email(s) remaining.`
+    );
+    processTimer = setTimeout(() => processNext(), waitMs);
+    return;
+  }
+
+  // Dequeue and process
+  const job = queue.shift()!;
+
+  try {
+    const emailService = getEmailService();
+    await emailService.sendTemplateEmail(job.params);
+    sentTimestamps.push(Date.now());
+    console.log(
+      `[EmailQueue] Sent email ${job.id} to ${job.params.to}. ` +
+      `Queue: ${queue.length} remaining. Sent this hour: ${sentTimestamps.length}/${maxPerHour}`
+    );
+  } catch (error: any) {
+    console.error(
+      `[EmailQueue] Failed to send email ${job.id} to ${job.params.to}:`,
+      error?.message || error
+    );
+    // The sendTemplateEmail method already logs the failure in the email_logs table,
+    // so we don't need to retry here. The error is logged and we move on.
+  }
+
+  // Small delay between sends to be gentle on the email server
+  processTimer = setTimeout(() => processNext(), 200);
+}
+
+/**
+ * Stop processing (for graceful shutdown)
+ */
+export function stopQueue(): void {
+  if (processTimer) {
+    clearTimeout(processTimer);
+    processTimer = null;
+  }
+  processing = false;
+  console.log(`[EmailQueue] Stopped. ${queue.length} email(s) remaining in queue.`);
+}

backend/src/lib/legal-placeholders.ts

@@ -0,0 +1,80 @@
+import { getLegalSettingsValues } from '../routes/legal-settings.js';
+
+/**
+ * Strict whitelist of supported placeholders.
+ * Only these placeholders will be replaced in legal page content.
+ * Unknown placeholders remain unchanged.
+ */
+const SUPPORTED_PLACEHOLDERS = new Set([
+  'COMPANY_NAME',
+  'LEGAL_ENTITY_NAME',
+  'RUC_NUMBER',
+  'COMPANY_ADDRESS',
+  'COMPANY_CITY',
+  'COMPANY_COUNTRY',
+  'SUPPORT_EMAIL',
+  'LEGAL_EMAIL',
+  'GOVERNING_LAW',
+  'JURISDICTION_CITY',
+  'CURRENT_YEAR',
+  'LAST_UPDATED_DATE',
+]);
+
+/**
+ * Replace legal placeholders in content using strict whitelist mapping.
+ *
+ * Rules:
+ * - Only supported placeholders are replaced
+ * - Unknown placeholders remain unchanged
+ * - Missing values are replaced with empty string
+ * - No code execution or dynamic evaluation
+ * - Replacement is pure string substitution
+ *
+ * @param content - The markdown/text content containing {{PLACEHOLDER}} tokens
+ * @param updatedAt - The page's updated_at timestamp (for LAST_UPDATED_DATE)
+ * @returns Content with placeholders replaced
+ */
+export async function replaceLegalPlaceholders(
+  content: string,
+  updatedAt?: string
+): Promise<string> {
+  if (!content) return content;
+
+  // Fetch legal settings values from DB
+  const settingsValues = await getLegalSettingsValues();
+
+  // Build the full replacement map
+  const replacements: Record<string, string> = { ...settingsValues };
+
+  // Dynamic values
+  replacements['CURRENT_YEAR'] = new Date().getFullYear().toString();
+
+  if (updatedAt) {
+    try {
+      const date = new Date(updatedAt);
+      if (!isNaN(date.getTime())) {
+        replacements['LAST_UPDATED_DATE'] = date.toLocaleDateString('en-US', {
+          year: 'numeric',
+          month: 'long',
+          day: 'numeric',
+        });
+      } else {
+        replacements['LAST_UPDATED_DATE'] = updatedAt;
+      }
+    } catch {
+      replacements['LAST_UPDATED_DATE'] = updatedAt;
+    }
+  }
+
+  // Replace only whitelisted placeholders using a single regex pass
+  // Matches {{PLACEHOLDER_NAME}} where PLACEHOLDER_NAME is uppercase letters and underscores
+  return content.replace(/\{\{([A-Z_]+)\}\}/g, (match, placeholderName) => {
+    // Only replace if the placeholder is in the whitelist
+    if (!SUPPORTED_PLACEHOLDERS.has(placeholderName)) {
+      return match; // Unknown placeholder - leave unchanged
+    }
+
+    // Return the value or empty string if missing
+    return replacements[placeholderName] ?? '';
+  });
+}