Email Notification System - Restaurant Reservation System

Overview

The Restaurant Reservation System uses a comprehensive email notification system to keep both customers and business owners informed about reservation activities. All notifications are sent automatically using Firebase’s Trigger Email Extension.

Email Service Architecture

Implementation

The ServicioEmail class handles all email operations:

class ServicioEmail {
  // Email templates and sending logic
}

Implementation: source/lib/adaptadores/servicio_email.dart

Firebase Integration

Emails are sent through Firebase Firestore triggers:

Add to Firestore

Email data is written to the mail collection

Extension triggers

Firebase Trigger Email Extension detects new document

SMTP delivery

Extension sends email via configured SMTP provider

Status update

Delivery status is written back to Firestore document

await FirebaseFirestore.instance.collection('mail').add({
  'to': [recipientEmail],
  'message': {
    'subject': emailSubject,
    'html': htmlContent,
  },
  'createdAt': FieldValue.serverTimestamp(),
});

Implementation reference: source/lib/adaptadores/servicio_email.dart:368-398

The Firebase Trigger Email Extension must be installed and configured for emails to be delivered. See the Email Configuration Guide.

Customer Notifications

Customers receive automated emails for all reservation activities.

Reservation Confirmed

Sent when a customer successfully creates a reservation:

await servicioEmail.enviarReservaConfirmada(
  emailCliente: '[email protected]',
  nombreCliente: 'John Doe',
  nombreNegocio: 'La Cocina',
  fechaHora: DateTime(2026, 3, 15, 19, 0),
  nombreMesa: 'Mesa 5',
  numeroPersonas: 4,
);

Email includes:

✅ Confirmation badge with green styling
📋 Complete reservation details table
💡 Important reminders:
- Arrive 10 minutes early
- Cancellation policy (2 hours advance notice)
- Save email for reference
📧 Restaurant contact information

Implementation reference: source/lib/adaptadores/servicio_email.dart:18-72

Customer Cancellation Confirmation

Sent when a customer cancels their own reservation:

await servicioEmail.enviarReservaCanceladaPorCliente(
  emailCliente: '[email protected]',
  nombreCliente: 'John Doe',
  nombreNegocio: 'La Cocina',
  fechaHora: DateTime(2026, 3, 15, 19, 0),
  nombreMesa: 'Mesa 5',
  numeroPersonas: 4,
);

Email includes:

❌ Cancellation confirmation with red accent
📋 Cancelled reservation details
🔄 Invitation to book again

Implementation reference: source/lib/adaptadores/servicio_email.dart:75-116

Restaurant Cancellation Notice

Sent when the restaurant cancels a customer’s reservation:

await servicioEmail.enviarReservaCanceladaPorRestaurante(
  emailCliente: '[email protected]',
  nombreCliente: 'John Doe',
  nombreNegocio: 'La Cocina',
  fechaHora: DateTime(2026, 3, 15, 19, 0),
  nombreMesa: 'Mesa 5',
  numeroPersonas: 4,
  motivo: 'Table unavailable due to unexpected maintenance',
);

Email includes:

⚠️ Cancellation notice with warning styling
📋 Original reservation details
📝 Reason for cancellation (if provided)
🙏 Apology for inconvenience
🔄 Invitation to rebook

Implementation reference: source/lib/adaptadores/servicio_email.dart:119-175

Always provide a clear, professional reason when cancelling customer reservations. This helps maintain customer trust and goodwill.

Business Owner Notifications

Restaurant owners receive notifications for customer reservation activities.

New Reservation Alert

Sent when a customer creates a new reservation:

await servicioEmail.enviarNuevaReservaAlDueno(
  emailDueno: '[email protected]',
  nombreCliente: 'John Doe',
  emailCliente: '[email protected]',
  telefonoCliente: '+54 9 261 123-4567',
  fechaHora: DateTime(2026, 3, 15, 19, 0),
  nombreMesa: 'Mesa 5',
  numeroPersonas: 4,
  nombreNegocio: 'La Cocina',
);

Email includes:

📋 “Nueva Reserva Recibida” header
👤 Customer contact information (email and phone)
📅 Complete reservation details
🏪 Restaurant name

Implementation reference: source/lib/adaptadores/servicio_email.dart:182-222

Customer Cancellation Alert

Sent when a customer cancels their reservation:

await servicioEmail.enviarCancelacionClienteAlDueno(
  emailDueno: '[email protected]',
  nombreCliente: 'John Doe',
  fechaHora: DateTime(2026, 3, 15, 19, 0),
  nombreMesa: 'Mesa 5',
  numeroPersonas: 4,
  nombreNegocio: 'La Cocina',
);

Email includes:

❌ “Un cliente ha cancelado su reserva” header
📋 Cancelled reservation details
ℹ️ Note that table is now available

Implementation reference: source/lib/adaptadores/servicio_email.dart:225-258

Business owners do NOT receive email notifications when they cancel reservations themselves, as they performed the action directly.

Email Templates

All emails use a consistent HTML template with responsive design.

Template Structure

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body style="font-family: Arial, sans-serif; background-color: #f5f5f5;">
  <div style="max-width: 600px; margin: 0 auto; background-color: white;">
    
    <!-- Header -->
    <div style="background-color: #27AE60; padding: 30px; text-align: center;">
      <h1 style="color: white; margin: 0;">✅ Reserva Confirmada</h1>
    </div>

    <!-- Content -->
    <div style="padding: 30px;">
      <!-- Email content here -->
    </div>

    <!-- Footer -->
    <div style="background-color: #f5f5f5; padding: 20px; text-align: center;">
      <p style="color: #666; font-size: 12px;">
        © 2026 Sistema de Reservas
      </p>
      <p style="color: #999; font-size: 11px;">
        Este es un email automático, por favor no respondas a este mensaje.
      </p>
    </div>

  </div>
</body>
</html>

Implementation reference: source/lib/adaptadores/servicio_email.dart:401-436

Color Scheme

Color	Usage	Hex Code
Green	Confirmation, success	`#27AE60`
Red	Cancellation	`#F44336`
Orange	Warning, restaurant cancellation	`#FF9800`
Gray	Neutral information	`#666666`

Reservation Details Table

All emails include a formatted details table:

<table style="width: 100%; border-collapse: collapse;">
  <tr>
    <td style="padding: 12px 0; color: #666;">👤 Nombre:</td>
    <td style="padding: 12px 0; font-weight: bold;">John Doe</td>
  </tr>
  <tr>
    <td style="color: #666;">🏪 Restaurante:</td>
    <td style="font-weight: bold;">La Cocina</td>
  </tr>
  <tr>
    <td style="color: #666;">📍 Mesa:</td>
    <td style="font-weight: bold;">Mesa 5</td>
  </tr>
  <tr>
    <td style="color: #666;">📅 Fecha:</td>
    <td style="font-weight: bold;">viernes 15 de marzo de 2026</td>
  </tr>
  <tr>
    <td style="color: #666;">🕐 Horario:</td>
    <td style="font-weight: bold;">19:00 hs</td>
  </tr>
  <tr>
    <td style="color: #666;">👥 Personas:</td>
    <td style="font-weight: bold;">4</td>
  </tr>
</table>

Implementation reference: source/lib/adaptadores/servicio_email.dart:439-498

Date and Time Formatting

Dates and times are formatted in Spanish:

Date Format

String _formatearFecha(DateTime fecha) {
  // "viernes 15 de marzo de 2026"
  final diaSemana = dias[fecha.weekday - 1];
  final dia = fecha.day;
  final mes = meses[fecha.month - 1];
  final anio = fecha.year;
  
  return '$diaSemana $dia de $mes de $anio';
}

Examples:

lunes 10 de marzo de 2026
viernes 15 de marzo de 2026
domingo 20 de diciembre de 2026

Implementation reference: source/lib/adaptadores/servicio_email.dart:501-532

Time Format

String _formatearHora(DateTime fecha) {
  // "19:00 hs"
  final hora = fecha.hour.toString().padLeft(2, '0');
  final minuto = fecha.minute.toString().padLeft(2, '0');
  return '$hora:$minuto hs';
}

Examples:

12:00 hs
19:30 hs
21:45 hs

Implementation reference: source/lib/adaptadores/servicio_email.dart:534-538

Using Email Service

With Reserva Entity

Convenience methods accept Reserva objects directly:

final servicioEmail = ServicioEmail();

// Notify customer of confirmed reservation
await servicioEmail.notificarReservaConfirmada(
  reserva,
  nombreNegocio: 'La Cocina',
  nombreMesa: 'Mesa 5',
  emailDueno: '[email protected]',
);

This automatically:

Sends confirmation email to customer
Sends new reservation alert to owner

Implementation reference: source/lib/adaptadores/servicio_email.dart:265-300

Customer Cancellation

await servicioEmail.notificarReservaCanceladaPorCliente(
  reserva,
  nombreNegocio: 'La Cocina',
  nombreMesa: 'Mesa 5',
  emailDueno: '[email protected]',
);

This automatically:

Sends cancellation confirmation to customer
Sends cancellation alert to owner

Implementation reference: source/lib/adaptadores/servicio_email.dart:303-335

Restaurant Cancellation

await servicioEmail.notificarReservaCanceladaPorRestaurante(
  reserva,
  nombreNegocio: 'La Cocina',
  nombreMesa: 'Mesa 5',
  motivo: 'Unexpected maintenance required',
);

This sends cancellation notice to customer only. Implementation reference: source/lib/adaptadores/servicio_email.dart:338-359

Email Validation

The system validates email addresses before sending:

final email = reserva.contactoCliente;
if (email == null || !email.contains('@')) {
  print('⚠️ No se puede enviar email: contacto no es email válido');
  return;
}

If a customer’s contactoCliente field is missing or invalid, email notifications will not be sent. Always validate customer contact information.

Firestore Email Collection

Emails are stored in Firestore for tracking:

mail/
  {emailId}/
    to: ["[email protected]"]
    message:
      subject: "✅ Reserva confirmada - La Cocina"
      html: "<html>...</html>"
    createdAt: Timestamp(2026-03-15 18:45:00)
    delivery:
      state: "SUCCESS"  // or "ERROR", "PENDING"
      attempts: 1
      startTime: Timestamp(...)
      endTime: Timestamp(...)
      error: null

Delivery States

State	Description
`PENDING`	Email queued for delivery
`PROCESSING`	Currently being sent
`SUCCESS`	Delivered successfully
`ERROR`	Delivery failed

You can monitor email delivery status in the Firebase Console under the mail collection.

Troubleshooting

Problem: Emails Not Being Sent

Possible causes:

Firebase Trigger Email Extension not installed
SMTP credentials not configured
Email quota exceeded
Invalid recipient email address

Solution:

Check Firebase Extensions

Verify Trigger Email Extension is installed in Firebase Console

Verify SMTP Configuration

Ensure SMTP credentials are correctly configured in extension settings

Check Firestore

Look for error messages in mail collection documents

Validate Email

Confirm customer email address is valid and contains ’@‘

Problem: Emails Going to Spam

Possible causes:

SMTP server reputation issues
Missing SPF/DKIM records
Generic “no-reply” sender address

Solution:

Configure SPF and DKIM records for your domain
Use a recognizable sender address
Include unsubscribe link (for marketing emails)
Test with multiple email providers

Problem: Duplicate Emails

Possible causes:

Multiple calls to email service
Retry logic triggering unnecessarily

Solution:

Add idempotency checks
Verify email service is called only once per event
Check for duplicate reservation confirmations

Best Practices

Test Before Production

Always test emails before deploying:

Send test emails to yourself
Verify formatting on multiple devices
Check spam folder
Test all notification types

Monitor Delivery

Regularly monitor email delivery:

Check Firebase Console for errors
Review mail collection delivery states
Track bounce rates
Monitor SMTP quota usage

Maintain Email Quality

Keep emails professional and useful:

Clear subject lines
Complete information
Professional tone
Mobile-responsive design

Respect Privacy

Handle customer data responsibly:

Only send relevant notifications
Secure email content
Don’t share customer emails
Comply with privacy regulations

Email Configuration

For detailed instructions on setting up the Firebase Trigger Email Extension and SMTP configuration, see:

Email Configuration Guide

Step-by-step guide to configure email delivery with Firebase

Next Steps

Reservation Management

Learn how reservation actions trigger email notifications

Business Configuration

Configure your restaurant settings

Get Started

For Customers

For Business Owners

Architecture

Guides

​Overview

​Email Service Architecture

​Implementation

​Firebase Integration

​Customer Notifications

​Reservation Confirmed

​Customer Cancellation Confirmation

​Restaurant Cancellation Notice

​Business Owner Notifications

​New Reservation Alert

​Customer Cancellation Alert

​Email Templates

​Template Structure

​Color Scheme

​Reservation Details Table

​Date and Time Formatting

​Date Format

​Time Format

​Using Email Service

​With Reserva Entity

​Customer Cancellation

​Restaurant Cancellation

​Email Validation

​Firestore Email Collection

​Delivery States

​Troubleshooting

​Problem: Emails Not Being Sent

​Problem: Emails Going to Spam

​Problem: Duplicate Emails

​Best Practices

​Email Configuration

Email Configuration Guide

​Next Steps

Reservation Management

Business Configuration

Build docs developers (and LLMs) love

Overview

Email Service Architecture

Implementation

Firebase Integration

Customer Notifications

Reservation Confirmed

Customer Cancellation Confirmation

Restaurant Cancellation Notice

Business Owner Notifications

New Reservation Alert

Customer Cancellation Alert

Email Templates

Template Structure

Color Scheme

Reservation Details Table

Date and Time Formatting

Date Format

Time Format

Using Email Service

With Reserva Entity

Customer Cancellation

Restaurant Cancellation

Email Validation

Firestore Email Collection

Delivery States

Troubleshooting

Problem: Emails Not Being Sent

Problem: Emails Going to Spam

Problem: Duplicate Emails

Best Practices

Email Configuration

Next Steps