rentall-app/backend/tests/unit/services/emailService.test.js

// Mock dependencies BEFORE requiring modules
jest.mock('@aws-sdk/client-ses');
jest.mock('../../../config/aws', () => ({
  getAWSConfig: jest.fn(() => ({
    region: 'us-east-1',
    credentials: {
      accessKeyId: 'test-key',
      secretAccessKey: 'test-secret'
    }
  }))
}));
jest.mock('../../../models', () => ({
  User: {
    findByPk: jest.fn()
  }
}));

const emailService = require('../../../services/emailService');
const { SESClient, SendEmailCommand } = require('@aws-sdk/client-ses');
const { getAWSConfig } = require('../../../config/aws');

describe('EmailService', () => {
  let mockSESClient;
  let mockSend;

  beforeEach(() => {
    mockSend = jest.fn();
    mockSESClient = {
      send: mockSend
    };

    SESClient.mockImplementation(() => mockSESClient);

    // Reset environment variables
    process.env.EMAIL_ENABLED = 'true';
    process.env.AWS_REGION = 'us-east-1';
    process.env.AWS_ACCESS_KEY_ID = 'test-key';
    process.env.AWS_SECRET_ACCESS_KEY = 'test-secret';
    process.env.SES_FROM_EMAIL = 'test@example.com';
    process.env.SES_REPLY_TO_EMAIL = 'reply@example.com';

    // Reset the service instance
    emailService.initialized = false;
    emailService.sesClient = null;
    emailService.templates.clear();
  });

  afterEach(() => {
    jest.clearAllMocks();
  });

  describe('initialization', () => {
    it('should initialize SES client using AWS config', async () => {
      await emailService.initialize();

      expect(getAWSConfig).toHaveBeenCalled();
      expect(SESClient).toHaveBeenCalledWith({
        region: 'us-east-1',
        credentials: {
          accessKeyId: 'test-key',
          secretAccessKey: 'test-secret'
        }
      });
      expect(emailService.initialized).toBe(true);
    });

    it('should handle initialization errors', async () => {
      SESClient.mockImplementationOnce(() => {
        throw new Error('AWS credentials not found');
      });

      // Reset initialized state
      emailService.initialized = false;

      await expect(emailService.initialize()).rejects.toThrow('AWS credentials not found');
    });
  });

  describe('sendEmail', () => {
    beforeEach(async () => {
      mockSend.mockResolvedValue({ MessageId: 'test-message-id' });
      await emailService.initialize();
    });

    it('should send email successfully', async () => {
      const result = await emailService.sendEmail(
        'recipient@example.com',
        'Test Subject',
        '<h1>Test HTML</h1>',
        'Test Text'
      );

      expect(result.success).toBe(true);
      expect(result.messageId).toBe('test-message-id');
      expect(mockSend).toHaveBeenCalledWith(expect.any(SendEmailCommand));
    });

    it('should handle single email address', async () => {
      const result = await emailService.sendEmail('single@example.com', 'Subject', '<p>Content</p>');

      expect(result.success).toBe(true);
      expect(mockSend).toHaveBeenCalledWith(expect.any(SendEmailCommand));
    });

    it('should handle array of email addresses', async () => {
      const result = await emailService.sendEmail(
        ['first@example.com', 'second@example.com'],
        'Subject',
        '<p>Content</p>'
      );

      expect(result.success).toBe(true);
      expect(mockSend).toHaveBeenCalledWith(expect.any(SendEmailCommand));
    });

    it('should include reply-to address when configured', async () => {
      const result = await emailService.sendEmail('test@example.com', 'Subject', '<p>Content</p>');

      expect(result.success).toBe(true);
      expect(mockSend).toHaveBeenCalledWith(expect.any(SendEmailCommand));
    });

    it('should handle SES errors', async () => {
      mockSend.mockRejectedValue(new Error('SES Error'));

      const result = await emailService.sendEmail('test@example.com', 'Subject', '<p>Content</p>');

      expect(result.success).toBe(false);
      expect(result.error).toBe('SES Error');
    });

    it('should skip sending when email is disabled', async () => {
      process.env.EMAIL_ENABLED = 'false';

      const result = await emailService.sendEmail('test@example.com', 'Subject', '<p>Content</p>');

      expect(result.success).toBe(true);
      expect(result.messageId).toBe('disabled');
      expect(mockSend).not.toHaveBeenCalled();
    });
  });

  describe('template rendering', () => {
    it('should render template with variables', () => {
      const template = '<h1>Hello {{name}}</h1><p>Your order {{orderId}} is ready.</p>';
      emailService.templates.set('test', template);

      const rendered = emailService.renderTemplate('test', {
        name: 'John Doe',
        orderId: '12345'
      });

      expect(rendered).toBe('<h1>Hello John Doe</h1><p>Your order 12345 is ready.</p>');
    });

    it('should handle missing variables by replacing with empty string', () => {
      const template = '<h1>Hello {{name}}</h1><p>Your order {{orderId}} is ready.</p>';
      emailService.templates.set('test', template);

      const rendered = emailService.renderTemplate('test', {
        name: 'John Doe',
        orderId: '' // Explicitly provide empty string
      });

      expect(rendered).toContain('Hello John Doe');
      expect(rendered).toContain('Your order');
    });

    it('should use fallback template when template not found', () => {
      const rendered = emailService.renderTemplate('nonexistent', {
        title: 'Test Title',
        content: 'Test Content',
        message: 'Test message'
      });

      expect(rendered).toContain('Test Title');
      expect(rendered).toContain('Test message');
      expect(rendered).toContain('RentAll');
    });
  });

  describe('notification-specific senders', () => {
    beforeEach(async () => {
      mockSend.mockResolvedValue({ MessageId: 'test-message-id' });
      await emailService.initialize();
    });

    it('should send condition check reminder', async () => {
      const notification = {
        title: 'Condition Check Required',
        message: 'Please take photos of the item',
        metadata: { deadline: '2024-01-15' }
      };
      const rental = { item: { name: 'Test Item' } };

      const result = await emailService.sendConditionCheckReminder(
        'test@example.com',
        notification,
        rental
      );

      expect(result.success).toBe(true);
      expect(mockSend).toHaveBeenCalled();
    });

    it('should send rental confirmation', async () => {
      const notification = {
        title: 'Rental Confirmed',
        message: 'Your rental has been confirmed'
      };
      const rental = {
        item: { name: 'Test Item' },
        startDateTime: '2024-01-15T10:00:00Z',
        endDateTime: '2024-01-17T10:00:00Z'
      };

      const result = await emailService.sendRentalConfirmation(
        'test@example.com',
        notification,
        rental
      );

      expect(result.success).toBe(true);
      expect(mockSend).toHaveBeenCalled();
    });
  });

  describe('error handling', () => {
    beforeEach(async () => {
      await emailService.initialize();
    });

    it('should handle missing rental data gracefully', async () => {
      mockSend.mockResolvedValue({ MessageId: 'test-message-id' });

      const notification = {
        title: 'Test',
        message: 'Test message',
        metadata: {}
      };

      const result = await emailService.sendConditionCheckReminder(
        'test@example.com',
        notification,
        null
      );

      expect(result.success).toBe(true);
    });
  });
});