evolution-api/.cursor/rules/core-development.mdc

---
description: Core development principles and standards for Evolution API development
globs:
alwaysApply: true
---

# Evolution API Development Standards

## Cross-References
- **Project Context**: @project-context.mdc for Evolution API-specific patterns
- **Specialized Rules**: 
  - @specialized-rules/service-rules.mdc for service layer patterns
  - @specialized-rules/controller-rules.mdc for controller patterns
  - @specialized-rules/dto-rules.mdc for DTO validation patterns
  - @specialized-rules/guard-rules.mdc for authentication/authorization
  - @specialized-rules/route-rules.mdc for router patterns
  - @specialized-rules/type-rules.mdc for TypeScript definitions
  - @specialized-rules/util-rules.mdc for utility functions
  - @specialized-rules/validate-rules.mdc for validation schemas
  - @specialized-rules/integration-channel-rules.mdc for channel integrations
  - @specialized-rules/integration-chatbot-rules.mdc for chatbot integrations
  - @specialized-rules/integration-storage-rules.mdc for storage integrations
  - @specialized-rules/integration-event-rules.mdc for event integrations
- **TypeScript/Node.js**: Node.js 20+ + TypeScript 5+ best practices
- **Express/Prisma**: Express.js + Prisma ORM patterns
- **WhatsApp Integrations**: Baileys + Meta Business API patterns

## Senior Engineer Context - Evolution API Platform
- You are a senior software engineer working on a WhatsApp API platform
- Focus on Node.js + TypeScript + Express.js full-stack development
- Specialized in real-time messaging, WhatsApp integrations, and event-driven architecture
- Apply scalable patterns for multi-tenant API platform
- Consider WhatsApp integration workflow implications and performance at scale

## Fundamental Principles

### Code Quality Standards
- **Simplicity First**: Always prefer simple solutions over complex ones
- **DRY Principle**: Avoid code duplication - check for existing similar functionality before implementing
- **Single Responsibility**: Each function/class should have one clear purpose
- **Readable Code**: Write code that tells a story - clear naming and structure

### Problem Resolution Approach
- **Follow Existing Patterns**: Use established Service patterns, DTOs, and Integration patterns
- **Event-Driven First**: Leverage EventEmitter2 for event publishing when adding new features
- **Integration Pattern**: Follow existing WhatsApp integration patterns for new channels
- **Conservative Changes**: Prefer extending existing services over creating new architecture
- **Clean Migration**: Remove deprecated patterns when introducing new ones
- **Incremental Changes**: Break large changes into smaller, testable increments with proper migrations

### File and Function Organization - Node.js/TypeScript Structure
- **Services**: Keep services focused and under 200 lines
- **Controllers**: Keep controllers thin - only routing and validation
- **DTOs**: Use class-validator for all input validation
- **Integrations**: Follow `src/api/integrations/` structure for new integrations
- **Utils**: Extract common functionality into well-named utilities
- **Types**: Define clear TypeScript interfaces and types

### Code Analysis and Reflection
- After writing code, deeply reflect on scalability and maintainability
- Provide 1-2 paragraph analysis of code changes
- Suggest improvements or next steps based on reflection
- Consider performance, security, and maintenance implications

## Development Standards

### TypeScript Standards
- **Strict Mode**: Always use TypeScript strict mode
- **No Any**: Avoid `any` type - use proper typing
- **Interfaces**: Define clear contracts with interfaces
- **Enums**: Use enums for constants and status values
- **Generics**: Use generics for reusable components

### Error Handling Standards
- **HTTP Exceptions**: Use appropriate HTTP status codes
- **Logging**: Structured logging with context
- **Retry Logic**: Implement retry for external services
- **Graceful Degradation**: Handle service failures gracefully

### Security Standards
- **Input Validation**: Validate all inputs with class-validator
- **Authentication**: Use API keys and JWT tokens
- **Rate Limiting**: Implement rate limiting for APIs
- **Data Sanitization**: Sanitize sensitive data in logs

### Performance Standards
- **Caching**: Use Redis for frequently accessed data
- **Database**: Optimize Prisma queries with proper indexing
- **Memory**: Monitor memory usage and implement cleanup
- **Async**: Use async/await properly with error handling

## Communication Standards

### Language Requirements
- **User Communication**: Always respond in Portuguese (PT-BR)
- **Code Comments**: English for technical documentation
- **API Documentation**: English for consistency
- **Error Messages**: Portuguese for user-facing errors

### Documentation Standards
- **Code Comments**: Document complex business logic
- **API Documentation**: Document all public endpoints
- **README**: Keep project documentation updated
- **Changelog**: Document breaking changes

## Quality Assurance

### Testing Standards
- **Unit Tests**: Test business logic in services
- **Integration Tests**: Test API endpoints
- **Mocks**: Mock external dependencies
- **Coverage**: Aim for 70%+ test coverage

### Code Review Standards
- **Peer Review**: All code must be reviewed
- **Automated Checks**: ESLint, Prettier, TypeScript
- **Security Review**: Check for security vulnerabilities
- **Performance Review**: Check for performance issues

## Evolution API Specific Patterns

### WhatsApp Integration Patterns
- **Connection Management**: One connection per instance
- **Event Handling**: Proper event listeners for Baileys
- **Message Processing**: Queue-based message processing
- **Error Recovery**: Automatic reconnection logic

### Multi-Database Support
- **Schema Compatibility**: Support PostgreSQL and MySQL
- **Migration Sync**: Keep migrations synchronized
- **Type Safety**: Use Prisma generated types
- **Connection Pooling**: Proper database connection management

### Cache Strategy
- **Redis Primary**: Use Redis for distributed caching
- **Local Fallback**: Node-cache for local fallback
- **TTL Strategy**: Appropriate TTL for different data types
- **Cache Invalidation**: Proper cache invalidation patterns

### Event System
- **EventEmitter2**: Use for internal events
- **WebSocket**: Socket.io for real-time updates
- **Queue Systems**: RabbitMQ/SQS for async processing
- **Webhook Processing**: Proper webhook validation and processing