# Building Your First Application

This guide walks through the concepts and workflow of building a blog application, focusing on understanding the framework's patterns rather than step-by-step code generation.

## Application Overview

We'll explore building a blog application with:
- **User management** - Registration and authentication
- **Blog posts** - Full CRUD operations
- **Comments** - User interactions
- **Web interface** - HTML views with Tailwind CSS
- **API endpoints** - JSON API for all operations

## Planning Your Application

### 1. Domain Modeling
Start by identifying your core entities and their relationships:

- **User** - The foundation for authentication and authorship
- **BlogPost** - Core content with title, content, and publishing state
- **Comment** - User feedback tied to posts

Consider the relationships between entities:
- Users author multiple blog posts
- Blog posts can have many comments
- Comments belong to both a post and an author

### 2. Database Design
Plan your schema with the framework's patterns in mind:

- **Standard Fields** - Every entity gets `id`, `created_at`, `updated_at`
- **Relationships** - Foreign keys with proper constraints
- **Indexes** - For common query patterns and relationships

### 3. Service Architecture Planning
For each entity, you'll need:

- **Fetcher** - Query capabilities with filtering
- **Handler** - CRUD operations with validation
- **Hydrator** - Relationship loading patterns
- **Molder** - Form transformation logic
- **Serializer** - Response formatting
- **Validator** - Input validation rules

## Development Workflow

### Phase 1: Foundation (Users)
1. **Model Definition** - Define User entity with authentication fields
2. **Database Layer** - Create ESO and Table for SQL mapping
3. **Service Suite** - Implement all user-related services
4. **Business Logic** - Create registration/authentication Maestros
5. **Web Layer** - Controllers and routes for user operations

### Phase 2: Core Content (Blog Posts)
1. **Extend Models** - Add BlogPost with author relationships
2. **Service Implementation** - Full CRUD service suite
3. **Business Logic** - Publishing workflows and permissions
4. **Relationships** - Hydrator patterns for loading authors
5. **Web Interface** - CRUD operations with rich forms

### Phase 3: Interactions (Comments)
1. **Comment System** - Models with nested relationships
2. **Complex Hydration** - Loading posts, authors, and comments
3. **Permissions** - Comment moderation and ownership
4. **Real-time Features** - Consider WebSocket integration

## Key Learning Concepts

### Understanding the Maestro Pattern
Business operations are orchestrated through Mae modules:

- **Sequential Steps** - Validation → Transformation → Persistence → Response
- **Dependency Injection** - Services injected for testability
- **Error Handling** - Structured error management throughout
- **Transaction Management** - Ensuring data consistency

### Service Integration Patterns
Learn how services work together:

- **Data Flow** - Form → Molder → Mae → Handler → Database
- **Query Patterns** - Fetcher → Hydrator → Serializer → Response
- **Validation Chain** - Form validation → Business rules → Database constraints
- **Testing Strategy** - Unit tests for services, functional tests for Maestros

### Relationship Management
Understanding how entities connect:

- **Preset Hydration** - Predefined relationship loading patterns
- **Batch Loading** - Preventing N+1 queries through efficient batching
- **Deep Relationships** - Loading nested entity relationships
- **Performance Optimization** - Selective loading based on context

## Development Best Practices

### Start Simple, Extend Gradually
- Begin with basic CRUD operations
- Add complexity incrementally
- Test each component before moving forward
- Keep business logic in Maestros, not controllers

### Follow Framework Conventions
- Use ESO pattern for database operations
- Implement complete service suites for entities
- Create Mae modules for complex business logic
- Test at appropriate levels (unit, functional, integration)

### Plan for Growth
- Design extensible relationship patterns
- Consider caching strategies early
- Plan API versioning if needed
- Structure templates for reusability

## Testing Your Application

### Testing Strategy
1. **Unit Tests** - Test services in isolation
2. **Functional Tests** - Test Maestro business logic end-to-end
3. **Integration Tests** - Test complete request cycles
4. **Manual Testing** - Verify user experience and edge cases

### What to Test
- **Validation Logic** - Ensure proper input handling
- **Business Rules** - Verify complex logic works correctly
- **Relationships** - Test data loading and consistency
- **Error Scenarios** - Verify graceful error handling

## Deployment Considerations

### Environment Setup
- Configure different environments (dev, staging, prod)
- Set up proper logging and monitoring
- Plan database migration strategy
- Configure static asset handling

### Performance Planning
- Implement appropriate caching layers
- Plan for database query optimization
- Consider CDN for static assets
- Monitor application performance metrics

## Next Steps

After building your first application:

1. **Explore Advanced Patterns** - Study complex business logic patterns
2. **Learn Performance Optimization** - Caching, query optimization, scaling
3. **Security Hardening** - Authentication, authorization, data protection
4. **Testing Mastery** - Advanced testing patterns and automation

## Common Pitfalls to Avoid

- **Over-engineering** early - Start simple, add complexity when needed
- **Skipping tests** - Testing is integral to framework methodology
- **Ignoring relationships** - Plan entity relationships from the start
- **Controller bloat** - Keep business logic in Maestros, not controllers
- **Database anti-patterns** - Follow ESO pattern consistently

The goal is to understand the framework's philosophy and patterns deeply, enabling you to build robust, maintainable applications efficiently.