pattern-advisor

name	pattern-advisor
description	Design Pattern Recommender - Suggests applicable design patterns from the 27 cataloged patterns based on context. Provides code skeletons using project conventions and anti-patterns to avoid. TRIGGERS: suggest pattern, which pattern, design pattern, pattern advice, recommend pattern, qual padrao, sugerir padrao

@pattern-advisor - Design Pattern Recommender

Recommends applicable design patterns from the architecture knowledge base catalog.

Required Reading

• .agent/System/architecture-knowledge/19-DESIGN-PATTERNS-CATALOG.md
• .agent/System/architecture-knowledge/01-CLEAN-ARCHITECTURE.md
• .agent/System/architecture-knowledge/04-PORTS-AND-ADAPTERS.md

Invocation Pattern

@pattern-advisor
  problem: [description of what needs to be built/solved]
  context: [relevant files, current architecture]
  constraints: [performance, complexity, team experience]

Pattern Catalog (27 Patterns)

Creational

#	Pattern	When to Use
1	Factory Method	Creating providers for DI, abstracting object creation
2	Abstract Factory	Generic provider helpers (createServiceProvider)
3	Builder	Fluent configuration (Swagger, query builders)

Structural

#	Pattern	When to Use
4	Facade	Simplifying complex subsystems (state + use cases + API)
5	Adapter	Translating domain interface to infrastructure
6	Proxy	HTTP interceptors, lazy loading, caching
7	Composite	Module composition, nested forms
8	Decorator	NestJS/Angular decorators, extending behavior

Behavioral

#	Pattern	When to Use
9	Command	Use case pattern (execute()), action dispatch
10	Strategy	Swappable service implementations
11	Template Method	Base classes with hooks (MongoService)
12	Observer	RxJS streams, signals, event-driven UI
13	Chain of Responsibility	Guard chains (Auth -> Roles -> Permission)
14	Mediator	Controller coordinating facades/use cases
15	State	State machine for UI/workflow states

Architectural

#	Pattern	When to Use
16	Hexagonal	Domain isolation, port/adapter separation
17	Clean Architecture	Layer separation, dependency rule
18	CQRS Lite	Read/write separation in facades
19	Repository	Abstract data access, generic CRUD
20	Module	Nx library boundaries, feature encapsulation

UI

#	Pattern	When to Use
21	Container/Presentational	Smart + dumb component separation
22	Sheet/Dialog	Modal/overlay workflows
23	Typed Form	Complex form architecture

Infrastructure

#	Pattern	When to Use
24	Dependency Injection	Decoupling, testability, composition
25	Barrel Export	Public API control per library
26	Environment	Typed configuration management
27	Interceptor	Cross-cutting concerns (auth, logging, loading)

Decision Matrix

Given a problem, evaluate these criteria to recommend patterns:

1. Is it about creating objects? → Creational (1-3)
2. Is it about composing/adapting structures? → Structural (4-8)
3. Is it about coordinating behavior? → Behavioral (9-15)
4. Is it about system organization? → Architectural (16-20)
5. Is it about UI interaction? → UI (21-23)
6. Is it about cross-cutting concerns? → Infrastructure (24-27)

Common Scenarios

Scenario	Recommended Patterns
New feature page	4 (Facade) + 21 (Container/Presentational) + 19 (Repository)
New API endpoint	14 (Mediator) + 9 (Command) + 13 (Chain of Resp)
New data source	5 (Adapter) + 11 (Template Method) + 16 (Hexagonal)
Complex form	23 (Typed Form) + 7 (Composite) + 12 (Observer)
Swappable service	10 (Strategy) + 1 (Factory) + 24 (DI)
State management	4 (Facade) + 15 (State) + 12 (Observer)
Auth/permissions	13 (Chain) + 8 (Decorator) + 27 (Interceptor)
Shared component	21 (Container/Presentational) + 25 (Barrel) + 20 (Module)

Output Format

## Pattern Recommendation

### Problem Analysis
[Brief analysis of what needs to be built]

### Recommended Patterns

#### Primary: [Pattern Name] (#N)
**Why**: [why this pattern fits]
**How**: [brief implementation guide]
```typescript
// Code skeleton using project conventions

Supporting: [Pattern Name] (#N)

Why: [complementary pattern] How: [brief guide]

Anti-Patterns to Avoid

• [pattern that seems right but isn't for this case, and why]

Architecture Knowledge References

• [relevant docs from knowledge base]