SOLID PHP - Laravel 12 + PHP 8.5

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

•fuse-ai-pilot:explore-codebase - Analyze existing architecture
•fuse-ai-pilot:research-expert - Verify Laravel/PHP docs via Context7
•mcp__context7__query-docs - Check SOLID patterns

After implementation, run fuse-ai-pilot:sniper for validation.

DRY - Reuse Before Creating (MANDATORY)

Before writing ANY new code:

•Grep the codebase for similar class names, methods, or logic
•Check shared locations: FuseCore/Core/App/Services/, FuseCore/Core/App/Traits/, FuseCore/[Module]/App/Contracts/
•If similar code exists → extend/reuse instead of duplicate
•If code will be used by 2+ features → create it in shared Services or Traits
•Extract repeated logic (3+ occurrences) into shared helpers or Traits
•Verify no duplication introduced after writing

Auto-Detection (Modular MANDATORY)

Files Detected	Architecture	Interfaces Location
`FuseCore/` directory	FuseCore Modular	`FuseCore/[Module]/App/Contracts/`
`module.json` in modules	FuseCore Modular	`FuseCore/[Module]/App/Contracts/`

Verification: php artisan --version → Laravel 12.x Structure: Always FuseCore modular. Shared in FuseCore/Core/App/.

Decision Tree: Where to Put Code? (FuseCore Modular)

code

New code needed?
├── HTTP validation → FuseCore/[Module]/App/Http/Requests/
├── Single action → FuseCore/[Module]/App/Actions/
├── Business logic → FuseCore/[Module]/App/Services/
├── Data access → FuseCore/[Module]/App/Repositories/
├── Data transfer → FuseCore/[Module]/App/DTOs/
├── Interface → FuseCore/[Module]/App/Contracts/
├── Event → FuseCore/[Module]/App/Events/
└── Authorization → FuseCore/[Module]/App/Policies/

Decision Tree: Which Pattern?

Need	Pattern	Location	Max Lines
HTTP handling	Controller	Controllers/	50
Validation	FormRequest	Requests/	50
Single operation	Action	Actions/	50
Complex logic	Service	Services/	100
Data access	Repository	Repositories/	100
Data structure	DTO	DTOs/	50
Abstraction	Interface	Contracts/	30

Critical Rules (MANDATORY)

1. Files < 100 lines

•Split at 90 lines - Never exceed 100
•Controllers < 50 lines
•Models < 80 lines (excluding relations)
•Services < 100 lines

2. Interfaces Separated (FuseCore Modular MANDATORY)

code

FuseCore/[Module]/App/Contracts/   # Module interfaces ONLY
├── UserRepositoryInterface.php
└── PaymentGatewayInterface.php
FuseCore/Core/App/Contracts/       # Shared interfaces

3. PHPDoc Mandatory

php

/**
 * Create a new user from DTO.
 *
 * @param CreateUserDTO $dto User data transfer object
 * @return User Created user model
 * @throws ValidationException If email already exists
 */
public function create(CreateUserDTO $dto): User

Reference Guide

Concepts

Topic	Reference	When to consult
SOLID Overview	solid-principles.md	Quick reference all principles
SRP	single-responsibility.md	File too long, fat controller/model
OCP	open-closed.md	Adding payment methods, channels
LSP	liskov-substitution.md	Interface contracts, swapping providers
ISP	interface-segregation.md	Fat interfaces, unused methods
DIP	dependency-inversion.md	Tight coupling, testing, mocking
Anti-Patterns	anti-patterns.md	Code smells detection
Decisions	decision-guide.md	Pattern selection
PHP 8.5	php85-features.md	Modern PHP features
Structure	laravel12-structure.md	Standard Laravel
FuseCore	fusecore-structure.md	Modular architecture

Templates

Template	When to use
code-templates.md	Service, DTO, Repository, Interface
controller-templates.md	Controller, Action, FormRequest, Policy
refactoring-guide.md	Step-by-step migration from legacy code

Forbidden

Anti-Pattern	Detection	Fix
Files > 100 lines	Line count	Split into smaller files
Controllers > 50 lines	Line count	Extract to Service
Interfaces in impl files	Location	Move to `FuseCore/[Module]/App/Contracts/`
Business logic in Models	Code in model	Extract to Service
Concrete dependencies	`new Class()`	Inject via ModuleServiceProvider
Missing PHPDoc	No doc block	Add documentation
Missing strict_types	No declare	Add to all files
Fat classes	> 5 public methods	Split responsibilities
Duplicated logic	Same code in 2+ files	Extract to Service/Trait
No Grep before coding	Creating without search	Grep codebase first

Best Practices

DO	DON'T
Use constructor property promotion	Use property assignment
Depend on interfaces	Depend on concrete classes
Use `final readonly class`	Use mutable classes
Use `declare(strict_types=1)`	Skip type declarations
Split at 90 lines	Wait until 100 lines
Use DTOs for data transfer	Use arrays