Technical Test - Value Estimator (Percentil)

This repository contains the solution for the Senior Developer technical test.

🏗 Architecture and Technical Decisions

1. Decorator Pattern (Backend)

I chose the Decorator Pattern for the pricing logic as it allows for horizontal scalability of business rules.

• Open/Closed Principle: We can add new rules (e.g., "Black Friday Bonus") by creating a new BlackFridayDecorator class without touching the existing base service code.
• Dynamic Composition: The controller can decide which decorators to apply at runtime (or via DI configuration), offering total flexibility.

2. Vue 3 Composition API (Frontend)

I opted for <script setup> and the Composition API over the Options API because:

• Better Type Inference: Native Support for TypeScript.
• Cleaner Code: Less boilerplate (no this, methods object, etc.).
• Reusable: Fetch logic could be easily extracted into a useValuation() composable if the application grows.

3. Testing (TDD)

The backend development followed a TDD (Test Driven Development) cycle:

1. Write a failing test.
2. Implement the minimum logic to pass the test.
3. Refactor.

This guarantees that each business rule (Brand Bonus, Condition Multiplier, High Season) is isolated and verified.

---

🛠 Project Structure

src/
├── Controller/
│   └── ValuationController.php      # API Endpoint
├── Dto/
│   └── ValuationRequest.php         # Data Transfer Object (PHP 8.2 Readonly)
└── Service/
    └── Valuation/
        ├── ValuationServiceInterface.php
        ├── BaseValuationService.php # Base Price
        └── Decorator/               # Business Rules
            ├── AbstractValuationDecorator.php
            ├── BrandBonusDecorator.php
            ├── ConditionMultiplierDecorator.php
            └── HighSeasonDecorator.php

assets/js/components/
└── ValuationEstimator.vue           # Vue 3 Component

---

---

🏃♂️ How to Run the Project

You need two terminal windows (or tabs) to run the full stack:

1. Start the Backend API (Symfony)

composer install # Only for the first time
php -S 127.0.0.1:8000 -t public

2. Start the Frontend Server (Node.js SSR)

npm ci # Only for the first time
npm run dev

Then open your browser at http://localhost:5173.

---

🧪 How to Run Tests

Although this is a simulation environment, the tests are prepared for PHPUnit.

# Run all backend tests
./bin/phpunit

# Run business logic tests (Unit)
./bin/phpunit tests/Service/Valuation

# Run frontend tests
npm test

🧹 Code Quality

To maintain the code standards, you can run the following commands:

# Frontend Linting (ESLint + Prettier)
npm run lint

# Backend Coding Standards (PHP-CS-Fixer)
# Note: Using IGNORE_ENV because the local PHP version (8.5) is newer than the tool's strict requirement.
PHP_CS_FIXER_IGNORE_ENV=1 vendor/bin/php-cs-fixer fix

Usage Example (cURL)

Once deployed:

curl -X POST https://api.percentil.com/api/v1/valuation/estimate \
  -H "Content-Type: application/json" \
  -d '{"brand": "Zara", "category": "dresses", "condition": "new"}'

---

📝 Implementation Notes

• HighSeasonDecorator: Uses Psr\Clock\ClockInterface to test time deterministically, avoiding issues with tests failing depending on the execution date.
• Validation: In a real environment, I would add symfony/validator to the ValuationRequest DTO.