# GitHub Copilot Coding Instructions

## Language and framework

- Use Vue 3, Vite, modern JavaScript, and the latest stable ECMAScript supported by the project.
- Prefer Composition API and reusable atomic components.
- Do not introduce TypeScript unless a concrete technical justification is documented.
- Use Vue Router for routing.
- Use Pinia only for genuinely shared client state; do not create stores for every component.
- Use Node.js and Fastify for the API.
- Use Drizzle ORM for PostgreSQL access.

## Frontend layering

`Component → Composable → API Service → REST API`

Components should focus on presentation and user interaction. Composables hold reusable UI behavior. API services encapsulate HTTP access.

## Backend layering

`Route → Validation → Application Service → Domain Logic → Repository → PostgreSQL`

- Routes translate HTTP requests/responses.
- Schemas validate requests and responses.
- Services coordinate use cases.
- Domain logic owns business rules.
- Repositories own persistence.
- Provider adapters own external APIs.
- Workers own asynchronous jobs.

## Data and financial rules

- Use integer minor units for money.
- Never use floating-point arithmetic for financial values.
- Store/calculation currency is USD unless a documented exception exists.
- Use purpose-built public and admin DTOs.
- Never serialize database models directly as public responses.

## External integrations

- Pricing providers implement a common provider interface.
- Currency conversion is behind a service/provider abstraction.
- Image storage is behind a storage interface.
- Provider-specific behavior must stay inside provider adapters.

## Search

Use the shared `SearchService`. Do not implement separate search algorithms for public and admin unless their data visibility requirements require separate query construction.

## Accessibility

Target WCAG 2.2 AA:
- semantic HTML
- keyboard operation
- visible focus
- accessible forms/errors
- meaningful alt text
- no color-only meaning
- accessible dynamic content
- proper focus management for dialogs/galleries

## Testing

Every meaningful feature should include appropriate unit, integration, component, E2E, and/or accessibility tests.

Do not disable tests merely to make CI pass.

## Code quality

Prefer:
- clear names
- small functions
- explicit dependencies
- reusable components
- predictable error handling
- minimal coupling
- comments only where they explain non-obvious decisions

Avoid:
- duplicated business rules
- giant components
- giant service classes
- magic financial calculations
- direct database access from routes
- hidden global state