# Repository Conventions

## Purpose

This document defines naming conventions, directory structure rules, and import boundaries
for `learning_ai_invt_trdg`. It is the authoritative reference for where code lives and
what each package is allowed to import.

---

## Package Names

| Package | Name in `package.json` | `pnpm --filter` alias |
|---|---|---|
| Backend | `@bytelyst/trading-backend` | `trading-backend` |
| Web | `@bytelyst/trading-web` | `trading-web` |
| Mobile | `@bytelyst/trading-mobile` | `trading-mobile` |
| Shared | `@bytelyst/trading-shared` (internal — not published) | — |

---

## Directory Structure

```
learning_ai_invt_trdg/
├── backend/
│   ├── src/
│   │   ├── backtest/       # Backtesting engine and guards
│   │   ├── config/         # Environment config loader (config/index.ts is the only place process.env is read)
│   │   ├── connectors/     # Exchange connectors (Alpaca, CCXT) + factory
│   │   ├── domain/         # Trading domain enums, value types, and pure domain logic
│   │   ├── repositories/   # Cosmos DB data-access layer (one file per entity)
│   │   ├── scripts/        # Internal one-time scripts and verification contracts (not imported by src/)
│   │   ├── services/       # Application services (apiServer, TradeExecutor, aiClient, etc.)
│   │   ├── strategies/     # 7-rule ProStrategyEngine and individual rule implementations
│   │   └── utils/          # Generic utilities (logger, symbolMapper, etc.)
│   ├── *.ts                # Root-level verification / reconciliation scripts (not part of the runtime)
│   └── package.json
├── web/
│   └── src/
│       ├── backtest/       # Backtest feature: hook, flags, UI components
│       ├── components/     # Shared React components (AuthContext, Login, ChatControl, etc.)
│       ├── hooks/          # React hooks (useWebSocket, useTabFeatureFlags, etc.)
│       ├── lib/            # Utility modules: authSession, runtime, profileApi, etc.
│       ├── tabs/           # Top-level tab components (one file per tab)
│       ├── test/           # Vitest test setup and fixtures
│       ├── App.tsx         # Root component: tab routing, auth gate, feature flags
│       └── main.tsx        # Vite entry point
├── mobile/
│   ├── app/                # Expo Router file-based routes
│   │   ├── (tabs)/         # Tab screens: index, positions, history, strategies, settings
│   │   ├── _layout.tsx     # Root layout (auth gate, kill-switch)
│   │   ├── chat.tsx        # AI chat surface
│   │   └── marketplace.tsx # Marketplace surface
│   ├── components/         # React Native shared components
│   ├── hooks/              # React Native hooks
│   ├── lib/                # runtime, telemetry, authSession equivalents
│   ├── providers/          # MobileAuthProvider, TradingDataProvider
│   └── utils/              # Utility functions
├── shared/                 # Cross-surface constants and TypeScript interfaces
│   ├── feature-flags.ts    # TradingFeatureFlagsResponse, TabFeatureFlags, BacktestFeatureFlags
│   ├── realtime.ts         # SOCKET_NAMESPACES, buildTradingSocketOptions, isUnauthorizedSocketError
│   ├── request-id.ts       # createRequestId()
│   ├── runtime.ts          # getRuntimeEnvironment()
│   ├── product.ts          # productConfig — canonical product identity
│   ├── control-plane.ts    # Control-plane state types
│   ├── platform-web.ts     # Web-specific platform helpers
│   └── platform-mobile.ts  # Mobile-specific platform helpers
├── docs/                   # All project documentation
├── scripts/                # Root-level build/verify scripts
└── vendor/                 # Local vendored @bytelyst/* packages (symlinked or copied)
```

---

## Import Boundary Rules

### Rule 1 — `shared/` is the only cross-surface code

No surface may import directly from another surface's `src/`.

| Importer | May import from |
|---|---|
| `backend/src/` | `shared/`, `vendor/bytelyst/*`, npm packages |
| `web/src/` | `shared/`, `vendor/bytelyst/*`, npm packages |
| `mobile/` | `shared/`, `vendor/bytelyst/*`, npm packages |
| `shared/` | npm packages only — never from backend, web, or mobile |

**Violation example (never do this):**
```ts
// In web/src — WRONG
import { TradeExecutor } from '../../../backend/src/services/TradeExecutor.js';
```

### Rule 2 — `config/index.ts` is the only `process.env` reader in the backend

All environment variable access in `backend/src/` goes through `config/index.ts`.
No other file calls `process.env` directly. This makes the config surface auditable
and testable in isolation.

### Rule 3 — `domain/` contains no I/O

`backend/src/domain/` is pure TypeScript: enums, value types, and functions with no
database calls, no HTTP, and no filesystem access. It may be imported by any other
backend module.

### Rule 4 — `repositories/` only talk to Cosmos

`backend/src/repositories/` (or `services/*Repository.ts`) are the only files that
import `@azure/cosmos` or call Cosmos client methods. Services and strategies call
repositories; they do not call Cosmos directly.

### Rule 5 — `scripts/` are not imported at runtime

`backend/src/scripts/` contains verification contracts (e.g., `verifyWebsocketContract.ts`)
that run as standalone processes. They are never `import`-ed by `backend/src/index.ts`
or any other runtime module. Root-level `backend/*.ts` scripts follow the same rule.

### Rule 6 — `shared/` exports must be serialisable

Everything exported from `shared/` must be importable in all three environments:
Node.js (backend), browser (web), and React Native (mobile). No Node.js built-ins,
no DOM APIs, no React Native-specific APIs.

### Rule 7 — Trading domain logic stays in the backend

No trading strategy logic, risk rules, capital guard calculations, or execution logic
may be moved into `shared/`, `web/`, or `mobile/`. Backend is authoritative.

---

## Naming Conventions

### Files

| Context | Convention | Example |
|---|---|---|
| TypeScript source | `camelCase.ts` | `apiServer.ts`, `healthTracker.ts` |
| React components | `PascalCase.tsx` | `OverviewTab.tsx`, `AuthContext.tsx` |
| React hooks | `use` prefix, `camelCase.ts` | `useWebSocket.ts`, `useTabFeatureFlags.ts` |
| Test files | `.test.ts` / `.test.tsx` | `App.dom.test.tsx` |
| Verification scripts | `verify*.ts` / `test*.ts` | `verifyApiContract.ts` |
| Docs | `SCREAMING_SNAKE.md` | `CONVENTIONS.md`, `OPERATIONS.md` |

### Identifiers

| Context | Convention | Example |
|---|---|---|
| Classes | `PascalCase` | `ApiServer`, `TradeExecutor` |
| Interfaces / types | `PascalCase` | `TradingFeatureFlagsResponse`, `BotState` |
| Constants (module-level) | `SCREAMING_SNAKE_CASE` | `SOCKET_NAMESPACES`, `BACKTEST_FLAG_KEYS` |
| Functions | `camelCase` | `buildTradingSocketOptions`, `createRequestId` |
| React components | `PascalCase` | `OverviewTab`, `LivePulseTicker` |
| Environment variables | `SCREAMING_SNAKE_CASE` | `COSMOS_ENDPOINT`, `TAB_MARKETPLACE_ENABLED` |

### API Endpoints

| Scope | Prefix | Auth |
|---|---|---|
| Public product API | `/api/` | `requireAuth` (platform JWT) |
| Internal operator tooling | `/internal/` | `requireAuth` — firewall-restrict in prod |
| Admin-only mutations | `/api/admin/` | `requireAuth` + `requireAdmin` |
| Health / observability | `/health`, `/metrics` | None — firewall-restrict in prod |

### Socket.IO Events (backend → client)

| Event | Payload type | Notes |
|---|---|---|
| `state` | `BotState` | Full state on connect |
| `symbol_update` | `{ symbol, data }` | Per-symbol signal/indicator update |
| `positions_update` | `Position[]` | Full position list replacement |
| `orders_update` | `Order[]` | Full order list replacement |
| `history_update` | `HistoryRow` | Single new closed trade |
| `new_alert` | `Alert` | Single new alert |
| `health_update` | `HealthSnapshot` | Loop health and trading control state |
| `account_snapshot` | `AccountSnapshot` | Exchange account balance snapshot |
| `order_failure` | `OrderFailureRecord` | Single order failure notification |
| `operational_event` | `OperationalEvent` | Structured operational log entry |
| `operational_event_cleared` | — | Signals log has been cleared |

---

## Feature Flag Conventions

- Feature flags are defined in `shared/feature-flags.ts` as TypeScript interfaces.
- Flag key constants (`BACKTEST_FLAG_KEYS`, `TAB_FLAG_KEYS`) are the single source of
  truth for env var names — never hardcode the string elsewhere.
- Backend reads env vars via `config/index.ts`; web/mobile read via `GET /api/feature-flags`.
- Admin accounts bypass all feature flags — they always see everything.
- New flags default to **enabled** (opt-out model) unless gating a genuinely unreleased feature.

---

## Request Tracing Convention

Every HTTP request from web or mobile must include:

```
x-request-id: <createRequestId('surface-context')>
Authorization: Bearer <accessToken>
```

Backend echoes `x-request-id` in all responses. Use this header as the primary correlation
key when tracing a request across client logs and backend logs.

---

## Test / Verification Script Convention

Backend verification scripts follow this pattern:

```ts
// verify*.ts or test*.ts at backend/ root or backend/src/scripts/
import assert from 'node:assert/strict';

function main() {
    // ... assertions ...
    console.log('[PASS] Description of what passed.');
}

main();
```

- Exit with a non-zero code on `AssertionError` (Node.js default behaviour).
- Print `[PASS] ...` on success; never `console.log` progress in the happy path.
- Never connect to real infrastructure — use in-memory fixtures only.
- Wire into `package.json` scripts as `check:*` and into `npm run test` or `npm run lint`.