# AGENTS.md — Aeroflot.Flights.Web

## Quick Start

```bash
# Install dependencies
pnpm install

# Development servers
pnpm dev          # Modern.js on :8081
pnpm dev:full     # Proxy on :8080 (API forwarding via curl to bypass WAF)

# Build targets
pnpm build:standalone  # SSR server at dist/standalone/
pnpm build:remote      # MF remote at dist/remote/ (with mf-manifest.json)
pnpm build:both        # Both targets

# Quality checks (run in order)
pnpm typecheck
pnpm lint
pnpm test
pnpm test:coverage
pnpm bundle-size      # CI gate: total gzip ≤ 2000 kB
pnpm check-coverage   # CI gate: line coverage ≥ 65%

# E2E tests
pnpm test:e2e                 # React app (port 8080)
pnpm test:e2e:angular         # Angular app (port 4203)
```

## Current State

React 18 SSR application built with **Modern.js 2.70.8** (Rspack bundler) and **Module Federation 2.3.3**. The app is a remote frontend component embeddable in the customer's channel apps (Web, PWA).

**Stack:** Modern.js 2.70.8, React 18.2, Rspack, Module Federation 2.3.3, i18next (9 languages), PrimeReact, Leaflet, SignalR, OpenTelemetry, Vitest, Playwright.

**Source:** `src/` (file-based routing under `src/routes/`). Legacy Angular 12 SPA in `ClientApp/` (read-only reference, not deployed).

**Builds:** `pnpm build:standalone` (SSR server at `dist/standalone/`), `pnpm build:remote` (MF remote at `dist/remote/` with `mf-manifest.json`).

**Dev:** `pnpm dev` (Modern.js on :8081), `pnpm dev:full` (proxy on :8080 with API forwarding via curl to bypass WAF).

**Known constraint:** Modern.js 3.x upgrade is blocked by `@module-federation/modern-js` ESM incompatibilities (broken `__filename`/`require` in ESM bundles, missing `api.modifyWebpackConfig` in Rsbuild 2.0). React Router v7 future flags are enabled to suppress deprecation warnings.

## Contractual Requirements

The following are contractual hard constraints for the remote frontend component.

### 1. Tech Stack

- **ModernJS (SSR)** for the frontend framework.
- **Module Federation 2.0**. Any bundler with MF 2.0 support is acceptable: Webpack 5, Rsbuild, Rspack, or Vite.
- Must emit `mf-manifest.json` at `https://<domain>/mf-manifest.json` exposing components and logic. Reference: https://module-federation.io/guide/basic/webpack.html.
- **React 18+**, Concurrent Mode compatible.
- `<Suspense>` support required when async loading is used.
- Component bodies must be side-effect free — **no `fetch` outside `useEffect`**.
- Dynamic imports must use `React.lazy()`.

### 2. Data & Integrations

- Consumes customer REST APIs, JSON payloads only.
- Rendered data must stay consistent with API responses (no stale state leaking into the UI).

### 3. Performance

- Must sustain **100 RPS**.

### 4. Availability & Fault Tolerance

- VMs hosting the component must be geographically distributed.
- 24/7/365 availability; recovery time ≤ 6 hours after infra is restored.

### 5. Security

- Component must be isolated — no attack surface exposed to other components of the host site.

### 6. SEO & Accessibility

- SEO optimization required.
- Render microdata: **JSON-LD** and **OpenGraph**.
- Web analytics integrations: **Yandex.Metrica, CTM, Variocube, Key-Astrom (Dynatrace)**.

### 7. Cross-Platform

- Embeddable in multiple channel apps (Web, PWA).
- Fully responsive ("fluid") layout across all screen sizes.

### 8. Logging & Monitoring

- Frontend log collection in a customer-specified format, shipped to the customer's log aggregation system.
- System event monitoring with export to a metrics aggregator.

### 9. Module Structure

- Must conform to the customer's standard remote frontend module structure for uniform deployment.

### 10. Design

- Implement against customer-provided mockups using the customer's design system.
- Must embed other customer remote components when available.

## Architecture

**Source structure:**
- `src/routes/` — File-based routing (React Router v7)
- `src/features/` — Feature modules (online-board, schedule, flights-map, popular-requests)
- `src/ui/` — Reusable UI primitives (never import routes/mf from here)
- `src/shared/` — Cross-cutting concerns (API client, SignalR, storage, hooks)
- `src/observability/` — Logger, metrics (OTel), analytics
- `src/i18n/` — Internationalization (9 languages)

**Entry points:**
- `src/routes/page.tsx` — Root redirect to `/{lang}/onlineboard`
- `src/routes/layout.tsx` — Root layout with global providers
- `src/routes/[lang]/layout.tsx` — Locale-scoped layout with i18n

**Module Federation:**
- Remote name: `aeroflot_flights`
- Exposes: `./OnlineBoard`, `./Schedule`, `./FlightsMap`, `./PopularRequests`
- mf-manifest.json at `https://<domain>/mf-manifest.json`

## Critical Constraints

1. **Side-effect-free components** — No `fetch` outside `useEffect`. API calls via `ApiClient` from context.

2. **Dynamic imports** — Use `React.lazy()` for code splitting. Wrap browser-only components (Leaflet) in `ClientOnly`.

3. **SSR safety** — SignalR (`@microsoft/signalr`) is dynamically imported. Never import in SSR bundle (routes/, server/).

4. **Layered architecture** — Enforced by ESLint:
   - `features/` → cannot import `routes/` or `mf/`
   - `ui/` → cannot import `features/`, `routes/`, `mf/`
   - `shared/` → cannot import `features/`, `routes/`, `mf/`, `observability/`
   - `observability/` → cannot import `features/`, `routes/`, `mf/`

5. **Restricted imports** (ESLint rules):
   - OTel SDK → use `@/observability/metrics/otel` (getMeter/getTracer)
   - react-i18next → use `@/i18n/provider`
   - localStorage/sessionStorage → use `@/shared/storage`

6. **Environment variables** — Read via `getEnv()` from `@/env/index.ts`. SSR injects `window.__ENV__`.

## Dev Server Details

- **Port 8081** — Modern.js dev server (SSR + HMR)
- **Port 8080** — `pnpm dev:full` proxy with:
  - `/api/*` and `/flights/*` → `https://flights.test.aeroflot.ru` (via curl to bypass WAF)
  - `/*` → Modern.js on 8081

## Testing

- **Unit tests** — Vitest (globals enabled, V8 coverage)
- **E2E tests** — Playwright (baseURL: `http://localhost:8080`)
- **Angular E2E** — Separate config for legacy app (port 4203)

**Coverage gates:**
- Line coverage ≥ 65%
- Bundle size (gzip) ≤ 2000 kB for remote target

## Build Artifacts

- `dist/standalone/` — SSR server (Node entrypoint)
- `dist/remote/` — MF remote with `mf-manifest.json`
- `dist/remote/static/js/` — JS bundles for bundle-size gate

## Deployment

- **Standalone** — Dockerfile.react (Node 24-slim, serves SSR)
- **Remote** — Dockerfile.remote (nginx serving static files)
- CI/CD: `.github/workflows/ci.yml`, `.github/workflows/deploy.yml`

## Commit Rules

- Never add `Co-Authored-By` lines to commit messages.
- Commit messages in English, concise, focused on "why" not "what".
- Commit autonomously when changes are complete and stable — no need to ask for permission. Group related edits into logical commits. Still ask before pushing, force-pushing, or any destructive git operation.