113 lines
4.2 KiB
Markdown
113 lines
4.2 KiB
Markdown
# CLAUDE.md
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This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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## What This Project Is
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**Line of Sight** is a geospatial web app that draws a great-circle line from a user-selected point on Earth in a chosen direction, then finds all cities along that path. It includes a flight-over animation that speeds up 20x over water and slows to normal speed over land.
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## Commands
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### Docker (preferred workflow)
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```bash
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docker-compose up --build # Start all services (frontend :3050, backend :3001, postgres)
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docker-compose down # Stop all services
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docker-compose logs -f # View logs
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# Run tests inside containers
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docker-compose exec backend npm test
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docker-compose exec frontend npm test -- --run
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docker-compose exec frontend npm run test:e2e
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```
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### Local development (without Docker)
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```bash
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# Backend
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cd backend && npm run dev # Nodemon dev server on :3001
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# Frontend
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cd frontend && npm run start # Vite dev server on :3050
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```
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### Tests
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```bash
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# Backend unit tests (Jest + Supertest)
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cd backend && npm test
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# Frontend unit tests (Vitest)
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cd frontend && npm test # Watch mode
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cd frontend && npm test -- --run # Single run (CI mode)
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# E2E tests (Playwright)
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cd frontend && npm run test:e2e
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# Seed the database with GeoNames city data
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cd backend && npm run seed-data
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```
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### Build
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```bash
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cd frontend && npm run build # Vite production build → frontend/build/
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```
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## Architecture
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This is a monorepo with three services orchestrated by Docker Compose:
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```
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frontend/ → React 19 + Vite 6 SPA (MapLibre GL, Turf.js, Axios)
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backend/ → Node 24 + Express 5 REST API
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docker/ → PostgreSQL + PostGIS initialization
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```
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### Data flow
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1. User clicks map → sets start point (lat/lon)
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2. User selects direction (0–360°) and tolerance (km radius)
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3. Frontend calls `GET /api/line-of-sight?lat=&lon=&direction=&tolerance=`
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4. Backend generates 80 path points along a great-circle arc (up to 20,000 km)
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5. For each point, a PostGIS `ST_DWithin()` query finds cities within tolerance
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6. Backend also checks whether each point is over land (500 km radius land check)
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7. Response includes line coordinates with per-point water flags and matching cities
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8. Frontend renders the path on a 3D globe map and shows city markers
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### Backend: `backend/app/server.js`
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Single-file Express app. Key internals:
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- `calculateDestination()` — Haversine formula for great-circle destination points
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- `GET /api/line-of-sight` — main endpoint: path generation + PostGIS city lookup
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- `GET /api/health` — health check
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- Returns up to 200 cities ordered by position along the line
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### Frontend: `frontend/src/App.jsx`
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Single large React component (~687 lines) managing all state and map logic:
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- MapLibre GL map with 3D globe projection and terrain/sky effects
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- Direction slider drives a live preview line before the user commits
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- After "Show Line of Sight", map locks (prevents moving start point)
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- Flight animation uses Turf.js to interpolate positions along the path; speed is 1× over land, 20× over water with smooth acceleration (0.005 step), predictive look-ahead of 2000 km
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- New cities are fetched every 2000 km during flight via the same API
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- Three map styles: light, dark, satellite (Esri tiles)
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### Database
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PostGIS `cities` table with a GIST index on `geom GEOGRAPHY(POINT, 4326)`. All coordinates use WGS84 / SRID 4326. The init SQL seeds 10 major cities; the `seed-data` script imports from GeoNames for a fuller dataset.
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## Conventions
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- **Geospatial**: WGS84 / SRID 4326 everywhere; PostGIS `GEOGRAPHY` type for distance queries
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- **API**: RESTful; query params for `GET /api/line-of-sight`; env var `VITE_API_URL` (frontend) or `DATABASE_URL` (backend)
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- **Styling**: Plain CSS files in `frontend/src/styles/` — no CSS framework
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- **Tests**: Backend mocks the `pg` Pool; frontend mocks MapLibre GL and the API service. E2E tests use Playwright with a mock API response
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## CI
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Gitea workflow (`.gitea/workflows/test.yml`) runs on push/PR to `main`:
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1. **backend-test** — `npm ci && npm test`
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2. **frontend-test** — `npm ci && npm test -- --run`
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3. **e2e-test** — uses `mcr.microsoft.com/playwright:v1.50.1` container
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