pos/README.md

# README.md

## Overview

This project is a full-stack TypeScript point-of-sale (POS) system: an Android POS frontend, a Node/Express API backend, and a React admin UI, all packaged in a **single Docker container**.

The backend exposes REST APIs for the Android app and serves the React admin UI for vendor configuration and reporting.

***

## Tech Stack

- Node.js + TypeScript (Express or Fastify)
- React + TypeScript (SPA)
- SQL database (PostgreSQL in production; SQLite acceptable for local/demo)
- Docker (single container for API + admin UI)

***

## Project Structure

Example layout (subject to refinement):

- `server/` – Node/TypeScript backend (Express/Fastify, Prisma, migrations)
- `client/` – React/TypeScript admin UI
- `android/` – Android POS app (separate repo or module)
- `Dockerfile` – single-image build for backend + admin
- `docker-compose.yml` – optional local DB wiring
- `AGENTS.md`, `INSTRUCTIONS.md`, `ROADMAP.md` – agent and project docs

***

## Prerequisites

For local (non-Docker) runs:

- Node.js 20+ installed
- npm or pnpm
- PostgreSQL (or SQLite if configured)

For Docker runs:

- Docker Engine (and optionally Docker Compose)

***

## Environment Variables

Backend expects:

- `PORT` – HTTP port (default: 8080)
- `NODE_ENV` – `development` or `production`
- `DATABASE_URL` – connection string (e.g., Postgres)
- `JWT_SECRET` – secret for JWT signing
- `LOG_LEVEL` – optional (`info`, `debug`, etc.)

Document any additional env vars you introduce in this section.

***

## Local Development (Without Docker)

Backend:

```bash
# from /server
npm install
npm run dev   # or equivalent, e.g. ts-node-dev / nodemon
```

Admin UI:

```bash
# from /client
npm install
npm run dev   # Vite/CRA dev server
```

You can either:

- Run React dev server separately and point it at the API (`VITE_API_URL=http://localhost:8080/api`), or
- Configure the backend to serve the built React app in production mode.

***

## Building \& Running with Docker

### 1. Build the Image

From the project root:

```bash
docker build -t vendor-pos:latest .
```


### 2. Run the Container (Simple)

For a quick start with SQLite or an in-container DB:

```bash
docker run --rm -p 8080:8080 \
  -e NODE_ENV=production \
  -e PORT=8080 \
  -e DATABASE_URL=sqlite:./data.db \
  -e JWT_SECRET=change-me \
  vendor-pos:latest
```

The admin UI will be available at `http://localhost:8080/` and the API at `http://localhost:8080/api/...`.

### 3. Run with Postgres via Docker Compose (Optional)

Example `docker-compose.yml` (to be refined):

```yaml
version: "3.9"
services:
  db:
    image: postgres:16
    environment:
      POSTGRES_USER: pos_user
      POSTGRES_PASSWORD: pos_password
      POSTGRES_DB: pos_db
    ports:
      - "5432:5432"
    volumes:
      - pos_db_data:/var/lib/postgresql/data

  app:
    image: vendor-pos:latest
    depends_on:
      - db
    ports:
      - "8080:8080"
    environment:
      NODE_ENV: production
      PORT: 8080
      DATABASE_URL: postgres://pos_user:pos_password@db:5432/pos_db
      JWT_SECRET: change-me

volumes:
  pos_db_data:
```

Then:

```bash
docker compose up
```


***

## Android Integration (High Level)

- Android app calls `http://<server>:8080/api/v1/...` for auth, catalog sync, and transaction upload.
- All POS operations work offline; app syncs when network is available.[^11][^12][^10]
- The web admin UI is used for vendor setup, catalog maintenance, user management, and reports.[^20][^17]